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2 years ago

I’m trying to find the number of representative particles in 0.4 mol KCL what is my first step?

Chemistry

1 answer:

Lady_Fox [76]2 years ago

6 0

Answer:

2.41 x 10²³ particles

Explanation:

Data Given:

no. of moles of KCl = 0.4 mol

no. of particles = ?

Solution:

To find number of particles we use following formula

number of moles = number of particles / Avogadro's number

as we have to find number of particles so rearrange the above equation

no. of particles = no. of moles x Avogadro's number . . . . . . . (1)

Where

Avogadro's number = 6.022 x 10²³ particles per mol

6.022 x 10²³ are number of particles in one mole of a substance. and this quantity is known as Avogadro's number

So,

put values in above equation 1

no. of particles = 0.4 mol x 6.022 x 10²³ (particles/mol)

no. of particles = 2.41 x 10²³ particles

So, 0.4 mol KCl contains 2.41 x 10²³ representative particles

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How many Joules must be removed to condense 150.0g of steam at 100.0 degrees Celsius to water at 100.0 degrees celcius

Elina [12.6K]

Answer:

339kJ

Explanation:

Given parameters:

Mass of steam = 150g = 0.15kg

Initial temperature of steam = 100°C

Final temperature of water = 100°C

Unknown:

Quantity of heat that must be removed to condense the steam = ?

Solution:

The heat involved here is a latent heat because there is no change temperature. The process is just a phase change.

H = mL

m is the mass

L is the latent heat of vaporization = 2,260 kJ/kg

Insert the parameters and solve;

H = 0.15kg x 2,260 kJ/kg

H = 339kJ

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3 years ago

The decomposition of a compound at 400⁰C is first order with half-life of 1570 seconds. what fraction of an initial amount of th

kirill115 [55]

Answer: After 4710 seconds, 1/8 of the compound will be left

Explanation:

Using the formulae

Nt/No = (1/2)^t/t1/2

Where

N= amount of the compound present at time t

No= amount of compound present at time t=0

t= time taken for N molecules of the compound to remain = 4710 seconds

t1/2 = half-life of compound = 1570 seconds

Plugging in the values, we have

Nt/No = (1/2)^(4710s/1570s)

Nt/No = (1/2)^3

Nt/No= 1/8

Therefore after 4710 seconds, 1/8 molecules of the compound will be left

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2 years ago

"The statements in the following multiple choices deal with various aspects of the relationship between vapor pressure and inter

solong [7]

Answer:

Explanation:

a ) false.

NH₃ is more polar molecule than PH₃ so inter-molucular attraction is greater in NH₃ ( hydrogen bond ) . Hence vapour pressure is low for NH₃ .

b ) false .

The average kinetic energy of boiling water molecules is lower on a mountaintop than it is at sea level. It is so because water boils at lower temperture on mountain and kinetic energy of molecules depends upon temperature .

c ) false

vapour pressure depends upon temperature .

d ) True

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e ) false

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3 years ago

How many oxygen atoms are in this chemical formula? 2CH3OH

svetoff [14.1K]

Answer:

1 oxygen atom is present.

Explanation:

8 0

2 years ago

Please help, and I’ll thank you.

coldgirl [10]

Answer:

There will be formed 13.82 grams of Fe3O4.

Explanation:

Step 1: the balanced reaction

3 Fe(s) + 4 H2O(l) —— Fe3O4(s) + 4 H2(g)

We see that for 3 moles Fe consumed, there will be consumed 4 moles of H20 and produced 1 mole of Fe3O4 and 4 moles of H2.

Step 2: Calculating moles

⇒mole = mass / Molar mass

⇒moles Fe = 10g / 55.845g/mole = 0.179 moles

⇒moles H2O = 10g / 18g/mole = 0.5556 moles

Since we have 4 moles of H2O consumed for 3 moles of Fe, this means that for 0.179 moles of Fe, we have :

0.179 / 4 *3 = 0.2387 moles of H2O consumed

This means that Fe will be completely consumed and there will remain 0.2387 moles of H2O.

Fe is the limiting reactant and H2O is in excess.

Step 3: Calculate moles of Fe3O4

For 3 moles of Fe consumed, we have 1 mole of Fe3O4 produced.

This means, that for 0.179 moles of Fe consumed, we have 0.179/3 =0.05967 molesof Fe3O4 produced.

Step 4: Calculating mass of Fe3O4

mass= number of moles * Molar mass

mass Fe3O4 = 0.05967 mole * 231.55g/mole = 13.8166 g ≈ 13.82grams of Fe3O4

There will be formed 13.82 grams of Fe3O4.

5 0

3 years ago