What color does cobalt-oxide produce? a. Blue-violet b. Red c. Yellow d. Green Please select the best answer from the choices provided A B C D.

Answers

Answer 1

Answer: Blue.

Explanation: Regardless of temperature, the metalic coloring oxide will produce a specific shade of blue.

Answer 2

Answer:

A BLUE-VIOLET

Explanation:

got it right on edge


Related Questions

What a bat hits a ball what is the impulse

Answers

Answer:

Plugging in the numbers we find the average force to be Favg=18,436 N, which is equivalent to 4124 lbs of force. The impulse delivered by this force is the product of the average force the the contact time, resulting in an impulse of 12.91 Ns.

Answer:

the force multiplied by the time the objects are in contact

Explanation:

took the quiz


What is a base?
A. A substance that increases the concentration of oxygen in
solution
B. A substance that increases the concentration of OH ions in
solution
C. A substance that increases the concentration of H+ ions when dissolved
D. A substance that contributes chloride ions to the solution

Answers

Answer:

A base releases OH~ in a solution, so the answer is B

What is the volume, in liters, of 0.250 moles of carbon monoxide at STP?
WRITE THE FORMULAS FOR THE COMPOUNDS, NOT JUST THE NAMES. INCLUDE UNITS!

Answers

The valume is 5.23 I believe

The American flag flies on a black flagpole. Light from the sun hits the flag and the flagpole. How is it that you can see the blue, red, and white colors of the flag and the black of the flagpole?(1 point)

Red stripes reflect red and absorb all other light, as does the blue square with blue; white stripes and stars absorb all wavelengths; and the flagpole reflects all wavelengths.
Red stripes reflect red and absorb all other light, as does the blue square with blue; white stripes and stars absorb all wavelengths; and the flagpole reflects all wavelengths.

Red stripes absorb red and reflect all other light, as does the blue square with blue; white stripes and stars absorb all wavelengths; and the flagpole reflects all wavelengths.
Red stripes absorb red and reflect all other light, as does the blue square with blue; white stripes and stars absorb all wavelengths; and the flagpole reflects all wavelengths.

Red stripes absorb red and reflect all other light, as does the blue square with blue; white stripes and stars reflect all wavelengths; and the flagpole absorbs all wavelengths.
Red stripes absorb red and reflect all other light, as does the blue square with blue; white stripes and stars reflect all wavelengths; and the flagpole absorbs all wavelengths.

Red stripes reflect red and absorb all other light, as does the blue square with blue; white stripes and stars reflect all wavelengths; and the flagpole absorbs all wavelengths.

Answers

Explanation:

you did there a copy/paste chaos.

anyway, whatever number in the sequence it is, the right answer is of course :

Red stripes reflect red and absorb all other light, as does the blue square with blue; white stripes and stars reflect all wavelengths; and the flagpole absorbs all wavelengths.

that is why white and black are scientifically not colors.

white is in fact all colors in one (because all light is reflected there), and black is the lack of any light and therefore color. this is like at night, when a lot of cars are driving, but one does not have any lights on - you can find that car by the dark spot it creates in the middle of all the light of the other cars. black means we see no light at all at that spot.

To solve this we must be knowing each and every concept related to reflection. Therefore, the correct option is option A among all the given options.

What is reflection?

Any surface will reflect light according to two criteria. They are known as the laws of reflection. Regular reflection occurs when any object's light reflects off of polished surfaces.

Because of the smooth surface's ability to reflect light, we can see the object's reflection in the mirror when light rays strike it. A plane mirror will reflect an image in which the distance of the object from the mirror is equal to the vertical distance from either the mirror.

Red stripes reflect red and absorb all other light, as does the blue square with blue; white stripes and stars reflect all wavelengths; and the flagpole absorbs all wavelengths.

Therefore, the correct option is option A.

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Denise wants to know which time of day is the warmest. She creates a chart to record the time and temperature at various times over several days. Which of the following best describes why Denise should keep detailed notes from her experiment?


to prevent others from doing the same investigation


to prevent others from making mistakes when doing the investigation


to allow someone to practice note-taking skills when doing science investigations


to allow someone to do the same investigation and check the accuracy of results

Answers

Denise ought to keep detailed record of the experiment to allow someone to do the same investigation and check the accuracy of results. Option D

What is an experiment?

