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2 years ago

How many atoms of Mg are present in 97.22 grams of Mg?

Chemistry

1 answer:

Lostsunrise [7]2 years ago

7 0

Answer: Option (b) is the correct answer.

Explanation:

It is given that mass of Mg is 97.22 g and it is known that molar mass of Mg is 24.305 g/mol.

So, calculate the number of moles as follows.

No. of moles = $\frac{mass given in grams}{Molar mass}$

= $\frac{97.22 g}{24.305 g/mol}$

= 4 mol

Also, it is known that 1 mole has $6.023 \times 10^{23}$ atoms/mol. Therefore, calculate the number of atoms in 4 mol as follows.

$4 mol \times 6.023 \times 10^{23} atoms/mol$

= $24.08 \times 10^{23}$ atoms

or, = $2.408 \times 10^{23}$ atoms

Thus, we can conclude that there are $2.408 \times 10^{23}$ atoms in 97.22 grams of Mg.

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BH+ClO4- is a salt formed from the base B (Kb = 1.00e-4) and perchloric acid. It dissociates into BH+, a weak acid, and ClO4-, w

Len [333]

Answer:

The pH of 0.1 M BH⁺ClO₄⁻ solution is 5.44

Explanation:

Given: The base dissociation constant: $K_{b}$ = 1 × 10⁻⁴, Concentration of salt: BH⁺ClO₄⁻ = 0.1 M

Also, water dissociation constant: $K_{w}$ = 1 × 10⁻¹⁴

The acid dissociation constant ( $K_{a}$ ) for the weak acid (BH⁺) can be calculated by the equation:

$K_{a}. K_{b} = K_{w}$

$\Rightarrow K_{a} = \frac{K_{w}}{K_{b}}$

$\Rightarrow K_{a} = \frac{1\times 10^{-14}}{1\times 10^{-4}} = 1\times 10^{-10}$

Now, the acid dissociation reaction for the weak acid (BH⁺) and the initial concentration and concentration at equilibrium is given as:

Reaction involved: BH⁺ + H₂O ⇌ B + H₃O+

Initial: 0.1 M x x

Change: -x +x +x

Equilibrium: 0.1 - x x x

The acid dissociation constant: $K_{a} = \frac{\left [B \right ] \left [H_{3}O^{+}\right ]}{\left [BH^{+} \right ]} = \frac{(x)(x)}{(0.1 - x)} = \frac{x^{2}}{0.1 - x}$

$\Rightarrow K_{a} = \frac{x^{2}}{0.1 - x}$

$\Rightarrow 1\times 10^{-10} = \frac{x^{2}}{0.1 - x}$

$As, x$

$\Rightarrow 0.1 - x = 0.1$

$\therefore 1\times 10^{-10} = \frac{x^{2}}{0.1 }$

$\Rightarrow x^{2} = (1\times 10^{-10})\times 0.1 = 1\times 10^{-11}$

$\Rightarrow x = \sqrt{1\times 10^{-11}} = 3.16 \times 10^{-6}$

Therefore, the concentration of hydrogen ion: x = 3.6 × 10⁻⁶ M

Now, pH = - ㏒ [H⁺] = - ㏒ (3.6 × 10⁻⁶ M) = 5.44

Therefore, the pH of 0.1 M BH⁺ClO₄⁻ solution is 5.44

5 0

1 year ago

Amino acids are the building blocks of proteins. The simplest amino acid is glycine (H2NCH2COOH). Draw a Lewis structure for gly

VashaNatasha [74]

Answer:

Explanation:

The lewis structure (indicating all the atoms and patterns provided as hint in the question) of glycine can be seen in the attachment below. While the chemical structure of glycine can be seen below

H₂N - C - C =O

| \

H OH

The structure (of glycine) above provides a "fair idea" of how the lewis structure will be.

3 0

1 year ago

The temperature of the carbon dioxide atmosphere near the surface of venus is 475°c. calculate the average kinetic energy per mo

harkovskaia [24]

Answer: 9330 j/mol

The temperature of the gas is 475 ° Celcius which is equal to: 475 +273= 748 °K. The formula for kinetic energy of individual atoms would be

K= 3/2 * kB * T
If kB is 1.38 * 10^-23 J/K and 1 mol is made from 6.02*10^23 molecule, then the kinetic energy of 1 mol CO2 would be:
K= 3/2 * kB * T
K= 3/2 * 1.38 * 10^-23 * 748 * 6.02 *10^23 =9324 J/mol

8 0

1 year ago

Consider a beaker of water sitting on the pan of an electronic scale that has been tared. A metal weight hanging from a string i

natka813 [3]

Answer:

See explanation below for answers

Explanation:

We know that the balance is tared, so the innitial weight would be zero. Now, let's answer this by parts.

a) mass of displaced water.

In this case all we need to do is to substract the 0.70 with the 0.13 g. so:

mW = 0.70 - 0.13

mW = 0.57 g of water

b) Volume of water.

In this case, we have the density of water, so we use the formula for density and solve for volume:

d = m/V

V = m/d

Replacing:

Vw = 0.57/0.9982

Vw = 0.5710 mL of water

c) volume of the metal weight

In this case the volume would be the volume displaced of water, which would be 0.5710 mL

d) the mass of the metal weight.

In this case, it would be the mass when the metal weight hits the bottom which is 0.70 g

e) density.

using the above formula of density we calculate the density of the metal

d = 0.70 / 0.5710

d = 1.2259 g/mL

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2 years ago

What commercially available compound is used to generate cl2?

GuDViN [60]

Bleach and ammonia can be used to make cl2. Bleach is commercially available and so people should be very careful during these experiments or even when mixing things in the household.

6 0

1 year ago

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