Answer:

Explanation:
Given the moles, we are asked to find the mass of a sample.
We know that the molar mass of methanol is 32.0 grams per mole. We can use this number as a fraction or ratio.

Multiply by the given number of moles, which is 2.0

The moles of methanol will cancel each other out.

The denominator of 1 can be ignored.

Multiply.

There are 64 grams of methanol in the sample.
Answer:
0.12 mol KCl
Explanation:
2 KClO3 (s) 2 KCl (s) + 3 O2 (g)
15 g x mol
x g KCl = 15 g KClO3 x[ (1 mol KClO3)/ (122.5 g KClO3) ] x [(2 mol KCl)/ (2 mol KClO3)]
x g KCl = 0.12 mol KCl
The reaction between boron sulfide and carbon is given as:
2B2S3 + 3C → 4B + 3CS2
As per the law of conservation of mass, for any chemical reaction the total mass of reactants must be equal to the total mass of the products.
Given data:
Mass of C = 2.1 * 10^ 4 g
Mass of B = 3.11*10^4 g
Mass of CS2 = 1.47*10^5
Mass of B2S3 = ?
Now based on the law of conservation of mass:
Mass of B2S3 + mass C = mass of B + mass of CS2
Mass of B2S3 + 2.1 * 10^ 4 = 3.11*10^4 + 1.47*10^5
Mass of B2S3 = 15.7 * 10^4 g
Answer: the empirical formula is C3H4O3
Explanation:Please see attachment for explanation
3.25 kg in g = 3.25 * 1000 = 3250 g
Molar mass C₂H₆O₂ = 62.0 g/mol
Mass solvent = 7.75 kg
Number of moles:
n = mass solute / molar mass
n = 3250 / 62.0
n = 52.419 moles
Molality = moles of solute / kilograms of solvent
M = 52.419 / 7.75
M = 6.7637 mol/kg
hope this helps!