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grigory [225]
3 years ago
11

A 78.0 g sample of an unknown compound contains 12.4 g of hydrogen. what is the percent by mass of hydrogen in the compound?

Chemistry
2 answers:
Harman [31]3 years ago
7 0

Answer:

The percentage by mass of hydrogen in the unknown compound is 15.9 %

Explanation:

The formula to be used here is

% by mass of an element in a compound =

(molar mass of the element ÷ molar mass of the compound) × 100

From the question, the mass of the element (Hydrogen) is <u><em>12.4 g</em></u>

The mass of the compound (unknown) is <u><em>78.0 g</em></u>

Hence,

% by mass of hydrogen in the unknown compound = (12.4 ÷ 78) × 100

= 15.9 %

AleksandrR [38]3 years ago
5 0
Formula to find the percent composition of an element in a compound is \frac {MolarMassOfElement}{MolarMassOfCompound}*100.

Now enter the variables into the formula.

\frac {12.4}{78.0}*100 = 15.897%
Round to 3 significant figures. 15.897% = 15.9%

The answer is 15.9% H
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Explanation:

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3 years ago
Propane gas, C3H8, is sometimes used as a fuel. In order to measure its energy output as a fuel a 1.860 g sample was combined wi
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Answer:

The heat of the reaction is 105.308 kJ/mol.

Explanation:

Let the heat released during reaction be q.

Heat gained by water: Q

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Heat capacity of water ,c= 4.184 J/g°C

Change in temperature = ΔT = 26.061°C - 25.000°C=1.061 °C

Q=mcΔT

Heat gained by bomb calorimeter =Q'

Heat capacity of bomb calorimeter ,C= 4.643 J/g°C

Change in temperature = ΔT'= ΔT= 26.061°C - 25.000°C=1.061 °C

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Total heat released during reaction is equal to total heat gained by water and bomb calorimeter.

q= -(Q+Q')

q = -mcΔT - CΔT=-ΔT(mc+C)

q=-1.061^oC(1000 g\times 4.184J/g^oC+4.643 J/^oC )=-4,444.15J=-4.444 kJ

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The heat of the reaction will be:

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3 0
3 years ago
Baking soda, NaHCO3, can be commercially produced during a series of chemical reactions called the Solvay process. In this proce
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Answer:

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Explanation:

The solvay process is an important process in the chemical industry. In this process, ammonia gas is first dissolved in concentrated brine to form a mixture known as ammoniacal brine. This solution is made to trickle down the tower. A counter stream of carbon dioxide is forced up the tower. The two substances react to form sodium hydrogen trioxocarbonate IV. This substance is only slightly soluble and separates out as a solid sludge. The product is now dried and heated to give sodium trioxocarbonate IV.

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Calcium chloride is merely a by-product.

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3 years ago
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