Stemscopes Chemical Equations and Law of Conservation of Mass

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.

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NGSS.MS-PS1-2

NGSS.MS-PS1-5

A scientist measures 4 g of Substance A and 5 g of Substance B and mixes the substances together in a beaker, as shown below. What happened to the original substances?

• The original substances rearranged to form products. Some of which were gases that were not included in the mass.

• The substances remained separate and did not react.

• The substances dissolved completely in each other.

• The substances evaporated.

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NGSS.MS-PS1-2

NGSS.MS-PS1-5

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

• A

• B

• C

• D

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NGSS.MS-PS1-5

In the hydrolysis of water, two water molecules are broken apart into hydrogen and oxygen, as shown below. Based on this equation, which of the following are true?

Select 2 correct answers

• There are 4 hydrogen atoms before the reaction and 4 hydrogen atoms after the reaction.

• Some of the reacting hydrogen was destroyed in the reaction.

• There is 1 oxygen atom before the reaction and 2 oxygen atoms after the reaction.

• There are 2 oxygen atoms before the reaction and 2 oxygen atoms after the reaction.

• Some of the reacting oxygen was destroyed in the reaction.

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NGSS.MS-PS1-2

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Using the Periodic Table above, identify the elements and number of atoms involved in the following chemical reaction:

• 12 Carbon, 6 hydrogen, and 12 oxygen atoms

• 6 Carbon, 12 hydrogen, and 18 oxygen atoms

• 1 carbon, 1 hydrogen, and 6 oxygen atoms

• 2 Glucose, 18 oxygen, 1 carbon dioxide, and 6 water atoms

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NGSS.MS-PS1-1

NGSS.MS-PS1-5

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

Select 2 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.

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NGSS.MS-PS1-2

NGSS.MS-PS1-5

The law of conservation of mass can be demonstrated by a chemical reaction. Which of the following chemical reaction models best represents the law of conservation of mass?

• A

• B

• C

• D

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NGSS.MS-PS1-2

NGSS.MS-PS1-5

The chemical equation provided here shows the process of photosynthesis. Which of the following correctly identifies the molecules involved in the chemical reaction?

Drag and drop the answers to the correct boxes.

​

​ ​ +​ ​ =​ +​

a

b

c

d

e

f

Water

Carbon Dioxide

Hydrogen

Carbon

Oxygen 12

Oxygen 6

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NGSS.MS-LS1-6

H₂ + S → H₂S is a chemical reaction that produces a colorless, flammable, extremely hazardous gas with a “rotten egg” smell. What two elements are found in this chemical reaction? 

• Hydrogen and silicon  

• Hydrogen and sulfur

• Mercury and silicon 

• 
  Holmium and selenium 

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NGSS.MS-PS1-1

NGSS.MS-PS1-2

Kio and Gael 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

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NGSS.MS-PS1-2

NGSS.MS-PS1-5