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Anarel [89]
3 years ago
15

Element X reacts with hydrogen gas at 200°C to form compound Y. When Y is heated to a higher temperature, it decomposes to the e

lement X and hydrogen gas in the ratio of 559 mL of H2 (measured at standard temperature and pressure) for 1.00 g of X reacted. X also combines with chlorine to form a compound Z, which contains 63.89 percent by mass of chlorine. Deduce the identity of X. The symbol of element X is
Chemistry
1 answer:
vfiekz [6]3 years ago
5 0

Answer:

X is calcium with the symbol Ca

Explanation:

From the first statement:

X reacted with H2 to produce Z i.e

X + H2 —> Y

Y is heated to form X and H2 i.e

Y —> X + H2

Let us obtain moles of H2 produced. This is illustrated below:

Volume of H2 produced = 559 mL = 0.559 L.

I mole of H2 occupy 22.4L at stp

Therefore, b mol of H2 will occupy 0.559 L at stp i.e

b mol of H2 = 0.559/22.4

b mol of H2 = 0.025 mole

Next 0.025 mole of H2 to gram..

Molar Mass of H2 = 2x1 = 2g/mol

Mole of H2 = 0.025 mole

Mass = number of mole x molar Mass

Mass of H2 = 0.025 x 2

Mass of H2 = 0.05g

From the question given, we were told that 1g of X reacted. This means that 1g of X reacted with 0.05g of H2. Now let us determine the mass of X that will react with 1 mol ( i.e 2g) of H2. This is illustrated below:

From the reaction,

It was discovered that 1g of X reacted with 0.05g of H2.

Therefore, P g of X will react with 2g of H2 i.e

P g of X = 2/0.05 = 40g/mol

The molar mass of X is 40g/mol.

Now let us consider the second statement to see if we'll obtained the same result as 40g/mol of X

From the second statement:

X also combines with chlorine to form a compound Z, which contains 63.89 percent by mass of chlorine i.e

X + Cl2 —> Z

Molar Mass of Z (X + 2Cl) = X + (35.5 x 2) = X + 71.

Z contains 63.89% by mass of Cl2.

We can obtain the molar mass of X as follow:

Percentage by mass of Cl2 in the compound Z is given by:

Mass of Cl2/Molar Mass x100

63.89/100 = 71/(X + 71)

Cross multiply to express in linear form

63.89(X + 71) = 100 x 71

Clear the bracket

63.89X + 4536.19 = 7100

Collect like terms

63.89X = 7100 - 4536.19

63.89X = 2563.81

Divide both side by 63.89

X = 2563.81/63.89

X = 40g/mol

Now we can see that in both experiments, the molar mass of X is 40g/mol.

Comparing the value of X i.e 40g/mol with that from the periodic table, X is calcium with the symbol Ca

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4.A 100 L sample of gas is at a pressure of 80 kPa and a temperature of 200 K. What volume does the same
dexar [7]

Answer:

V₂ = 107.84 L

Explanation:

Given data:

Initial volume = 100 L

Initial pressure = 80 KPa (80/101 =0.79 atm)

Initial temperature = 200 K

Final temperature =273 K

Final volume = ?

Final pressure = 1 atm

Formula:  

P₁V₁/T₁ = P₂V₂/T₂  

P₁ = Initial pressure

V₁ = Initial volume

T₁ = Initial temperature

P₂ = Final pressure

V₂ = Final volume

T₂ = Final temperature

Solution:

V₂ = P₁V₁T₂  /T₁P₂

V₂ = 0.79 atm × 100 L × 273 K / 200 K × 1 atm

V₂ =21567 atm.L.K /200 K.atm

V₂ = 107.84 L

8 0
3 years ago
Instant cold packs, often used to ice athletic injuries on the field, contain ammonium nitrate and water separated by a thin pla
RSB [31]

<u>Answer:</u> The enthalpy change of the reaction is -27. kJ/mol

<u>Explanation:</u>

To calculate the mass of water, we use the equation:

\text{Density of substance}=\frac{\text{Mass of substance}}{\text{Volume of substance}}

Density of water = 1 g/mL

Volume of water = 25.0 mL

Putting values in above equation, we get:

1g/mL=\frac{\text{Mass of water}}{25.0mL}\\\\\text{Mass of water}=(1g/mL\times 25.0mL)=25g

To calculate the heat released by the reaction, we use the equation:

q=mc\Delta T

where,

q = heat released

m = Total mass = [1.25 + 25] = 26.25 g

c = heat capacity of water = 4.18 J/g°C

\Delta T = change in temperature = T_2-T_1=(21.9-25.8)^oC=-3.9^oC

Putting values in above equation, we get:

q=26.25g\tiimes 4.18J/g^oC\times (-3.9^oC)=-427.9J=-0.428kJ

To calculate the number of moles, we use the equation:

\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}

Given mass of ammonium nitrate = 1.25 g

Molar mass of ammonium nitrate = 80 g/mol

Putting values in above equation, we get:

\text{Moles of ammonium nitrate}=\frac{1.25g}{80g/mol}=0.0156mol

To calculate the enthalpy change of the reaction, we use the equation:

\Delta H_{rxn}=\frac{q}{n}

where,

q = amount of heat released = -0.428 kJ

n = number of moles = 0.0156 moles

\Delta H_{rxn} = enthalpy change of the reaction

Putting values in above equation, we get:

\Delta H_{rxn}=\frac{-0.428kJ}{0.0156mol}=-27.44kJ/mol

Hence, the enthalpy change of the reaction is -27. kJ/mol

4 0
3 years ago
Are inic bonds formed when electrons are equally or unequally shared
lisabon 2012 [21]

The electrons are unequally shared. The electronegative element receives the electrons from the electropositive one.

8 0
3 years ago
Attempt 4 A galvanic cell has an X electrode with X 2 plus ions in the left beaker and a Y electrode with Y 2 plus ions in the r
babymother [125]

Answer:

See explaination

Explanation:

Since X is more reactive than Y

=> X is oxidized to X2+ and Y2+ is reduced to Y

Overall cell reaction is:

X(s) + Y2+(aq) => X2+(aq) + Y(s)

please kindly see attachment for further solution.

4 0
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What is another name for the sunlit zone of the ocean?
motikmotik

Answer:

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Explanation:

i hope it will help

4 0
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