The term experiment has to do with cause and effect relationships. We know that the cause is what leads to the effect if the process can be tested in a laboratory. The experiment that as performed by Denise was targeted at finding what time of the day is warmest.

From the results of the experiment, we can conclude that Denise ought to keep detailed record of the experiment to allow someone to do the same investigation and check the accuracy of results.

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lowest second ionization energy: Ar, K, Ca

Answers

Answer is Ca

Hope this helps. :)

A container of gas is initially at 0.25 atm and 0 ˚C. What will the pressure be at 125 ˚C?

Answers

Answer:

0.37atm

Explanation:

Given parameters:

Initial pressure  = 0.25atm

Initial temperature  = 0°C  = 273K

Final temperature  = 125°C  = 125 + 273  = 398K

Unknown:

Final pressure  = ?

Solution:

To solve this problem, we use a derivative of the combined gas law;

           \(\frac{P1}{T1}\)  = \(\frac{P2}{T2}\)

  P and T are pressure and temperature

  1 and 2 are initial and final values

        \(\frac{0.25}{273}\)   = \(\frac{P2}{398}\)  

         P2  = 0.37atm

Plsss help with this ASAP TT

Plsss help with this ASAP TT

Answers

Answer: lithium- 3 protons, 3 electrons, 3 neutrons

Oxygen- nucleon no. 16, Atomic no. 8, 8 protons, overall charge (-2)

Sorry I don't the others. Hope this helps

Help
adding an additional oxygen atom to o2 creates _____.
ozone
cfc
oxygen
methane

Answers

Adding an additional oxygen atom to O₂ creates ozone (O₃). Option A is correct.

Ozone is the molecule which is composed of three oxygen atoms bonded together. When an O₂ molecule gains an additional oxygen atom, it forms an ozone molecule. This process occurs primarily in the upper atmosphere, specifically in the ozone layer, which is located in the stratosphere.

The formation of ozone is important for the Earth's atmosphere as it serves as a protective layer against harmful ultraviolet (UV) radiation from the sun. Ozone absorbs a significant amount of UV radiation, preventing it from reaching the Earth's surface.

However, the addition of an oxygen atom to O₂ does not create CFCs (chlorofluorocarbons), oxygen, or methane. CFCs are synthetic compounds that consist of carbon, chlorine, and fluorine atoms, and they have been identified as significant contributors to ozone depletion. Oxygen is already present in O₂, and methane is a separate compound composed of carbon and hydrogen atoms.

Hence, A. is the correct option.

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--The given question is incomplete, the complete question is

"Adding an additional oxygen atom to O₂ creates _____. A)  ozone B) CFC C) oxygen D) methane."--

given 2PbS + 3O2 = 2PbO + 2SO2 A) determine the theoretical yield of PbO is 50g of O2 is used? B) what is the %yield if 170.0g PbO is obtained

Answers

A. The theoretical yield of PbO is 232.08 grams.

B. The percent yield of PbO is 73.26%.

A. Determine the theoretical yield of PbO if 50g of O2 is used:

We first need to determine the molar mass of O2, which is 32 g/mol (16 g/mol per oxygen atom).

Next, we can set up a stoichiometric ratio using the balanced equation:

2 moles of PbS react with 3 moles of O2 to produce 2 moles of PbO.

Using the molar ratio, we can calculate the moles of O2 used:

moles of O2 = (mass of O2 used) / (molar mass of O2)

moles of O2 = 50 g / 32 g/mol = 1.5625 mol

From the stoichiometry, we know that 2 moles of PbO are produced for every 3 moles of O2.

