Question
Which changes to matter are described by the law of conservation of mass? (1 point)
Responses
Only physical changes, not chemical changes
Only physical changes, not chemical changes
Most changes, but not chemical changes that involve gases.
Most changes, but not chemical changes that involve gases.
All physical and chemical changes, including changes that involve gases
All physical and chemical changes, including changes that involve gases
Only chemical changes, not physical changes
Use the chemical reaction to answer the question.
2H2+O2→2H2O
There are four atoms of hydrogen (H
) before the reaction. How many atoms of hydrogen are present after the reaction?
(1 point)
Responses
2
2
8
8
5
5
4
4
Use the chemical reaction to answer the question.
CaCO3→CO2+CaO
A scientist heats 30 grams of calcium carbonate (CaCO3
) in the chemical reaction shown. What is the total mass of the products?
(1 point)
Responses
10 grams
10 grams
15 grams
15 grams
60 grams
60 grams
30 grams
30 grams
The balanced chemical equation shows a reaction between iron (Fe) and oxygen (O2
).
4Fe+3O2→2Fe2O3
How does the equation show the law of conservation of mass?
(1 point)
Responses
The number of reactants is equal to the number of products.
The number of reactants is equal to the number of products.
The number of atoms of each element is the same on both sides.
The number of atoms of each element is the same on both sides.
Each element has the same subscript or coefficient on each side.
Each element has the same subscript or coefficient on each side.
The sum of the coefficients and subscripts is the same on both sides.
Responses
Only physical changes, not chemical changes
Only physical changes, not chemical changes
Most changes, but not chemical changes that involve gases.
Most changes, but not chemical changes that involve gases.
All physical and chemical changes, including changes that involve gases
All physical and chemical changes, including changes that involve gases
Only chemical changes, not physical changes
Use the chemical reaction to answer the question.
2H2+O2→2H2O
There are four atoms of hydrogen (H
) before the reaction. How many atoms of hydrogen are present after the reaction?
(1 point)
Responses
2
2
8
8
5
5
4
4
Use the chemical reaction to answer the question.
CaCO3→CO2+CaO
A scientist heats 30 grams of calcium carbonate (CaCO3
) in the chemical reaction shown. What is the total mass of the products?
(1 point)
Responses
10 grams
10 grams
15 grams
15 grams
60 grams
60 grams
30 grams
30 grams
The balanced chemical equation shows a reaction between iron (Fe) and oxygen (O2
).
4Fe+3O2→2Fe2O3
How does the equation show the law of conservation of mass?
(1 point)
Responses
The number of reactants is equal to the number of products.
The number of reactants is equal to the number of products.
The number of atoms of each element is the same on both sides.
The number of atoms of each element is the same on both sides.
Each element has the same subscript or coefficient on each side.
Each element has the same subscript or coefficient on each side.
The sum of the coefficients and subscripts is the same on both sides.
Answers
Answered by
GPT-4o mini
1. **Which changes to matter are described by the law of conservation of mass?**
**Response:** All physical and chemical changes, including changes that involve gases
2. **How many atoms of hydrogen are present after the reaction (2H2 + O2 → 2H2O)?**
**Response:** 4
3. **What is the total mass of the products when 30 grams of calcium carbonate (CaCO3) is heated (CaCO3 → CO2 + CaO)?**
**Response:** 30 grams
4. **How does the balanced chemical equation show the law of conservation of mass?**
**Response:** The number of atoms of each element is the same on both sides.
**Response:** All physical and chemical changes, including changes that involve gases
2. **How many atoms of hydrogen are present after the reaction (2H2 + O2 → 2H2O)?**
**Response:** 4
3. **What is the total mass of the products when 30 grams of calcium carbonate (CaCO3) is heated (CaCO3 → CO2 + CaO)?**
**Response:** 30 grams
4. **How does the balanced chemical equation show the law of conservation of mass?**
**Response:** The number of atoms of each element is the same on both sides.