HELP I DON'T HAVE LONG LEFT AND I'M STRUGGLING SO BAD PLEASE I BEG U TO HELP

Calculate the energy required to melt 21 g of ice at 0 oC.

vladimir1956 [14]

We are given:

Mass of ice = 21 grams

The ice is already at 0°c, the temperature at which it melts to form water

Molar heat of fusion of Ice = 6.02 kJ/mol

Finding the energy required:

Number of moles of Ice:

Molar mass of water = 18 g/mol

Number of moles = given mass/ molar mass

Number of moles = 21 / 18 = 7/6 moles

Energy required to melt the given amount of ice:

Energy = number of moles * molar heat of fusion

Energy = (7/6) * (6.02)

Energy = 7.02 kJ OR 7020 joules

7 0

2 years ago

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

Alexxandr [17]

Answer: 530 hours

Explanation:

The reduction of Nickel ions to nickel is shown as:

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

$96500\times 2=193000Coloumb$ of electricity deposits 1 mole of Nickel

1 mole of Nickel weighs = 58.7 g

Given quantity = 18.0 kg = 18000 g (1kg=1000g)

58.7 g of Nickel is deposited by 193000 C of electricity

18000 g of Nickel is deposited by = $\frac{193000}{58.7}\times 18000=59182282.8C$ of electricity

$Q=I\times t$

where Q= quantity of electricity in coloumbs = 59182282.8C

I = current in amperes = 31.0 A

t= time in seconds = ?

$59182282.8C=31.0A\times t$

$t=1909105.9sec$

(1h=3600 sec)

$t=530hours$

Thus 530 hours are required to plate 18.0 kg of nickel onto the cathode if the current passed through the cell is held constant at 31.0 A

3 0

2 years ago

Please match the example with the classification of matter in which it belongs. Column A 1. soil: soil 2. chocolate milk: chocol

bekas [8.4K]

Answer:

34

Explanation:

add

8 0

2 years ago

Steam initially at 0.3 MPa, 2500 C is cooled at constant volume. (a) At what temperature will steam become saturated vapour? [12

AlladinOne [14]

Answer:

a. 123.9°C

b.

c.

Explanation:

Hello, I'm attaching a picture with the numerical development of this exercise.

a. Since the steam is overheated vapour, the specific volume is gotten from the corresponding table. Then, as it became a saturated vapour, we look for the interval in which the same volume of state 1 is, then we interpolate and get the temperature.

b. Now, at 80°C, since it is about a rigid tank (constant volume for every thermodynamic process), the specific volume of the mixture is 0.79645 m^3/kg as well, so the specific volume for the liquid and the vapour are taken into account to get the quality of 0.234.

c. Now,since this is an isocoric process, the heat transfer per kg of steam is computed as the difference in the internal energy, considering the initial condition (showed in a. part) and the final one computed here.

** The thermodynamic data were obtained from Cengel's thermodynamics book 7th edition.

Best regards.

5 0

3 years ago

Which of the following has dispersion forces as its only intermolecular force? A) CH4 B) HCl C) C6H13NH2 D) NaCl E) CH3Cl

Natali5045456 [20]

D is the right answer

4 0

2 years ago