Therefore, the moles of PbO produced can be calculated as follows:

moles of PbO = (moles of O2) × (2 moles of PbO / 3 moles of O2)

moles of PbO = 1.5625 mol × (2/3) = 1.0417 mol

Finally, we can calculate the theoretical yield of PbO using its molar mass:

theoretical yield of PbO = (moles of PbO) × (molar mass of PbO)

theoretical yield of PbO = 1.0417 mol × 223.2 g/mol = 232.08 g

Therefore, the theoretical yield of PbO is 232.08 grams.

B) Calculate the percent yield if 170.0 g of PbO is obtained:

The percent yield is calculated by dividing the actual yield by the theoretical yield, then multiplying by 100%:

percent yield = (actual yield / theoretical yield) × 100%

percent yield = (170.0 g / 232.08 g) × 100% = 73.26%

Therefore, the percent yield of PbO is 73.26%.

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What is the density of xylene (in g/mL) to two significant figures at 25°C?

Answers

Answer:

865 kg/m³; 0865 g/cm³

Explanation:

a 250 gram sample of water at the boiling point had 35.0 kj of heat added. how many grams of water were vaporized? heat of vaporization for water is 40.6 kj/mole.

Answers

The required mass of water vaporized is 15.5 grams, from a 250 gram sample of water at the boiling point had 35.0 kj

Given: Mass of water (m) = 250 gHeat added (q) = 35.0 kJHeat of vaporization (ΔHvap) = 40.6 kJ/mole

To find:Mass of water vaporized (x) Formula:q = ΔHvap × nx = (q / ΔHvap) × nMass = moles × molar mass

We know that molar mass of water (H2O) = 18 g/molMoles of water vaporized (n) = (35.0 kJ / 40.6 kJ/mol) = 0.861 mol

Therefore,Mass of water vaporized (x) = 0.861 mol × 18 g/mol= 15.5  

Detailed Solution: According to the given statement,250g of water was taken at its boiling point and 35.0 kJ of heat was added to it, we need to find how many grams of water were vaporized. To solve this question, first, we need to know the heat of vaporization for water, which is 40.6 kJ/mole. It means to vaporize 1 mole of water, 40.6 kJ of heat is required.

Mass of water (m) = 250 g Heat added (q) = 35.0 kJHeat of vaporization (ΔHvap) = 40.6 kJ/molen = q / ΔHvapn = (35.0 kJ / 40.6 kJ/mol) = 0.861 molMoles of water vaporized (n) = 0.861 mol

Therefore, Mass of water vaporized (x) = 0.861 mol × 18 g/mol= 15.5 g Hence, the required mass of water vaporized is 15.5 grams.

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A chemical engineer must calculate the maximum safe operating temperature of a high-pressure gas reaction vessel. The vessel is a stainless-steel cylinder that measures
48.0cm
wide and
57.6cm
high. The maximum safe pressure inside the vessel has been measured to be
3.40MPa
.
For a certain reaction the vessel may contain up to
2.45kg
of carbon dioxide gas. Calculate the maximum safe operating temperature the engineer should recommend for this reaction. Write your answer in degrees Celsius. Round your answer to
3
significant digits.

Answers

The maximum safe operating temperature the engineer should recommend for this reaction is approximately 1063.77 degrees Celsius.

To calculate the maximum safe operating temperature, we need to consider the dimensions of the vessel, the maximum safe pressure, and the amount of gas inside.

First, let's convert the dimensions of the vessel from centimeters to meters:

Width = 48.0 cm = 0.48 m

Height = 57.6 cm = 0.576 m

Next, we need to calculate the volume of the vessel:

Volume = π * (radius)^2 * height

The radius of the vessel can be calculated as half of the width:

Radius = 0.48 m / 2 = 0.24 m

Volume = π * (0.24 m)^2 * 0.576 m

Volume ≈ 0.099 m^3

Now, we can use the ideal gas law to determine the maximum safe operating temperature. The ideal gas law is given by:

PV = nRT

where P is the pressure, V is the volume, n is the number of moles, R is the gas constant, and T is the temperature.

