Law of Conservation of Mass Recap

Law of conservation of mass states that

• mass is created

• mass is destroyed

• mass is neither created nor destroyed

• mass does not change

Tags

NGSS.MS-PS1-5

100g of white powder reacts with 77g of clear liquid. The reaction bubbles and changes color producing a yellow liquid that has a mass of 90g. What can be concluded?

• 97g of gas was produced

• This experiment violates the conservation of mass

• 87g of gas was produced

• The excess reactant is destroyed & disappears during the reaction

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NGSS.MS-PS1-2

NGSS.MS-PS1-5

What are the REACTANTS :
H₂O + CO₂ → HCO + HO

• H₂O and CO₂
• HCO and HO
• H₂O ONLY
• HCO ONLY

Tags

NGSS.MS-PS1-1

NGSS.MS-PS1-2

REACTANTS are always on what side of the chemical equation?

• right
• left
• top
• bottom

Which of the following are PRODUCTS?
H₂O + CO₂ → HCO + HO

• H₂O and CO₂
• HCO and HO
• H₂O ONLY
• HCO ONLY

Tags

NGSS.MS-PS1-2

PRODUCTS are always on what side of the equation?

• right
• left
• top
• bottom

Tags

NGSS.MS-PS1-5

If there are 4 H atoms on the reactant side, how many H atoms will be on the product side? 

• 2
• 4
• 6
• You need more information to answer this question

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NGSS.MS-PS1-2

NGSS.MS-PS1-5

Suppose a reaction were to happen in an open container in a lab. During the reaction, the scientist observes the chemicals bubble, and produce a gas. During the analysis the scientist notices that the reactants weighed 20 g when he started, and the product weighed 18 g. Explain what happened.

• His chemical reaction defied the law of conservation of mass

• The product destroyed mass during the reaction

• The reactants created matter during the reaction

• The gas that was produced was not able to be weighed since the container was open.

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5

How many nitrogen atoms does NH₃ have?

• 1
• 2
• 3
• 4

Tags

NGSS.MS-PS1-1

Mass cannot be created or__________ during a chemical reaction?

• Reacted

• Transferred

• Born

• Destroyed

Tags

NGSS.MS-PS1-5