amount of substance

• What is the mole in chemistry?

  The mole is a way of measuring the amount of substance in chemistry.
• What is Avogadro's number?

  Avogadro's number is $6.02 \times 10^{23}$.
• How many molecules are in one mole of water?

  One mole of water contains $6.02 \times 10^{23}$ molecules of water.
• How do you calculate the number of particles in a substance?

  You multiply Avogadro's number by the number of moles.
• If you have 0.67 moles of ammonia, how many particles do you have?

  The number of particles is $6.02 \times 10^{23} \times 0.67$.
• What is the formula to calculate the number of moles using mass?

  The formula is number of moles = mass (in grams) / molar mass (Mr or Ar).
• How do you calculate the number of moles in 23 g of gold( mr=197)?

  The number of moles is $\frac{23 \text{ g}}{197 \text{ g/mol}} =$$0.12 \text{ moles}$.
• What should you do if you need to rearrange the formula for moles, mass, or molar mass?

  You should look for any two of the three components in the question to use the equation.
• How can you calculate the number of moles in a solution?

  You can calculate it from its concentration and volume.
• What is the formula for calculating moles in a solution?

  The formula is number of moles = concentration (in moles per dm³) × volume (in dm³).
• How do you convert volume from cm³ to dm³?

  You divide the volume in cm³ by 1000.
• How do you calculate the number of moles of 200 cm³ of 0.35 moles per dm³ HCl?

  The number of moles is $0.35 \times \frac{200}{1000} =$$0.07 \text{ moles}$.
• What is the ideal gas equation?

  The ideal gas equation is $PV =$$nRT$.
• What does each variable in the ideal gas equation represent?

  P is pressure in pascals, V is volume in m³, n is number of moles, R is the gas constant, and T is temperature in Kelvin.
• How do you convert pressure from kilopascals to pascals?

  You multiply the pressure in kilopascals by 1000.
• How do you convert temperature from degrees Celsius to Kelvin?

  You add 273 to the degrees Celsius temperature.
• How do you calculate the volume of a gas using the ideal gas equation?

  You rearrange the equation to $V =$$\frac{nRT}{P}$.
• What is the volume of 0.36 moles of gas at 100 kilopascals and 298 Kelvin?

  The volume is $V =$$\frac{0.36 \times 8.31 \times 298}{100000} =$$8.91 \times 10^{-3} \text{ m}^3$.
• How do you convert volume from m³ to cm³?

  You multiply the volume in m³ by 1,000,000.
• What are the relationships between different units of measurement in chemistry?

  • 1 meter = 10 decimeters
  • 1 decimeter = 10 centimeters
  • 1 meter = 100 centimeters
  • For area: multiply by 100 (m² to dm²) or 10,000 (m² to cm²)
  • For volume: multiply by 1000 (m³ to dm³) or 1,000,000 (m³ to cm³)
• What should you do if you are unsure about the calculations involving moles?

  • If in doubt, work out the moles.
  • Knowing moles allows you to calculate concentration or volume.
• How do you convert meters to decimeters?

  Multiply by 100
• Why do we multiply by 100 to convert from meters to centimeters?

  Because there are 100 centimeters in a meter
• If you want to convert 5 meters to centimeters, what calculation would you perform?

  5 meters × 100 = 500 centimeters
• What is the general rule for converting between dimensions in metric units?

  For every dimension, add a zero from the previous dimension
• How do you convert square meters to square decimeters?

  Multiply by 100
• What is the conversion factor from square meters to square centimeters?

  Multiply by 10,000
• If you have an area of 2 square meters, how many square centimeters is that?

  2 square meters × 10,000 = 20,000 square centimeters
• How do you convert cubic meters to cubic decimeters?

  Multiply by 1,000
• What is the conversion factor from cubic decimeters to cubic centimeters?

  Multiply by 1,000
• If you have a volume of 3 cubic meters, how many cubic centimeters is that?

  3 cubic meters × 1,000,000 = 3,000,000 cubic centimeters
• What are ionic equations used for in chemistry?

  They show the ions formed in solution and which particles are reacting
• What types of substances typically form ions in solution?

  Acids, bases, and salts
• What are spectator ions in an ionic equation?

  They are ions that do not participate in the reaction
• What must be true about the charges in an ionic equation?

  The charges must balance on both sides of the equation
• What are the state symbols used in chemistry?

  S for solid, L for liquid, G for gas, and AQ for aqueous
• How can balanced equations be used in chemistry?

  To work out theoretical masses and percentage yields
• How do you calculate the theoretical mass of calcium oxide produced from burning 34 grams of calcium?

  Use the balanced equation and molar masses to find the mass produced
• What is the molar mass of calcium (Ca)?

  40 g/mol
• How do you find the mass of calcium oxide produced from a given mass of calcium?

  Divide the mass of calcium by its molar mass and multiply by the molar mass of calcium oxide