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3 years ago

Which of the following represents an endothermic reaction?

Chemistry

1 answer:

Softa [21]3 years ago

8 0

Answer:

<h2>ANSWER</h2>

The second one would be one of the application of an endothermic reaction as because endothermic reaction always have the heat in the process to mix the reactants and form the products as here in a burning wood when the wood is supplied with heat then it change into products as ashes and smoke fumes So here due to the heat is involved to form the products thats the reaction is endothermic reaction.

Hope it helps

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Toluene (C6H5CH3 ), an organic compound often used as a solvent in paints, is mixed with a similar organic compound, benzene (C6

Sergeeva-Olga [200]

Explanation:

The given data is as follows.

Weight of solute = 75.8 g, Molecular weight of solute (toulene) = 92.13 g/mol, volume = 200 ml

Therefore, molarity of toulene is calculated as follows.

Molarity = $\frac{\text{weight of solute}}{\text{molecular weight of solute}} \times \frac{1000}{\text{volume of solution in ml}}$

= $\frac{75.8 g}{92.13 g/mol} \times \frac{1000}{200 ml}$

= 4.11 M

Hence, molarity of toulene is 4.11 M.

As molality is the number of moles of solute present in kg of solvent.

So, we will calculate the molality of toulene as follows.

Molality = $\frac{\text{given weight of solute}}{\text{given molecular weight of solute}} \times \frac{1000}{\text{weight of solvent in grams}}$

= $\frac{75.8 g}{92.13 g/mol} \times \frac{1000}{95.6 g}$

= 8.6 m

Hence, molality of given toulene solution is 8.6 m.

Now, calculate the number of moles of toulene as follows.

No. of moles = $\frac{mass}{\text{molar mass}}$

= $\frac{75.8 g}{92.13 g/mol}$

= 0.8227 mol

Now, no. of moles of benzene will be as follows.

No. of moles = $\frac{mass}{\text{molar mass}}$

= $\frac{95.6 g}{78.11 g/mol}$

= 1.2239 mol

Hence, the mole fraction of toulene is as follows.

Mole fraction = $\frac{\text{moles of toulene}}{\text{total moles}}$

= $\frac{0.8227 mol}{(0.8227 + 1.2239) mol}$

= 0.402

Hence, mole fraction of toulene is 0.402.

As density of given solution is 0.857 $g/cm^{3}$ so, we will calculate the mass of solution as follows.

Density = $\frac{mass}{volume}$

0.857 $g/cm^{3}$ = $\frac{mass}{200 ml}$ (As 1 $cm^{3}$ = 1 g)

mass = 171.4 g

Therefore, calculate the mass percent of toulene as follows.

Mass % = $\frac{\text{mass of solute}}{\text{mass of solution}} \times 100$

= $\frac{75.8 g}{171.4 g} \times 100$

= 44.22%

Therefore, mass percent of toulene is 44.22%.

8 0

4 years ago

Iron has a density of 7.87 g/cm3. What is the volume in cm3 of 3.729 g of iron?

KIM [24]

If iron has a density of 7.87g/cm³ and a mass of 3.729g, then the volume of iron is 0.474cm³

HOW TO CALCULATE VOLUME:

The volume of a substance can be calculated by dividing the mass by its density. That is;

Volume (mL) = mass (g) ÷ density (g/mL)

The density of iron is given as 7.87g/cm³ while its mass is 3.729g of iron. Hence, the volume can be calculated as follows:

Volume = 3.729 ÷ 7.87

Volume = 0.474cm³

Therefore, the volume of iron is 0.474cm³

Learn more: brainly.com/question/2040396?referrer=searchResults

6 0

2 years ago

A beam balance is called a first class lever why?

Dmitriy789 [7]

Answer:

A beam balance is an example of a first class lever.

Explanation:

A beam balance is an example of a first class lever. In a first class lever, the fulcrum is between the effort (force) and the load. The effort (force) moves over a large distance to move the load a smaller distance.

Other examples of first class lever are pliers, scissors, a crow bar, a claw hammer, a see-saw and a weighing balance etc.

8 0

3 years ago

A teardrop-shaped hill that points the direction a glacier has flowed is a:

mote1985 [20]

The answer is A Drumlin

3 0

4 years ago

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1. How is a bicycle race like a chemical reaction? The Tour de France is one of the most famous bicycle races in the world. It i

MrRa [10]

During the riding of the steep mountain, the body needs more energy because going up consume more energy and oxygen due to additional effect of gravity on your momentum.

<h3>What is the effect of cycling?</h3>

Cycling is a good exercise as swimming, while cycling, happy hormones are released like dopamine and serotonin.

The primary forces that work while cycling are gravity, friction, rolling resistance, and air resistance.

Thus, During the riding of the steep mountain, the bod needs more energy because going up consume more energy and oxygen due to additional effect of gravity on your momentum.

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4 0

2 years ago