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3 years ago

What occurs when a 35-gram aluminum cube at 100.°C is placed in 90. grams of water at 25°C in an insulated cup?

1 answer:

8 0

Heat always flows from hot to cold. The aluminum is hotter than the water in the cup so the answer is 2: The heat is transferred from the aluminum to the water, and the temperature of the water increases.

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A 50/50 blend of engine coolant and water (by volume) is usually used in an automobile's engine cooling system. If a car's cooli

Diano4ka-milaya [45]

Answer:

$\large \boxed{109.17 \, ^{\circ}\text{C}}$

Explanation:

Data:

50/50 ethylene glycol (EG):water

V = 4.70 gal

ρ(EG) = 1.11 g/mL

ρ(water) = 0.988 g/mL

Calculations:

The formula for the boiling point elevation ΔTb is

$\Delta T_{b} = iK_{b}b$

i is the van’t Hoff factor — the number of moles of particles you get from 1 mol of solute. For EG, i = 1.

1. Moles of EG

$\rm n = 0.50 \times \text{4.70 gal} \times \dfrac{\text{3.785 L}}{\text{1 gal}} \times \dfrac{\text{1000 mL}}{\text{1 L}} \times \dfrac{\text{1.11 g}}{\text{1 mL}} \times \dfrac{\text{1 mol}}{\text{62.07 g}} = \text{159 mol}$

2. Kilograms of water

$m = 0.50 \times \text{4.70 gal} \times \dfrac{\text{3.785 L}}{\text{1 gal}} \times \dfrac{\text{998 g}}{\text{1 L}} \times \dfrac{\text{1 kg}}{\text{1000 g}} = \text{8.88 kg}$

3. Molal concentration of EG

$b = \dfrac{\text{159 mol}}{\text{8.88 kg}} = \text{17.9 mol/kg}$

4. Increase in boiling point

$\rm \Delta T_{b} = iK_{b}b = 1 \times 0.512 \, \, ^{\circ}\text{C} \cdot kg \cdot mol^{-1} \, \times 17.9 \cdot mol \cdot kg^{-1} = 9.17 \, ^{\circ}\text{C}$

5. Boiling point

$\rm T_{b} = T_{b}^{\circ} + \Delta T_{b} = 100.00 \, ^{\circ}\text{C} + 9.17 \, ^{\circ}\text{C} = \mathbf{109.17 \, ^{\circ}C}\\\rm \text{The boiling point of the solution is $\large \boxed{\mathbf{109.17 \, ^{\circ}C}}$}$

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3 years ago

What do radio waves and microwaves have in common?

Anastasy [175]

1) A
2)A
3)C
4)A
That should be all of them. Hope this helps?

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3 years ago

Which is the correct Lewis structure for carbon tetrabromide (CBr4), in which a central carbon atom is bound to four atoms of th

AveGali [126]

The answer is b hope I helped

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3 years ago

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What is weathering? Please explain in your own words.

Annette [7]

To slowly erode and crumble.

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3 years ago

Solubility (polar vs. Nonpolar)

eduard

<u>Explanation:</u>

It is given that polar solutes can be dissolved in polar solvents and non-polar solutes can be dissolved in non-polar solvent.

Alcohol being polar, does not dissolves ionic salt in it.

$CCl_4$ is a non-polar solvent.

From the given options:

1. NaCl: This is an ionic salt and hence, it will be soluble in water only.

2. $I_2$ : Iodine gas is a non-polar solute and hence, will be dissolved in non-polar solvent which is $CCl_4$

3. Ethanol: As, it is a polar molecule and is not an ionic salt, therefore it can be soluble in both water and alcohol.

4. Benzene: It is a non-polar molecule and hence, it will be dissolved in $CCl_4$

5. $Br_2$ : Bromine gas is a non-polar solute and hence, will be dissolved in $CCl_4$

6. $KNO_3$ : This is an ionic salt and hence, it will be soluble in water only.

7. Toluene: This is a non-polar solute and hence, will be dissolved in $CCl_4$

8. $Ca(OH)_2$ : This is an ionic salt and hence, it will be soluble in water only.

4 0

3 years ago

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