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2 years ago

Find the molar mass of potassium dichromate, K2Cr2O7

Chemistry

1 answer:

prisoha [69]2 years ago

6 0

The molar mass of K is 39, Cr is 52, and O is 16. The rough calculation of these numbers are 294.

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Dissolving 5.28 g of an impure sample of calcium carbonate in hydrochloric acid produced 1.14 l of carbon dioxide at 20.0 Â°c an

kvv77 [185]

Answer:

Percentage by mass of calcium carbonate in the sample is 93.58%.

Explanation:

Assumptions:

calcium carbonate was dissolved completely and the amount of carbon dioxide released was proportional to the amount of calcium carbonate.
the sample did not contain any other compound that released or reacted with carbon dioxide.

$PV = nRT$

$n = \frac{PV}{RT}$

$P = 791 mmHg = \frac{791 mmHg}{760 mmHg} x 1 atm = 1.040789 atm.$

$R = 8.314 \frac{J}{K*mol} = 0.082 \frac{L*atm}{K*mol}$

$T = 20^{0}C + 273^{0} C = 293 K$

$n = \frac{1.040789 atm * 1.14 L}{0.082 \frac{L * atm}{K * mol} * 293 K }$

$n = 0.0493839 mol.$

given the equation of the reaction:

$CaCO_{3} + 2HCL = CaCl_{2} + CO_{2} + H_{2}O$

from assumption:

amount carbon dioxide = amount of calcium carbonate

$n(CaCO_{3} ) = n(CO_{2} )$

reacting mass ( m ) = Molar Mass ( M ) * Amount ( n )

$m(CaCO_{3} ) = n(CaCO_{3} ) * M(CaCO_{3} )$

m = 0.04938397 $mol$ * 100 $\frac{g}{mol}$ = 4.93839 $g$

percentage by mass of CaC $O_{3}$ = $\frac{mass of pure }{mass of impure}*100 = \frac{4.93839g}{5.28g}*100 = 93.5802%$ .

8 0

2 years ago

When drinking water, how soon does it reach the bladder.

Alex Ar [27]

Answer:

Water absorption can occur as soon as 5 minutes after ingestion and peaks around 20 minutes after ingestion.

Explanation:

3 0

1 year ago

If more solute can be dissolved in a solvent, the solution is:

iragen [17]

The answer is number 1

6 0

2 years ago

Read 2 more answers

The following chemical equations are organized by reaction type. You must balance each reaction, and show your work

sukhopar [10]

Answer:

lets be honest

Explanation:

no one knows and this is worthless to answer for the worth of 5 points

4 0

2 years ago

For the following chemical equation.

kotegsom [21]

Sr is the limiting reactant.

Given the reaction equation;

2Sr + O2 (g) → 2SrO

2 moles of Sr reacts with 1 mole of O2

2 moles Sr will react with x mole of O2

x = 2 ×1/2

x = 1 mole of O2

Since we have more O2 than required, it is the reactant in excess, hence Sr is the limiting reactant.

Learn more: brainly.com/question/14225536

5 0

2 years ago