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3 years ago

Please help and thank you

Chemistry

1 answer:

leonid [27]3 years ago

6 0

The answer is C . Hope it helps

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Calculate the molarity when 135 g of KCl is dissolved to make a 2.50 L solution. Round to two significant digits.

inysia [295]

Explanation:

$\textrm{Molarity of a solution}=\frac{\textrm{Number of moles of solvent}}{\textrm{Volume of solution in Liters}}$

We are given a $2.50L$ solution which contains $135g$ of $KCl$ .

To calculate number of moles of $KCl$ present, we need to find it's molar mass from charts. Molar Mass of $KCl$ is known to be $74.55\frac{g}{Mol}$ .

Number of moles of $KCl$ present = $\frac{\textrm{Given weight}}{\textrm{Molar Mass}}\textrm{ = }\frac{135g}{74.55\frac{g}{Mol}}\textrm{ = }1.81087mol$

Molarity = $\frac{1.81087mol}{2.50L}=0.7243\frac{mol}{L}$

∴ Molarity of given $KCl$ solution = $0.72\frac{mol}{L}$

7 0

3 years ago

the comparison of the number of atoms in a copper coin the size of a penny with the number of people on earth is made to illustr

vampirchik [111]

The atoms are very small hope this helps.

5 0

3 years ago

Read 2 more answers

Which feature is one of the defining features of a hurricane?

Sauron [17]

Answer:

low pressure

Explanation:

it will draw in warm water and air.

5 0

2 years ago

The thin outer layer of Earth, called the crust, contains only 0.50 percent of Earth's total mass and yet is the source of almos

Rzqust [24]

Answer:

The mass of silicon in kilograms in Earth's crust is $7.2729\times 10^{21} kg$ .

Explanation:

Mass of Earth = $5.9\times 10^{21} tons$

(1 ton= 2000 lb)

(1 lb =453.6 g)

1 ton = 2000 × 453.6 g =907,200 g

Mass of Earth = $5.9\times 10^{21}\times 907,200 g=5.3524\times 10^{27} g$

Percentage of earth crust = 0.50%

Mass of earth crust = M

$0.50\%=\frac{M}{5.3524\times 10^{27}}\times 100$

$M=2.6762\times 10^{25} g$

Percentage of the silicon in Earth's crust = 27.2 %

Mass of silicon in in Earth's crust = m

$Si\%=\frac{m}{M}\times 100$

$27.2\%=\frac{m}{2.6762\times 10^{25} g}\times 100$

$m = 7.2792\times 10^{24} g=7.2729\times 10^{21} kg$

1000 g = 1 kg

The mass of silicon in kilograms in Earth's crust is $7.2729\times 10^{21} kg$ .

7 0

3 years ago

Help question 9 is due today also :)

devlian [24]

Answer:

Car 3 with a net force of 12N

Explanation:

The formula is F=MA

Hope this helps friend

8 0

3 years ago