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2 years ago

Using the temperature change provided, which of the following best describes the direction of energy flow in this reaction

Chemistry

2 answers:

kherson [118]2 years ago

7 0

Answer:

: the answer is C

Explanation:

:State the law of conservation of energy.

Define and endothermic process.

Define an exothermic process.

Make conversions involving heat units.

g100num [7]2 years ago

5 0

The answer is c energy flows from the system to the thermometer

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If 50 ml of 0.235 M NaCl solution is diluted to 200.0 ml what is the concentration of the diluted solution

Helen [10]

This is a straightforward dilution calculation that can be done using the equation

$M_1V_1=M_2V_2$

where <em>M</em>₁ and <em>M</em>₂ are the initial and final (or undiluted and diluted) molar concentrations of the solution, respectively, and <em>V</em>₁ and <em>V</em>₂ are the initial and final (or undiluted and diluted) volumes of the solution, respectively.

Here, we have the initial concentration (<em>M</em>₁) and the initial (<em>V</em>₁) and final (<em>V</em>₂) volumes, and we want to find the final concentration (<em>M</em>₂), or the concentration of the solution after dilution. So, we can rearrange our equation to solve for <em>M</em>₂:

$M_2=\frac{M_1V_1}{V_2}.$

Substituting in our values, we get

$\[M_2=\frac{\left ( 50 \text{ mL} \right )\left ( 0.235 \text{ M} \right )}{\left ( 200.0 \text{ mL} \right )}= 0.05875 \text{ M}\].$

So the concentration of the diluted solution is 0.05875 M. You can round that value if necessary according to the appropriate number of sig figs. Note that we don't have to convert our volumes from mL to L since their conversion factors would cancel out anyway; what's important is the ratio of the volumes, which would be the same whether they're presented in milliliters or liters.

5 0

2 years ago

Explain reaction of metals with the following with the help of chemical equations; i) with acids ii) with oxygen iii) with water

Cerrena [4.2K]

i. When an acid reacts with metal, a salt and hydrogen are produced:

ii. When oxygen and metal react, metal oxide forms also known as rust

iii. Acid and water produce hydroxide ions

3 0

3 years ago

1. Which of the following pairs of factors affects the solubility of a particular substance? (1 point)

Lina20 [59]

<h2>Question no 1:</h2><h3>Answer:</h3>

The correct answer is option A which is temperature and the nature of solute and solvent

<h3>Explanation:</h3>

The solubility of a substance is its ability to dissolve in a particular solution.
Solubility is highly dependent on the temperature and nature of solute and solvent.
It is directly proportional to the temperature. As we increase the temperature, the solubility of substantial increases but for the exothermic reactions, solubility is inversely proportional to temperature.
Solubility is absolutely dependent on the nature of solute and solvent, as polar solute and solvents have high solubility than non polar.

<h2>Question no. 2</h2><h3>Answer:</h3>

The correct answer is option B which is a large amount of solute.

<h3>Explanation:</h3>

A concentrated solution contains the maximum amount of solute which can be dissolved in the solvent.
For example, in water sugar solution concentrated solution will contain a large amount of sugar dissolved in water without the addition of heat.
In dilute solution, there is a small amount of solute.

<h2>Question no. 3:</h2><h3>Answer:</h3>

The correct answer is option B which is molarity × liters of solution.

<h3>Explanation:</h3>

Molarity of a solution is the total number of moles of solute per unit volume of solution.

Its formula is:

Molarity = Number of moles of the solute/volume of solution in liters.

A number of moles of solute = Molarity × Volume of the solution.

So the number of moles of solute is equal to the molarity and volume of solution. Hence correct option is B.

<h2>Question no 4.</h2><h3>Answer:</h3>

The correct answer is option D. Molarity of the dilute solution = 0.81 M

<h3>Explanation:</h3>

Given data:

initial volume = V1 = 225 mL = 0.225 L

Initial molarity = M1 = 0.80M

Final volume = V2 = 1 L

Final molarity = M2 = ?

Solution:

It is the dilution of the stock solution and the formula is given below:

V1M1 = V2M2

M2 = V1.M1/V2

By putting values in the formula:

M2 = 0.225 × 0.8/1

M2= 0.18

So the final molarity of the solution will be 0.18 M. Hence the correct answer is option D.

<h2>Question no. 5</h2><h3>Answer:</h3>

The correct answer is option B which is supersaturation.

<h3>Explanation:</h3>

Colligative properties of the solution are the properties which are not dependent on the number of particles of the solute in the solution.
While supersaturation of the solution means the solution containing the highest number of solute particles dissolved in the solution.
Since supersaturation is dependent on a number of solutes, it is not a colligative property.

<h2>Question no 6.</h2><h3>Answer:</h3>

The correct answer is option B/C, "which disrupts crystal formation of the solvent".

<h3>Explanation:</h3>

Depression of freezing point is the colligative property of the solution.
Which the lowering of the freezing point of a solution by adding the solute.
The addition of solute disrupts the crystal formation in the solvent, as it disrupts the intermolecular forces between solute particles.
Hence option B and C are the correct options because both have the same statement.

<h2>Question no 7.</h2><h3>Answer:</h3>

The correct answer is option D which is 142.

<h3>Explanation:</h3>

<u>Given data:</u>

Volume of solution = 167 ml

Percentage of solution = 85%

The volume of alcohol =?

<u>Solution:</u>

Percentage of solution ( v/v) = volume of solute/volume of solution × 100

The volume of solute = percentage × volume of solution/100

By putting values in above formula:

Volume of alcohol = 85 × 167/100 = 141.95 ml

<em><u>Hence the correct answer is option D which is approximately 142(141.95).</u></em>

8 0

2 years ago

Read 2 more answers

Find the pH of 8.4x10^-8 M HCl. Report the answer to the hundredths place.

Hunter-Best [27]

Answer:

pH = 7.08

Explanation:

HCl ---------> H^+ + Cl^-

It's an acid, we are using this formula

pH = -log [H]^+

H^+ = 8.4 * 10^-8

pH = - log [8.4 * 10^-8]

It can also be solved as

-log 8.4-(-8log 10)

-0.924-(-8×1)

-0.924+8

7.076

To the nearest hundredth

pH = 7.08

8 0

3 years ago

Once you have collected 40 mL of distillate, you should ________. turn off your hot plate lower your lab jack carelessly use you

sweet-ann [11.9K]

Answer:

Once you have collected 40 mL of distillate, you should ________.

turn off the hot plate and carefully lower the lab jack, making sure that no cords or hoses get caught in it.

Explanation:

Distillate is the product obtained from the process of distillation. Distillation is the separation of components of a liquid mixture based on different boiling points. Distillation can be used to purify alcohol, for desalination, refining of crude oil, and for obtaining liquefied gases. A lab jack is an essential tool that supports and lifts hotplates, glassware, baths, and other small lab equipment requiring stable surfaces at a specific height.

5 0

2 years ago