Rearranging the equation to solve for T:

T = (PV) / (nR)

To calculate the number of moles, we can use the molar mass of carbon dioxide (CO2):

Molar mass of CO2 = 12.01 g/mol (for carbon) + 2 * 16.00 g/mol (for oxygen)

Molar mass of CO2 ≈ 44.01 g/mol

Converting the mass of carbon dioxide from kilograms to grams:

Mass of CO2 = 2.45 kg * 1000 g/kg

Mass of CO2 = 2450 g

Now, we can calculate the number of moles:

Number of moles = Mass of CO2 / Molar mass of CO2

Number of moles = 2450 g / 44.01 g/mol

Number of moles ≈ 55.67 mol

The gas constant R is approximately 8.314 J/(mol·K).

Now, we can substitute the values into the equation:

T = (3.40 MPa * 0.099 m^3) / (55.67 mol * 8.314 J/(mol·K))

T ≈ 1063.77 K

Converting from Kelvin to Celsius:

T ≈ 1063.77 °C

The maximum safe operating temperature that the engineer should recommend for this reaction is approximately 1063.77 degrees Celsius.

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As a gaseous element condenses, the atoms become ________ and they have ________ attraction for one another.

Answers

As a gaseous element condenses, the atoms become closer together and they have more attraction for one another.

What is Condensation?

The transformation of water vapour into liquid is known as condensation. The process is the opposite of evaporation, in which liquid water turns into a vapour. Either the air is chilled to its dew point or it gets too saturated with water vapour to retain any more water, causing condensation to occur.

Attraction - Gas Particles move continuously in a straight path in a gas. They are significantly further apart and move independently of one another because the kinetic energy of the molecule is larger than the attraction force between them. There are often almost no attractive forces between particles.

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What type of chemical reaction occurs when more energy is released during a chemical reaction than is needed to start a chemical reaction

Answers

Answer:

exothermic reaction

Explanation:

your welcome :)

Flourine is the most electronegative element on the periodic table, which means that, in an ionic bond fluorine will always

Answers

This means that fluorine will always be reduced.

Characteristics of electronegative elements:

Electronegative elements are those elements that has the ability to attract other electrons of elements for sharing in a covalent bonding.

But in an ionic chemical bond, it accepts electrons to complete it's outermost shell.

The most electronegative elements is fluorine which is located at the left of periodic table.

In an ionic chemical reaction, fluorine will always be reduced because it will accept electrons to complete the outermost shell leading to decrease in its oxidation number.

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Balance the following chemical equation by indicating a number for cach coefficient (including 1 ' if applicable). ค. NH
3

(λ)+ O
2

( g)→ NO(Q)+H
2

O(l)

Answers

The balanced chemical equation for the given chemical reaction is: NH3 + 2O2 → NO + 3H2O

The given chemical equation is: NH3 + O2 → NO + H2O

We can balance the above chemical equation by following the law of conservation of mass, which states that the mass of the reactants and the products should be equal. Thus, to balance this chemical equation, we need to ensure that the number of atoms of each element in the reactants is equal to the number of atoms of each element in the products.

To balance the above chemical equation, we need to add coefficients in front of the reactants and the products. This is known as balancing the chemical equation. In the given equation, the number of nitrogen (N) and hydrogen (H) atoms are equal on both sides. But, the number of oxygen (O) atoms is not equal.

To balance the oxygen atoms, we need to add a coefficient of 2 in front of O2. The balanced chemical equation for the given chemical reaction is:

NH3 + 2O2 → NO + 3H2O

Thus, the coefficient of NH3 is 1, the coefficient of O2 is 2, the coefficient of NO is 1, and the coefficient of H2O is 3. This is the balanced chemical equation for the given chemical reaction.

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which statement accurately describes part kf the dissolving process of a polar solute in water

Answers

Water molecules surround solute molecules. Option B

What is the solvation by water?

The principle of "like dissolves like" states that non-polar chemicals are soluble in non-polar solvents and polar compounds are soluble in polar solvents.

Water can only dissolve other polar solutes since it is a polar solvent; it cannot dissolve non-polar solutes.

The polar molecules that surround the polar solutes when they are dissolved in water are separated when they do so because of the high dielectric constant of water.

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Missing parts;

Which statement accurately describes part of the dissolving process of a polar solute in water?

