A) When iron rusts and forms iron oxide, the iron oxide has more mass than the iron. Which

Question

statement correctly explains this difference in mass? (1 point)
The oxygen atoms in iron oxide have more mass than the iron atoms in pure iron.
Iron oxide has oxygen atoms, and pure iron does not.
The iron atoms in iron oxide have more mass than pure iron.
There are more iron atoms in iron oxide than in pure iron.
A) One molecule of calcium oxide, CaO, and one molecule of carbon dioxide, CO2
, combine in
a chemical reaction to form one substance. Given that matter is neither created nor destroyed,
which chemical formula identifies the product of this reaction? (1 point)
Ca2CO3
CaCO2
CaCO3
Ca2O3

Answer 1

A) The correct statement that explains the difference in mass when iron rusts and forms iron oxide is: Iron oxide has oxygen atoms, and pure iron does not.

B) The correct chemical formula that identifies the product of the reaction between one molecule of calcium oxide (CaO) and one molecule of carbon dioxide (CO2) is: CaCO3.

Answer 2

A) Which statement correctly explains why the ashes of burnt paper have less mass than the
original paper? (1 point)
Some of the atoms in the paper became gases.
Some of the atoms in the paper are destroyed when it burns.
The ash is created from new atoms that have less mass than the paper.
Other atoms combine with the paper to produce the ash.
A)
It takes 1 molecule of nitrogen and 3 molecules of hydrogen to produce 2 molecules of
ammonia using the following formula:
1N2 + 3H2 → 2NH3
Identify which combination of molecules will produce ammonia with no leftovers?
(1 point)
8N2 and 4H2
4N2 and 4H2
2N2 and 6H2
5N2 and 6H2

Answer 3

A) The correct statement that explains why the ashes of burnt paper have less mass than the original paper is: Some of the atoms in the paper became gases.

B) To produce ammonia with no leftovers based on the reaction: 1N2 + 3H2 → 2NH3

You need 1 molecule of nitrogen (N2) for every 3 molecules of hydrogen (H2) to produce 2 molecules of ammonia (NH3).

To determine which combination has no leftovers:

• The ratio of N2 to H2 is 1:3, so for every 1 N2, you need 3 H2.

Looking at the options:

1. 8N2 and 4H2: This does not work because you would need 24 H2 to react with 8 N2.
2. 4N2 and 4H2: This does not work because you would need 12 H2 to react with 4 N2.
3. 2N2 and 6H2: This works! (2N2 will use 6H2 perfectly; 2N2 + 6H2 → 4NH3).
4. 5N2 and 6H2: This does not work because you would need 15 H2 to react with 5 N2.

Therefore, the correct combination that produces ammonia with no leftovers is: 2N2 and 6H2.

Answer 4

A)
In the equation
2H2 + 1O2 →→ 2H2O
if you change the 2H2
to 3H2 molecules and balance the equation, identify which statement is
correct?
(1 point)
The equation will produce three molecules of water.
Each oxygen molecule will combine with 2 hydrogen molecules with no leftover molecules.
The result of the equation will be the same.
It is not possible to produce water without leftover molecules.

Answer 5

In the equation:

\( 2H_2 + 1O_2 → 2H_2O \)

If you change \( 2H_2 \) to \( 3H_2 \) and balance the equation, the new equation becomes:

\( 3H_2 + 1.5O_2 → 3H_2O \)

To balance with whole numbers, you would actually use:

\( 4H_2 + 2O_2 → 4H_2O \)

Now, let's analyze the statements:

1. The equation will produce three molecules of water. - Incorrect. It produces four molecules of water after adjusting to balance.

2. Each oxygen molecule will combine with 2 hydrogen molecules with no leftover molecules. - Incorrect. With the balanced equation \( 4H_2 + 2O_2 → 4H_2O \), each \( O_2 \) combines with 4 hydrogen (2 molecules of \( O_2 \) combine with 8 hydrogen).

3. The result of the equation will be the same. - Incorrect. The amounts of reactants and products would differ after balancing.

4. It is not possible to produce water without leftover molecules. - Correct if referring to the original change (3H2 is not balanced). In the case of \( 3H_2 + 1.5O_2 → 3H_2O \), the original would require fractional amounts of \( O_2 \) or would indeed have leftover.

Thus, the correct statement in this context would be: It is not possible to produce water without leftover molecules.