Conservation of Mass

In the complete reaction of 22.99 g of sodium with 35.45 g of chloride, what mass of sodium chloride is formed?

Answer explanation

Mass of Reactants = Mass of Products

mass sodium + mass chlorine = mass sodium chloride

Tags

NGSS.HS-PS1-7

A 12.2 g sample of X reacts with a sample of Y to form 78.9 g of XY.  What is the mass of Y that reacted?

Answer explanation

Mass of Reactants = Mass of Products

mass of X + mass Y = mass of XY

Rearrange to solve for mass of Y

Tags

NGSS.HS-PS1-7

A 10.0 g sample of magnesium reacts with oxygen to form 16.6 g of magnesium oxide.  How many grams of oxygen reacted?

Answer explanation

Mass of Reactants = Mass of Products

mass of magnesium + mass oxygen = mass of magnesium oxide

Rearrange to solve for mass of oxygen

Tags

NGSS.HS-PS1-7

From a laboratory process designed to separate water into hydrogen and oxygen gas, a student collected 10.0 g of hydrogen and 79.4 g of oxygen.  How much water was originally involved in the process?

Answer explanation

Mass of Reactants = Mass of Products

mass of water = mass of hydrogen + mass of oxygen

Tags

NGSS.HS-PS1-7

A student carefully placed 15.6 g of sodium in a reactor supplied with an excess quantity of chloride gas.  When the reaction was complete, the student obtained 39.7 g of sodium chloride.  How many grams of chloride gas reacted?

Answer explanation

Mass of Reactants = Mass of Products

mass of sodium + mass of chlorine = mass of sodium chloride

Rearrange to solve for chlorine

A sample of 16.3 g of methane reacted with 64.9 grams of oxygen to form carbon dioxide and water. How many grams of the products were formed?

Answer explanation

Mass of Reactants = Mass of Products

Methane and oxygen are the reactants. Carbon dioxide and water are the products.

mass of methane + mass of oxygen = mass of products.

Tags

NGSS.HS-PS1-7

A student mixes 480. g of silver nitrate with 253 g of sodium chloride. The resulting reaction produces 217 g of silver chloride and an unknown mass of sodium nitrate. What is the mass of sodium nitrate formed?

Answer explanation

Mass of Reactants = Mass of Products

mass of silver nitrate + mass sodium chloride = mass of silver chloride + mass of sodium nitrate

Rearrange for mass of sodium nitrate

Tags

NGSS.HS-PS1-7

A sample of magnesium with a mass of 97.0 g is reacted with 23.0 g of copper(II) nitrate to form 86.0 g of copper. How many grams of magnesium nitrate was formed?

Answer explanation

Mass of Reactants = Mass of Products

mass of magnesium + mass copper(II) nitrate = mass of magnesium nitrate + mass of copper

Rearrange for mass of magnesium nitrate

Tags

NGSS.HS-PS1-7

The masses of 18.41 g of zinc chloride and 2.98 g of hydrogen were formed when 16.30 g of zinc was added to hydrochloric acid. What mass of hydrochloric acid reacted?

Answer explanation

Mass of Reactants = Mass of Products

mass of zinc + mass of hydrochloric acid = mass of zinc chloride + mass of hydrogen

Rearrange for mass of hydrochloric acid

Tags

NGSS.HS-PS1-7

After burning for three hours, a candle has lost half of its mass.  Explain why this example does not violate the law of conservation of mass.

Tags

NGSS.HS-PS1-7