When iron rusts and forms iron oxide, the iron oxide has more mass than the iron. Which statement correctly explains this observation?
The iron atoms in iron oxide have more mass than pure iron.
There are more iron atoms in iron oxide than in pure iron.
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.
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 is the product of this reaction?
***CaCO3
CaCO2
Ca2CO3
Ca2O3
Which statement correctly explains why the ashes of burnt paper have less mass than the original 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.
***Some of the atoms in the paper became gases.
Some of the atoms in the paper are destroyed when it burns.
It takes 1 molecule of nitrogen and 3 molecules of hydrogen to produce 2 molecules of ammonia using the following formula:
1N2 + 3H2 → 2NH3
Which combination of molecules will produce ammonia with no leftovers?
The ash is created from new atoms that have less mass than the paper.
Other atoms combine with the paper to produce the ash.
***Some of the atoms in the paper became gases.
Some of the atoms in the paper are destroyed when it burns.
In the equation
2H2 + 1O2 →→ 2H2O
if you change the 2H2 to 3H2 molecules and balance the equation, which statement is correct?
***The equation will produce three molecules of water.
The result of the equation will be the same.
It is not possible to produce water without leftover molecules.
Each oxygen molecule will combine with 2 hydrogen molecules with no leftover molecules.
1. Iron oxide has oxygen atoms, and pure iron does not
2. CaCO3
3. Some of the atoms in the paper became gases
4. 2N2 and 6H2
5. It is not possible to produce water without leftover molecules
Darth Relyt is correct
fixed version
Question 1
When iron rusts and forms iron oxide, the iron oxide has more mass than the iron. Which statement correctly explains this observation?
The iron atoms in iron oxide have more mass than pure iron.
There are more iron atoms in iron oxide than in pure iron.
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.
Question 2
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 is the product of this reaction?
***CaCO3
CaCO2
Ca2CO3
Ca2O3
Question 3
Which statement correctly explains why the ashes of burnt paper have less mass than the original 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.
***Some of the atoms in the paper became gases.
Some of the atoms in the paper are destroyed when it burns.
Question 4
It takes 1 molecule of nitrogen and 3 molecules of hydrogen to produce 2 molecules of ammonia using the following formula:
1N2 + 3H2 → 2NH3
Which combination of molecules will produce ammonia with no leftovers?
5N2 and 6H2
***2N2 and 6H2
4N2 and 4H2
8N2 and 4H2
Question 5
In the equation
2H2 + 1O2 →→ 2H2O
if you change the 2H2 to 3H2 molecules and balance the equation, which statement is correct?
***The equation will produce three molecules of water.
The result of the equation will be the same.
It is not possible to produce water without leftover molecules.
Each oxygen molecule will combine with 2 hydrogen molecules with no leftover molecules.