limiting and excess

When does a chemical reaction stop?

• When the lab is finished
• When the excess reactant is used up
• When the limiting reactant is used up
• Chemical reactions never stop

Tags

NGSS.HS-PS1-6

The limiting reactant

• slows the reaction down
• is used up first
• is the reactant that is left over
• controls the speed of the reaction

How many grams of FeS are formed from 7.62g of Fe reacted with excess S?

• 3.82g
• 7.62g
• 12.2g
• 11.4g 

Tags

NGSS.HS-PS1-7

What is a limiting reactant?

• the reactant that determines how much product can be made
• the reactant that is in excess
• the product that you can make the most of
• the amount of reactants that react with each other

The excess reactant

• .
• is used up first
• is the reactant that is left over
• .

1 car frame + 4 Tires --> 1 car

How many cars can you make with 92 tires and 34 car frames?

• 23

• 34

• 68

• 46

1 car frame + 4 Tires --> 1 car

How many cars can you make with 92 tires and 34 car frames?

In this senario the tires would be the _____________ reactant.

• Limiting

• Excess

Mole ratios are obtained from the

• balanced chemical equation
• periodic table
• molar mass

Tags

NGSS.HS-PS1-7

In a balanced equation, the ratio between the coeffients of any two substances is called the _______. 

• mole ratio
• stoichiometry
• limiting reactant
• excess reactant

The coefficients in a chemical equation represent the

• number of atoms in each compound in a reaction
• relative numbers of moles of reactants and products
• masses, in grams, of all reactants and products
• number of valence electrons involved in the reaction