Help me Plz, I am really confused

chemistry student needs of thiophene for an experiment. She has available of a w/w solution of thiophene in carbon tetrachloride

kumpel [21]

The question is incomplete, here is the complete question:

A chemistry student needs 75 g of thiophene foran experiment. He has available 0.50 kg of a 29.3% w/w solution of thiophene in carbon tetrachloride.

Calculate the mass of solution the student should use. If there's not enough solution, press the "No solution" button.

Answer: The mass of solution the student should use is 255.97 grams

Explanation:

We are given:

Mass of thiophene needed = 75 gram

29.3 % w/w thiophene solution

This means that 29.3 grams of thiophene is present in 100 grams of solution

Applying unitary method:

If 29.3 grams of thiophene is present in 100 grams of solution

So, 75 grams of thiophene will be present in = $\frac{100}{29.3}\times 75=255.97g$

Given amount of solution = 0.50 kg = 500 grams (Conversion factor: 1 kg = 1000 g)

Hence, the mass of solution the student should use is 255.97 grams

4 0

3 years ago

Glycerol (molar mass 92.09 g/mol) has been suggested for use as an alternative fuel. The enthalpy of combustion, Δ

victus00 [196]

The mass of glycerol to that would need to be combusted to heat 500.0g of water from 20.0°C to 100.0°C is; 9.32 grams.

We must establish the fact that energy is neither created nor destroyed.

Therefore, the amount of heat absorbed by water is equal to the amount of heat released by the combustion of glycerol.

Total heat absorbed by water, H(water) is;

Q(water) = m C (T2 - T1)

Q(water) = 500 × 4.184 × (100-20)

Q(water) = 167.36 kJ

Consequently, the quantity of heat evolved by the combustion of glycerol is;

Q(glycerol) = 167,360 J = n × ΔH°comb

where, n = no. of moles of glycerol.

167.36 kJ= n × 1654 kJ/mole

n = 167.36/1654

n = 0.1012 moles of glycerol.

Therefore, mass of glycerol combusted, m is;

m = n × Molar mass

m = 0.1012 × 92.09

m = 9.32 g.

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6 0

3 years ago

Arrange the events in the life of a star in the correct order.

tatiyna

Answer:

1. The temperature increases in the center of a nebula, and nuclei begin to fuse.

2. As the nuclear fusion sets off a chain reaction, the nebula gets hotter and brighter and turns into a star.

3. The star stays in the main sequence stage for a long time.

4. The star runs out of hydrogen and turns into a planetary nebula or a supernova, depending on its mass.

5. Heavy elements are created when the supernova explodes.

6. All that remains of the star now is the core. In some cases, the star turns into a black hole.

Explanation:

3 0

3 years ago

Name four products of incomplete combustion Which four?

Y_Kistochka [10]

Answer:

1. Carbon Monoxide

2.Water

3. sulfuric acid

4.sulfur dioxide

Explanation:

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8 0

4 years ago

Molecular compounds are composed of what particles?

olga nikolaevna [1]

Answer:

Explanation:

A binary molecular compound is a molecular compound that is composed of two elements. In general, the elements that combine to form binary molecular compounds are both nonmetals. This contrasts with ionic compounds, which usually involve bonds between metal ions and nonmetal ions.

3 0

3 years ago