Please help me! Thank you!

What is the best conclusion according to the energy diagram of the chemical reaction?

Rashid [163]

Answer:

The reaction will absorb energy

Explanation:

A potential energy diagram shows the energy changes that occur during a chemical reaction. It is also called a reaction progress curve. The diagram shows the changes that occur as reactants are converted into products.

The best conclusion according to the energy diagram of the chemical reaction is that the reaction will absorb energy.

5 0

3 years ago

PLEASE HELP!!

uranmaximum [27]

Answer: - 25.8 kJ

The overall process of interest in the question is the following

Hg (g) (650 K) → Hg (l) (297 K)

However, for mercury to pass from a gaseous state in 650 K to a liquid state in 297 K, it must go through a series of steps:

Step 1. Gaseous mercury at 650 K should cool down to 629.88 K, temperature corresponding to the vaporization temperature of this substance.

Step 2. Gaseous mercury goes to liquid state at 629.88 K .

Step 3. The liquid mercury at 629.88 K is cooled until it reaches 297 K.

This series of steps can be represented through the following diagram:

Hg (g) (650 K) → Hg (g) (629.88 K) → Hg (l) (629.88 K) → Hg (l) (297 K)

(1) (2) (3)

Then the total heat involved in the process will be equal to the sum of the heats inherent to steps 1, 2 and 3. We proceed to calculate the heats for each of the steps.

Step 1:

The heat in step 1 will be given by

Q = n Cp ΔT

where n is the number of moles of mercury, Cp is the heat capacity and ΔT is equal to the difference between the temperatures at the end (T₂) and at the beginning of the process (T₁), that is to say

ΔT = T₂ - T₁

You should know that the heat capacity or thermal capacity is the energy needed to increase the temperature of a certain substance in a unit of temperature. The heat capacity of mercury is Cp = 27.983 J / mol K

Then the heat in step 1 will be,

Q₁ = 75.0 g x $\frac{1 mol}{200.59 g}$ x 27.983 $\frac{J}{mol K}$ x (629.88 K - 650 K)

→ Q₁ = - 210.5 J

Step 2:

In this step a change in the state of the mercury occurs, since it condenses from a gaseous state to a liquid state. In this case the heat involved in the process will be given by ,

Q = - n ΔHvap

where ΔHvap is the enthalpy of vaporization. The enthalpy of vaporization is the amount of energy necessary for the mass unit of a substance that is in equilibrium with its own vapor at a pressure of one atmosphere to pass completely from the liquid state to the gaseous state. Therefore, to determine the energy necessary for the mercury to pass from gaseous state to liquid, the negative of the enthalpy of vaporization must be taken, as it is done in the previous equation with the minus sign that is placed.

The enthalpy of vaporization of mercury is ΔHvap = 59.11 kJ/mol

Then the heat in step 2 will be,

Q₂ = - 75.0 g x $\frac{1 mol}{200.59 g}$ x 59.11 $\frac{kJ}{mol}$

→ Q₂ = 22.10 kJ → Q₂ = 22100 J

Step 3:

The heat in step 3 will be

Q₃ = n Cp ΔT = 75.0 g x $\frac{1 mol}{200.59 g}$ x 27.983 $\frac{J}{mol K}$ x (297 K - 629.88 K)

→ Q₃ = - 3483 J

Finally the heat involved in the overall process will be ,

Q = Q₁ + Q₂ + Q₃ = - 210.5 J - 22100 J - 3483 J = - 25794 J

→ Q = - 25.8 kJ

So, the heat lost when 75.0 g of mercury vapor at 650 K condenses to a liquid at 297 K is - 25.8 K

3 0

3 years ago

Assume that a milliliter of water contains 20 drops. How long, in hours, will it take you to count the number of drops

garri49 [273]

Answer:

126.18 hr

Explanation:

Data given:

1 mL of water = 20 drops

count rate = 10 drops/s

time in hours for one gallon = ?

Solution:

First we calculate number of mL (milliliter) of water in gallon

As we know

1 gallon = 3785.4 mL

As,

1 galon consist of 3785.4 mL of water, so now we count number of drops that contain 3785.4 mL of water

As we Know 1 mL water contain 20 drops then 3785.4 mL of water contain how many drops:

Apply unity formula

1 mL water ≅ 20 drops

3785.4 mL water ≅ X drops

Do cross multiplication

X drops of water = 20 drops x 3785.4 mL / 1 mL

X drops of water = 75708 drops

So, we come to know that one gallon contain 75708 drops of water and we have to calculate the time in hour to count these drops

First we calculate time in seconds

As we Know 10 drops water count in one second then how many seconds it will take to count 75708 drops

Apply unity formula

1 second ≅ 10 drops

X second ≅ 75708 drops

Do cross multiplication

X second = 1 second x 75708 drops / 10 drops

X second = 7570.8 second

So it take 7570.8 second to count 1 gallon water drops

Now convert seconds to hours

As,

60 seconds = 1 hr

7570.8 second = 7570.8 / 60 = 126.18 hr

So it take 126.18 hr to count 1 gallon water drops.

6 0

4 years ago

What mass (g) of potassium chloride is contained in 430.0 mL of a potassium chloride solution that has a chloride ion concentrat

fredd [130]

Answer:

6.178 g.

Explanation:

KCl is ionized in the solution as:

KCl → K⁺ + Cl⁻.

∴ [KCl] = [K⁺] = [Cl⁻] = 0.193 M.

Molarity is defined as the no. of moles of the solute per 1.0 L of the solution.

∵ M = [(mass/molar mass)KCl][(1000)/(V of the solution)].

∴ mass of KCl = (M)(molar mass of KCl)(V of the solution)/1000 = (0.193 M)(74.55 g/mol)(430.0 mL)/1000 = 6.178 g.

8 0

3 years ago

How much water should be mixed with 237 ml of ammonia, whose strength is 100%, in order to create a mixture that is diluted to

azamat

Answer

79 ml

Explanation

You have 237 237 ml of ammonia, whose strength is 100%.

If you want to make it 75%, then;

let 75% ⇒ 237 ml of ammonia and

25% ⇒ x ml of water.

∴ x = (25% ×237) / 75%

= 5,925/75

= 79 ml of water.

8 0

4 years ago

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