Question 1

Question

A)When iron rusts and forms iron oxide, the iron oxide has more mass than the iron. Which statement correctly explains this difference in mass?(1 point)
Responses

The oxygen atoms in iron oxide have more mass than the iron atoms in pure iron.
The oxygen atoms in iron oxide have more mass than the iron atoms in pure iron.

The iron atoms in iron oxide have more mass than pure iron.
The iron atoms in iron oxide have more mass than pure iron.

There are more iron atoms in iron oxide than in pure iron.
There are more iron atoms in iron oxide than in pure iron.

Iron oxide has oxygen atoms, and pure iron does not.
Iron oxide has oxygen atoms, and pure iron does not.
Question 2
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)
Responses

CaCO2
C a C O sub 2

CaCO3
C a C O sub 3

Ca2CO3
Ca sub 2 C O sub 3

Ca2O3
Ca sub 2 O sub 3
Question 3
A)Which statement correctly explains why the ashes of burnt paper have less mass than the original paper?(1 point)
Responses

The ash is created from new atoms that have less mass than the paper.
The ash is created from new atoms that have less mass than the paper.

Other atoms combine with the paper to produce the ash.
Other atoms combine with the paper to produce the ash.

Some of the atoms in the paper are destroyed when it burns.
Some of the atoms in the paper are destroyed when it burns.

Some of the atoms in the paper became gases.
Some of the atoms in the paper became gases.
Question 4
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)
Responses

8N2 and 4H2
8 n sub 2 and 4 h sub 2

5N2 and 6H2
5 n sub 2 and 6 h sub 2

4N2 and 4H2
4 n sub 2 and 4 h sub 2

2N2 and 6H2
2 n sub 2 and 6 h sub 2
Question 5
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)
Responses

It is not possible to produce water without leftover molecules.
It is not possible to produce water without leftover molecules.

The equation will produce three molecules of water.
The equation will produce three molecules of water.

Each oxygen molecule will combine with 2 hydrogen molecules with no leftover molecules.

Answer 1

Here are the answers to your questions:

Question 1: The correct statement explaining why iron oxide has more mass than the original iron is:

• Iron oxide has oxygen atoms, and pure iron does not.

Question 2: The 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 (Calcium Carbonate)

Question 3: The statement that correctly explains why the ashes of burnt paper have less mass than the original paper is:

• Some of the atoms in the paper became gases.

Question 4: The combination of molecules that will produce ammonia with no leftovers is:

• 8N2 and 4H2

Question 5: When changing 2H2 to 3H2 and balancing the equation, the correct statement is:

• It is not possible to produce water without leftover molecules.

Let me know if you need further assistance!