Ar, Mr and Mol calculations

• What is an atom?

  The smallest unit of an element
• What is a compound?

  A substance formed from two or more elements
• What type of compound is NaCl?

  Ionic compound
• What type of compound is H2O?

  Covalent compound
• How many atoms are there in a molecule of H2?

  2 atoms
• How many atoms are there in a molecule of sulfuric acid (H2SO4)?

  7 atoms
• What is the formula for oxygen?

  O2
• What is the formula for hydrogen?

  H2
• What is the formula for nitrogen?

  N2
• What is the formula for carbon dioxide?

  CO2
• What is the formula for ammonia?

  NH3
• What is the formula for sodium chloride?

  NaCl
• What is the formula for calcium chloride?

  CaCl2
• What is the formula for aluminum chloride?

  AlCl3
• What is the formula for sodium oxide?

  Na2O
• What is the formula for calcium fluoride?

  CaF2
• What is the formula for aluminum oxide?

  Al2O3
• What does Ar stand for?

  Relative atomic mass
• What is an isotope?

  An atom with a different number of neutrons
• Which atom is the mass of all other atoms compared to?

  Carbon-12
• How do you calculate the relative atomic mass of magnesium from isotopes?

  Weighted average of isotopes' masses
• What is a mole?

  6.02 x 10^23 particles
• How do you calculate the number of moles in a pure sample of a solid compound?

  Mass divided by molar mass
• What is the mass of one atom of carbon-12?

  12 g/mol
• What is the relative atomic mass of an element?

  Average mass compared to carbon-12
• How is the relative molecular mass (Mr) calculated?

  Add relative atomic masses of all atoms
• What is the formula for relative atomic mass (Aᵣ)?

  Average mass of an atom / 1/12 mass of carbon-12
• What is Avogadro's constant (L)?

  6.02 x 10^23 particles
• How can Avogadro's constant be used?

  Convert between number of particles and moles
• How many atoms are there in 3 moles of carbon?

  1.806 x 10^24 atoms
• How many atoms are there in 0.5 moles of iron?

  3.011 x 10^23 atoms
• How many molecules are there in 2 moles of water?

  1.2044 x 10^24 molecules
• What does the relative atomic mass of an element in grams represent?

  Mass of 6.02 x 10^23 atoms
• How is the mass of one atom calculated?

  Molar mass divided by Avogadro's constant
• What is the mass of one atom of sodium with a relative atomic mass of 23?

  3.82 x 10^-23 g
• What is the mass of one atom of hydrogen with a relative atomic mass of 1.0078?

  1.67 x 10^-24 g
• What is the mass of one atom of magnesium with a relative atomic mass of 24.3?

  4.04 x 10^-23 g
• What does Avogadro's number describe?

  Number of particles in one mole
• How many atoms are there in one mole of carbon?

  6.02 x 10^23 atoms
• How many molecules are there in one mole of water?

  6.02 x 10^23 molecules