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4 years ago

Give a theoretical reason why lithium and oxygen combine in the ratio 2:1

1 answer:

4 0

Lithium is in the first column of the periodic table and thus can only form one bond with another atom (its ion is Li+)

Oxygen can form two bonds (as in the dioxygen O2).

Hence if you conbine Li and O it has to be Li2O.

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Urgent help please!!

sveta [45]

Answer:

1. 2.1 moles of Mg

2. 0.72 mole of Mg(OH)2

Explanation:

1. We'll begin by writing the balanced equation for the reaction. This is given below:

3Mg + 2AlBr3 —> 3MgBr2 + 2Al

From the balanced equation above, 3 moles of Mg reacted to produce 2 moles of Al.

Therefore, Xmol of Mg will react to produce 1.4 moles of Al i.e

Xmol of Mg = (3 x 1.4)/2

Xmol of Mg = 2.1 moles.

Therefore, 2.1 moles of Mg is required to 1.4 moles of Al.

2. We'll begin by calculating the number of mole in 26g of water, H2O.

This is illustrated below:

Molar mass of H2O = (2x1) + 16 = 18g/mol

Mass of H2O = 26g

Number of mole of H2O =?

Mole = Mass /Molar Mass

Number of mole of H2O = 26/18

Number of mole of H2O = 1.44 moles

Next, we shall write the balanced equation for the reaction. This is given below:

2HNO3 + Mg(OH)2 —> Mg(NO3)2 + 2H2O

Finally, we can obtain the number of mole of Mg(OH)2 used in the reaction as follow:

From the balanced equation above,

1 mole of Mg(OH)2 reacted to produce 2 mole of H2O.

Therefore, Xmol of Mg(OH)2 will react to produce 1.44 moles of H2O i.e

Xmol of Mg(OH)2 = (1 x 1.44)/2

Xmol of Mg(OH)2 = 0.72 mole.

Therefore, 0.72 mole of Mg(OH)2 was used in the reaction.

3 0

3 years ago

A certain liquid X has a normal boiling point of 108.30 °C and a boiling point elevation constant Kb=1.07 °C kg/mol. A solution

Fynjy0 [20]

Answer:

34,6g of (NH₄)₂SO₄

Explanation:

The boiling-point elevation describes the phenomenon in which the boiling point of a liquid increases with the addition of a compound. The formula is:

ΔT = kb×m

Where ΔT is Tsolution - T solvent; kb is ebullioscopic constant and m is molality of ions in solution.

For the problem:

ΔT = 109,7°C-108,3°C = 1,4°C

kb = 1.07 °C kg/mol

Solving:

m = 1,31 mol/kg

As mass of X = 600g = 0,600kg:

1,31mol/kg×0,600kg = 0,785 moles of ions. As (NH₄)₂SO₄ has three ions:

0,785 moles of ions× $\frac{1(NH_{4})_{2}SO_{4}}{3Ions}$ = 0,262 moles of (NH₄)₂SO₄

As molar mass of (NH₄)₂SO₄ is 132,14g/mol:

0,262 moles of (NH₄)₂SO₄× $\frac{132,14g}{1mol}$ = <em>34,6g of (NH₄)₂SO₄</em>

I hope it helps!

7 0

4 years ago

What is the missing word in the word equation below?

ss7ja [257]

Answer:

sodium carbonate

Explanation:

Sodium hydrogen carbonate (also known as sodium bicarbonate or bicarbonate of soda) has the chemical formula NaHCO3. When it is heated above about 80°C it begins to break down, forming sodium carbonate, water and carbon dioxide. This type of reaction is called a thermal decomposition.

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8 0

3 years ago

15. transition metals has ____ valence electrons

Gemiola [76]

2 valence electrons

Explanation:

Most transition metals have 2 valence electrons. Valence electrons are the sum total of all the electrons in the highest energy level (principal quantum number n). Most transition metals have an electron configuration that is ns2(n−1)d , so those ns2 electrons are the valence electrons.

8 0

3 years ago

Is this statement true or false?

Snezhnost [94]

The correct answer is False.

5 0

2 years ago

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