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3 years ago

37.9 grams of an unknown substance undergoes a temperature increase of

Chemistry

1 answer:

jenyasd209 [6]3 years ago

4 0

Answer:

1.023 J / g °C

Explanation:

m = 37.9 grams

ΔT = 25.0*C

H = 969 J

c = ?

The equation relating these equation is;

H = mcΔT

making c subject of formulae;

c = H / mΔT

c = 969 J / (37.9 g * 25.0*C)

Upon solving;

c = 1.023 J / g °C

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Explanation:

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3 years ago

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Answer:

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Explanation:

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Calculate the equilibrium constant for the following reaction: Co2+ (aq) + Zn(s> CO (s) + Zn2+ (aq)

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Answer: The $K_{eq}$ of the reaction is $1.73\times 10^{16}$

Explanation:

For the given half reactions:

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Reduction half reaction: $Co^{2+}+2e^-\rightarrow Co(s);E^o_{Co^{2+}/Co}=-0.28V$

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To calculate the $E^o_{cell}$ of the reaction, we use the equation:

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Putting values in above equation, we get:

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$\Delta G^o=-nfE^o_{cell}$

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$\Delta G^o=-RT\ln K_{eq}$

Equating these two equations, we get:

$nfE^o_{cell}=RT\ln K_{eq}$

where,

n = number of electrons transferred = 2

F = Faraday's constant = 96500 C

$E^o_{cell}$ = standard electrode potential of the cell = 0.48 V

R = Gas constant = 8.314 J/K.mol

T = temperature of the reaction = $25^oC=[273+25]=298K$

$K_{eq}$ = equilibrium constant of the reaction = ?

Putting values in above equation, we get:

$2\times 96500\times 0.48=8.314\times 298\times \ln K_{eq}\\\\K_{eq}=1.73\times 10^{16}$

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3 years ago

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Answer:

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Pure substances are elements or compounds which are not mixed with more substances.

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Homogeneous mixtures are when the different components can be identified.

Heterogeneous mixtures are when the different components can be identified just by looking at the mixture.

In concrete we can identify the different components like gravel, sand, crushed rocks, etc, so concrete is a heterogeneous mixture.

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