Question

Rusting of an iron nail is an example of a change of phase.

Question 1 options:

True

False

Question 2 (10 points)

Which of the following amounts is closest to the molar mass of C18H25NO?

Question 2 options:

1.9419 kg

1.30 lbs

128.44 g

200 g

Question 3 (10 points)

Occasionally an asteroid will break into fragments due to a collision. These fragments, which often contain ice, can leave the asteroid belt and even make their way to Earth. Upon entering the Earth's atmosphere, such a fragment is heated to high temperature by frictional forces. Ice contained within a fragment typically liquefies or vaporizes. This type of change is considered a chemical change.

Question 3 options:

True

False

Question 4 (10 points)

The following chemical equation is not balanced: A + R2 → A2R3. After balancing, this chemical equation is ____ .

Question 4 options:

A2 + R3 → A2R3

4A + 3R2 → 2A2R3

2A + R2 → A2R3

A4 + R6 → A4R6

Question 5 (10 points)

Burning gasoline is an example of a physical change.

Question 5 options:

True

False

Question 6 (10 points)

During a chemical reaction, atoms in the reactants rearrange their chemical bonds to make products. The new arrangement of bonds does not have the same total energy as the bonds in the reactants. Therefore, when chemical reactions occur, _____

Question 6 options:

there will always be an accompanying energy change.

energy is always released.

there will never be an accompanying energy change. Any change would violate the law of energy conservation.

energy is always absorbed.

Question 7 (10 points)

Which of the following does not affect the rate of a reaction?

Question 7 options:

temperature

catalyst

surface area

molar mass

Given the following reaction: N2H4 → 2H2 + N2, how many moles of H2 will be produced if 2.20 moles of N2H4 react?

How many moles of caffeine are there in 488.0 g of caffeine?

43.0 grams of F2 react according to the following balanced chemical equation: F2 + 2NaI → I2 + 2NaF. As a result of this reaction _____ grams of I2 are produced.

Answer 1