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Dmitry_Shevchenko [17]
4 years ago
15

Why was 1990 an important year regarding air quality?

Chemistry
1 answer:
s344n2d4d5 [400]4 years ago
5 0

Answer:

C. Modifications and improvements were made to the Clean Air Act.

Explanation:

The Clean Air act was originally established in 1970 and was concerned with the aim of protecting people and the environment in general from polluted air. Polluted air could cause different illnesses and environmental degradation.

The law was amended in 1990 in which modifications and improvements were made to the Clean Air Act. There was the need to reduce acid rain, toxic emissions which could deplete the ozone layer and cause varying respiratory illnesses in humans and to increase visibility.

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Suppose a solution is prepared by dissolving 15.0 g NaOH in 0.150 L of 0.250 M nitric acid. What is the final concentration of O
Kipish [7]

Answer:

2.25 M is the final concentration of hydroxide ions ions in the solution after the reaction has gone to completion.

Explanation:

Moles of NaOH = \frac{15.0 g}{40 g/mol}=0.375 mol

Molarity of the nitric acid solution = 0.250 M

Volume of the nitric solution = 0.150 L

Moles of nitric acid = n

Molarity=\frac{Moles}{Volume(L)}

n=0.250 M\times 0.150 L=0.0375 mol

NaOH+HNO_3\rightarrow NaNO_3+H_2O

According to reaction, 1 mole of nitric acid recats with 1 mole of NaOH, then 0.0375 moles of nitric acid will react with :

\frac{1}{1}\times 0.0375 mol of NaOH

Moles of NaOH left unreacted  in the solution =

= 0.375 mol - 0.0375 mol = 0.3375 mol

NaOH(aq)\rightarrow Na^+(aq)+OH^-(aq)

1 mole of sodium hydroxide gives 1 mol of sodium ions and 1 mole of hydroxide ions.

Then 0.3375 moles of NaOH will give :

1\times 0.3375 moles=0.3375 mol of hydroxide ion

The molarity of hydroxide ion in solution ;

=\frac{0.3375 mol}{0.150 L}=2.25 M

2.25 M is the final concentration of hydroxide ions ions in the solution after the reaction has gone to completion.

3 0
3 years ago
the ratio of dahlias to tulips in a flower arrangement is 2 to 5 which of these could be the number of dahlias and tulips in the
Elena L [17]
12 Dahlias, 30 Tulips

12:30
12/2=6
30/6=5
12/6=2 
=2:5
5 0
4 years ago
Which law states that at constant temperature the pressure of a given amount of gas is inversely proportional to the volume of t
Phantasy [73]
That law is known as Boyle's Law, "The volume of a given mass of a gas is inversely related to pressure when the temperature is constant"
8 0
4 years ago
Why are summer days longer than winter days on Earth?
zimovet [89]

Answer:

A. During the summer, Earth's rotational axis is parallel to the Sun's rotational axis.

Explanation:

Actually, though, the Earth is tilted 23.4 degrees! (A circle is 360 degrees.) This tilt is the reason that days are longer in the summer and shorter in the winter. The hemisphere that's tilted closest to the Sun has the longest, brightest days because it gets more direct light from the Sun's rays.

Plz mark me brainliest if correct :)

8 0
3 years ago
Read 2 more answers
'Synthetic detergents are better than soaps'. Justify this statement​
Shtirlitz [24]

Answer:

Synthetic detergents can be used for washing purposes even when the water is hard, whereas soaps are not suitable for washing with hard water. This is because of the fact that synthetic detergents can lather with hard water. Hence, Synthetic detergents better than soaps.

3 0
3 years ago
Read 2 more answers
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