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almond37 [142]
3 years ago
7

About one-third of the toxic metal, mercury (Hg), is released into the air from natural sources, such as rocks, soil, volcanoes,

and the ocean. The remaining two-thirds come from human activities such as ____. a. airplane exhaust b. gold mining c. livestock farming d. automobile exhaust e. plastic recycling
Chemistry
1 answer:
Stolb23 [73]3 years ago
7 0

Answer:

Two-third of the toxic metal, mercury comes from gold mining.

Explanation:

During gold mining small pieces of gold which are within  the soil are separated with the help of mercury. Both gold and mercury are mixed and they forms amalgam. Further gold can be extracted by vaporizing the mercury, thus releasing it into air and contributing to two-third of the air pollution by human activities.

Therefore (d) gold mining is the correct answer.

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1. A 25 g rock is placed in a graduated cylinder with water. The volume of the liquid rises from 18.3 mL to 21.4 mL Calculate th
MaRussiya [10]

Answer:

1. \rho=8.06g/cm^3

2. H=10cm

Explanation:

Hello,

1. In this case, since the volume of the rock is obtained via the difference between the volume of the cylinder with the water and the rock and the volume of the cylinder with the water only:

V=21.4mL-18.3mL=3.1mL

Thus, the density turns out:

\rho=\frac{m}{V}=\frac{25g}{3.1cm^3}  \\\\\rho=8.06g/cm^3

2. In this case, given the density and mass of aluminum we can compute its volume as follows:

V=\frac{m}{\rho}=\frac{1080g}{2.7g/cm^3}=400cm^3

Moreover, as the volume is also defined in terms of width, height and length:

V=W*H*L

The height is computed to be:

H=\frac{V}{L*W}=\frac{400cm^3}{5cm*8cm}\\ \\H=10cm

Best regards.

3 0
3 years ago
A chemist must prepare 300.0mL of nitric acid solution with a pH of 0.70 at 25°C. He will do this in three steps: Fill a 300.0mL
d1i1m1o1n [39]

<u>Answer:</u> The volume of concentrated solution required is 9.95 mL

<u>Explanation:</u>

To calculate the pH of the solution, we use the equation:

pH=-\log[H^+]

We are given:

pH = 0.70

Putting values in above equation, we get:

0.70=-\log[H^+]

[H^+]=10^{-0.70}=0.199M

1 mole of nitric acid produces 1 mole of hydrogen ions and 1 mole of nitrate ions.

Molarity of nitric acid = 0.199 M

To calculate the volume of the concentrated solution, we use the equation:

M_1V_1=M_2V_2

where,

M_1\text{ and }V_1 are the molarity and volume of the concentrated nitric acid solution

M_2\text{ and }V_2 are the molarity and volume of diluted nitric acid solution

We are given:

M_1=7.0M\\V_1=?mL\\M_2=0.199M\\V_2=350mL

Putting values in above equation, we get:

7.0\times V_1=0.199\times 350.0\\\\V_1=\frac{0.199\times 350}{7.0}=9.95mL

Hence, the volume of concentrated solution required is 9.95 mL

6 0
2 years ago
Ammonia, NH3; ammonium nitrate, NH4NO3; and ammonium hydrogen phosphate, (NH4)2HPO4, are all common fertilizers. Rank the compou
ValentinkaMS [17]

Answer:

Ammonia, NH₃ > ammonium nitrate, NH₄NO₃ > ammonium hydrogen phosphate, (NH₄)₂HPO₄

Explanation:

Mass percentage -

Mass percentage of A is given as , the mass of the substance A by mass of the total solution multiplied by 100.

i.e.

mass % A = mass of A / mass of solution * 100

Given,  

mass of nitrogen = 14 g/mol

mass of hydrogen = 1 g/mol

mass of oxygen = 16 g/mol

mass of phosphorus = 31 g/mol

1. Ammonia, NH₃

Hence , the mass of solution is calculated as the summation of the mass of the atom * number of atom ,  

Hence ,  

mass of solution = 1 * 14 g/mol  + 3 * 1 g/mol  

mass of solution = 17 g/mol

and ,

mass of nitrogen = 14 g/mol

The mass percent of nitrogen can be calculated from using the above formula  

mass % N = mass of N / mass of solution * 100

mass % N = 14 g/mol / 17 g/mol * 100

mass % N = 82.35 % .

2.   ammonium nitrate, NH₄NO₃

Hence , the mass of solution is calculated as the summation of the mass of the atom * number of atom ,  

Hence ,  

mass of solution = 2 * 14 g/mol  + 4 * 1 g/mol  + 3 * 16 g/mol

mass of solution = 80 g/mol

and ,

mass of nitrogen = 14 g/mol

The mass percent of nitrogen can be calculated from using the above formula  

mass % N = mass of N / mass of solution * 100

mass % N = 14 g/mol / 80 g/mol * 100

mass % N = 17.50 % .

3.   ammonium hydrogen phosphate, (NH₄)₂HPO₄

Hence , the mass of solution is calculated as the summation of the mass of the atom * number of atom ,  

Hence ,  

mass of solution = 2 * 14 g/mol  + 9 * 1 g/mol  + 4 * 16 g/mol + 1 * 31 g/mol

mass of solution = 132 g/mol

and ,

mass of nitrogen = 14 g/mol

The mass percent of nitrogen can be calculated from using the above formula  

mass % N = mass of N / mass of solution * 100

mass % N = 14 g/mol / 132 g/mol * 100

mass % N = 10.60 % .

Hence , the correct order is -

Ammonia, NH₃ > ammonium nitrate, NH₄NO₃ > ammonium hydrogen phosphate, (NH₄)₂HPO₄

3 0
2 years ago
How does a volcano form?
stealth61 [152]
A volcano is formed when magma (Lava) spews up from deep within the earth. After each eruption the Volcano gets bigger and bigger, so basically after periods of time the volcano will get larger. Lava will rise in cracks in the earth or weak spots in the earths crust. The pressure is relieved thus resulting in a volcanic eruptions it forms the new crust and then eventually builds up in that spot making a volcano. They also form in places called hot spots and various other places.
5 0
3 years ago
This reaction type occurs when different atoms in two different compounds trade places.
Scorpion4ik [409]
Your answer would be D, single replacement
3 0
2 years ago
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