How does one determine a percent composition from an empirical

In the reaction between copper and silver nitrate, 95.3 g of silver and 82.9g of copper nitrate are produced. How much of each r

Nastasia [14]

Reaction

2AgNO₃ + Cu ⇒ Cu(NO₃)₂ + 2Ag

mol silver (Ag): 95.3 : 108 g/mol = 0.882

mol copper nitrate (Cu(NO₃)₂): 82.9 : 187.5 g/mol = 0.441

mol Ag = 2 x mol Cu(NO₃)₂, so 0.441 being the mole basis of the reactants

mol Cu = 0.441

mass Cu = 0.441 x 63.5 g/mol = 28 g

mol AgNO₃ = 0.882

mass AgNO₃ = 0.882 x 170 g/mol = 149.94 g

5 0

3 years ago

Compounds like CCl₂F₂ are known as chlorofluorocarbons, or CFCs. These compounds were once widely used as refrigerants but are n

Nataliya [291]

Explanation:

The given data is as follows.

Specific heat of water = $4.18 J/g^{o}C$

Heat of fusion of water = 334 J/g

Mass of water = 200 g

On bringing water at $0^{o}C$ , heat released will be as follows.

$q_{1} = m \times C \times \Delta T$

= $200 g \times 4.18 J/g^{o}C \times (0 - 15)^{o}C$

= -12540 J

or, = -12.540 kJ (as 1 kJ = 1000 J)

Now, calculate the heat releasedwhen water freezes at $0^{o}C$ as follows.

$q_{2} = mass \times \text{-heat of fusion}$

= $200 g \times -334 J/g$

= -66800 J

or, = -66.80 kJ

Therefore, total heat released in freezing water will be as follows.

$q_{total} = q_{1} + q_{2}$

= (-12.540 - 66.80) kJ

= -79.34 kJ

Hence,

amount of heat released in freezing water = heat used to vaporize $CCl_{2}F_{2}$

Now, heat of vaporization of $CCl_{2}F_{2}$ = 289 J/g

Total heat released in freezing water = -79.34 kJ

Heat consumed to vaporize $CCl_{2}F_{2}$ = 79.34 kJ = -79340 J

Therefore, calculate the mass of $CCl_{2}F_{2}$ vaporized as follows.

Mass of $CCl_{2}F_{2}$ vaporized = $\frac{\text{heat consumed}}{\text{heat of vaporization}}$

= $\frac{79340 J}{289 J/g}$

= 274.53 g

Thus, we can conclude that 274.53 g mass of this substance must evaporate to freeze 200 g of water initially at $15^{o}C$ .

5 0

4 years ago

What is the phase of water at 0.25 atm and 0°C?

seropon [69]

D.) as you can tell the temperature is the x axis while pressure (atm) is the y axis, so therefore you’d find (0,0.25) which gives u solid because its not near water or gas

5 0

2 years ago

"Thermite" reactions have been used for welding metal parts such as railway rails and in metal refining. One such thermite react

frosja888 [35]

<u>Answer:</u> The given reaction is non-spontaneous in nature.

<u>Explanation:</u>

Entropy change is defined as the difference in entropy of all the product and the reactants each multiplied with their respective number of moles.

The equation used to calculate entropy change is of a reaction is:

$\Delta S^o_{rxn}=\sum [n\times \Delta S^o_{(product)}]-\sum [n\times \Delta S^o_{(reactant)}]$

For the given chemical reaction:

$3Mg(s)+Cr_2O_3(s)\rightarrow 3MgO(s)+2Cr(s)$

The equation for the entropy change of the above reaction is:

$\Delta S^o_{rxn}=[(3\times \Delta S^o_{(MgO(s))})+(2\times \Delta S^o_{(Cr(s))})]-[(3\times \Delta S^o_{(Mg(s))})+(1\times \Delta S^o_{(Cr_2O_3(s))})]$