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3 years ago

What is thermal expansion?

1 answer:

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Thermal expansion is the tendency of matter to change in shape, area, and volume in response to a change in temperature, through heat transfer. Temperature is a monotonic function of the average molecular kinetic energy of a substance. When a substance is heated, the kinetic energy of its molecules increases.

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Identify which reaction is NOT a chemical reaction. es )

vova2212 [387]

Answer:

You never listed the options

Explanation:

A chemical reaction is a process that involves rearrangement of the molecular or ionic structure of a substance, as opposed to a change in physical form or a nuclear reaction.

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3 years ago

A rigid tank that contains 2 kg of N2 at 25°C and 550 kPa is connected to another rigid tank that contains 4 kg of O2 at 25°C an

koban [17]

Answer:

The volume in the first tank = 0.32 $m^{3}$

The volume in the second tank = 2.066 $m^{3}$

The final pressure of the mixture = 203.64 K pa

Explanation:

First Tank

Mass = 2 kg

Pressure = 550 k pa

Temperature = 25 °c = 298 K

Gas constant for nitrogen = 0.297 $\frac{KJ}{Kg K}$

From the ideal gas equation

P V = m R T

550 × V = 2 × 0.297 × 298

V = 0.32 $m^{3}$

This is the volume in the first tank.

Second tank

Mass = 4 kg

Pressure = 150 K pa

Temperature = 25 °c = 298 K

Gas constant for oxygen = 0.26 $\frac{KJ}{Kg K}$

From the ideal gas equation

P V = m R T

150 × V = 4 × 0.26 × 298

V = 2.066 $m^{3}$

This is the volume in the second tank.

This is the iso thermal mixing. i.e.

$P_{3} V_{3} = P_{1} V_{1} + P_{2} V_{2}$ ----- (1)

$V_{3} = V_{1} + V_{2}$

$V_{3} = 0.32 + 2.066$

$V_{3} = 2.386 \ m^{3}$

Put this value in equation (1)

$P_{3}$ × 2.386 = 550 × 0.32 + 150 × 2.066

$P_{3}$ = 203.64 K pa

Therefore the final pressure of the mixture = 203.64 K pa

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3 years ago

Which one of the following statements about mixtures is correct [2] [3] The different substances in a mixture are always in a de

aivan3 [116]

Answer: Option (4) is the correct answer.

Explanation:

A mixture is defined as a substance that contains two or more different substance that are physically mixed with each other.

If solute particles are evenly distributed in a solvent then it is known as a homogeneous mixture.

For example, salt dissolved in water is a homogeneous mixture.

If solute particles are unevenly distributed into the solvent then it is known as a heterogeneous mixture.

For example, sand in water is a heterogeneous mixture.

Thus, we can conclude that the statement a mixture must contain at least two different substances, is correct about mixtures.

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3 years ago

explain why it is a common laboratory procedure to heat analytical reagents and store them in a dessicated atmosphere (a sealed

Readme [11.4K]

Explanation:

Most reagent forms are going to absorb water from the air; they're called "hygroscopic". Water presence can have a drastic impact on the experiment being performed For fact, it increases the reagent's molecular weight, meaning that anything involving a very specific molarity (the amount of molecules in the final solution) will not function properly.

Heating will help to eliminate water, although some chemicals don't react well to heat, so it shouldn't be used for all. A dessicated environment is simply a means to "dry." That allows the reagent with little water in the air to attach with.

6 0

2 years ago

If water were a linear (not bent) molecule like co2, electrostatic interactions between water molecules would be much weaker. wh

Ksenya-84 [330]

Answer;

The partial negative charge on oxygen would stick out less and be less able to participate in hydrogen bonding.

Explanation;

Water is a polar molecule because the electrons are not shared equally, they're closer to the oxygen atom than the hydrogen.

-Normally, the water molecule is a bent shape because of the pair of lone electrons - they repulse each other and exert a compression to the hydrogen atoms at a slight 104º angle. It is a bent molecular geometry that results from tetrahedral electron pair geometry.

-The 2 lone electron pairs exerts a little extra repulsion on the two bonding hydrogen atoms to create a slight compression to a 104 degrees bond angle. Therefore, the water molecule is bent molecular geometry because the lone electron pairs.

Thus, If water were a linear molecule like co2, electrostatic interactions between water molecules would be much weaker, then the partial negative charge on oxygen would stick out less and be less able to participate in hydrogen bonding.

3 0

3 years ago