I believe the answer is D) 2
Answer: the percent composition of carbon in heptane is 83.9%
Explanation:
<u>1) Atomic masses of the atoms:</u>
<u>2) Molar mass of heptane:</u>
- C₇H₁₆: 7 × 12.01 g/mol + 16×1.008 g/mol = 100.2 g/mol
<u>3) Mass of carbon in one mole of heptane:</u>
- C₇: 7 × 12.01 g/mol = 84.07 g/mol
<u>3) Percent composition of carbon:</u>
- % = (mass in grams of C) / (mass in grams of C₇H₁₆) × 100 =
= (84.07 g/ 100.2 g) × 100 = 83.9% ← answer
Answer:
D) N2O5
Explanation:
The molar mass of a substance is defined as the mass of this substance in 1 mol. To solve this question we must find the molar mass of each option:
<em>Molar mass NO:</em>
1N = 14g/mol*1
1O = 16g/mol*1
14+16 = 30g/mol
<em>Molar mass NO2:</em>
1N = 14g/mol*1
2O = 16g/mol*2
14+32 = 46g/mol
<em>Molar mass N2O:</em>
2N = 14g/mol*2
1O = 16g/mol*1
28+16 = 44g/mol
<em>Molar mass N2O5:</em>
2N = 14g/mol*2
5O = 16g/mol*5
28+80 = 108g/mol
That means the compound with the greatest mass is:
<h3>D) N2O5</h3>
I suppose that the answer is A
