All categories

3 years ago

When you put an ice cube into a glass of room temperature water, why does the water get cold?

1 answer:

6 0

The water gets cold because the ice cube is endothermic. Which means it takes in heat. It takes the warmth from the water and melts the ice cube which the ice cube releases coldness which cools down the water.

You might be interested in

Three factors affecting gas pressure are the amount of gas, temperature, and __________.

Olenka [21]

It's A. volume
Pressure = $\frac{moles * const * temperature}{volume}$
with const depends on the chosen unit of volume
I think so...

8 0

3 years ago

Read 2 more answers

The vapor pressure of water at 25.0°C is 23.8 torr. Determine the mass of glucose (molar mass = 180 g/mol) needed to add to 500.

mrs_skeptik [129]

According to Raoult's law the relative lowering of vapour pressure of a solution made by dissolving non volatile solute is equal to the mole fraction of the non volatile solute dissolved.

the relative lowering of vapour pressure is the ratio of lowering of vapour pressure and vapour pressure of pure solvent

$\frac{p^{0-}p}{p^{0}}=x_{B}$

Where

xB = mole fraction of solute=?

$p^{0}=23.8torr$

p = 22.8 torr

$x_{B}=\frac{23.8-22.8}{23.8}=0.042$

mole fraction is ratio of moles of solute and total moles of solute and solvent

moles of solvent = mass / molar mass = 500 /18 = 27.78 moles

putting the values

$molefraction=\frac{molessolute}{molesolute+molessolvent}$

$0.042=\frac{molessolute}{27.78+molessolute}$

$1.167+0.042(molesolute)=molessolute$

$molessolute=1.218$

mass of glucose = moles X molar mass = 1.218 X 180 = 219.24 grams

3 0

3 years ago

Which of these solutions are basic at 25 Â°C? Solution A: [OHâˆ’]=3.13Ã—10âˆ’7 M Solution C: [H3O+]=0.000747 M Solution B: [H3O+

solong [7]

Answer:

Are basic:

[OH⁻] = 3.13x10⁻⁷M and [H₃O⁺] = 9.55x10⁻⁹M

Explanation:

A solution is basic when pH = - log [H₃O⁺] is higher than 7.

It is possible to convert [OH⁻] to [H₃O⁺] using:

[H₃O⁺] = 1x10⁻¹⁴ / [OH⁻]

a. [OH⁻] = 3.13x10⁻⁷M

[H₃O⁺] = 1x10⁻¹⁴ / [3.13x10⁻⁷M]

[H₃O⁺] = 3.19x10⁻⁸M

pH = - log [H₃O⁺] = 7.50

[OH⁻] = 3.13x10⁻⁷M is basic

b. pH = -log [H₃O⁺] = - log 0.000747M = 3.13.

This solution is not basic

c. [H₃O⁺] = 9.55x10⁻⁹M

pH = 8.02

This solution is also basic.

8 0

3 years ago

Explain the concept: Law of Multiple Proportions.<br> Short and simple please

cricket20 [7]

In chemistry the law of multiple proportions states that if two elements from more than one compound between them then the ratios of the masses of the second element which combine with a fixed mass of the first element will always be ratios of small whole numbers .

4 0

3 years ago

Read 2 more answers

If the pressure on a gas sample is tripled and the absolute temperature is quadrupled, by what factor will the volume of the sam

antoniya [11.8K]

Answer:

b. 4/3

Explanation:

Given data

Initial pressure: P₁

Initial volume: V₁

Initial temperature: T₁

Final pressure: P₂ = 3 P₁

Final volume: V₂

Final temperature: T₂ = 4 T₁

We can find by what factor will the volume of the sample change using the combined gas law.

$\frac{P_{1}.V_{1}}{T_{1}} =\frac{P_{2}.V_{2}}{T_{2}}\\\frac{P_{1}.V_{1}}{T_{1}} =\frac{3P_{1}.V_{2}}{4T_{1}}\\V_{1} =\frac{3V_{2}}{4}\\V_{2}=4/3 V_{1}$

7 0

3 years ago