Unit 5 - Moles Flashcards
What is the total number of atoms in 1.00 mole of Carbon?
6.02 x 10²³ atoms
What is the total number of atoms in 1.00 mole of Zinc?
6.02 x 10²³ atoms
What is the total number of atoms in 1.00 mole of Uranium?
6.02 x 10²³ atoms
What is the molar mass of CH₄?
What is the molar mass of CH₄? From periodic table: C - 12.01g H - 1.01g x 4 12.01 + 4.04 = 16.05 grams molar mass of CH₄
What is the molar mass of Mg(OH)₂ ?
From P.T. : Mg - 24.31g, 0 -16g x 2 H - 1.01g x 2
24.31 + 32 + 2.02 = 58.32 g molar mass Mg(OH)₂
What is the molar mass of barium chloride?
write formula: Ba²⁺ Cl⁻ makes BaCl₂
Ba - 137.33g Cl - 35.45g x 2
137.33 + 70.9 = 208.23g molar mass of BaCl₂
What is the percent composition of oxygen in H₂0?
H-1.01g x2 0-16.00 g 2.02 +16.00 = 18.02g
16.00/18.02 = .89 x 100 = 89% of O in H₂O
How many moles are in 100 grams of NaCl?
100 g x 1mol/(23g+35.45g) = 1.7 moles
How many molecules are there in 2 moles of N₂?
2 mol x (6.02x10²³ molecules)/1 mol = 1.20x10²⁴ molecules
What is an empirical formula?
The formula of a compound having the lowest whole number ration of atoms in the compound.
Can’t be reduced anymore.
Which is an example of an empirical formula?
CH₄ or C₄H₁₆
CH₄
What is a molecular formula?
The molecular formula of a compound is the actual number of atoms of each element present. It is a multiple of the empirical formula. For example, the molecular formula of ethene is C₂H₄.
A compound has an empirical formula of C₃H₆O. Which ( CH₁₂0₆ or C₉H₁₈O₃ ) could be a molecular formula?
C₉H₁₈O₃ (C₃H₆O x 3)
A compound contains 92.3% carbon, 7.7% hydrogen and has a molecular mass of 91 g. What is its molecular formula?
C - 92.3 g x 1 mol/12.01 g = 7.68 mol H - 7.7 g x 1 mol/1.01 g = 7.62 mol then divide by lowest C 7.68 / 7.62 = 1 H 7.62 / 7.62 = 1 then CH is empirical molar mass is 13 g 91 g /13 g = 7 then Molecular formula is C₇H₇
mole
SI unit used to measure the amount of a substance
