Use the chemical reaction to answer the question.

Question

​CaCO3→CO2​+CaO
​
CaCO
3
→
CO
2
​
+
CaO
A scientist heats 30 grams of calcium carbonate (CaCO3
CaCO
3
) in the chemical reaction shown. What is the total mass of the products?

(1 point)
Responses

15 grams
15 grams

10 grams
10 grams

60 grams
60 grams

30 grams

Answer 1

In a chemical reaction, the law of conservation of mass states that mass is neither created nor destroyed. This means that the total mass of the reactants must equal the total mass of the products.

In this case, the reactant is calcium carbonate (CaCO₃), and the scientist starts with 30 grams of it.

When VCaCO₃ decomposes, it produces carbon dioxide (CO₂) and calcium oxide (CaO). Regardless of how much of each product is formed, the total mass of all products combined will equal the mass of the starting CaCO₃.

Since 30 grams of CaCO₃ is used, the total mass of the products (CO₂ + CaO) will also be 30 grams.

Therefore, the correct answer is:

30 grams.

Answer 2

Use the chemical reaction to answer the question.

4​Fe+3O2→2Fe2O3​
4
​Fe
+
3O
2
→
2Fe
2
O
3
​
What happens to atoms of Fe and O2 during the reaction?

(1 point)
Responses

They are lost.
They are lost.

They are rearranged.
They are rearranged.

They gain mass.
They gain mass.

They maintain their properties.
They maintain their properties.

Answer 3

In the reaction \(4 \text{Fe} + 3 \text{O}_2 \rightarrow 2 \text{Fe}_2\text{O}_3\), the atoms of iron (Fe) and oxygen (O₂) are not lost or gained; instead, they are rearranged to form new products.

During the reaction, the iron atoms combine with oxygen molecules to create iron(III) oxide (Fe₂O₃). The total number of atoms for each element before and after the reaction remains the same, but they are reorganized into different chemical compounds.

Therefore, the correct response is:

They are rearranged.

Answer 4

Which is most likely to occur during a chemical reaction?(1 point)
Responses

Mass is conserved.
Mass is conserved.

New atoms are created.
New atoms are created.

The original substance maintains its properties.
The original substance maintains its properties.

Atoms of the original substance are lost.

Answer 5

During a chemical reaction, the most likely occurrence is that:

Mass is conserved.

This is in accordance with the law of conservation of mass, which states that mass cannot be created or destroyed in a chemical reaction. The number of atoms of each element remains the same before and after the reaction, although they may be rearranged into different molecules or compounds.

Answer 6

Use the chemical reaction to answer the question.

NaHCO3+HC2H3O2→NaC2H3O2+H2O+CO2
NaHCO
3
+
HC
2
H
3
O
2
→
NaC
2
H
3
O
2
+
H
2
O
+
CO
2
A student mixes baking soda (NaHCO3
NaHCO
3
) and acetic acid (HC2H3O2
HC
2
H
3
O
2
) to produce a chemical reaction shown. Which statement about the reaction is correct?

(1 point)
Responses

Some atoms gain mass after the reaction.
Some atoms gain mass after the reaction.

The atoms of the reactants are regrouped during the reaction.
The atoms of the reactants are regrouped during the reaction.

There are more H atoms after the reaction.
There are more H atoms after the reaction.

Atoms of Na are destroyed during the reaction.

Answer 7

In the given reaction:

\[ \text{NaHCO}_3 + \text{HC}_2\text{H}_3\text{O}_2 \rightarrow \text{NaC}_2\text{H}_3\text{O}_2 + \text{H}_2\text{O} + \text{CO}_2 \]

the correct statement about the reaction is:

The atoms of the reactants are regrouped during the reaction.

During a chemical reaction, the atoms of the reactants are rearranged to form new products, but no atoms are created or destroyed, and the total mass remains constant.

Answer 8

Use the chemical reaction to answer the question.

2H2+O2→2H2O
2
H
2
+
O
2
→
2
H
2
O
There are four atoms of hydrogen (H
H
) before the reaction. How many atoms of hydrogen are present after the reaction?

(1 point)
Responses

4
4

2
2

8
8

5

Answer 9

In the chemical reaction:

\[ 2\text{H}_2 + \text{O}_2 \rightarrow 2\text{H}_2\text{O} \]

Before the reaction, there are 4 hydrogen atoms (as \(2 \text{H}_2\) means 2 molecules of hydrogen, each containing 2 hydrogen atoms).

After the reaction, the products are \(2\text{H}_2\text{O}\), which means there are also 4 hydrogen atoms in total (since each water molecule \( \text{H}_2\text{O} \) contains 2 hydrogen atoms, and there are 2 water molecules).

So, the number of hydrogen atoms present after the reaction is:

4.