To find them you would have numbers of the elements in percentage or grams then you divide them by their molar mass to get their moles. From there you divide by the smallest number. Round it to two or one sig fig. If you have a number that is for ex. 2.5 you multiply it by 2 to make it whole as well the other whole numbers. Then to find the molecular formula the problem must give you another molar mass and using your empirical formula convert it to its molar mass then you divide them, larger number over smaller number. You should get a number round it to 1 sig fig. Now you use that number and multiply the subscripts on the empirical formula to get the molecular formula.
Decreased, this is due to the roots of the plants holding the soil together
Answer:
118750 ml
Explanation:
The chemical equation for complete combustion of hexane is given as;
2C6H14 + 19O2 → 12CO2 + 14H2O
From the equation of the reaction;
2 mol of C6H14 reacts with 19 mol of O2
2 ml of C6H14 reacts with 19 ml of O2
2500 mL of C6H14 would react with x ml of O2
2 = 19
2500 = x
x = 2500 * 19 / 2 = 23750 ml
Since oxygen is 20% of air;
23750 = 20 / 100 * (Volume of air)
Volume of air = 23750 * 100 / 20 = 118750 ml
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
