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4 years ago

A solution with the concentration of 0.15 M is made using 8.00 grams of K2CrO4. How many milliliters of H2O should be used?

Chemistry

1 answer:

babymother [125]4 years ago

6 0

Answer:

274.7mL

Explanation:

Molarity is defined as the number of mols of solute per liter of the solvent. Here, the solute is potassium chromate ( $K_{2}CrO_{4}$ ) and the solvent is water. Hence, molarity is defined as the number of mols of potassium chromate per litre of water. And this molarity is equal to 0.15M.

Now, the molar mass of potassium chromate can be found by simply adding the atomic masses of the component atoms. This is equal to : 2×atomic mass of potassium + 1×atomic mass of chromium + 4×atomic mass of oxygen = 2×39 + 52 + 4×16 = 194g /mol.

The number of mols of potassium chromate is the ratio of the given mass of potassium chromate to the molar mass of potassium chromate.

Here, this is equal to $\frac{8}{194}$ = 0.0412 mols.

This much potassium chromate is present in 'V' litres of water. Hence, molarity is given by : 0.15 = $\frac{0.0412}{V}$ .

Thus, V = $\frac{0.0412}{0.15}$ = 0.2747L = 274.7mL

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Answer:

in an atom or molecule, no two electrons can have the same four electronic quantum numbers. As an orbital can contain a maximum of only two electrons, the two electrons must have opposing spins.

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3 years ago

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algol13

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3 years ago

the pressure in a sealed plastic container is 108 kPa at 41 degrees Celsius. What is the pressure when the temperature drops to

Katarina [22]

<u>Answer:</u> The new pressure will be 101.46 kPa.

<u>Explanation:</u>

To calculate the new pressure, we use the equation given by Gay-Lussac Law. This law states that pressure is directly proportional to the temperature of the gas at constant volume.

The equation given by this law is:

$\frac{P_1}{T_1}=\frac{P_2}{T_2}$

where,

$P_1\text{ and }T_1$ are initial pressure and temperature.

$P_2\text{ and }T_2$ are final pressure and temperature.

We are given:

By using conversion factor: $T(K)=T(^oC)+273$

$P_1=108kPa\\T_1=41^oC=314K\\P_2=?kPa\\T_2=22^oC=295K$

Putting values in above equation, we get:

$\frac{108kPa}{314K}=\frac{P_2}{295K}\\\\P_2=101.46kPa$

Hence, the new pressure will be 101.46 kPa.

3 0

3 years ago

Calculate the number of moles in 9 g of water

tangare [24]

Answer:

= 0.5 moles of water

$formular \: mass \: of \: water \: = (2 \times 1) + 16 = 18 \\ 18g \: of \: water \: are \: weighed \: by \: 1 \: mole. \\ 9g \: will \: be \: weighed \: by \: \frac{9 \times 1}{18} \\ = \frac{9}{18} moles \\ = 0.5 \: moles \: of \: water$

7 0

3 years ago

Read 2 more answers

Write the beta decay equation for the following isotope: 15/6 C?

vesna_86 [32]

Answer:

$\rm _{6}^{15}\text{C} \longrightarrow \, _{-1}^{0}\text{e} + \, _{7}^{15}\text{N}$

Explanation:

The unbalanced nuclear equation is

$\rm _{6}^{15}\text{C} \longrightarrow \, _{-1}^{0}\text{e} + \, ?$

Let's write the question mark as a nuclear symbol.

$\rm _{6}^{15}\text{C} \longrightarrow \, _{-1}^{0}\text{e} + \, _{Z}^{A}\text{X}$

The main point to remember in balancing nuclear equations is that the sums of the superscripts and the subscripts must be the same on each side of the equation.

Then

15 = 0 + A, so A = 15 - 0 = 15, and

6 = -1 + Z, so Z = 6 + 1 = 7

Then, your nuclear equation becomes

$\rm _{6}^{15}\text{C} \longrightarrow \, _{-1}^{0}\text{e} + \, _{7}^{15}\text{X}$

Element 7 is nitrogen, so the balanced nuclear equation is

$\rm _{6}^{15}\text{C} \longrightarrow \, _{-1}^{0}\text{e} + \, _{7}^{15}\text{N}$

8 0

4 years ago