Which substance is not a solid at 20˚C and one atmosphere of pressure?

2H2+ O2 —> 2H2 O

lukranit [14]

Answer:bubuvuvuvftctcrchj

Explanation:

8 0

3 years ago

16.6g CaCl2 dissolved in water and completely dissociates. The molality of chloride ions in 300g of water is

vova2212 [387]

Answer:

— The molality of chloride ions in 300g of water is. A) 1.00 molal. B) 0.500 molal. C) 0.0553 molal. D) 0.111 molal.

3 0

3 years ago

What is thermal energy?

timurjin [86]

Thermal energy is THE MEASURE OF TEMPERATURE IN A SYSTEM.
Thermal energy refers to the internal energy that is present in a system as a result of its temperature. The motion of the particles of an object depends on the temperature of the object and the higher the temperature, the faster the movement of the particles. The reverse is also true.

7 0

3 years ago

Read 2 more answers

Hydrogen fluoride is used in the manufacture of Freons (which destroy ozone in the stratosphere) and in the production of alumin

Lerok [7]

<u>Answer:</u> The percentage yield of HF is 73.36 %

<u>Explanation:</u>

To calculate the number of moles, we use the equation:

$\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}$ ....(1)

For calcium fluoride:

Given mass of calcium fluoride = 6.25 kg = 6250 g (Conversion factor: 1 kg = 1000 g)

Molar mass of calcium fluoride = 78.07 g/mol

Putting values in above equation, we get:

$\text{Moles of calcium fluoride}=\frac{6250g}{78.07g/mol}=80.05mol$

For the given chemical reaction:

$CaF_2+H_2SO_4\rightarrow CaSO_4+2HF$

By Stoichiometry of the reaction:

1 mole of calcium fluoride produces 2 moles of hydrofluoric acid

So, 80.05 moles of calcium fluoride will produce = $\frac{2}{1}\times 80.05=160.1mol$ of hydrofluoric acid

Now, calculating the theoretical yield of hydrofluoric acid using equation 1, we get:

Moles of of hydrofluoric acid = 160.1 moles

Molar mass of hydrofluoric acid = 20.01 g/mol

Putting values in equation 1, we get:

$160.1mol=\frac{\text{Theoretical yield of hydrofluoric acid}}{20.01g/mol}=3203.6g=3.20kg$

To calculate the percentage yield of hydrofluoric acid, we use the equation:

$\%\text{ yield}=\frac{\text{Experimental yield}}{\text{Theoretical yield}}\times 100$

Experimental yield of hydrofluoric acid = 2.35 kg

Theoretical yield of hydrofluoric acid = 3.20 kg

Putting values in above equation, we get:

$\%\text{ yield of hydrofluoric acid}=\frac{2.35g}{3.20g}\times 100\\\\\% \text{yield of hydrofluoric acid}=73.36\%$

Hence, the percentage yield of HF is 73.36 %

4 0

3 years ago

What is the mass of a cube of aluminum that is 3.0 cm on each edge? The density of aluminum is 2.7 g/cm3.

n200080 [17]

Do you know the formula? I can’t find it.

8 0

3 years ago