ch 2
How many sig figs in 389,890?
5
An atom has 20 protons, 20 neutrons, and 18 electrons. Write the symbol for this ion.
40Ca²⁺
Name the molecular compound SF₆
Sulfur hexafluoride
Balance the chemical equation below:
Al2(SO4)3 + Ca(OH)2 → Al(OH)3 + CaSO4
Al2(SO4)3 + 3 Ca(OH)2 → 2 Al(OH)3 + 3 CaSO4
Calculate the molar mass of NaHCO₃ (sodium bicarbonate)
84.01 g/mol
22.98+1.00+12.01+3(15.99)
solve the following and answer with the correct number of sig figs:
6.22 + 14.311
What is the ionic formula of the compound formed between magnesium and chlorine?
MgCl₂
How many lone electrons (nonbonding electrons) are there on the central O atom of H₂O?
4 nonbonding (lone) electrons on oxygen
How many H₂O molecules are in 1.25 moles of H₂O?
7.53 × 10²³ H₂O molecules
1.25 mol×6.022×1023 molecule/mole=7.53×1023 molecules
A container of baking soda contains 425 g of NaHCO₃. How many moles of NaHCO₃ are in the container?
5.059 mol NaHCO₃
425 g NaHCO3 x (1 mol/ 22.98+1.00+12.01+3(15.99)g)
Convert 8.77 cm to km
8.77 × 10-5 km
8.77 cm×(0.01 m/1 cm)×(1 km/1000 m)
What is the name of the compound SnO₂?
Tin(IV) oxide
What is the molecular geometry and bond angle for boron trihydride?
trigonal planar; 120
What is the number of moles of aluminum atoms in 1.204 × 10²⁴ atoms of Al?
2.00 mol Al
(1.204×1024 atoms) x (1 mol/6.022×1023 atoms) =2.00 mol
A cup contains 500.0 g of water.
a) How many moles of water are in the cup?
b) How many hydrogen atoms are in the cup of water?
a. 27.75 mol H₂O
b. 3.34×1025 H atoms
500 g H2O x (1 mol/(2(1)+16 g))
27.75 mol H2O (6.02x1023atom/mol) (2 atoms H/molecule)
A prescription requires 0.300 mg of a medication. Each capsule contains 50 μg of the active ingredient.
How many capsules are needed to provide the prescribed dose?
6 capsules
0.300 mg×1000=300 μg
300 μg (1 capsule/50 μg)
Write the formula for the ionic compound: tin(IV) sulfide
SnS₂
What is the molecular geometry, bond angle, and polarity for carbon dioxide?
linear; 180; nonpolar
How many atoms of O are there in 0.100 moles of glucose, C₆H₁₂O₆?
3.61 × 10²³ O atoms
0.100 mol C6H12O6 × (6.022×1023 atoms/mol) × (6 mol O2/ 1 mol C₆H₁₂O₆)
Given the reaction 2 Al(s) + 3Cl2(g) --> 2AlCl3(s), how many moles of Cl2 are required to react with 5 moles of Al?
7.50 mol Cl2
5 mol Al (3 mol Cl/2 mol Al)
A nurse gives a patient 1.5 teaspoons of medicine. The solution’s density is 1.10 g/mL, and there are 5.0 mL per teaspoon. What is the mass (in grams) of the medicine given?
8.25 g
1.5×5.0=7.5 mL
1.10×7.5=8.25 g
What is the formula for the ionic compound formed with potassium and sulfate?
K₂SO₄
What is the molecular geometry, bond angle, polarity, and IMFs in phosphorus trichloride?
trigonal pyramidal; 109; polar; london dispersion and dipole dipole
How many H atoms are present in 0.340 mol NH₃?
6.14×1023 H atoms
0.340 mol NH3 × (3 mol H/1 mol NH₃) x (6.02 ×1023 atoms/mol)
Identify the reaction type for Fe(s) + CuSO₄(aq) → FeSO₄(aq) + Cu(s)
(combination, decomposition, combustion, single replacement, or double replacement).
single replacement