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sdas [7]
3 years ago
8

Subsurface mining disturbs more land than surface mining true or false

Chemistry
1 answer:
Allisa [31]3 years ago
5 0

Answer:

False

Explanation:

Surface mining disturbs more land compared to subsurface mines.

During surface mining, huge mounds of earth is removed inorder to access mineral deposits. The deeper lying the deposit, the more the earth is removed and disturbed.

In subsurface mines, tunnels and a system of shaft are used to access the ore body. Data about the geometry and positioning of the ore helps to plan how to effectively access it.

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Lewis structures for the perchlorate ion (ClO4−) can be drawn with all single bonds or with one, two, or three double bonds. Dra
Vanyuwa [196]

Answer:

The most important resonance structure is 4 (attached picture). Its bon order is \frac{7}{4} or 1\frac{3}{4}.

Explanation:

A picture with 4 forms of the perchlorate structure is attached. The first structure has simple bonds. The second structure contains a double bond, the third structure has two double bonds and the fourth structure has three double bonds.

Formal charge = group number of the periodic table - number of bonds (number of bonding electrons / 2) - number of non-shared electrons (lone pairs)

The formal charges in the first structure is +3 in chlorine and -1 in oxygen.

The formal charges in the second structure is +2 in chlorine, -1 in oxygen and 0 in the double bond oxygen.

The formal charges in the third structure is +1 in chlorine, -1 in the single bond oxygens and 0 in the double bond oxygens.

The formal charges in the fourth structure is 0 in chlorine, -1 in the single bond oxygen and 0 in the double bond oxygens.

The most important resonance structure is given by:

  • Most atoms have 0 formal charge.
  • Lowest magnitude of formal charges.
  • If there is a negative formal charge, it's on the most electronegative atom.

Hence, the fourth structure is the mosr important.

The bond order of the structure is:

Total number of bonds: 7

Total number of bond groups: 4

Bond order= \frac{7}{4} =1\frac{3}{4}

5 0
3 years ago
What state of matter is at 35 Celsius
Otrada [13]
Different forms of matter have different melting/boiling points. For example, at 100 degrees Celsius, H2O (water) will turn from lliquid to gas. But NaOH (table salt) doesn't even go from solid to liquid until some 800 degrees Celsius. So, in order to figure out which state matter is at 35 Celsius, you'd have to be more specific about what kind of matter...
7 0
3 years ago
a 4.50 g coin of copper absorbed 54 calories of heat. what was the final temperature of the copper if the initial temperature wa
vlada-n [284]

Answer:

Final temperature =  T₂ = 155.43 °C

Explanation:

Specific heat capacity:

It is the amount of heat required to raise the temperature of one gram of substance by one degree.

Formula:

Q = m.c. ΔT

Q = amount of heat absorbed or released

m = mass of given substance

c = specific heat capacity of substance

ΔT = change in temperature

Given data:

Mass of coin = 4.50 g

Heat absorbed = 54 cal

Initial temperature = 25 °C

Specific heat of copper = 0.092 cal/g °C

Final temperature = ?

Solution:

Q = m.c. ΔT

ΔT = T₂ -T₁

Q = m.c. T₂ -T₁

54 cal = 4.50 g × 0.092 cal/g °C ×  T₂ -25  °C

54 cal = 0.414 cal/ °C ×  T₂ -25  °C

54 cal /0.414 cal/ °C =  T₂ -25  °C

130.43 °C  =  T₂ -25 °C

130.43 °C + 25 °C = T₂

155.43 °C = T₂

4 0
3 years ago
Which of the following is not a statement of Dalton's atomic theory of matter?a. Elements are made of atomsb. Atoms of a given e
Alona [7]

Answer:

c. The atoms of one element can be identical to the atoms of another element.

Explanation:

<em>Which of the following is not a statement of Dalton's atomic theory of matter?</em>

<em>a. Elements are made of atoms.</em> TRUE. An atom is the smallest particle of a chemical element that can exist.

<em>b. Atoms of a given element are identical.</em> TRUE. The only slight difference is in the mass of isotopes.

<em>c. The atoms of one element can be identical to the atoms of another element.</em> FALSE. The atoms of different elements are different from one to another.

<em>d. A given compound always has the same number and kinds of atoms. </em>TRUE. This is known as Dalton's law of constant composition.

3 0
3 years ago
Do you think that the human being is the center of the universe?
Andrej [43]
I think that the sun is the center of the universe, not a human being. Everything revolves around the sun, not someone. U know when to sleep, when the time is, and when to wake up based on the sun. All the planets revolve around it. This is why I think the sun is the center of the universe, not a human being.
3 0
2 years ago
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