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iren [92.7K]
3 years ago
9

Which are correct ???

Chemistry
1 answer:
pav-90 [236]3 years ago
7 0

Answer:

last one

Explanation:

endothermic reactions release energy

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A mixture of CO2 and Kr weighs 31.7 g and exerts a pressure of 0.665 atm in its container. Since Kr is expensive, you wish to re
elena-s [515]

Answer:

11.94 grams of carbon dioxide were originally present.

19.94 grams of krypton can you recover.

Explanation:

Mass of carbon dioxide gas = x

Mass of krypton gas = y

x + y = 31.7 g

Moles of carbon dioxide gas = n_1=\frac{x}{44 g/mol}=

Moles of krypton gas = n_2=\frac{y}{84 g/mol}=

Mole fraction of krpton =\chi '

Total pressure of the mixture = P = 0.665 atm

Partial pressure of carbon dioxide gas = p

Partial pressure of krypton gas before removal  of carbon dioxide gas = p'

Partial pressure of krypton gas after removal  of carbon dioxide gas = p'' = 0.309 atm

p' = p'' = 0.309 atm

0.665 atm = p + 0.309 atm

p = 0.665 atm - 0.306 atm = 0.359 atm

Partial pressure of krypton can also be given by :

p'=P\times \chi '

0.309 atm=0.665 atm\times \frac{n_2}{n_1+n_2}

0.309 atm=0.665 atm\times \frac{\frac{y}{84}}{\frac{x}{44}+\frac{y}{84}}

0.4645=\frac{\frac{y}{84}}{\frac{x}{44}+\frac{y}{84}}..[2]

Solving [1] and [2]:

x = 11.94 g

y = 19.76 g

11.94 grams of carbon dioxide were originally present.

19.94 grams of krypton can you recover.

7 0
4 years ago
5.00 g of solid silver nitrate AgNO3 is added to 100ml of deionized H2O to make a substance that can test the presence of chlori
Mars2501 [29]

Answer:

The solvent is deionised water

The solute is AgNO3

The solution is [Ag(aq) + NO3(aq)-]

Explanation:

  • This is because it contains no ions which would otherwise react with AgNO3 thus AgNO3 just disolves releasing free Ag+ and NO3- . The resiltant solution can test for Cl presence
  • AgNO3 is a soluble salt in water thus disolves in water
  • AgNO3 disolves releasing free ions which can be called ionisation

6 0
3 years ago
If you have two peaks in your gas chromatograph, how many compounds are in your sample?
3241004551 [841]

Answer:

Two compounds.

Explanation:

If you have two peaks in your gas chromatograph, this means that you have two compounds.

The gas chromatograph is an instrument that helps identify how many compounds a substance has by observing its behavior against a solid medium through adsorption and the velocity of each compound in it.

7 0
4 years ago
45.5 g of ice is heated from -25 degrees celsius to 150 degrees celcius. Calculate the total amount of heat required for the ent
tino4ka555 [31]

Answer:

Q = 16163.88 Joules

Explanation:

Given the following data;

Initial temperature, T1 = -25°C

Final temperature, T2 = 150°C

Mass = 45.5 g

Specific heat capacity of ice = 2.03 J/g°C

To find the quantity of heat required;

Heat capacity is given by the formula;

Q = mcdt

Where;

Q represents the heat capacity or quantity of heat.

m represents the mass of an object.

c represents the specific heat capacity of water.

dt represents the change in temperature.

dt = T2 - T1

dt = 150 - (-25)

dt = 150 + 25

dt = 175°C

Substituting into the formula, we have;

Q = 45.5 * 2.03 * 175

Q = 16163.88 Joules

4 0
3 years ago
Which of these is an example of a physical change?
Vikki [24]

Answer:

b metal denting

Explanation:

8 0
4 years ago
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