A mixture of potassium bromide and potassium hydroxide has a total mass of 5.50 g. if the mixture contains 2.45 g k, what is the mass in grams of potassium hydroxide in the mixture? give the numerical part of your answer only; don't include the units.

Question

Chemistry

Mendoza

23 January, 22:33

A mixture of potassium bromide and potassium hydroxide has a total mass of 5.50 g. if the mixture contains 2.45 g k, what is the mass in grams of potassium hydroxide in the mixture? give the numerical part of your answer only; don't include the units.

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Answers (1)

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Nash Rios · Answer 1

Answer is: mass in grams of KOH is 1,68.

m (KBr + KOH) = 5,50 g.

m (K) = 2,45 g.

M (KBr) = 39 g/mol + 80 g/mol = 119 g/mol.

M (KOH) = 39 g/mol + 16 g/mol + 1 g/mol = 56 g/mol.

ω (K) = 2,45 g : 5,50 g.

ω (K) = 0,445 = 44,5%.

n (K) = m (K) : M (K).

n (K) = 2,45 g : 39 g/mol.

n (K) = 0,062 mol.

m (Br + OH) = 5,50 g - 2,45 g = 3,05 g.

n (K) = n (KBr + KOH) = 0,062 mol.

M (KBr + KOH) = 5,50 g : 0,062 mol = 88,7 g/mol.

Set two equations:

1) m (KBr) + m (KOH) = 5,50 g.

2) m (KBr) / M (KBr) + m (KOH) / M (KOH) = 0,062 mol.

m (KOH) = 5,50 g - M (KBr), put that in second equation.

m (KBr) = 3,82 g.

m (KOH) = 5,50 g - 3,82 g = 1,68 g.