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erastovalidia [21]
2 years ago
13

1. Butane has a chemical formula CH4H10. The equation 2C4H10 + 13O2 → 8CO2 + 10H2O represents which of these?

Chemistry
1 answer:
Eddi Din [679]2 years ago
3 0

1) Answer is: B) A chemical change of butane into other substances.

Balanced chemical reaction: 2C₄H₁₀ + 13O₂ → 8CO₂ + 10H₂O.

This is chemical change (chemical reaction), because two new substances are formed (carbon dioxide and waters), the atoms are rearranged and the reaction is followed by an energy change.

This is not physical change, because the same substance is present before and after the psysical change, just with different form or state of matter.

2) Answer is: A) It increases.

Electrons can jump from one energy level to another, absorbing or emitting electromagnetic radiation with a frequency ν (energy difference of the levels).

Albert Einstein (1879-1955) proposed that a beam of light is a collection of discrete wave packets (photons) with energy hν, where h is Planck constant and ν is frequency.

Energy level 2 has higher energy than energy level 1.

3) Answer is: C) 400 kPa.

Boyle's Law (the pressure-volume law): volume of a given amount of gas held at constant temperature varies inversely with the applied pressure when the temperature and mass are constant.  

p₁V₁ = p₂V₂ (the product of the initial volume and pressure is equal to the product of the volume and pressure after a change).  

p₁ = 100 kPa; starting pressure.  

V₁ = 1.0 L., starting volume.

V₂ = 0.25 L; final volume, smaller than starting volume.

p₂ = ?; final pressure.  

100 kPa · 1 L = p₂ · 0.25 L.  

p₂ = 100 kPa · 1 L / 0.25 L.  

p₂ = 400 kPa.  

When volume goes up, pressure goes down.  

When volume goes down, pressure goes up.  

4) Answer is: C) HClO₄.

Balanced chemical reaction of dissociation of perchloric acid in water:

HClO₄(aq) → H⁺(aq) + ClO₄⁻(aq).

Ionic compounds (in this example perchloric acid) conduct electricity, because it dissociate in ions and ions conduct electicity.  

Ionic substances dissociate in water on cations and anions.  

Perchloric acid (HCO₄) is one of strongest inorganic acids.  

NH₃ is ammonia, NaOH is sodium hydroxide and NH₄OH ammonium hydroxide, all are bases.

5) Answer is: D) A and D.

A catalyst is a chemical species that is present at the beginning of a reaction and reappears at the end.

An intermediate forms during the reaction and disappears before the end.

Catalysis is the increase in the rate of a chemical reaction due to the participation of an additional substance called a catalyst.

Reactions occur faster with a catalyst because they require less activation energy.

6) Answer is: D) H2O has stronger intermolecular force of attraction.

Intermolecular forces are the forces between molecules or particles.

Because of hydrogen bonds, water has higher melting and boiling temperatures than H₂S.

In molecule of water there are dipole-dipole forces between negatively charged oxygen from one molecule of water and positively charger hydrogen of another molecule of water.

Hydrogen bond is an electrostatic attraction between two polar groups that occurs when a hydrogen atom (H), covalently bound to a highly electronegative atom such as flourine (F), oxygen (O) and nitrogen (N) atoms.

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How to convert 12g of H2O to moles
Anna35 [415]

Answer:

moles = given mass/atomic mass

so H2O mass = 2 +16=18

so 12g of h2o= 12/16 = 3/4 moles

8 0
2 years ago
A 6.000L tank at 19.2°C is filled with 18.0g of carbon monoxide gas and 10.6g of chlorine pentafluoride gas. You can assume both
Jobisdone [24]

Answer:

Total pressure: 2.89 atm

Mole fraction CO: 0.88

Partial pressure CO: 2.56 atm

Mole fraction ClF₅: 0.12

Partial pressure ClF₅: 0.33 atm

Explanation:

We should apply the Ideal Gases Law to solve this:

P . V = n . R . T

We need n, which is the total moles for the mixture

Total moles = Moles of CO + Moles of ClF₅

Moles of CO = mass of CO / molar mass CO → 18 g/28 g/mol = 0.643 mol

Moles of ClF₅ = mass of ClF₅ / molar mass ClF₅ → 10.6g/ 130.45 g/m = 0.0812 mol

0.643 mol + 0.0812 mol → 0.724 moles in the mixture

So we have the total moles so with the formula we would know the total pressure.

P . 6L = 0.724 mol . 0.082L.atm/mol.K . 292.2K

P = ( 0.724 mol . 0.082L.atm/mol.K . 292.2K) / 6L

P = 2.89 atm

Mole fraction is defined as the quotient between the moles of gas over total moles, and it is equal to partial pressure of that gas over total pressure

Moles of gas X /Total moles = Partial pressure of gas X/Total pressure

(Moles of gas X / Total moles) . Total pressure = Partial pressure of gas X

Mole fraction CO = 0.643 / 0.724 = 0.88

Partial pressure CO = 0.88 . 2.89 atm → 2.56 atm

Mole fraction ClF₅ = 0.0812 / 0.724 = 0.12

Partial pressure ClF₅ = 0.12 . 2.89 atm → 0.33 atm

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damaskus [11]
Mostly in my opinion I think it’s the secound one
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repartExiplanation:cionde atomos

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Hept for 7, hence the number is seven.
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