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3 years ago

What is the energy change if 84.0 g of calcium oxide (CaO) reacts with excess water in the following reaction?

1 answer:

6 0

The energy change if 84.0 g of CaO react with excess water is 98KJ of heat is released.

calculation
heat = number of moles x delta H

delta H = - 65.2 Kj/mol

first find the number of moles of CaO reacted

moles = mass/molar mass
the molar mass of CaO = 40 + 16= 56 g/mol
mass = 84 g
moles therefore = 84 g/56 g/mol =1.5 moles

Heat is therefore = 1.5 moles x -65.2 = - 97.8 Kj = -98 Kj

since sign is negative the energy is released

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3 years ago

A compound of a transition metal and iodine is 56.7% metal by mass.How many grams of the metal can be obtained from 630 g of thi

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Answer:

357 g of the transition metal are present in 630 grams of the compound of the transition metal and iodine

Explanation:

In any sample of the compound, the percentage by mass of the transition metal is 56.7%. This means that for a 100 g sample of the compound, 56.7 g is the metal while the remaining mass, 43.3 g is iodine.

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3 years ago

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2 years ago

Determine the formula weights of each of the following compounds.Part A) Nitrous oxide, N2O, known as laughing gas and used as a

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Answer:

See explanation

Explanation:

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Percentage nitrogen = (2*14.007 amu/ 44.014 amu ) *100% = 63.6%

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Percentage oxygen = (16 amu/60.064amu)*100% = 26.6%

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Percentage hydrogen = (14*1.01 amu/130.2 amu)*100% = 10.8%

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Percentage oxygen =(2*16 amu/130.2 amu)*100% = 24.6%

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2 years ago

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