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3 years ago

14

Chemistry is often called the __________ science because it involves the study of the materials in the universe and the changes

these materials undergo

1 answer:

Delvig [45]3 years ago

4 0

Answer:

Central

Explanation:

Chemistry is often called the central science because of connects the physical sciences, life sciences and applied sciences.

Chemistry is the study of matter and changes undergone by matter. This makes chemistry to occupy a central place in many scientific disciplines including medicine, engineering, pharmacy, geology etc. Basic knowledge of chemistry is usually required by experts in these disciplines.

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Purification of copper can be achieved by electrorefining copper from an impure copper anode onto a pure copper cathode in an el

Likurg_2 [28]

Answer: 281 hours

Explanation:-

1 electron carry charge= $1.6\times 10^{-19}C$

1 mole of electrons contain= $6.023\times 10^{23}$ electrons

Thus 1 mole of electrons carry charge= $\frac{1.6\times 10^{-19}}{1}\times 6.023\times 10^{23}=96500C$

$Cu^{2+}+2e^-\rightarrow Cu$

$96500\times 2=193000Coloumb$ of electricity deposits 1 mole or 63.5 g of copper

0.0635 kg of copper is deposited by 193000 Coloumb

11.5 kg of copper is deposited by= $\frac{193000}{0.0635}\times 11.5=34952756$ Coloumb

$Q=I\times t$

where Q= quantity of electricity in coloumbs = 34952756 C

I = current in amperes = 34.5 A

t= time in seconds = ?

$34952756 C=34.5A\times t$

$t=1013123sec=281hours$

Thus it will take 281 hours to plate 11.5 kg of copper onto the cathode if the current passed through the cell is held constant at 34.5 A.

8 0

3 years ago

A vessel of 120ml capacity contains a certain amount of gas at 35°C and 1.2 bar pressure. The gas is transferred to another vess

Rainbow [258]

Given parameters:

Initial volume = 120ml

Initial temperature = 35°C

Initial pressure = 1.2bar

Final volume = 180ml

Final temperature = 35°C

Unknown:

Final pressure = ?

To solve this problem, we apply the combined gas law. The expression is given below;

$\frac{P_{1}V_{1} }{T_{1} } = \frac{P_{2}V_{2} }{T_{2} }$

Where P₁ is the initial pressure

P₂ is the final pressure

V₁ is the initial volume

V₂ is the final volume

T₁ is the initial temperature

T₂ is the final temperature

We need to convert the parameters to standard units

take the volume to dm³;

1000ml = 1dm³

120ml = $\frac{120}{1000}$ dm³ = 0.12dm³ = initial volume

Final volume;

1000ml = 1dm³

180ml = $\frac{180}{1000}$ dm³ = 0.18dm³

Now, the temperature;

K = 273 + °C

Initial temperature = 273 + 35 = 308k

Final temperature = 308k

We then input the parameters into the equation;

$\frac{1.2bar x 0.12 }{308} = \frac{P_{2} x 0.18 }{308}$

Solving for P₂;

P₂ = 0.8bar

The new pressure or final pressure in the vessel is 0.8bar

5 0

3 years ago

Potassium fluoride (KF, a salt, has a molecular weight of 58.10 grams. How many grams would be needed to make 1.0 liter of 5.0 m

AlladinOne [14]

The concentration of the solution is 5.0 molar, which is 5.0 mole/L. So in the 1.0 L of 5.0 molar KF salt solution, the moles of KF is 5.0molar*1.0L=5.0 mole. The molecular weight of KF is given in the question as 58.10 gram/mole, so the grams of KF is 58.10 gram/mole * 5.0 mole = 290.5 gram.

3 0

3 years ago

Calculate the density of nitrogen gas at STP, in g/L

viva [34]

Answer:

Explanation:

To find the density of nitrogen gas at STP which is standard temperature and pressure, certain parameters must be known.

The mass of the gas must be given or its volume.

Density of a substance is the mass per unit area;

Volume of gas at STP = number of moles x 22.4

Using the volume obtained here,

Density = $\frac{mass}{volume}$

Then we can find the density.

The mass is very important.

5 0

3 years ago

What is the solubility of ethylene (in units of grams per liter) in water at 25 °C, when the C2H4 gas over the solution has a pa

vredina [299]

<u>Answer:</u> The solubility of ethylene gas in water is $9.16\times 10^{-2}g/L$

<u>Explanation:</u>

To calculate the molar solubility, we use the equation given by Henry's law, which is:

$C_{C_2H_4}=K_H\times p_{C_2H_4}$

where,

$K_H$ = Henry's constant = $4.78\times 10^{-3}mol/L.atm$

$C_{C_2H_4}$ = molar solubility of ethylene gas = ?

$p_{C_2H_4}$ = partial pressure of ethylene gas = 0.684 atm

Putting values in above equation, we get:

$C_{C_2H_4}=4.78\times 10^{-3}mol/L.atm\times 0.684atm\\\\C_{C_2H_4}=3.27\times 10^{-3}mol/L$

Converting this into grams per liter, by multiplying with the molar mass of ethylene:

Molar mass of ethylene gas = 28 g/mol

So, $C_{C_2H_6}=3.27\times 10^{-3}mol/L\times 28g/mol=9.16\times 10^{-2}g/L$

Hence, the solubility of ethylene gas in water is $9.16\times 10^{-2}g/L$

6 0

3 years ago