There is a sample of rock with a volume of 8 cm^3 and a mass of 20 g. What is its density?

How many particles are there in 1 mole of hand sanitizer?.

andre [41]

Answer: 6.02214 × 1023 particles

Explanation: did math

4 0

2 years ago

Classify each of the following compounds as a strong acid, weak acid, strong base, or weak base, and write the Ka expression for

Katyanochek1 [597]

Answer:

See explanation below

Explanation:

There are several ways to know if an acid or base is strong. One method is calculating the pH. If the pH is really low, is a strong acid, and if it's really high is a strong base.

However we do not have a pH value here.

The other method is using bronsted - lowry theory. If an acid is strong, then his conjugate base is weak. Same thing with the bases.

Now, Looking at the 4 compounds, we can say that only two of them is weak and the other two are strong compounds. Let's see:

LiOH ---> Strong. If you try to dissociate :

LiOH ------> Li⁺ + OH⁻ The Li⁺ is a weak conjugate acid.

HF -----> Weak

HF --------> H⁺ + F⁻ The Fluorine is a relatively strong conjugate base.

HCl -----> Strong

This is actually one of the strongest acid.

NH₃ ------> Weak

Now writting the Ka and Kb expressions:

Ka = [H⁺] [F⁻] / [HF]

Kb = [NH₄⁺] [OH⁻] / [NH₃]

Finally, to calculate the [OH⁻] we need to use the following expression:

Kw = [H⁻] [OH⁻]

Solving for [OH⁻] we have:

[OH⁻] = Kw / [H⁺]

Remember that the value of Kw is 1x10⁻¹⁴. So replacing:

[OH⁻] = 1x10⁻¹⁴ / 7x10⁻⁶

[OH⁻] = 1.43x10⁻⁹ M

And now, multiplying by 10¹⁰ we have:

[OH⁻] = 1.429x10⁻⁹ * 1x10¹⁰

Hope this helps

4 0

3 years ago

When should a lab coat, safety goggles, and gloves be worn in the laboratory?

Sever21 [200]

I would say that you should wear a lab coat, safety goggles, and gloves when the teacher says so - not everything in a lab is dangerous, so there is no need to always wear these. But when the teacher says you should - then you should.

8 0

3 years ago

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The pressure inside a compressed gas cylinder is 144 atm at 48°C. What will the pressure inside the cylinder be after it is cool

Andrews [41]

<h3>Answer:</h3>

134 atm

<h3>Explanation:</h3>

Based on the pressure law, the pressure of a gas varies directly proportionally to the absolute temperature at a constant volume.

Therefore; we are going to use the equation;

$\frac{P1}{T1}=\frac{P2}{T2}$

In this case;

Initial pressure, P1 = 144 atm

Initial temperature, T1 (48°C) = 321 K

Final temperature, T2 (25°C) = 298 K

We need to find the final pressure,

Therefore;

P2 = (P1/T1)T2

= (144/321)× 298 K

= 133.68 atm

= 134 atm

Therefore, the new pressure will be 134 atm.

5 0

4 years ago

In some regions of the world, forests are cut down and then burned to create room for farmland. How might this local environment

UkoKoshka [18]

The answer is D.

<u>Explanation</u>

Without trees, no carbon dioxide will be released into the air. It would not raise oxygen levels, and it wouldn’t effect rising sea levels.

6 0

3 years ago

Read 2 more answers