The properties of a substance are not affected by chemical reactions. O True O False

What is the percentage by mass of sulphur in Al2(SO4)3[A12SO4 = 342g/mol, S = 32]

valentinak56 [21]

Answer: The percentage by mass of sulphur in $Al_2(SO_4)_3$ is 9.36%

Explanation:

Mass percent of an element is the ratio of mass of that element by the total mass expressed in terms of percentage.

${\text {Mass percentage}}=\frac{\text {mass of sulphur}}{\text {Total mass}}\times 100\%$

Given: mass of sulphur = 32 g/mol

mass of $Al_2(SO_4)_3$ = 342 g/mol

Putting in the values we get:

${\text {Mass percentage}}=\frac{32g/mol}{342g/mol}\times 100\%=9.36\%$

The percentage by mass of sulphur in $Al_2(SO_4)_3$ is 9.36%

4 0

3 years ago

Covalent bonds usually occur between atoms that have

marta [7]

Answer: A: high ionization energies; high electron affinitlies.

Explanation: Covalent bonds are basically about sharing of electrons between two atoms to achieve that stable structure. They are formed between two atoms when both have similar tendencies to attract electrons to themselves (i.e., when both atoms have identical or fairly similar ionization energies and electron affinities). Covalent bonding usually occurs between two non-metals.

For effective and proper bonding, the two atoms involved in the covalent bonding exercise should be small and hungry for electrons. This is to enable the nuclei of both atoms to effectively attract and hold the shared electron(s) in place; hence, the need for high ionization energies & high electron affinities for a more effective covalent bonding.

7 0

3 years ago

HNO3 + S --> H2SO4 + NO Now identify the element oxidized and the element reduced. Which element is oxidized? Which element i

OleMash [197]

Answer: S is getting oxidized, N is getting reduced and O and H undergo no oxidation or reduction

Explanation:

The oxidation reaction is defined as the reaction in which a chemical species loses electrons in a chemical reaction. It occurs when oxidation number of a species increases.

A reduction reaction is defined as the reaction in which a chemical species gains electrons in a chemical reaction. It occurs when oxidation number of a species decreases.

For the given chemical reaction:

$HNO_3+S\rightarrow H_2SO_4+NO$

On the reactant side:

Oxidation number of H = +1

Oxidation number of N = +5

Oxidation number of O = -2

Oxidation number of S = 0

On the product side:

Oxidation number of H = +1

Oxidation number of N = +2

Oxidation number of O = -2

Oxidation number of S = +6

As the oxidation number of S is increasing from 0 to +6. Thus, it is getting oxidized. Similarly, the oxidation number of N is decreasing from +5 to +2. Thus, it is getting reduced.

The oxidation numbers of O and H remain the same on both sides of the reaction. Thus, they are neither getting oxidized or reduced.

Hence, S is getting oxidized, N is getting reduced and O and H undergo no oxidation or reduction

3 0

3 years ago

13

kifflom [539]

Answer:

Cultural Pest Control.

Explanation:

The cultural pest control is one of the oldest methos of pest control. This form of pest control is less practiced these days since curative form of pest control methods have been invented. The cultural pest control method is a preventive method of managing pest population. This pest control method takes long days of planning and execution.

In this form of pest control method, the farmer had to change the timings of his farming operations in his field. This method requires careful timing in seeding and planting. This method of pest controlling requires knowledge and skills of fields.

Thus the correct answer is the third option.

8 0

4 years ago

Balance the following reaction. A coefficient of "1" is understood. Choose option "blank" for the correct answer if the

Vera_Pavlovna [14]

2NH₂ + O₂ → N₂ + 2H₂O

Explanation:

Balancing the equation means, the number of atoms on both sides of the equation must be the same.

In the case of the given equation, we have to find out whether it is balanced or not.

2NH₂ + O₂ → N₂ + 2H₂O

Atoms Number of atoms before balancing after balancing

LHS RHS LHS RHS

N 1 2 2 2

H 2 2 4 4

O 2 1 2 2

To balance the N atoms, we have to put 2 in front of NH₂, and then to balance the H, O atoms, we have to put 2 in front of H₂O, so that each atom in left hand as well as right hand side of the equation was balanced.

8 0

4 years ago