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2 years ago

How to write a chemical formula ?

Chemistry

2 answers:

Kaylis [27]2 years ago

8 0

Answer:

To write a chemical equation, the reactants should be written on the left, and the products should be written on the right and the coefficients should be written next to the symbols of entities to indicate the number of moles of a substance produced used in the chemical reaction.

uranmaximum [27]2 years ago

5 0

Answer:

→ A Chemical formula represents the proportions, by mass of the different elements in a compound.

→ A binary compound is composed of two different elements only. Formulae of binary compounds can be written using valencies since both types of atom forming the compound must lose, gain or share the same number of electrons.

• To write the chemical formula of a binary compound.

Determine the valencies of the two elements present.

Write the chemical formula such that the sums of the valencies of the two elements are equal. Do this by determining the lowest common multiple of the two valencies.

If a metal is present, always place it first in the formula.

Solved Examples

1. Aluminium oxide

Valencies of elements:

Al = 3 (Group III)

O = 2 (Group VI)

Lowest common multiple of valencies = 6

Al = 2 x 3 = 6

O = 3 x 2 = 6

Therefore the chemical formula = Al2O3

You might be interested in

The solubility table helps predict the products of what kind of reactions?

Ganezh [65]

Answer:

B. double replacement

Explanation:

Rate, or give brainliest if you can :)

3 0

3 years ago

Lauryl alcohol is obtained from cocon ut oil and is used to make detergents. A solution of 5.00 g of lauryl alcohol in 0.100 kg

Len [333]

Answer:

185.2 g/mol.

Explanation:

Solvent = Benzene

Solute = lauryl alcohol

Given:

Mass of solute = 5 g

Mass of solvent = 0.1 kg

Freezing point of solvent, Temp.f = 4.1 °C

Initial freezing point of solvent, Temp.i = 5.5 °C

Molal freezing depression constant for Benzene, kf = 5.12 °C/m

ΔTemp.f = Temp.f - Temp.i

= 5.5 - 4.1

= 1.4 °C

ΔTemp.f = kf * m

Where m = molality

m = 1.4/5.12

= 0.27 mol/kg

Molality = number of moles of solute/mass of solvent

Number of moles = 0.27/0.1

= 0.027 mol.

Molar mass = mass/number of moles

= 5/0.027

= 185.2 g/mol.

3 0

3 years ago

acetylene gas c2h2 undergoes combustion to produce carbon dioxide and water vapor How many grams of water are produced by the sa

ella [17]

Answer: The amount of water produced in the given reaction is $0.692x$ grams.

Explanation:

Let us assume that the initial amount of acetylene gas given be 'x' grams. Now, to calculate the number of moles, we will use the formula:

$\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}$ ....(1)

Given mass of acetylene = x grams

Molar mass of acetylene = 26 g/mol

Putting values in above equation, we get:

$\text{Number of moles of acetylene}=\frac{xg}{26g/mol}=\frac{x}{26}mol$

The reaction of combustion of acetylene is given by the equation:

$2C_2H_2+5O_2\rightarrow 4CO_2+2H_2O$

By Stoichiometry of the reaction:

2 moles of acetylene produces 2 moles of water.

So, $\frac{x}{26}$ moles of acetylene will produce = $\frac{2}{2}\times \frac{x}{26}=\frac{x}{26}$ moles of water.

Now, to calculate the amount of water produced, we use equation 1:

Molar mass of water = 18 g/mol

Moles of water = $\frac{x}{26}mol$

Putting values in equation 1, we get:

$\frac{x}{26}mol=\frac{\text{Mass of water}}{18g/mol}$

$\text{Mass of water}=\frac{x}{26}\times 18=0.692x$ grams

8 0

3 years ago

Calculate the wavelength for the transition from n = 4 to n = 2, and state the name given to the spectroscopic series to which t

finlep [7]

Answer:

The wavelength for the transition from n = 4 to n = 2 is 486nm and the name name given to the spectroscopic series belongs to The Balmer series.

Explanation

lets calculate -

Rydberg equation- $\frac{1}{\pi } =R(\frac{1}{n_1^2} -\frac{1}{n_2^2})$

where , $\pi$ is wavelength , R is Rydberg constant ( $1.097\times10^7$ ), $n_1$ and $n_2$ are the quantum numbers of the energy levels. (where $n_1=2 , n_2=4$ )