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2 years ago

How is the atomic mass of an atom calculated?

Chemistry

1 answer:

azamat2 years ago

8 0

Adding the number of protons by the number of neutrons

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If a gas is cooled from 315K to 231K and the volume is kept constant, what would the final pressure be if the original pressure

goblinko [34]

Answer:

455.4 mmHg

Explanation:

To solve this problem we can use Gay Lussac's Law, which describe the temperature and pressure of a gas, at constant volume and composition:

P₁T₂ = P₂T₁

In this case:

P₁ = 621 mmHg

P₂ = ?

T₁ = 315 K

T₂ = 231 K

We input the data:

621 mmHg * 231 K = P₂ * 315 K

And solve for P₂:

P₂ = 455.4 mmHg

5 0

2 years ago

If the [A-]/[HA] ratio of a base/weak acid mixture changes from 10/1 to 1/10, how much does the pH change:

andreev551 [17]

Answer:

The pH changes by 2.0 if the [A-]/[HA] ratio of a base/weak acid mixture changes from 10/1 to 1/10.

Explanation:

To solve this problem we use the Henderson-Hasselbach equation:

pH = pKa + log [A⁻]/[HA]

Let's say we have a weak acid whose pKa is 7.0:

pH = 7.0 + log [A⁻]/[HA]

If the [A⁻]/[HA] ratio is 10/1, we're left with:

pH = 7.0 + log (10/1)

pH = 7.0 + 1

pH = 8.0

Now if the ratio is 1/10:

pH = 7.0 + log (1/10)

pH = 7.0 - 1

pH = 6.0

The difference in pH from one case to the other is (8.0-6.0) 2.0.

So the pH changes by 2.0 if the [A-]/[HA] ratio of a base/weak acid mixture changes from 10/1 to 1/10.

Keep in mind that no matter the value of pKa, the answer to this question will be the same.

3 0

3 years ago

A water treatment tablet contains 20.0 mg of tetraglycine hydroperiodide, 40.0% of which is available as soluble iodine. If two

Galina-37 [17]

Answer:

$16\ \text{ppm}$

Explanation:

Mass of one tablet = 20 mg

Mass of two tablets = $2\times 20=40\ \text{mg}$

Percent that is soluble in water = 40%

Mass of tablet that is soluble in water = $0.4\times 40=16\ \text{mg}$

So, mass of solute is $16\ \text{mg}$

Density of water = 1 kg/L

Volume of water = 1 L

So, mass of 1 L of water is $1\times 1=1\ \text{kg}=1000\ \text{g}$

PPM is given by

$\dfrac{\text{Mass of solute}}{\text{Mass of solvent}}\times 10^6=\dfrac{16\times 10^{-3}}{1000}\times 10^6\\ =16\ \text{ppm}$

Hence, the concentration of iodine in the treated water $16\ \text{ppm}$ .

8 0

2 years ago

Giving brainliest please help with this question

siniylev [52]

Answer:

Explanation:

6 0

2 years ago

Investigate and explain that when a force is applied to an object but it does not move, it is because another opposing force is

N76 [4]

Answer:

4. Force 1 Force 2 Comparison of Forces

Friction Gravity Force 1 is equal to Force 2

Explanation:

5 0

2 years ago

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