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4 years ago

How many li are in 2.5 moles of li

Chemistry

1 answer:

NARA [144]4 years ago

8 0

Answer:

15.06 × 10²³ atoms of Li

Explanation:

Given data:

Number of moles of Li = 2.5 mol

Number of toms of Li = ?

Solution:

The given problem will solve by using Avogadro number.

It is the number of atoms , ions and molecules in one gram atom of element, one gram molecules of compound and one gram ions of a substance.

The number 6.022 × 10²³ is called Avogadro number.

For example,

18 g of water = 1 mole = 6.022 × 10²³ molecules of water

1.008 g of hydrogen = 1 mole = 6.022 × 10²³ atoms of hydrogen

For 2.5 mol of Li:

1 mole of lithium = 6.022 × 10²³ atoms of Li

2.5 mol × 6.022 × 10²³ atoms of Li / 1 mol

15.06 × 10²³ atoms of Li

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To solve this question you need to calculate the number of the gas molecule. The calculation would be:
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The volume at bottom of the lake would be:
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3 years ago

What is the temperature of CO2 gas if the average speed (actually the root-mean-square speed) of the molecules is 750 m/s?

erastova [34]

Answer:

992.302 K

Explanation:

V(rms) = 750 m/s

V(rms) = √(3RT / M)

V = velocity of the gas

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T = temperature of the gas

M = molar mass of the gas

Molar mass of CO₂ = [12 + (16*2)] = 12+32 = 44g/mol

Molar mass = 0.044kg/mol

From

½ M*V² = 3 / 2 RT

MV² = 3RT

K = constant

V² = 3RT / M

V = √(3RT / M)

So, from V = √(3RT / M)

V² = 3RT / M

V² * M = 3RT

T = (V² * M) / 3R

T = (750² * 0.044) / 3 * 8.314

T = 24750000 / 24.942

T = 992.302K

The temperature of the gas is 992.302K

Note : molar mass of the gas was converted from g/mol to kg/mol so the value can change depending on whichever one you use.

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3 years ago

A 1.0 g sample of hydrogen reacts completely with 19.0 g of fluorine to form a compound of hydrogen and fluorine. a. What is the

Rashid [163]

Explanation:tr

a) Molar mass of HF = 20 g/mol

Atomic mass of hydrogen = 1 g/mol

Atomic mass of fluorine = 19 g/mol

Percentage of an element in a compound:

$\frac{\text{Number of atoms of element}\times \text{Atomic mass of element}}{\text{Molar mass of compound }}\times 100$

Percentage of fluorine:

$\frac{1\times 19 g/mol}{20g/mol}\times 100=95\%$

Percentage of hydrogen:

$\frac{1\times 1g/mol}{20 g/mol}\times 100=5\%$

b) Mass of hydrogen in 50 grams of HF sample.

Moles of HF = $\frac{50 g}{20 g/mol}=2.5 mol$

1 mole of HF has 1 mole of hydrogen atom.

Then 2.5 moles of HF will have:

$1\times 2.5 mol=2.5 mol$ of hydrogen atom.

Mass of 2.5 moles of hydrogen atom:

1 g/mol × 2.5 mol = 2.5 g

2.5 grams of hydrogen would be present in a 50 g sample of this compound.

c) As we solved in part (a) that HF molecules has 5% of hydrogen by mass.

Then mass of hydrogen in 50 grams of HF compound we will have :

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3 years ago

What is the speed of each vehicle? (Remember S=d/t)

Aleksandr [31]

Answer:

A: 20 km/h, B: 10 km/h

Explanation:

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If A is 20km/h, B is 10km/h as given in option

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3 years ago

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deff fn [24]

Explanation:

As it is given that boiling point of propanamide is very high. So, reason for this is that easy formation of hydrogen bonds which are strong enough that we have to provide large amount of heat to break it.

As in $-NH_{2}$ , the hydrogen atoms which are present are positive in nature. Due to this they are able to form hydrogen bonds with the neighboring oxygen atom.

Hence, these bonds are so strong that high heat needs to given to break them.

A propanoic acid contain carboxylic group as the functional group. So, this group is also able to form hydrogen bonding as it forms a hydrogen bond between an acid group and hydroxyl group of neighboring molecule.

Hence, it will also require high heat to break the bond due to which there will be increase in boiling point.

In propanal, there is presence of aldehyde functional group and three carbon atoms chain which will not form strong bonding with the hydrogen atom of CHO. Due to this there will exist weak Vander waal's force that is not at all strong enough.

As a result, less energy will be needed to break the bonds in propanal. Hence, it has very low boiling point.

4 0

3 years ago

How many li are in 2.5 moles of li​

How many li are in 2.5 moles of li