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4 years ago

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Chemistry

2 answers:

Vlada [557]4 years ago

7 0

Answer:

The correct answer will be option- all options except It did not work well at wiping out the insect population are correct.

Explanation:

DDT or Dichlorodiphenyltrichloroethane is the first modern synthetic insecticide used by the farmers.

Earlier it proved beneficial to the farmers but later it proved lethal to humans as it caused many hazards to the environment like:

1. caused contamination of groundwater and running water due to leaching or washing from the fields.

2. DDT proved fatal as it is non-degradable and if then slow degradation.

3. stored in animal fat tissue like in Hawks and Eagles.

4. cases of human cancer reported and increased due to the consumption of this DDT.

5. Insects like a house fly evolved resistance to DDT.

Thus, all options except It did not work well at wiping out the insect population are correct.

julsineya [31]4 years ago

6 0

OK so the answer will be that 2 3 4 5 are correct the first choice is incorrect.

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There are 12 inches (in). in 1 foot (ft). which expression can be used to find the number of inches in 2.5 feet?

Nady [450]

Given:
12 inches in 1 foot
number of inches in 2.5 feet

2.5 feet * 12 inches/1foot = 2.5 * 12 inches = 30 inches

1 foot + 1 foot + 0.5 foot = 2.5 feet
12 inches + 12 inches + 6 inches = 30 inches

12 inches : 1 foot = x : 2.5 feet
12 inches * 2.5 feet = x*1foot
30 inches * feet = x * foot
30 inches = x

4 0

3 years ago

Read 2 more answers

11.

vagabundo [1.1K]

Answer:

1.22 × 10^22 H atoms

Explanation:

From this question, TNT has the chemical formula: C-H5N306. The number of nitrogen atoms in the TNT substance is said to be 7.30 × 10^21 atoms.

The number of hydrogen atoms in the same TNT substance can be got using mole ratio. Based on the chemical formula, the mole ratio of hydrogen to nitrogen is 5:3 i.e. H5N3.

This means that;

Number of atoms of hydrogen = 5/3 of the number of atoms of nitrogen.

Hence, number of H atoms = 5/3 × 7.30 × 10^21

number of H atoms = (7.30 × 5/3) × 10^21

number of H atoms = (36.5/3) × 10^21

number of H atoms = 12.1666 × 10^21

number of H atoms = 1.2166 × 10^22 atoms.

Approximately, number of H atoms in TNT is 1.22 × 10^22 atoms.

8 0

3 years ago

How do you make these equations balanced?

Sedaia [141]

Explanation:

both iron and sulphur in FeS2 undergo a change in oxidation state.

O2° -->2O degree2- Total decrease = 2×2=4

So, 4FeS2+11O2 --> 2Fe2O3+8 SO2

Hence, balanced

3 0

3 years ago

Which bag held the most vibrant beads?

Zolol [24]

Answer:

The bag with no sunscreen held the most vibrant beads.

Explanation:

SPF is the Sun Protection Factor. It indicates how long a person can stay out in the sun before his skin start burning. It is a factor that is multiplied by 15 minutes. SPF 30 means 30 times 15 = 450 minutes. SPF 70 means 70 times 15 = 1,050 minutes.

Thus, the bag covered in SPF 30 sunscreen will raise its temperature faster than the bag covered in SPF 70 sunscreen. And the bag with no sunscreen will raise its temperature faster than the other two.

The higher the temperature the more vibrant the particles that consititute the substances, thus, you conclude that the bag that held the most vibrant beads is the bag with no sunscreen.

Remember that the temperature is a measure of the kinetic energy:. The relation is: the higher the temperature the higher the kinetic energy.

Therefore, the more the particles vibrate, the higher the kinetic energy and the higher the temperature.

3 0

3 years ago

Oxygen (

Nataly_w [17]

Answer:

The average atomic mass of oxygen is 15.999u

5 0

3 years ago