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How many moles are 1.20 x 1025 formula units of calcium iodide?

madam [21]

Answer:

19.9 mol

Explanation:

Use <em>Avogadro’s number</em> to convert formula units of CaI₂ to moles of CaI₂.

1 mol CaI₂ ≡ 6.022 × 10²³ formula units CaI₂

Moles of CaI₂ = 1.20 × 10²⁵ × (1 /6.022 × 10²³)

Moles of CaI₂ = 19.9 mol

6 0

3 years ago

1.How many moles of each element are in 0.0250 mol of K 2 Cr O 4? 2. How many moles of ammonium ions are in 4.50 mol of (N H 4 )

noname [10]

Answer:

1. 0.0500 moles K, 0.0250 moles Cr and 0.1000 moles O.

2. 9.00 moles ammonium ions are present.

Explanation:

1. In 1mol of K2CrO4 there are 2 moles of K, 1 mole of Cr and 4 moles of O.

The moles in 0.0250 moles K2CrO4 are:

0.0250mol * 2 = 0.0500 moles K

0.0250mol * 1 = 0.0250 moles Cr

0.0250mol * 4 = 0.1000 moles O

2. In 1 mole of (NH4)2CO3 there are 2 moles of ammonium ions, NH₄⁺.

In 4,50 moles are:

4.50 moles * 2 = 9.00 moles ammonium ions are present

5 0

3 years ago

1. A gas having the following composition is burnt under a boiler with 50% excess air.

jeka94

The composition of the stack gas are :

$CH_4$ = 0.8713

$C_3H_8$ = 0.0202

CO = 0.107

<h3 /><h3>What is a mole fraction?</h3>

The ratio of the number of moles of one component of a solution or other mixture to the total number of moles representing all of the components.

Assuming 100 g of the stack gas. Calculate the mass of each species in this sample according to their percentages.

Mass of $CH_4$ : 70% of 100 g = 70 g

Mass of $C_3H_8$ : 15% of 100 g = 15 g

Mass of CO : 15% of 100 g = 15 g

Now calculate the number of moles of each species:

Number of moles of $CH_4$ : $\frac{70 g}{16.04 g/mol}$ = 4.3 mole

Number of moles of $C_3H_8$ : $\frac{15 g}{144.1 g/mol}$ = 0.10 mole

Mass of CO : $\frac{15 g}{28.01 g/mol}$ = 0.53 mole

Now to calculate the mole fraction of each we use the formula:

Mole fraction of $CH_4$ : $\frac{4.3}{4.935}$ = 0.8713

Mole fraction of $C_3H_8$ : $\frac{0.10}{4.935}$ = 0.0202

Mole fraction of CO : $\frac{0.53}{4.935}$ = 0.107

Hence, composition of the stack gas are:

$CH_4$ = 0.8713

$C_3H_8$ = 0.0202

CO = 0.107

Learn more about mole fraction here:

brainly.com/question/13135950

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8 0

3 years ago

If an exothermic chemical reaction occurs, the surroundings become warmer. Where does this energy come from?

Elena L [17]

It comes to from the chemical reaction itself. Exothermic reaction release heat because the energy level of the products is lower than that of the reactants. Therefore, the net enthalpy change of the reaction is negative (-), meaning heat or light (or any other form of energy) is released into the environment. An example of an exothermic reaction is the combustion of fuel.

5 0

3 years ago

Read 2 more answers

One crystalline form of silica (SiO2) has a cubic unit cell, and from X-ray diffraction data it is known that the cell edge leng

Sav [38]

Answer:

8 Silicon atom are present in unit cell.

16 oxygen atoms are present unit cell.

Explanation:

Number of atoms in unit cell = Z =?

Density of silica = tex]2.32 g/cm^3[/tex]

Edge length of cubic unit cell = a = 0.700 nm = $0.700\times 10^{-7} cm$