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2 years ago

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Chemistry

1 answer:

lukranit [14]2 years ago

7 0

From the calculations, the heat that is required is 2.1 kJ.

<h3>What is the specific heat capacity?</h3>

The term specific heat capacity has to do with the amount of heat that must be supplied to 1Kg of a substance in order to raise its temperature by 1K.

In this case;

H = mcdT

H = 100 grams * 4.18 J/gC * (25 - 20)

H = 2.1 kJ

Learn more abut specific heat capacity:brainly.com/question/1747943

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1.00 M CaCl2 Density = 1.07 g/mL

Lesechka [4]

Explanation:

Molarity of solution = 1.00 M = 1.00 mol/L

In 1 L of solution 1.00 moles of calcium chloride is present.

Mass of solute or calcium chloride = m

$m = 1 mol\times 111 g/mol = 111 g$

Mass of solution = M

Volume of solution = V = 1L = 1000 mL

Density of solution , d= 1.07 g/mL

$M=d\times V=1.07 g/mL\times 1000 mL=1,070 g$

1) The value of %(m/M):

$\frac{m}{M}\times 100=\frac{111 g}{1,070 g}\times 100=10.37\%$

2) The value of %(m/V):

$\frac{m}{V}\times 100=\frac{111 g}{1000 L}\times 100=11.1\%$

$Molality = \frac{\text{Moles of compound }}{\text{mass of solvent in kg}}$

$Normality=\frac{\text{Moles of compound }}{n\times \text{volume of solution in L}}$

n = Equivalent mass

n = $\frac{\text{molar mass of ion}}{\text{charge on an ion}}$

3) Normality of calcium ions:

Moles of calcium ion = 1 mol (1 $CaCl_2$ mole has 1 mole of calcium ion)

$n=\frac{40 g/mol}{2}=20$

$=\frac{1 mol}{20 g/mol\times 1L}=0.050 N$

4) Normality of chlorine ions:

Moles of chlorine ion = 2 mol (1 $CaCl_2$ mole has 2 mole of chlorine ion)

$n=\frac{35.5 g/mol}{1}=35.5$

$=\frac{2 mol}{35.5 g/mol\times 1L}=0.056 N$

Moles of calcium chloride = 1.00 mol

Mass of solvent = Mass of solution - mass of solute

= 1,070 g - 111 g = 959 g = 0.959 kg ( 1 g =0.001 kg)

5) Molality of the solution :

$\frac{1 mol}{0.959 kg}=1.043 mol/kg$

Moles of calcium chloride = $n_1=1mol$

Mass of solvent = 959 g

Moles of water = $n_2=\frac{959 g}{18 g/mol}=53.28 mol$

Mass of solvent = 959 g

6) Mole fraction of calcium chloride =

$\chi_1=\frac{n_1}{n_1+n_2}=\frac{1mol}{1 mol+53.28 mol}=0.01842$

7) Mole fraction of water =

$\chi_2=\frac{n_2}{n_1+n_2}=\frac{53.28 mol}{1mol+53.28 mol}=0.9816$

8) Mass of solution = m'

Volume of the solution= v = 100 mL

Density of solution = d = 1.07 g/mL

$m'=d\times v=1.07 g/ml\times 100 g= 107 g$

Mass of 100 mL of this solution 107 grams of solution.

9) Volume of solution = V = 100 mL

Mass of solution = M'' = 107 g

Mass of solute = m

The value of %(m/V) of solution = 11.1%

$11.1\%=\frac{m}{100 mL}\times 100$

m = 11.1 g

Mass of solvent = M''- m = 107 g -11.1 g = 95.9 g

95.9 grams of water was present in 100 mL of given solution.

3 0

3 years ago

In the ground state, which atom has a completely filled valence electron shell?(1) C (2) V (3) Ne (4)Sb

AVprozaik [17]

The answer is (3)Ne. Usually, the elements belongs to group 18 all have completely filled valence electron shell. Among the four elements carbon, vanadium, neon and antimony, only neon belongs to group 18.

7 0

2 years ago

Read 2 more answers

14. What volume (mL) of water do I need to add to 425

Reptile [31]

Answer:

212.5 mL

both the original and the diluted solution have 0.765 moles of KCl

Explanation:

c1V1 = c2V2

V2 = c1V1/c2 = (1.8 M×425 mL)/1.2 M = 637.5 mL

(637.5 - 425) mL = 212.5 mL

n = (1.8 mol/L)(0.425 L) = 0.765 moles of KCl

since it's a dilution, the diluted solution has the same number of moles as the original solution, 0.765 moles of KCl

7 0

3 years ago

Why is it important to use low flame when evaporating water from a recovered filtrate?

goldfiish [28.3K]

It is important to use low flame when evaporating water from a recovered filtrate because then the water and filtrate will not spatter and the filtrate can also be recovered after evaporating water.

If flame is not low then water as well as got spatter so it is important to use low flame so that the water and filtrate will not spatter.

4 0

3 years ago

Consider the following data for five hypothetical elements: Q, W, X, Y, and Z. Rank the elements from most reactive to least rea

Natalka [10]

Answer:

Y, Q, W, Z and X

Y > Q > W > Z > X

Explanation:

To know the most reactive element, the element will be able to displace other metal in it compound. We also have to observe if the reaction occur. If the reaction didn't occur, that means the element is not reactive than the metal found in the other reactant. Invariably their will be no displacement.

Q + w+ Reaction occurs

Q element displace the metal w in it compound . This means Q is more reactive.

x +z+ No reaction

No reaction here. This means x is less reactive than z as it couldn't displace z in it compound.

w + z+ Reaction occurs

w is more reactive than z as it displaces z in it compound.

Q+ + Y Reaction occurs

Y is more reactive than Q as it displaces Q in it compounds.

Therefore, the most reactive to the least reactive is arrange as follows.

Y, Q, W, Z and X

8 0

3 years ago