Solute molecules repel water molecules.

Water molecules surround solute molecules.

Water molecules are strongly attracted to nonpolar substances.

Solute molecules remain concentrated in one part of the solvent.

What is the force that attracts one water molecule to another water molecule?.

Answers

Answer:

hydrogen bonds

Explanation:

What is a limitation for using solar energy to meet global energy needs?

Answers

Answer:

The sun provides more than enough energy to meet the whole world's energy needs, and unlike fossil fuels, it won't run out anytime soon. As a renewable energy source, the only limitation of solar power is our ability to turn it into electricity in an efficient and cost-effective way.

The hydroxyl end groups of a sample (2. 00 g) of linear poly(ethylene oxide) were acetylated by reaction with an excess of acetic anhydride (2. 5 x10-3 mol) in pyridine: After completion of the reaction, water was added to convert the excess acetic anhydride to acetic acid, which together with acetic acid produced in the acetylation reaction was neutralized by addition of 30 cm3 (note different number than textbook) of 0. 100 mol/dm3 solution of sodium hydroxide. Calculate the number average molar mass for the sample of poly(ethylene oxide) given that each molecule has two hydroxyl end groups. Poly(ethylene oxide):

Answers

The number average molar mass for the sample of poly(ethylene oxide) is 13000 g/mol.

The number of moles of acetic anhydride used in the reaction can be calculated as follows:

Moles of acetic anhydride = (mass of acetic anhydride) / (molar mass of acetic anhydride)

Molar mass of acetic anhydride = (2 x molar mass of carbon) + (3 x molar mass of oxygen) = (2 x 12.011) + (3 x 15.999) = 102.09 g/mol

Moles of acetic anhydride = (2.5 × 10⁻³) / 102.09 = 2.45 × 10⁻⁵ mol

Since the hydroxyl end groups of each molecule of poly(ethylene oxide) react with one molecule of acetic anhydride, the number of moles of poly(ethylene oxide) can be calculated as follows:

Moles of poly(ethylene oxide) = moles of acetic anhydride / 2 = 1.23 x 10⁻⁵ mol

The mass of the sample of poly(ethylene oxide) is given as 2.00 g, so the number average molar mass can be calculated as follows:

Number average molar mass = (mass of sample) / (moles of sample)

Number average molar mass = 2.00 / 1.23 x 10⁻⁵ = 1.626 x 10⁸ g/mol

However, each molecule of poly(ethylene oxide) has two hydroxyl end groups, so the actual number average molar mass is half of this value:

Number average molar mass = 1.626 x 10⁸ / 2 = 13000 g/mol.

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Your mission is to generate a higher concentration of ethanol from ethanol 20%(v/v): What type of matter is ethanol 20% (v/v)? Remember you can click the View Theory button whenever you are in doubt.
a) Heterogeneous mixture
b) Homogenous mixture
c) Compound
d) Element

Answers

Ethanol 20% (v/v) is a homogenous mixture kind of material. Because they are soluble in one another, ethyl alcohol and water combine to create a homogenous combination. Later, they combine to produce a homogeneous solution.

What kind of substance is ethanol?

Alcohol's chemical name is ethanol, with the molecular formula C2H5OH. It has a molar mass of 46.06844 g/mol and is produced through fermentation. Alcohol is a liquid chemical molecule called ethanol (C2H5OH), which is flammable and volatile.

Is 20% ethanol a substance?

Alcohols are a class of chemical compounds that include substances like ethanol, CH3CH2OH, which has a hydroxyl group, or -OH, attached to a carbon atom. A chemical molecule called ethanol is combustible and colorless. It is present in alcoholic beverages.

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guess what 2nd language i can speak:
A1. german
B2. french
C3. Sarcasum

Answers

Answer:

B2 French I hope I'm right

Answer:

English

Explanation:

I mean u typing in English lol

Who was the first person to introduce the concept of atomic mass?

Answers

John dalton is the answer

What mass of Fe(OH)3 is produced when 35 mL of 0.250 M Fe(NO3)3 solution is mixed with 55 mL of a 0.180 M
KOH solution? (this is a limiting reactant problem).

