University:
University of North Carolina at Charlotte
Course:
CHEM 1251 | General Chemistry I
Academic year:

2024
Views:

333

Pages:

8
Author:

Kamila P.

ALEKS #8 1. SrS (chemical formula) Sr: 87.62 g/mol S: 32.07 g/mol Molar mass of SrS: 87.62 + 32.07 = 119.69 g/mol 0.0900 moles * 119.69 g/mol = 10.8 g of SrS 2. HF (hydrogen fluoride) 115 g of hydrogen fluoride ? number of moles Molar mass: 1.00784 g/mol + 18.99840316 g/mol = 20.00624316 g/mol 115 g / 20.00624316 g/mol = 5.75 mol of hydrogen fluoride 3. HBr 0.080 moles ? grams Molar mass: 1.00784 g/mol + 79.904 g/mol = 80.91184 g/mol 0.080 moles * 80.91184 g/mol = 6.59 g 4. NaCl 18 g ? number of moles Molar mass: 22.989768 g/mol + 35.453 g/mol = 58.443 g/mol 18 g / 58.443 g/mol = 0.31 mol RbCl 0.050 moles ? mass Molar mass = 85.4678 g/mol + 35.453 g/mol = 120.9138 × 10⁻¹ g/mol 0.050 moles * 1.209138 × 10² g/mol = 6.09 g Finding moles from chemical formula: 1. (CH₃CH₂)NH₂ 4C: 4(12.01 g/mol) = 48.04 g/mol 11H: 11(1.008 g/mol) = 11.088 g/mol N: 14.01 g/mol Total: 73.138 g/mol 2. Zn(NO₃)₂ Zn: 65.38 g/mol 2N: 2(14.01 g/mol) = 28.02 g/mol 6O: 6(16.00 g/mol) = 96.00 g/mol Total: 189.4 g/mol 3. (CH₃CH₂)₂SO 4C: 4(12.01 g/mol) = 48.04 g/mol 10H: 10(1.008 g/mol) = 10.08 g/mol S: 32.07 g/mol O: 16.00 g/mol Total: 106.23 g/mol 4. (CH₃)₃COH 10H: 10(1.008 g/mol) = 10.08 g/mol 4C: 4(12.01 g/mol) = 48.04 g/mol O: 16.00 g/mol Total: 74.12 g/mol Counting Valence Electrons: SF₆: S: 6 × 1 = 6 F: 6 × 7 = 42 Total Valence Electrons: 48 CO₃²⁻: C: 1 × 4 = 4 O: 3 × 6 = 18 Total Valence Electrons: 22 + 2 = 24 (CH₃)₃C⁺: 4C: 4 × 4 = 16 9H: 9 × 1 = 9 Total Valence Electrons: 35 - 1 = 24 (CH₃)₃COH: 10H: 10 × 1 = 10 4C: 4 × 4 = 16 O: 1 × 6 = 6 Total Valence Electrons: 32 CH₃COO⁻: 2C: 2 × 4 = 8 3H: 3 × 1 = 3 2O: 2 × 6 = 12 Total Valence Electrons: 23 + 1 = 24 Finding Mass Percent from Chemical Formula: Zr(BrO₃)₂ Zr: 1 mol × 65.38 g/mol = 65.38 g 2Br: 2 mol × 79.90 g/mol = 159.81 g 6O: 6 mol × 16.00 g/mol = 96.00 g Total Mass: 321.18649 g Mass percent of Zr: 65.38 g / 321.18649 g = 0.2037 ≈ 20% Mass percent of Br: 159.81 g / 321.18649 g = 0.4975 ≈ 50%