1.) Calculate the molar mass of barium sulfate

1.) Calculate the molar mass of barium sulfate, BaSO4. a.) 233.4 g/mol b.) 217.4 g/mol c.) 104.0 g/mol d.) 96.0 g/mol 2.) Calculate the molar mass of lead (IV) oxalate, Pb(C2O4)2. a.) 235.21 g/mol b.) 271.24 g/mol c.) 347.21 g/mol d.) 383.24 g/mol 3.) Ethylene glycol is a coolant widely used in automobiles. If its molecular formula is C2H602, how many moles would be present if you had 2500 g of this in your vehicle? a.) 1.6 x 10$ mol b.) 2.5 x 10-2 mol c.) 40. mol d.) 62 mol 4.) Hydrogen peroxide H2O2 is commonly used to clean bacteria in scrapes and cuts. It can be used as a mouthwash and is an additive in some toothpastes. If a sample contained 5.23 x 1021 molecules of H:0, what would the equivalent be in moles? a.) 8.69 x 103 mol b.) 8.69 x 10-mol c.) 115 mol d.) 8.69 x 1043 mol 5.) Calculate the percent composition of ammonium nitrate, NH NO.. a.) 17.5 %N, 5.0%H, 77.5%O b.) 17.5 % N, 3.2% H, 51.6%O c.) 35.0%N, 1.2 % H, 57.2%O d.) None of the above English (United States) Focus LE

The correct answer and explanation is:

Here are the answers with detailed explanations:

1) Molar Mass of Barium Sulfate, BaSO₄

The atomic masses of the elements are:
- Ba = 137.33 g/mol
- S = 32.07 g/mol
- O = 16.00 g/mol (there are 4 oxygen atoms in BaSO₄)
The molar mass of BaSO₄ is calculated as: Molar Mass of BaSO₄=137.33+32.07+(4×16.00)=137.33+32.07+64.00=233.4 g/mol\text{Molar Mass of BaSO₄} = 137.33 + 32.07 + (4 \times 16.00) = 137.33 + 32.07 + 64.00 = 233.4 \, \text{g/mol} Therefore, the correct answer is a) 233.4 g/mol.

2) Molar Mass of Lead (IV) Oxalate, Pb(C₂O₄)₂

The atomic masses of the elements are:
- Pb = 207.2 g/mol
- C = 12.01 g/mol (there are 4 carbon atoms in Pb(C₂O₄)₂)
- O = 16.00 g/mol (there are 8 oxygen atoms in Pb(C₂O₄)₂)
The molar mass of Pb(C₂O₄)₂ is calculated as: Molar Mass of Pb(C₂O₄)₂=207.2+(4×12.01)+(8×16.00)\text{Molar Mass of Pb(C₂O₄)₂} = 207.2 + (4 \times 12.01) + (8 \times 16.00) =207.2+48.04+128.00=383.24 g/mol= 207.2 + 48.04 + 128.00 = 383.24 \, \text{g/mol} Therefore, the correct answer is d) 383.24 g/mol.

3) Moles of Ethylene Glycol (C₂H₆O₂) in 2500 g

The atomic masses of the elements are:
- C = 12.01 g/mol (there are 2 carbon atoms in C₂H₆O₂)
- H = 1.008 g/mol (there are 6 hydrogen atoms in C₂H₆O₂)
- O = 16.00 g/mol (there are 2 oxygen atoms in C₂H₆O₂)
The molar mass of C₂H₆O₂ is calculated as: Molar Mass of C₂H₆O₂=(2×12.01)+(6×1.008)+(2×16.00)\text{Molar Mass of C₂H₆O₂} = (2 \times 12.01) + (6 \times 1.008) + (2 \times 16.00) =24.02+6.048+32.00=62.068 g/mol= 24.02 + 6.048 + 32.00 = 62.068 \, \text{g/mol} To find the number of moles in 2500 g: Moles=2500 g62.068 g/mol≈40.2 mol\text{Moles} = \frac{2500 \, \text{g}}{62.068 \, \text{g/mol}} \approx 40.2 \, \text{mol} Therefore, the correct answer is c) 40 mol.

4) Moles of Hydrogen Peroxide (H₂O₂) in 5.23 x 10²¹ molecules

One mole of any substance contains 6.022×10236.022 \times 10^{23} molecules (Avogadro’s number). To convert molecules to moles: Moles=5.23×10216.022×1023=8.69×10−3 mol\text{Moles} = \frac{5.23 \times 10^{21}}{6.022 \times 10^{23}} = 8.69 \times 10^{-3} \, \text{mol} Therefore, the correct answer is b) 8.69 x 10⁻³ mol.

5) Percent Composition of Ammonium Nitrate, NH₄NO₃

The atomic masses of the elements are:
- N = 14.01 g/mol (there are 2 nitrogen atoms in NH₄NO₃)
- H = 1.008 g/mol (there are 4 hydrogen atoms in NH₄NO₃)
- O = 16.00 g/mol (there are 3 oxygen atoms in NH₄NO₃)
The molar mass of NH₄NO₃ is calculated as: Molar Mass of NH₄NO₃=(2×14.01)+(4×1.008)+(3×16.00)\text{Molar Mass of NH₄NO₃} = (2 \times 14.01) + (4 \times 1.008) + (3 \times 16.00) =28.02+4.032+48.00=80.052 g/mol= 28.02 + 4.032 + 48.00 = 80.052 \, \text{g/mol} The percent composition of each element is:
- Percent N = 28.0280.052×100≈35.0%\frac{28.02}{80.052} \times 100 \approx 35.0\%
- Percent H = 4.03280.052×100≈5.0%\frac{4.032}{80.052} \times 100 \approx 5.0\%
- Percent O = 48.0080.052×100≈60.0%\frac{48.00}{80.052} \times 100 \approx 60.0\%
Therefore, the correct answer is d) None of the above, since the composition does not match any given choices exactly.

Summary of Answers:

a) 233.4 g/mol
d) 383.24 g/mol
c) 40 mol
b) 8.69 x 10⁻³ mol
d) None of the above