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3 years ago

Why does thermal energy decreases when potassium is dissolved in water

Chemistry

1 answer:

Levart [38]3 years ago

8 0

Answer:

The process of dissolving can be endothermic (temperature goes down) or exothermic (temperature goes up).

When water dissolves a substance, the water molecules attract and “bond” to the particles (molecules or ions) of the substance causing the particles to separate from each other.

The “bond” that a water molecule makes is not a covalent or ionic bond. It is a strong attraction caused by water’s polarity.

It takes energy to break the bonds between the molecules or ions of the solute.

Energy is released when water molecules bond to the solute molecules or ions.

If it takes more energy to separate the particles of the solute than is released when the water molecules bond to the particles, then the temperature goes down (endothermic).

If it takes less energy to separate the particles of the solute than is released when the water molecules bond to the particles, then the temperature goes up (exothermic).

Explanation:

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6.0 mol NaOH reacts with

kodGreya [7K]

2 moles of Na3PO4 form from 6.0 mol NaOH. Details about stoichiometry can be found below.

<h3>How to calculate number of moles?</h3>

The number of moles of a substance can be calculated stoichiometrically as follows:

3NaOH + H3PO4 → 3H₂O + Na3PO4

According to this equation,

3 moles of NaOH produces 1 mole of Na3PO4

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2 years ago

A mixture containing 0.477 mol he(g), 0.265 mol ne(g), and 0.115 mol ar(g) is confined in a 7.00-l vessel at 25 ∘c. part a calcu

enot [183]

Q1)
we can use the ideal gas law equation to find the total pressure of the system ;
PV = nRT
where P - pressure
V - volume - 7 x 10⁻³ m³
n - number of moles
total number of moles - 0.477 + 0.265 + 0.115 = 0.857 mol
R - universal gas constant - 8.314 Jmol⁻¹K⁻¹
T - temperature in K - 273 + 25 °C = 298 K
substituting the values in the equation
P x 7 x 10⁻³ m³ = 0.857 mol x 8.314 Jmol⁻¹K⁻¹ x 298 K
P = 303.33 kPa
1 atm = 101.325 kPa
Therefore total pressure - 303.33 kPa / 101.325 kPa/atm = 2.99 atm

Q2)
partial pressure is the pressure exerted by the individual gases in the mixture.
partial pressure for each gas can be calculated by multiplying the total pressure by mole fraction of the individual gas.

total number of moles - 0.477 + 0.265 + 0.115 = 0.857 mol
mole fraction of He - $\frac{0.477}{0.857} = 0.557$
mole fraction of Ne - $\frac{0.265}{0.857} = 0.309$
mole fraction of Ar - $\frac{0.115}{0.857} = 0.134$
partial pressure - total pressure x mole fraction
partial pressure of He - 2.99 atm x 0.557 = 1.67 atm
partial pressure of Ne - 2.99 atm x 0.309 = 0.924 atm
partial pressure of Ar - 2.99 atm x 0.134 = 0.401 atm

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3 years ago

After spilling a liquid solution on a lab table, Ari grabs a trash can and paper towels. He then begins to soak up the solution

devlian [24]

Answer: The correct statement is the liquid solution might have been dangerous to touch with bare hands.

Explanation:

In the question, it is given that Ari has wiped the spilled liquid with paper towels without putting on the gloves.

While working in a lab, one must follow some safety rules:

There are chemicals all around the lab, so it should be handled with care that is by wearing gloves.
If by chance there is spilling on liquid on the shelf, it should be cleaned with the help of paper towels while wearing gloves.
Any chemical must not be touched with bare hands.

Hence, the correct answer is the liquid solution might have been dangerous to touch with bare hands.

4 0

3 years ago

Why does thermal energy decreases when potassium is dissolved in water​

Why does thermal energy decreases when potassium is dissolved in water