Answers

Answer:

0.35 g.

Explanation:

We'll begin by calculating the number of mole of Fe(NO3)3 in 35 mL of 0.250 M Fe(NO3)3 solution.

This is illustrated below:

Molarity of Fe(NO3)3 = 0.250 M

Volume = 35 mL = 35/1000 = 0.035 L

Mole of Fe(NO3)3 =?

Molarity = mole /Volume

0.250 = mole of Fe(NO3)3 / 0.035

Cross multiply

Mole of Fe(NO3)3 = 0.25 x 0.035

Mole of Fe(NO3)3 = 8.75×10¯³ mole

Next, we shall determine the number of mole of KOH in 55 mL of 0.180 M

KOH solution. This is illustrated below:

Molarity of KOH = 0.180 M

Volume = 55 mL = 55/1000 = 0.055 L

Mole of KOH =.?

Molarity = mole /Volume

0.180 = mole of KOH /0.055

Cross multiply

Mole of KOH = 0.180 x 0.055

Mole of KOH = 9.9×10¯³ mole.

Next, we shall write the balanced equation for the reaction. This is given below:

3KOH + Fe(NO3)3 —> Fe(OH)3 + 3KNO3

From the balanced equation above,

3 moles of KOH reacted with 1 mole of Fe(NO3)3 to produce 1 mole of Fe(OH)3.

Next, we shall determine the limiting reactant. This can be obtained as follow:

From the balanced equation above,

3 moles of KOH reacted with 1 mole of Fe(NO3)3.

Therefore, 9.9×10¯³ mole of KOH will react with = (9.9×10¯³ x 1)/3 = 3.3×10¯³ mole of Fe(NO3)3.

From the above illustration, we can see that only 3.3×10¯³ mole out of 8.75×10¯³ mole of Fe(NO3)3 given is needed to react completely with 9.9×10¯³ mole of KOH.

Therefore, KOH is the limiting reactant and Fe(NO3)3 is the excess reactant.

Next, we shall determine the number of mole of Fe(OH)3 produced from the reaction.

In this case, we shall use the limiting reactant because it will give the maximum yield of Fe(OH)3 as all of it is consumed in the reaction.

The limiting reactant is KOH and the mole of Fe(OH)3 produce can be obtained as follow:

From the balanced equation above,

3 moles of KOH reacted to produce 1 mole of Fe(OH)3.

Therefore, 9.9×10¯³ mole of KOH will react to produce = (9.9×10¯³ x 1)/3 = 3.3×10¯³ mole of Fe(OH)3.

Finally, we shall convert 3.3×10¯³ mole of Fe(OH)3 to grams. This can be obtained as follow:

Molar mass of Fe(OH)3 = 56 + 3(16 + 1) = 56 + 3(17) = 107 g/mol

Mole of Fe(OH)3 = 3.3×10¯³ mole

Mass of Fe(OH)3 =?

Mole = mass /Molar mass

3.3×10¯³ = Mass of Fe(OH)3 / 107

Cross multiply

Mass of Fe(OH)3 = 3.3×10¯³ x 107

Mass of Fe(OH)3 = 0.3531 ≈ 0.35 g.

Therefore, 0.35 g of Fe(OH)3 was produced from the reaction.

during a chemistry lab exploring chemical reactions, students placed a 30g antacid tablet in a zip-lock bag. then they added 50 grams of water and quickly sealed the bag. the tablet began to fizz and soon disappeared. the bag was filled with gas. how much gas was produced if the mass of the liquid after the reaction is completed is still 50 grams? question 3 options: 30 grams 80 grams 50 grams 90 grams

Answers

The two main postulates that was given by Antoine Lavoisier are, oxygen play an important role in combustion and the other is mass of the reactant and product is conserved. Therefore,  the mass of the gas after the reaction is completed is 30g.

What is law of conservation of mass?

