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3 years ago

How to determine oxidation numbers

Chemistry

1 answer:

nadezda [96]3 years ago

7 0

Answer:

1. The oxidation number of a free element is always 0.

2. The oxidation number of a monatomic ion equals the charge of the ion.

3. The oxidation number of H is +1, but it is -1 in when combined with less electronegative elements.

4. The oxidation number of O in compounds is usually -2, but it is -1 in peroxides.

Explanation:

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A certain substance X has a normal freezing point of 5.6 °C and a molal freezing point depression constant Kf-7.78 °C-kg·mol-1.

Harrizon [31]

Answer:

27.60 g urea

Explanation:

The freezing-point depression is expressed by the formula:

ΔT= Kf * m

In this case,

ΔT = 5.6 - (-0.9) = 6.5 °C

Kf = 7.78 °C kg·mol⁻¹

m is the molality of the urea solution in X (mol urea/kg of X)

First we calculate the molality:

6.5 °C = 7.78 °C kg·mol⁻¹ * m

m = 0.84 m

Now we calculate the moles of urea that were dissolved:

550 g X ⇒ 550 / 1000 = 0.550 kg X

0.84 m = mol Urea / 0.550 kg X

mol Urea = 0.46 mol

Finally we calculate the mass of urea, using its molecular weight:

0.46 mol * 60.06 g/mol = 27.60 g urea

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3 years ago

Ice cream is made by freezing a liquid mixture that, as a first approximation, can be considered a solution of sucrose (C12H22O1

AlladinOne [14]

Answer:

Hi.

The temperature is approximately zero degrees (0°C)

Explanation:

It is important to keep in mind that in the production of ice cream the decrease in the freezing point of the water present in the mixture is called the antifreeze power of the mixture. In ice cream, the freezing point decrease will be caused by each substance that is dissolved in the mixture: lactose, salts, sugars and any other substance. Each of these substances will contribute to the decrease in the freezing point of the mixture. The phase diagram attached in the file shows the sugar solutions in water. When a solution cools (point A), there comes a time when the freezing curve is reached (point B). At that moment ice begins to appear. As shown in the diagram this temperature is approximately zero degrees (0 ° C).

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3 years ago

Calculate mass of hydrogen chloride produced from 11.3g H and 11.3g Cl. H2 + Cl2 -> 2HCl

S_A_V [24]

Answer:

22.6According to the law of conservation of mass, the total mass of reactants should be equal to the total mass of products. Here, total mass of reactants= 11.3+11.3=22.6

•

• • Mass of Hcl produced=22.6 g

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2 years ago

4Fe + 30₂ ⇒ Fe₂0₃

DaniilM [7]

Answer:

The nuber of each one should be same

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1 year ago

What physical property makes metal pots good for cooking?

jeka94

Metal pots are good for cooking because they have heat conductivity.

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3 years ago

Read 2 more answers