Law of Conservation of Mass

Which of the following best describes the law of conservation of mass?

• Mass can be created or destroyed in a chemical reaction.

• Mass is neither created nor destroyed in a chemical reaction.

• Mass is always increased in a chemical reaction.

• Mass is always decreased in a chemical reaction.

• 18 grams

• 36 grams

• 36 grams

• 36 grams

• The mass of sodium and chlorine before the reaction is equal to the mass of sodium chloride after the reaction.

• The mass of sodium chloride is less than the mass of sodium and chlorine.

• The mass of sodium chloride is more than the mass of sodium and chlorine.

• The mass of sodium is equal to the mass of chlorine.

Which of the following is an example of the law of conservation of mass?

• Burning wood results in ash and smoke, with the total mass being less than the original wood.

• Dissolving sugar in water results in a solution with the same mass as the sugar and water combined.

• Melting ice results in water with less mass than the original ice.

• Evaporating water results in vapor with more mass than the original water.

• 44 grams

• 24 grams

• 32 grams

• 12 grams

In a closed system, 10 grams of hydrogen react with 80 grams of oxygen to form water. What is the total mass of water formed?

• 70 grams

• 90 grams

• 100 grams

• 80 grams

A chemical reaction in a closed container starts with 50 grams of reactants. After the reaction, the products weigh 48 grams. What can be inferred?

• The law of conservation of mass is violated.

• There was a measurement error or gas was released.

• The products are heavier than the reactants.

• The reactants were not completely used.

If 5 grams of magnesium react with 10 grams of oxygen to form magnesium oxide, what is the mass of magnesium oxide produced?

• 10 grams

• 15 grams

• 5 grams

• 20 grams

• The mass of water is less than the mass of hydrogen and oxygen.

• The mass of water is equal to the mass of hydrogen and oxygen.

• The mass of water is more than the mass of hydrogen and oxygen.

• The mass of hydrogen is equal to the mass of oxygen.

In a chemical reaction, 20 grams of reactant A react with 30 grams of reactant B to form 40 grams of product C and some other products. What is the total mass of the other products?

• 10 grams

• 20 grams

• 30 grams

• 50 grams