According to Law of conservation of mass, mass can neither be created nor be destroyed. Mass can only be transformed from one form to another. The law of conservation of mass was given by Antoine Lavoisier. Every reaction in nature follow the law given by Antoine Lavoisier that is mass is always conserved.

mass of antacid tablet+ mass of water =mass of solution

30g+50 g=80g

mass of solution = mass of liquid +mass of gas

80g=50g+mass of gas

mass of gas=30g

Therefore,  the mass of the gas after the reaction is completed is 30g.

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A sample of a certain substance weighs 25 mg. One year later, the sample weighs 19.95 mg. What is the half-life of the substance, in years?

Answers

The substance's half-life is determined to be 1.46 years on average.

In this case, the sample of the substance weighs 25 mg initially and decreases to 19.95 mg after one year. To determine the half-life, we can use the equation,

\(Finalmass = Initial mass*(1/2)^{t/halflife}\), where the time elapsed is t. Rearranging the equation, we have,

\(\frac{19.95 }{25} = (\frac{1}{2})^{1 / half-life}\\\)

Taking the logarithm base 2 of both sides, we get:

log2(19.95 / 25) = (1 / half-life) * log2(1/2)

Solving for half-life, we find,

half-life ≈ (1 / log2(1/2)) * log2(19.95 / 25)

half-life ≈ (1 / log2(1/2)) * (-1)

half-life ≈ 1.46 years

Hence, the compound's half-life is 1.46 years.

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Complete and balance the following half-reaction in acidic solution NO3- (aq) → NO(9)

Answers

The complete balanced chemical reaction can be written from the half reaction in acidic solution is,

           NO3- + 4H+ + 3e ----> NO + 2H2O.

The half reaction is the part of reaction which represents either an oxidation or a reduction. There are two half-reactions. one is oxidation and other is reduction. Both are necessary to completely describe a redox reaction.

NO3- ----> NO.

This reaction is not balanced and not completed.

NO3- + 4H+ + 3e----> NO + 2H2O.

This is a balanced chemical reaction. A balanced equation contains the same number of each type of atoms on both the left and right sides of the reaction arrow. To write a balanced equation, the reactants go on the left side of the arrow, while the products go on the right side of the arrow.

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a particular first-order reaction has a rate constant of 7.85 × 104 s-1 at 25.0 °c. what is the magnitude of k at 42.5 °c if ea = 34.7kj/mol?

Answers

A particular first-order reaction has a rate constant of 7.85 × 104 s-1 at 25.0 °c. The magnitude of k at 42.5 °C is 6.01 × 10^7 s^-1.

We can use the Arrhenius equation to relate the rate constant k at two different temperatures:

k2 = A * exp(-Ea/R * (1/T2 - 1/T1))

where k2 is the rate constant at the new temperature T2, A is the pre-exponential factor, Ea is the activation energy, R is the gas constant, and T1 is the initial temperature.

We are given k1 = 7.85 × 10^4 s^-1 at T1 = 25.0 °C = 298.15 K, Ea = 34.7 kJ/mol, and T2 = 42.5 °C = 315.65 K.

We can calculate A by rearranging the equation to solve for A:

A = k1 / exp(-Ea/R * 1/T1)

A = 7.85 × 10^4 s^-1 / exp(-34.7 kJ/mol / (8.314 J/mol·K) * (1/298.15 K))

A = 2.07 × 10^13 s^-1

Now, we can use A and Ea to calculate k2 at T2:

k2 = A * exp(-Ea/R * (1/T2 - 1/T1))

k2 = 2.07 × 10^13 s^-1 * exp(-34.7 kJ/mol / (8.314 J/mol·K) * (1/315.65 K - 1/298.15 K))

k2 = 2.07 × 10^13 s^-1 * exp(-3.86)

k2 = 6.01 × 10^7 s^-1

Therefore, the magnitude of k at 42.5 °C is 6.01 × 10^7 s^-1.

To learn more about first-order reaction refer here:

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What are major companies that sell most plastic straws ?

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Answer:

One of the biggest global suppliers of plastic straws is Tetra Pak:

Here are two brands that sell lots of plastic straws Hoffmaster Group inc. and Aardvark. Hope this helps :)
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