WITCH IS MADE BY WEATHERING ASH SEDEMENTS MAGMA OR MINERALS

The reaction of hydrogen(g) with fluorine(g) to form hydrogen fluoride(g) proceeds as follows: H2(g) + F2(g) 2 HF(g) When 0.647

Nata [24]

Answer: The value of $\Delta H$ for the reaction will be -537 kJ

Explanation:

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

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

Given mass of hydrogen gas = 0.647 g

Molar mass of hydrogen gas = 2 g/mol

Putting values in above equation, we get:

$\text{Moles of hydrogen gas}=\frac{0.647g}{2g/mol}=0.324mol$

We are given:

Energy released for 0.324 moles of hydrogen reacted is 174 kJ

For the given chemical reaction:

$H_2(g)+F_2(g)\rightarrow 2HF(g)$

By Stoichiometry of the reaction:

When 0.324 moles of hydrogen gas is reacted, the energy evolved is 174 kJ

So, when 1 mole of hydrogen gas will react, the energy evolved will be = $\frac{174kJ}{0.324mol}\times 1mol=537kJ$

Sign convention of heat:

When heat is absorbed, the sign of heat is taken to be positive and when heat is released, the sign of heat is taken to be negative.

Hence, the value of $\Delta H$ for the reaction will be -537 kJ

6 0

3 years ago

Calculate the number of C atoms in 0.190 mole C6H14O. can anyone help me on this one?

likoan [24]

In 0.190 mole of C6H14O, there is 0.190*6 (number of C in one molecule) = 1.140 mole of C atoms. The total number of C atoms = 1.14 * 6* $10^{23}$ (atoms of C in one mole) = 6.84* $10^{23}$ atoms.

8 0

3 years ago

What is the percent composition of the u.s quarter, which has the mass of 5.670g

Vitek1552 [10]

The percent composition of each element can be calculated as follows:
% composition = (mass of element / total mass) * 100

The total mass of the quarter is given to be 5.670 grams
Mass of Cu = 5.198 grams
Mass of Ni = 0.472 grams

Substitute in the above equation to get the mass percentage of each element as follows:
% of Cu = (5.198/5.670) * 100 = 91.675%
% of Ni = (0.472/5.670) * 100 = 8.325%

6 0

3 years ago

URGENT PLEASE HELP!!!

mote1985 [20]

Even though two grams seemed to disappear or vanish, the law of conversation of mass still holding true. Mercuric oxide, when heated, forms a gas of mercury and oxygen. During the investigation, some gas could have escaped or evaporated.

5 0

3 years ago

Read 2 more answers

A student titrates 10.00 milliliters of hydrochloric acid of unknown molarity with 1.000 m naoh. it takes 21.17 milliliters of b

Dima020 [189]

Mole ratio for the reaction is 1:1
no of moles in NaOH that reacted= 1*21.17/1000=0.02117mols
molarity of HCl=0.02117*10/1000
=2.117M

4 0

3 years ago