Chemical Calculations

If a chemist calculates the maximum amount of product that could be obtained in a chemical reaction, he or she is calculating the

• theoretical yield

• mole ratio

• actual yield

• percentage yield

How would you work out the theoretical yield of water if you start with 90g ethane (C₂H₆).

C₂H₆ + O₂ --> CO₂ + H₂O

• Balance the equation

  find the mole ratio of ethane to water

  calculate the Mr of ethane

  calculate the moles of ethane

  Use the mole ratio to find the moles of water

  calculate the Mr of water

  calculate the mass of water

• Balance the equation

  find the mole ratio of ethane to water

  Use the mole ratio to work out the mass of water

• calculate the Mr of ethane

  calculate the moles of ethane

  Use the mole ratio to find the moles of water

  calculate the Mr of water

  calculate the mass of water

• Use mass =moles x Mr

  then moles = concentration x volume

• Balance the equation

  calculate the Mr of ethane

  calculate the moles of ethane

  calculate the Mr of water

  calculate the mass of water

Tags

NGSS.HS-PS1-7

Work out the theoretical yield of water if you start with 90g ethane (C₂H₆).

C₂H₆ + O₂ --> CO₂ + H₂O

• 180g

• 162g

• 90g

• 27g

• 54g

What is the measured amount of a product obtained from a chemical reaction?

• mole ratio

• theoretical yield

• percentage yield

• actual yield

Tags

NGSS.HS-PS1-7

The blue numbers in the image below are called ___________.

• compounds

• coefficients

• subscripts

• chemical formulas

Tags

NGSS.HS-PS1-7

This appears on the left side of a chemical formula, and represents how many compounds there are.  What is the name of this number?

• Dangling Participle 

• The Subscript

• Prime Number

• Coefficient

Mole ratios are obtained from the

• balanced chemical equation

• periodic table

• molar mass

What is the mole ratio of H₂O to H₃PO₄ in the following chemical equation?   P₄O₁₀ + 6 H₂O --> 4 H₃PO₄ 

• 6:4

• 4:6

• 1:3

• 3:1

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

Balance the equation below

C₂H₆ + O₂ --> CO₂ + H₂O

• 1:1:1:1

• 1:2:1:2

• 1:3:2:3

• 2:7:4:6

• 2:9:5:7

Tags

NGSS.HS-PS1-7