Question

How many electrons are present in 180 gm of water

(a) 1 mole
(b) 10 moles
(c) 18 moles
(d) 100 moles

AND

The total number of protons in 8.4 g of MgCO is

(a) 2.52 x 10^22
(b) 2.52 x 10^24
(c) 3.01 X 10;24
(d) 3.01 x 10^22

Give answer of both to get brainliest​

Answer 1

Answer:

• 180gm water contains 100 moles of electrons
• 8.4 g of MgCO contains 2.52 × 10²⁴ protons

Explanation:

★ Question - 1

Given, mass (m) = 180 gm

           Molecular weight (M) = 18 gm

Lets calculate first No. of electrons in total H₂O molecule,

⇒ No. of e⁻ = 2 × (Hydrogen e⁻) + Oxygen e⁻

⇒ No. of e⁻ = 2 × (1) + 8

⇒ No. of e⁻ = 2 + 8 = 10     _____[1]

Now, lets calculate the total no. of moles of water molecules present in 180 gm of water,

From the formula,

⇒ n = m/M

Substituting the values,

⇒ n = 180/18

⇒ n = 10 moles       _____[2]

So, 10 mole/180gm of  H₂O contains  (10×10) 100 moles e⁻.

Option - d is correct!

★ Question - 2

Given, mass (m) = 8.4 g

           Molecular weight (M) = 84 gm

Lets calculate first No. of electrons in total MgCO₃ molecule,

⇒ No. of e⁻ = Magnesium p + Carbon p + 3 × (Oxygen p)

⇒ No. of e⁻ = 12 + 6 + 3 × 8

⇒  No. of e⁻ = 12 + 6 + 24 = 42 protons      _____[1]

Now, lets calculate the no. of molecules of MgCO₃

⇒ N = n × Nₐ

⇒ N = (8.4/84) × 6.023 × 10²³

⇒ N = 0.1 × 6.023 × 10²³

⇒ N = 6.023 × 10²²      _____[2]

So, 8.4g of MgCO₃ contains (42 × 6.023 × 10²²) 252 × 10²² (or) 2.52 × 10²⁴ protons.

Option - b is correct!

Answer 2

Answer:

$\sf\tt\large{\green {\underline {\underline{⚘\;Question:}}}}$

1)How many electrons are present in 180 gm of water.

• 1 mole
• 10moles
• 180 moles
• 100 moles

2)The total number of protons in 8.4 g of MgCO3 is

• 2.52×10^22
• 2.52×10^24
• 3.01×10^24
• 3.01×10^22.

$\sf\tt\large{\green {\underline {\underline{⚘\;Answers:}}}}$

1)100 moles are present in 180gm of water .

2)The total number of protons in 8.4 g of MgCO3 is 2.52 ×10^24 .

$\sf\tt\large{\red {\underline {\underline{⚘\;Solution:}}}}$

$\sf\tt\large{\blue {\underline {\underline{\;Question(1):}}}}$

1. How many electrons are present in 180 gm of water.

$\sf\tt\large{\purple {\underline {\underline{⚘\;Answer(1):}}}}$

In the question given that we should find how many electrons are present in 180 gm of water .

So,

Here we know that,

1 mole of H2O contains

1 × 2 + 8 = 10 moles of electrons.

According to this,

180 gm of water = 180/18 = 10 moles .

And ,

Also we know from this that is

10 moles of water contains

10 × 10 = 100moles electrons.

$\sf\tt\large{\red {\underline {\underline{⚘\;Hence\;option \;D \;is \;the \;answer:}}}}$

$\sf\tt\large{\blue {\underline {\underline{\;Question(2):}}}}$

2)The total number of protons in 8.4g of MgCO3 is

$\sf\tt\large{\purple {\underline {\underline{⚘\;Answer(2):}}}}$

Here ,

First we should molar mass of MgCO3 .By this we get that,

24+12×1+3×16

36+48

84g.

Next ,

we should find number of moles of MgCO3 we get that,

=8.4/84

=0.1moles.

Next,

we should find number of moles in 1 molecules then finding this we get,

12 + 6 +3×8

42elctrons.

Then,

The total number of protons in 8.4g of MgCO3 ,

0.1 × 6.02 × 10^23 × 42

2.52 × 10^24 protons.

$\sf\tt\large{\red {\underline {\underline{⚘\;Hence \;option \;B \;is \;the \;Answer:}}}}$