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2 years ago

What happens to water when it freezes?

Chemistry

2 answers:

disa [49]2 years ago

8 0

Explanation:

When an object undergoes a physical change (solid to liquid, decrease in temperature etc.), the mass of the object remains constant.

When water freezes, the water molecules vibrate closer to one another and there is less space between the molecules.

The same number of water molecules now occupy a smaller volume, therefore their density increases.

The correct answer is the 3rd option.

Genrish500 [490]2 years ago

5 0

Answer:

Its density decreases

Explanation:

water expands when it freezes making it less dense than before.

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Arguments in favor of renewable energy

fenix001 [56]

I actually did the math for this a while ago. In order to install solar panels to every house in America it would cost a one time payment of about 900 billion dollars. We spend 700 billion on fossil fuels each year so in two years it would already pay itself off them we'd actually profit from it. Even if you don't believe in global warming you can't argue with that.

5 0

3 years ago

A Helium gas in a tube with a volume of 9.583 L under pressure of 4.972 atm at 31.8 c

andre [41]

1.905 moles of Helium gas are in the tube. Hence, option A is correct.

<h3>What is an ideal gas equation?</h3>

The ideal gas law (PV = nRT) relates the macroscopic properties of ideal gases. An ideal gas is a gas in which the particles (a) do not attract or repel one another and (b) take up no space (have no volume).

Calculate the moles of the gas using the gas law,

PV=nRT, where n is the moles and R is the gas constant. Then divide the given mass by the number of moles to get molar mass.

Given data:

P= 4.972 atm

V= 9.583 L

n=?

R= $0.082057338 \;L \;atm \;K^{-1}mol^{-1}$

T=31.8 +273= 304.8 K

Putting value in the given equation:

$\frac{PV}{RT}$ =n

n= $\frac{4.972 \;atm\; X \;9.583 \;L}{0.082057338 \;L \;atm \;K^{-1}mol^{-1} X 304.8}$

Moles = 1.905 moles

1.905 moles of Helium gas are in the tube. Hence, option A is correct.

Learn more about the ideal gas here:

brainly.com/question/27691721

#SPJ1

3 0

2 years ago

PLEASE HELP <3

frutty [35]

In order for carbon to be stable and have 8 electrons, it must make 4 total covalent bonds.

In prefer for oxygen to be stable and have 8 electrons, it must make 2 covalent bonds.

So, we can deduce that CO2 looks like this:

O=C=O

This molecule has two double bonds.

Pssst...Can I get a brainliest?

8 0

3 years ago

Consider a 1260-kg automobile clocked by law-enforcement radar at a speed of 85.5 km/h. If the position of the car is known to w

-BARSIC- [3]

The expected speed is v = 85.5 km/h
v = 85.5 km/h = (85.5 km/h)*(0.2778 (m/s)/(km/h)) = 23.75 m/s

If there is an uncertainty of 2 meters in measuring the position, then within a 1-second time interval:
The lower measurement for the speed is v₁ = 21.75 m/s,
The upper measurement for the speed is v₂ = 25.75 m/s.
The range of variation is
Δv = v₂ - v₁ = 4 m/s

The uncertainty in measuring the speed is
Δv/v = 4/23.75 = 0.1684 = 16.84%

Answer: 16.8%

3 0

2 years ago

How much heat does it take to melt 5.0g solid copper?

Leya [2.2K]

Answer:

$Q=1.04kJ$

Explanation:

Hello,

In this case, for latent heat (phase change) we need to consider the enthalpy associated with the involved process, here, melting or fusion; thus, the enthalpy of fusion of copper is 13.2 kJ/mol, therefore, the heat is computed as:

$Q=m\Delta H_{fus}$

Nevertheless, since the given enthalpy is per mole of copper, we need to use its atomic mass to perform the correct calculation as follows:

$Q=5.0g*\frac{1mol}{63.54}* 13.2\frac{kJ}{mol}\\ \\Q=1.04kJ$

Which is positive as it needs to be supplied to the system.

Best regards.

5 0

2 years ago