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3 years ago

In atoms, electrons surround the nucleus in?

Chemistry

2 answers:

kolbaska11 [484]3 years ago

6 0

The answer is B specific energy levels

Charra [1.4K]3 years ago

4 0

either the answer is B or D

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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

2 years ago

Conociendo el volumen de la solución y la masa del soluto y su masa molar, ¿qué concentración es posible determinar

NISA [10]

Answer:

Conociendo el volumen de solución, masa de soluto y su masa molar, es posible determinar: B) Concentración molar

La molaridad es la relación entre el número de moles de soluto y los litros de solución. Más:

M = No moles de solución de soluto / volumen (L)

Y a su vez los moles de soluto se encuentran por:

No moles de soluto = masa soluto / masa molar soluto

8 0

3 years ago

What is the volume of 0.20 moles of helium at STP?

stealth61 [152]

The volume of 0.20 moles of helium at STP is 4.5 liters.

Explanation:

Given:

Number of moles = 0.20 moles

To Find:

The volume of Helium at STP =?

Solution:

According to ideal gas law

PV = nRT

where

P is pressure,

V is volume,

n is the number of moles

R is the gas constant, and

T is temperature in Kelvin.

The question already gives us the values for p and T ,because helium is at STP. This means that temperature is 273.15 K and pressure is 1 atm .

We also already know the gas constant. In our case, we'll use the value of

0.08206 L atm/K mol since these units fit the units of our given values the best

On substituting these values we get

$1 atm \times V = 0.20 moles \times 0.08206 L atm/K mol$

$V = \frac{0.20 moles \times 0.08206 L atm/K mol }{ 1 atm}$

$V = \frac{4.482}{1}$

V = 4.5 Liters

7 0

3 years ago

Which determine the charge of an atom?

Andre45 [30]

Answer:

the answer is B its the number of protons and neutrons

8 0

3 years ago

Elaborate on the role of activation energy in chemical reactions. A) Decreasing the activation energy leads to higher randomness

Zina [86]

B is right answer ithink bro/sis

4 0

3 years ago

Read 2 more answers