Question

4.How many atoms of carbon (C) are present in the reactants of the following chemical equation?

C7H16+O2→CO2+H2O

(1 point)
Responses

23 atoms
23 atoms

16 atoms
16 atoms

7 atoms
7 atoms

1 atom
3.Use the equation to answer the question.

CH4+2O2→CO2+2H2O

If you change the 2 in front of 2O2
to a 3, what will be the change in the results on the right side of the equation?

(1 point)
Responses

Nothing changes in the equation
Nothing changes in the equation

There is an extra O2
molecule left over
There is an extra cap o sub 2 molecule left over

There are now 3 H2O
molecules
There are now 3 cap h sub 2 cap o molecules

There are now 3 CO2
molecules
2.According to the Law of Conservation of Matter, what happens to atoms during a chemical reaction?(1 point)
Responses

Nothing; they stay the same
Nothing; they stay the same

The atoms are rearranged to form new substances
The atoms are rearranged to form new substances

Atoms are converted into energy during the chemical reaction
Atoms are converted into energy during the chemical reaction

More atoms are produced to form new substances
1. Balance the following the chemical equation:

_ Na2O + _ CaBr2 → _ NaBr + _ CaO

(1 point)
Responses

2:1:1:1
2:1:1:1

1:2:1:1
1:2:1:1

1:1:2:1
1:1:2:1

1:1:1:2

Answer 1

4. 7 atoms

3. There is an extra O2 molecule left over

2. The atoms are rearranged to form new substances

1. 1:1:2:1