Conservation of Mass

Match each term to the correct definition.

• Atom

• The smallest particle of an element; made of electrons, protons, and neutrons

• Conserve

• The measure of how much matter is present in a substance

• Mass

• To prevent the loss of something

• Chemical reaction

• A chemical reaction during which plants convert radiant energy from the Sun to chemical energy; the reaction converts Carbon Dioxide and water into sugar and Oxygen

• Photosynthesis

• The process by which one or more substances change to produce one or more different substances

Tags

NGSS.MS-LS1-6

Use the words below to label the equation in the image.

a

b

c

d

e

f

Product

Subscript

Chemical equation

Reactant

Coefficient

Chemical formula

During a chemical reaction, the products must equal the reactants. How does this show the law of conservation of mass?

• The law of conservation of mass states that mass cannot be created or destroyed. If matter disappears during a reaction, then the law of conservation of mass is not being upheld. The matter must go somewhere.

• The law of conservation of mass states that energy is always lost during a reaction.

• The law of conservation of mass states that new elements are formed in every reaction.

• The law of conservation of mass states that mass can be created from nothing during a reaction.

Tags

NGSS.MS-PS1-5

How is it possible to check whether a chemical reaction follows the law of conservation of mass?

• First, you need to find the equation of the reaction. Next, you count the atoms of each element in the reactants, and then you count the products. They should be equal.

• By measuring the temperature change during the reaction.

• By observing the color change in the reactants and products.

• By checking if the reaction produces a gas.

Tags

NGSS.MS-PS1-5

NGSS.MS-PS1-2

Students want to conduct an investigation to gather evidence for the claim that the number of atoms present before a chemical reaction is equal to the number of atoms present after the chemical reaction. They decide to combine vinegar and baking soda in a sealed plastic bag. Which of the following would provide the evidence the students need?

• The mass of the plastic bag, baking soda, and vinegar before the reaction was equal to the mass after the reaction.

• Bubbles were produced during the reaction, which means that a gas was being produced.

• The plastic bag did not change in any way, indicating that it was not involved in the reaction.

• The mass of baking soda was exactly equal to the mass of the vinegar used to create the chemical reaction.

Tags

NGSS.MS-PS1-5

NGSS.MS-PS1-2

Which of the following atomic models correctly demonstrates the law of conservation of mass?

• 
• 
• 
• 

Tags

NGSS.MS-PS1-5

Photosynthesis is a process that plants use to transform light energy into chemical energy. The reactants in the chemical reaction are carbon dioxide and water. The products are sugar and oxygen. Which of the following statements is true about the mass of the reactants and products?

• The mass of the 6CO₂ + 6H₂O + Sunlight will be less than the mass of the C₆H₁₂O₆ + 6O₂.

• The mass of the 6CO₂ + 6H₂O + Sunlight will be greater than the mass of the C₆H₁₂O₆ + 6O₂.

• The mass of the 6CO₂ + 6H₂O + Sunlight will be destroyed to make C₆H₁₂O₆ + 6O₂.

• The mass of the 6CO₂ + 6H₂O + Sunlight will be equal to the mass of the C₆H₁₂O₆ + 6O₂.

Tags

NGSS.MS-PS1-5

NGSS.MS-PS1-2

NGSS.MS-LS1-6

Students are given the following equation. Which atoms are included in this equation? NaOCl + 2HCl → NaCl + H₂O + Cl₂ sodium hypochlorite + hydrochloric acid → salt + water + chlorine gas

• Nickel, oxygen, chlorine, and helium

• Sodium, oxygen, chlorine, and hydrogen

• Nadium, oxide, chlorine, and hydrogen

• Sodium, oxygen, chlorine, and helium

Tags

NGSS.MS-PS1-1

Students planned an investigation to see if they could show that matter is conserved in a chemical reaction. Which one of their experiments shows that mass was conserved?

• Sodium bicarbonate and acetic acid

• Calcium chloride and water

• Sulfuric acid and sugar

• Hydrochloric acid and calcium carbonate

Tags

NGSS.MS-PS1-5

NGSS.MS-PS1-2

The chemical equation for water is shown in the image provided. Which statements about this equation are true? Select two correct answers.

• There are different numbers of oxygen atoms on the reactants and products side of the equation.

• Some of the atoms were destroyed in the reaction.

• There is the same number of hydrogen atoms on the reactants and products side of the equation.

• Two more hydrogen atoms are needed to make this equation balanced.

• The equation shows that mass has been conserved.

Tags

NGSS.MS-PS1-5

NGSS.MS-PS1-2