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3 years ago

Explain what you understand by valency, give examples

Chemistry

1 answer:

Lostsunrise [7]3 years ago

3 0

Answer:

Valency is defined as the number of hydrogen atoms which combine directly or indirectly with one atom of an element.

Example:

One atom of nitrogen combines with three atoms of hydrogen to form ammonia gas. So, the valency of nitrogen is 3.

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Gaseous ethane (CH,CH,) will react with gaseous oxygen (0,) to produce gaseous carbon dioxide (CO) and gaseous water (H2O). Supp

notka56 [123]

Answer:

0.00 g

Explanation:

We have the masses of two reactants, so this is a limiting reactant problem.

We will need a balanced equation with masses, moles, and molar masses of the compounds involved.

1. Gather all the information in one place with molar masses above the formulas and masses below them.

Mᵣ 30.07 32.00

2CH₃CH₃ + 7O₂ ⟶ 4CO₂ + 6H₂O

Mass/g: 1.50 11.

2. Calculate the moles of each reactant

$\text{moles of C$_{2}$H}_{6} = \text{1.50 g C$_{2}$H}_{6} \times \dfrac{\text{1 mol C$_{2}$H}_{6}}{\text{30.07 g C$_{2}$H}_{6}} = \text{0.04988 mol C$_{2}$H}_{6}\\\\\text{moles of O}_{2} = \text{11. g O}_{2} \times \dfrac{\text{1 mol O}_{2}}{\text{32.00 g O}_{2}} = \text{0.34 mol O}_{2}$

3. Calculate the moles of CO₂ we can obtain from each reactant

From ethane:

The molar ratio is 4 mol CO₂:2 mol C₂H₆

$\text{Moles of CO}_{2} = \text{0.04988 mol C$_{2}$H}_{6} \times \dfrac{\text{4 mol CO}_{2}}{\text{2 mol C$_{2}$H}_{6}} = \text{0.09976 mol CO}_{2}$

From oxygen:

The molar ratio is 4 mol CO₂:7 mol O₂

$\text{Moles of CO}_{2} = \text{0.34 mol O}_{2}\times \dfrac{\text{4 mol CO}_{2}}{\text{7 mol O}_{2}} = \text{0.20 mol CO}_{2}$

4. Identify the limiting and excess reactants

The limiting reactant is ethane, because it gives the smaller amount of CO₂.

The excess reactant is oxygen.

5. Mass of ethane left over.

Ethane is the limiting reactant. It will be completely used up.

The mass of ethane left over will be 0.00 g.

8 0

3 years ago

Dan wants to test the effects of different amounts of antibiotic on bacteria. While setting up his experiment he makes sure to u

iVinArrow [24]

The answer is C.
hope this helps.

3 0

3 years ago

Read 2 more answers

Which description is true of earth’s four layers?

Levart [38]

Answer:

The astenosphere is located below the lithosphere

The mantle is composed of silicate material

Explanation:

The Earth has several different layers, and they can be presented in two different manners, depending on their chemical composition and their physical properties. According to the chemical composition the Earth has three layers, crust, mantle, and core, while in accordance to the physical properties it has five, lithosphere, astenosphere, mesosphere, outer core, and inner core.

The astenosphere is the second layer from the top, and it lies just below the lithosphere. It is also the upper part of the mantle. The mantle is a layer that is largely composed of silicate material, mostly silicate molten rock. It can easily be seen from the volcanic activities that this layer is composed of silicate material because the magma is rich in it, and the magma comes from this layer.

6 0

3 years ago

Which of the following statements is/are CORRECT?1. For a chemical system, if the reaction quotient (Q) is greater than K, react

tankabanditka [31]

Explanation:

A chemical equilibrium is defined as the state of reaction in which the rate of forward reaction is equal to the rate of backward reaction.

When Q > $K_{eq}$ , then it means that the reaction is proceeding in the backward reaction. Whereas if Q < $K_{eq}$ , then it means that the reaction is proceeding in the forward direction. Hence, formation of products will be favored.

On the other hand, if Q = $K_{eq}$ , then it means reaction is at equilibrium.

At equilibrium, it is not necessary that the concentrations of products divided by the concentrations of reactants equals one.

Thus, we can conclude that the statement for a chemical system at equilibrium, the forward and reverse rates of reaction are equal, is correct.

8 0

3 years ago

A sample of ammonia is found to occupy 0.250 L under laboratory conditions of 27 °C and 0.850 atm. Find the volume of this sampl

Rzqust [24]

Answer:

0.193 L

Explanation:

Step 1:

Data obtained from the question.

Initial Volume (V1) = 0.250 L

Initial temperature (T1) = 27°C

Initial pressure (P1) = 0.850 atm

Final volume (V2) =?

Final temperature (T2) = 0°C

Final pressure (P2) = 1.00 atm

Step 2:

Conversion of celsius temperature to Kelvin temperature.

Temperature (Kelvin) = temperature (celsius) + 273

Initial temperature (T1) = 27°C = 27°C + 273 = 300K

Final temperature (T2) = 0°C = 0°C + 273 = 273K

Step 3:

Determination of the new volume of the sample of ammonia gas.

The new volume can be obtain by using the general gas equation as shown below:

P1V1/T1 = P2V2/T2

0.850x0.250/300 = 1xV2/273

Cross multiply to express in linear form

300 x V2 = 0.850x0.250x273

Divide both side by 300

V2 = (0.850x0.250x273) /300

V2 = 0.193 L

Therefore, the volume of the sample at 0 °C and 1.00 atm is 0.193 L

6 0

3 years ago

Explain what you understand by valency, give examples​

Explain what you understand by valency, give examples