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erastovalidia [21]
3 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]3 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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Do electric or magnetic fields affect the x-rays?
Levart [38]
Electric and magnetic fields do not affect xrays as they only affect charged particles and xrays have no charge

hope that helps
3 0
3 years ago
calculate the volume (in mL) of 0.100 M CaCl2 needed to produce 1.00 g of CaCO3 (s). There is an excess of Na2CO3. Volume of cal
shepuryov [24]

Answer:

100. mL

Explanation:

Step 1: Write the balanced equation for the double displacement reaction

CaCl₂ + Na₂CO₃ ⇒ 2 NaCl + CaCO₃

Step 2: Calculate the moles corresponding to 1.00 g of CaCO₃

The molar mass of CaCO₃ is 100.09 g/mol.

1.00 g × 1 mol/100.09 g = 0.0100 mol

Step 3: Calculate the moles of CaCl₂ required to produce 0.0100 moles of CaCO₃

The molar ratio of CaCl₂ to CaCO₃ is 1:1. The moles of CaCl₂ required are 1/1 × 0.0100 mol = 0.0100 mol.

Step 4: Calculate the volume of 0.100 M CaCl₂ that contains 0.0100 mol

0.0100 mol × 1 L/0.100 mol × 1000 mL/1 L = 100. mL

5 0
2 years ago
10 pts) A student titrates a 20.00 mL sample of an aqueous borax solution with 1.03 M H2SO4. If 2.07 mL of acid are needed to re
Natasha2012 [34]

Answer: The molarity of the borax solution is 0.107 M

Explanation:

The neutralization reaction is:

Na_2B_4O_7.10H_2O+H_2SO_4(aq)\rightarrow Na_2SO_4+4H_3BO_3+5H_2O

According to neutralization law:

n_1M_1V_1=n_2M_2V_2

where,

n_1 = basicity of H_2SO_4 = 2

n_2 = acidity of borax = 2

M_1 = concentration of H_2SO_4 = 1.03 M

M_2 = concentration of borax =?

V_1 = volume of H_2SO_4  = 2.07ml

V_2 = volume of borax = 20.0 ml

Now put all the given values in the above law, we get the molarity of borax:

(2\times 1.03\times 2.07)=(2\times M_2\times 20.0)

By solving the terms, we get :

M_2=0.107M

Thus the molarity of the borax solution is 0.107 M

7 0
3 years ago
A proton has a charge that is opposite the charge of
emmainna [20.7K]
An electron

proton=positive charge
electron=negative charge
7 0
2 years ago
ASAP! What is the total number of electrons that can occupy the f sublevel? a 2 electrons b 6 electrons c 10 electrons d 14 elec
vaieri [72.5K]

Answer:

14 electrons

Explanation:

The total number of electrons that can occupy the f sublevel is 14.

The d sublevel can have 10 electrons.

The p sublevel can have 6 electrons

The s sublevel can have 2 electrons.

4 0
3 years ago
Read 2 more answers
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