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4 years ago

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Chemistry

2 answers:

Maurinko [17]4 years ago

4 0

Answer:

Explanation:

i believe the answer is a. sorry if it's wrong...

damaskus [11]4 years ago

3 0

I think it’s a. I only !

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The freezing-point depression of a 0.100 m MgSO4 solution is 0.225°C. Determine the experimental van't Hoff factor of MgSO4 at t

Andrews [41]

Answer: The experimental van't Hoff factor is 1.21

Explanation:

The expression for the depression in freezing point is given as:

$\Delta T_f=iK_f\times m$

where,

i = van't Hoff factor = ?

$\Delta T_f$ = depression in freezing point = 0.225°C

$K_f$ = Cryoscopic constant = 1.86°C/m

m = molality of the solution = 0.100 m

Putting values in above equation, we get:

$0.225^oC=i\times 1.86^oC/m\times 0.100m\\\\i=\frac{0.225}{1.86\times 0.100}=1.21$

Hence, the experimental van't Hoff factor is 1.21

7 0

3 years ago

How many calories of heat are necessary to raise the temperature of 319.5 g of water from 35.7 °C

rjkz [21]

20600Cal

Explanation:

Given parameters:

Mass of water = 319.5g

Initial temperature = 35.7°C

Final temperature = 100°C

Unknown:

Calories needed to heat the water = ?

Solution:

The calories is the amount of heat added to the water. This can be determined using;

H = m c Ф

c = specific heat capacity of water = 4.186J/g°C

H is the amount of heat

Ф is the change in temperature

H = m c (Ф₂ - Ф₁)

H = 319.5 x 4.186 x (100 - 35.7) = 85996.56J

Now;

1kilocalorie = 4184J

85996.56J to kCal; $\frac{85996.56}{4184}$ = 20.6kCal = 20600Cal

learn more:

Specific heat brainly.com/question/3032746

#learnwithBrainly

6 0

3 years ago

A monoprotic weak acid when dissolved in water is 0.66% dissociated and produces a solution with a pH of 3.04. Calculate the Ka

raketka [301]

Answer:

Ka = 6.02x10⁻⁶

Explanation:

The equilibrium that takes place is:

HA ⇄ H⁺ + A⁻

Ka = [H⁺][A⁻]/[HA]

We calculate [H⁺] from the pH:

pH = -log[H⁺]

[H⁺] = $10^{-pH}$

[H⁺] = 9.12x10⁻⁴ M

Keep in mind that [H⁺]=[A⁻].

As for [HA], we know the acid is 0.66% dissociated, in other words:

[HA] * 0.66/100 = [H⁺]

We calculate [HA]:

[HA] = 0.138 M

Finally we calculate the Ka:

Ka = $\frac{[9.12x10^{-4}]*[9.12x10^{-4}]}{[0.138]}$ = 6.02x10⁻⁶

3 0

3 years ago

How are the atomic number and the number of protons related to each other? how do the number of protons, number of neutrons, and

jarptica [38.1K]

The atomic number (Z) uniquely identifies a chemical element. In an uncharged atom, the atomic number is also equal to the number of electrons.

The atomic number, Z, should not be confused with the mass number, A, which is the number of nucleons, the total number of protons and neutrons in the nucleus of an atom.

In this video Kristine Born explains this two concepts in more detail.

5 0

4 years ago

4. How many moles of KBr are found in 3 Liters of 0.4 M solution?

Allisa [31]

There are 1.2 moles of KBr found in 3 Liters of 0.4 M solution.

<h3>HOW TO CALCULATE NUMBER OF MOLES?</h3>

The number of moles of a substance can be calculated by multiplying the molarity by the volume.

No. of moles = Molarity × volume

According to this question, 3L of a KBr solution are contained in a 0.4M.

no. of moles = 3L × 0.4M = 1.2moles

Therefore, there are 1.2 moles of KBr found in 3 Liters of 0.4 M solution.

Learn more about no. of moles at: brainly.com/question/14919968

4 0

3 years ago