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2 years ago

How many atoms are present in 179.0 g of iridium

1 answer:

8 0

<span>Avogadro's number represents the number of units in one mole of any substance. This has the value of 6.022 x 10^23 units / mole. This number can be used to convert the number of atoms or molecules into number of moles. We do as follows:

</span>179.0 g of iridium (1 mol / 192.217 g) ( 6.022 x 10^23 atoms / 1 mol ) = 5.61 x 10^23 atoms of iridium

Hope this answers the question.

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Silicon is an element that is found directly underneath carbon in the periodic table and thus has similar properties to carbon,

kirza4 [7]

Answer:

Four electrons are present in the valence shell of Silicon.

Explanation:

Valence shell electrons are those electrons which are present in the outermost shell of an atom. These valence shell electrons are responsible for in the formation of bonds with other atoms.

Silicon having atomic number 14 has fourteen electrons in its neutral state and has the electronic configuration as follow;

1s², 2s², 2p⁶, 3s², 3p²

In given configuration the valence shell (outermost shell) is 3 and the number of electrons present in it are four i.e. 3s² and 3p² (2 + 2 = 4) respectively.

7 0

3 years ago

1.00 M CaCl2 Density = 1.07 g/mL

Lesechka [4]

Explanation:

Molarity of solution = 1.00 M = 1.00 mol/L

In 1 L of solution 1.00 moles of calcium chloride is present.

Mass of solute or calcium chloride = m

$m = 1 mol\times 111 g/mol = 111 g$

Mass of solution = M

Volume of solution = V = 1L = 1000 mL

Density of solution , d= 1.07 g/mL

$M=d\times V=1.07 g/mL\times 1000 mL=1,070 g$

1) The value of %(m/M):

$\frac{m}{M}\times 100=\frac{111 g}{1,070 g}\times 100=10.37\%$

2) The value of %(m/V):

$\frac{m}{V}\times 100=\frac{111 g}{1000 L}\times 100=11.1\%$

$Molality = \frac{\text{Moles of compound }}{\text{mass of solvent in kg}}$

$Normality=\frac{\text{Moles of compound }}{n\times \text{volume of solution in L}}$

n = Equivalent mass

n = $\frac{\text{molar mass of ion}}{\text{charge on an ion}}$

3) Normality of calcium ions:

Moles of calcium ion = 1 mol (1 $CaCl_2$ mole has 1 mole of calcium ion)

$n=\frac{40 g/mol}{2}=20$

$=\frac{1 mol}{20 g/mol\times 1L}=0.050 N$

4) Normality of chlorine ions:

Moles of chlorine ion = 2 mol (1 $CaCl_2$ mole has 2 mole of chlorine ion)

$n=\frac{35.5 g/mol}{1}=35.5$

$=\frac{2 mol}{35.5 g/mol\times 1L}=0.056 N$

Moles of calcium chloride = 1.00 mol

Mass of solvent = Mass of solution - mass of solute

= 1,070 g - 111 g = 959 g = 0.959 kg ( 1 g =0.001 kg)

5) Molality of the solution :

$\frac{1 mol}{0.959 kg}=1.043 mol/kg$

Moles of calcium chloride = $n_1=1mol$

Mass of solvent = 959 g

Moles of water = $n_2=\frac{959 g}{18 g/mol}=53.28 mol$

Mass of solvent = 959 g

6) Mole fraction of calcium chloride =

$\chi_1=\frac{n_1}{n_1+n_2}=\frac{1mol}{1 mol+53.28 mol}=0.01842$

7) Mole fraction of water =

$\chi_2=\frac{n_2}{n_1+n_2}=\frac{53.28 mol}{1mol+53.28 mol}=0.9816$

8) Mass of solution = m'

Volume of the solution= v = 100 mL

Density of solution = d = 1.07 g/mL

$m'=d\times v=1.07 g/ml\times 100 g= 107 g$

Mass of 100 mL of this solution 107 grams of solution.

9) Volume of solution = V = 100 mL

Mass of solution = M'' = 107 g

Mass of solute = m

The value of %(m/V) of solution = 11.1%

$11.1\%=\frac{m}{100 mL}\times 100$

m = 11.1 g

Mass of solvent = M''- m = 107 g -11.1 g = 95.9 g

95.9 grams of water was present in 100 mL of given solution.

3 0

2 years ago

If a solution containing A+ ions and a solution containing B- ions have just been mixed and [A+][B-] is greater than Ksp of AB,

frozen [14]

Answer:

Explanation:

In the solution of AB , they are split to give ions as follows

AB ⇄ A⁺ + B⁻

Product of concentration of A⁺ and B⁻ in saturated solution of AB is constant .

This is called Ksp

Ksp = [A⁺] [ B⁻]

If product of concentration of A⁺ and B⁻ exceeds Ksp , the equilibrium shifts to the left side and excess ions come out of solution in the form of precipitate. So second option is the answer.

4 0

2 years ago

Can the same fertilizer be applied to all types of soil ? Explain

Arte-miy333 [17]

You cant use the same fertilizer for all soils bc differnt soils have different nutrients like lets say ur growing tomatoes with cabbage it wouldnt work bc they need different nutrients for them to grow. This is used with trees, veggies, plants and fruits. it is true somw can use the same fertilizer if they can be grown with it. if you give it the wrong nutrients it can die or not grow

4 0

2 years ago

An experiment applies heat to a substance and produces a gas that is a new and different substance. Choose the true statement.

bearhunter [10]

Well if the change is reversible then it is a physical change, but if not then it is a chemical change.

4 0

3 years ago