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2 years ago

Why is mining for coal a long-term concern?

Chemistry

2 answers:

Delvig [45]2 years ago

8 0

Answer:

Explanation:

Coal is a non-renewable resource, so the supply can't produce faster than we can mine it.

Step2247 [10]2 years ago

8 0

Answer: Is B: the supply will eventually be exhausted.

Explanation:

there is only so much coal in the world as in many other elements. That is why we are looking for more appropriate and resourceful way of supplying energy and it is a lot safer for the workers involved

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Freshwater is distributed in both time and space

Neko [114]

Answer:

Unevenly

Explanation:

Fresh water is distributed unevenly in both time and space.

7 0

2 years ago

Please help! BRAINLIEST to right answer

Anastasy [175]

Answer:

Hailey the answer is D.

Explanation:

if liquid to solid is exothermic then then the other way around would be endorhermic

5 0

3 years ago

PLEASE HELP DUE SOON

jonny [76]

Answer:

This is all true if the atom has to be neutral.

Also what does V mean?

Helium: one shell with 2 neutrons and 2 protons in the center, with 2 electrons in the first shell.

Lithium: two shells with 4 neutrons and 3 protons in the center, with 2 electrons in the first shell, and 1 electron in the second shell.

Nitrogen: two shells with 7 neutrons and 7 protons in the center, with 2 electrons in the first shell, and 5 electrons in the second shell.

Flourine: two shells with 9 protons and 10 neutrons in the center, with 2 electrons in the first shell, and 7 electrons in the second shell.

Neon: two shells with 10 neutrons and 10 protons in the center, with 2 electrons in the first shell, and 8 electrons in the second shell.

Boron: two shells with 6 neutrons and 5 protons in the center, with 2 electrons in the first shell, and 3 electrons in the second shell.

3 0

3 years ago

What is the theoretical yield of Calcium if we begin with 12.6 grams of Aluminium?

AlladinOne [14]

The question is incomplete, here is the complete question:

The given chemical reaction is:

$2Al+3Cu(NO_3)_2\rightarrow 3Cu+2Al(NO_3)_3$

What is the theoretical yield of Calcium if we begin with 12.6 grams of Aluminium?

<u>Answer:</u> The theoretical yield of copper is 44.48 grams

<u>Explanation:</u>

To calculate the number of moles, we use the equation:

$\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}$ .....(1)

Given mass of aluminium = 12.6 g

Molar mass of aluminium = 27 g/mol

Putting values in equation 1, we get:

$\text{Moles of aluminium}=\frac{12.6g}{27g/mol}=0.467mol$

The given chemical equation follows:

$2Al+3Cu(NO_3)_2\rightarrow 3Cu+2Al(NO_3)_3$

By Stoichiometry of the reaction:

2 moles of aluminium produces 3 moles of copper

So, 0.467 moles of aluminium will produce = $\frac{3}{2}\times 0.467=0.7005mol$ of copper

Now, calculating the mass of copper from equation 1, we get:

Molar mass of copper = 63.5 g/mol

Moles of copper = 0.7005 moles

Putting values in equation 1, we get:

$0.7005mol=\frac{\text{Mass of copper}}{63.5g/mol}\\\\\text{Mass of copper}=(0.7005mol\times 63.5g/mol)=44.48g$

Hence, the theoretical yield of copper is 44.48 grams

4 0

3 years ago

The total volume required to reach the endpoint of a titration required more than the 50 mL total volume of the buret. An initia

Margaret [11]

Answer:

The endpoint volume is 50.52 ± 0.14 mL

Explanation:

In a titration always is necessary to subtract the blank volume to the titrant volume to obtain the real volume of the titrant. Thus in this case, the total endpoint volume is the sum of the initial volume delivered and the second volume delivered, minus the blank volume:

V = (49.16±0.06 mL) + (1.69±0.04 mL) - (0.33±0.04 mL)

V = (49.16 + 1.69 - 0.33) ± (0.06+0.04+0.04) mL

V = 50.52 ± 0.14 mL

It is necessary to consider the sum of the errors too.

7 0

3 years ago