After some wood has completely burned in a fire some of the matter that made up the wood has been destroyed

(I)how many atoms are present in 7g of lithium?

ICE Princess25 [194]

Answer :

(i) The number of atoms present in 7 g of lithium are, $6.07\times 10^{23}$

(ii) The number of atoms present in 7 g of lithium are, $1.204\times 10^{24}$

(iii) The number of moles of $F_2$ is, 1 mole

The number of moles of $CO_2$ is, 0.5 mole

The number of moles of $OH^-$ is, 1 mole

Explanation :

Part (i) :

First we have to calculate the moles of lithium.

$\text{Moles of }Li=\frac{\text{Mass of }Li}{\text{Molar mass of }Li}$

Molar mass of Li = 6.94 g/mole

$\text{Moles of }Li=\frac{7g}{6.94g/mol}=1.008mole$

Now we have to calculate the number of atoms present.

As, 1 mole of lithium contains $6.022\times 10^{23}$ number of atoms

So, 1.008 mole of lithium contains $1.008\times 6.022\times 10^{23}=6.07\times 10^{23}$ number of atoms

Thus, the number of atoms present in 7 g of lithium are, $6.07\times 10^{23}$

Part (ii) :

First we have to calculate the moles of carbon.

$\text{Moles of }C=\frac{\text{Mass of }C}{\text{Molar mass of }C}$

Molar mass of C = 12 g/mole

$\text{Moles of }C=\frac{24g}{12g/mol}=2mole$

Now we have to calculate the number of atoms present.

As, 1 mole of carbon contains $6.022\times 10^{23}$ number of atoms

So, 2 mole of carbon contains $2\times 6.022\times 10^{23}=1.204\times 10^{24}$ number of atoms

Thus, the number of atoms present in 7 g of lithium are, $1.204\times 10^{24}$

Part (iii) :

To calculate the moles of $F_2$ :

$\text{Moles of }F_2=\frac{\text{Mass of }F_2}{\text{Molar mass of }F_2}$

Molar mass of $F_2$ = 38 g/mole

$\text{Moles of }F_2=\frac{19g}{19g/mol}=1mole$

Thus, the number of moles of $F_2$ is, 1 mole

To calculate the moles of $CO_2$ :

$\text{Moles of }CO_2=\frac{\text{Mass of }CO_2}{\text{Molar mass of }CO_2}$

Molar mass of $CO_2$ = 44 g/mole

$\text{Moles of }CO_2=\frac{22g}{44g/mol}=0.5mole$

Thus, the number of moles of $CO_2$ is, 0.5 mole

To calculate the moles of $OH^-$ ions :

$\text{Moles of }OH^-=\frac{\text{Mass of }OH^-}{\text{Molar mass of }OH^-}$

Molar mass of $OH^-$ = 17 g/mole

$\text{Moles of }OH^-=\frac{17g}{17g/mol}=1mole$

Thus, the number of moles of $OH^-$ is, 1 mole

4 0

3 years ago

the formation of all heavenly bodies is governed by the law of electricity and magnetism the law of universal gravitation the el

maksim [4K]

The law of Universal Gravitation.

8 0

3 years ago

The proper answer gets marked brainiest, answer what the question is asking.

Keith_Richards [23]

A substance is an element if it consists of a single type of atom. A substance is a compound if it is made up of more than one element.

<h3>Elements and compounds</h3>

In chemistry, an element is defined as all pure substances consisting of the same atom. For example, magnesium and potassium metal are all elements because they consist of magnesium and potassium atoms only.

On the other hand, compounds are defined as substances consisting of 2 or more atoms of different elements. For example, sodium chloride consists of atoms of sodium and chlorine. Hence, it is considered to be a compound.

More on elements and compounds can be found here: brainly.com/question/13516179

#SPJ1

6 0

2 years ago

How many Oxygen elements are in a carboxylic acid

Amanda [17]

Answer:

Carboxylic acid, any of a class of organic compounds in which a carbon atom is ... to an oxygen atom by a double bond and to a hydroxyl group by a single bond. ... sour-milk products) and citric acid (found in citrus fruits), and many keto acids ...

Explanation:

5 0

3 years ago

How many grams of zinc chloride could be formed from the reaction of 3.57g of zinc with excess HCl?

lorasvet [3.4K]

MZn: 65 g/mol
mZnCl₂: 65g+35,5g×2 = 136 g/mol
.....................
Zn + 2HCl -----> ZnCl₂ + H₂
65g.......................136g............

65g Zn ---- 136g ZnCl₂
3,57g Zn ---- X
X = (3,57×136)/65
X = 7,47g ZnCl₂

5 0

3 years ago

Read 2 more answers