How likely do you think it is that life exists on other planets

Which substance has AHf defined as O kJ/mol?

Andru [333]

Answer:

(C). is the answer, I think

5 0

3 years ago

How many atoms are present in 48.60 g of Mg

Ganezh [65]

1.204 x 10 ( 24 ) atoms of magnesium are present.
In order to go from mass of magnesium there have to do 2 things

1. convert mass of Mg to moles of Mg using the molar mass of Mg as converted to a factor

2. convert moles of Mg to atoms of Mg using the Avogadro's number ( 6.02 x 10 (23) as a conversion factor

Hope my it helped a little :)

3 0

4 years ago

What are the concentrations of A , A, B , B, and C C at equilibrium if, at the beginning of the reaction, their concentrations a

Elenna [48]

The question is incomplete, here is the complete question:

A reaction

$A+B\rightleftharpoons C$

has a standard free-energy change of -4.88 kJ/mol at 25°C

What are the concentrations of A, B, and C at equilibrium if at the beginning of the reaction their concentrations are 0.30 M, 0.40 M and 0 M respectively?

Answer: The equilibrium concentrations of A, B and C are 0.117 M, 0.217 M, 0.183 M respectively.

Explanation:

Relation between standard Gibbs free energy and equilibrium constant follows:

$\Delta G^o=-RT\ln K_c$

where,

$\Delta G^o$ = Standard Gibbs free energy = -4.88 kJ/mol = -4880 J/mol (Conversion factor: 1 kJ = 1000 J)

R = Gas constant = $8.314J/K mol$

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

$K_c$ = equilibrium constant of the reaction

Putting values in above equation, we get:

$-4880J/mol=-(8.3145J/Kmol)\times 298K\times \ln K_c\\\\K_c=7.17$

We are given:

Initial concentration of A = 0.30 M

Initial concentration of B = 0.40 M

Initial concentration of C = 0 M

The chemical reaction follows:

$A+B\rightleftharpoons C$

Initial: 0.30 0.40 0

At eqllm: 0.30-x 0.40-x x

The expression of equilibrium constant for the above reaction follows:

$K_c=\frac{[C]}{[A][B]}$

We are given:

$K_c=7.17$

Putting values in above equation, we get:

$7.17=\frac{x}{(0.30-x)\times (0.40-x)}\\\\x=0.183,0.657$

Neglecting the value of x = 0.657, because change cannot be greater than the initial concentration

So, equilibrium concentration of A = $(0.30-x)=(0.30-0.183)=0.117M$

Equilibrium concentration of B = $(0.40-x)=(0.40-0.183)=0.217M$

Equilibrium concentration of C = $x=0.183M$

Hence, the equilibrium concentrations of A, B and C are 0.117 M, 0.217 M, 0.183 M respectively.

5 0

3 years ago

Write the word and balanced chemical equations for the reaction between: Sodium and water

devlian [24]

Answer:

The balanced chemical equation for the reaction between sodium and water is:2 Na ( s ) + 2 H2O ( l ) 2 NaOH ( aq ) + H2 ( g ) We can interpret this to mean: 2 moles of water and ? ... mole(s) of hydrogen.

4 0

3 years ago

Please help I’m failing

denis-greek [22]

Answer:

C.

Explanation:

Solubility KClO3 at 45°C is around 15 g KClO3 in 100 g of water. We have

30 g that is more. So, solution is supersaturated.

3 0

3 years ago