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1 year ago

Why is mining for coal a long-term concern?

Chemistry

2 answers:

Free_Kalibri [48]1 year ago

8 0

A. Fossil fuels take a very long time to form so we mine it faster than it can replenish.

maw [93]1 year ago

5 0

Answer: I believe its A

Explanation:

You might be interested in

which intensive physical property is observed when droppings of a person seated inside a closed room has able to reach a person

zavuch27 [327]

Answer:

The right response will be "Speed".

Explanation:

Intensive or Individualized physical property becomes found when "speed" seems to be the excrement of either an individual who sits within a closed or contained environment that can hit a person one meter away after sneezing or coughing.
This measure seems to be "meter per second", its a intense property.

5 0

2 years ago

What mass of ni2+ is produced in solution by passing a current of 67.0 a for a period of 14.0 h , assuming the cell is 90.0 % ef

Ira Lisetskai [31]

When we have the current = 67 coulombs/second

and mol of electrons of Ni2+= 2

faraday's constant = 96500

molar mass of Ni = 58.69 g/mol

time (sec) = 14 h * 3600

∴ the mass of Ni2+ = 50400 sec * 67 coulombs/second * 1 mol of electrons / 96500 coulombs * 1 mol of Ni / 2 mol of electrons * 58.69 g/mol / mol of Ni

= 1027 g Ni

6 0

2 years ago

A student pours exactly 26.9 mL of HCl acid of unknown molarity into a beaker. The student then adds 2 drops of the indicator an

Assoli18 [71]

a.
Acids react with bases and give salt and water and the products.

Hence, HCl reacts with NaOH and gives NaCl salt and H₂O as the products. The reaction is,
HCl(aq) + NaOH(aq) → NaCl(aq) + H₂O(l)

To balance the reaction equation, both sides hould have same number of elements.

Left hand side, Right hand side,
H atoms = 2 H atoms = 2
Cl atoms = 1 Cl atoms = 1
Na atoms = 1 Na atoms = 1
O atoms = 1 O atoms = 1

Hence, the reaction equation is already balanced.

b.
Molarity (M)= moles of solute (mol) / Volume of the solution (L)

HCl(aq) + NaOH(aq) → NaCl(aq) + H₂O(l)

Molarity of NaOH = 0.13 M
Volume of NaOH added = 43.7 mL
Hence, moles of NaOH added = 0.13 M x 43.7 x 10⁻³ L
= 5.681 x 10⁻³ mol

Stoichiometric ratio between NaOH and HCl is 1 : 1

Hence, moles of HCl = moles of NaOH
= 5.681 x 10⁻³ mol

5.681 x 10⁻³ mol of HCl was in 26.9 mL.

Hence, molarity of HCl = 5.681 x 10⁻³ mol / 26.9 x 10⁻³ L
= 0.21 M

6 0

2 years ago

When an athlete gets hurt they apply sometimes an instant cold pack to the injury. The instant cold pack works by mixing two che

NeX [460]

Answer:

The evidence showing that there is a chemical reaction taking place is the instantaneous temperature drop once the cold pack is shaken.

Explanation:

When an athlete applies a cold pack to the injury, they shake it before, mixing the water and ammonium-nitrate fertilizer inside the cold pack. This mixing is an endothermic reaction, which means it absorbs heat. In turn, the temperature falls to 35 F for around 10 minutes.

3 0

2 years ago

Magnesium reacts with iron(III) chloride to form magnesium chloride (which can be used in fireproofing wood and in disinfectants

svet-max [94.6K]

Answer:

154.0831 g

Explanation:

The formula for the calculation of moles is shown below:

$moles = \frac{Mass\ taken}{Molar\ mass}$

Given: For $Mg$

Given mass = 41.0 g

Molar mass of $Mg$ = 24.31 g/mol

Moles of $Mg$ = 41.0 g / 24.31 g/mol = 1.6865 moles

Given: For $FeCl_3$

Given mass = 175 g

Molar mass of $FeCl_3$ = 162.2 g/mol

Moles of $FeCl_3$ = 175 g / 162.2 g/mol = 1.0789 moles

According to the given reaction:

$3Mg_{(s)}+2FeCl_3_{(s)}\rightarrow 3MgCl_2_{(s)}+2Fe_{(s)}$

3 moles of Mg react with 2 moles of $FeCl_3$

1 mole of Mg react with 2/3 moles of $FeCl_3$

1.6865 mole of Mg react with (2/3)*1.6865 moles of $FeCl_3$

Moles of $FeCl_3$ = 1.1243 moles

Available moles of $FeCl_3$ = 1.0789 moles

Limiting reagent is the one which is present in small amount. Thus, $FeCl_3$ is limiting reagent. (1.0789 < 1.1243)

The formation of the product is governed by the limiting reagent. So,

2 moles of $FeCl_3$ gives 3 moles of magnesium chloride

1 mole of $FeCl_3$ gives 3/2 moles of magnesium chloride

1.0789 mole of $FeCl_3$ gives (3/2)*1.0789 moles of magnesium chloride

Moles of magnesium chloride = 1.61835 moles

Molar mass of magnesium chloride = 95.21 g/mol

Mass of magnesium chloride = Moles × Molar mass = 1.61835 × 95.21 g = 154.0831 g

6 0

2 years ago