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4 years ago

Calculate the number of kilojoules to warm 125 g of iron from 23.5°C to 78.0°C.

Chemistry

1 answer:

Feliz [49]4 years ago

6 0

1014.97 Joules or 1.015 kilojoules This is the amount of heat produced in warming 125g of iron.

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In a unimolecular reaction with twice as much starting material as product at equilibrium, what is the value of Keq? Is ΔG o pos

lubasha [3.4K]

Answer : The value of $K_{eq}$ is, 0.5 and $\Delta G$ = positive.

Explanation :

The unimolecular reaction is:

$A\rightarrow B$

In unimolecular reaction, the starting material is 2 times to the product.

$A=2B$ .........(1)

As we know that:

$K_{eq}=\frac{B}{A}$ ...........(2)

Now substitute equation 1 in 2, we get:

$K_{eq}=\frac{\frac{A}{2}}{A}$

$K_{eq}=0.5$

Now we have to calculate the value of $\Delta G^o$ at 298 K.

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

where,

$\Delta G^o$ = standard Gibbs free energy = ?

R = gas constant = 8.314 J/mol.K

T = temperature = 298 K

$K_{eq}$ = equilibrium constant = 0.5

Now put all the given values on the above formula, we get:

$\Delta G^o=-(8.314J/mol.K)\times (298K)\ln (0.5)$

$\Delta G^o=1717.32J/mol$

Thus, the value of $\Delta G^o$ at 298 K is, 1717.32 J/mol

As we know that:

$\Delta G$ = +ve, reaction is non spontaneous

$\Delta G$ = -ve, reaction is spontaneous

$\Delta G$ = 0, reaction is in equilibrium

Thus, the $\Delta G$ = +ve. So, the reaction is non spontaneous.

8 0

4 years ago

Which of the following scenarios would drive the reaction below to the left? 2A+B+ Energy >< symbol thingy C+D

OLEGan [10]

Answer:
A. Adding D

Explanation:
Based on Le Chatelier's principle, a chemical reaction will reach equilibrium when the rate of the forward reaction is equal to the rate of the backwards (reverse) reaction.
Adding more reactants will cause the equilibrium to shift to the right and form more products in order to reach equilibrium again.
While adding more products will shift the equilibrium to the left and form more reactants in order to reach equilibrium again.

In the given question, we need the equilibrium to shift to the left and form more reactants. This means that we will need to add more products.
Therefore, we will need to add either C or D.

Applying this to the choices, we will find that the correct choice is A.

Hope this helps :)

6 0

4 years ago

What type of bonds are formed between silicon(Si) and oxygen(O) in silicon dioxide (SiO2), a commonly component of sand?

Sladkaya [172]

Answer:

Silicone Dioxide

Explanation:

It is found on sand since ancient times and also a major component of glass..I have heard of a case when a lightning hit the sand and the sand actually turned into a somewhat glasslike figure

6 0

3 years ago

Using data from Ms.Baltzers students, they found the mass of a piece of brown metal was 14.2 grams, and the volume of that same

Hunter-Best [27]

Answer:

d = 7.9 g/mL

Explanation:

Density:

Density is equal to the mass of substance divided by its volume.

Units:

SI unit of density is Kg/m3.

Other units are given below,

g/cm3, g/mL , kg/L

Formula:

D=m/v

D= density

m=mass

V=volume

Symbol:

The symbol used for density is called rho. It is represented by ρ. However letter D can also be used to represent the density.

Given data:

Mass of brown metal = 14.2 g

Volume = 1.8 mL

Density = ?

Solution:

d = m/v

d = 14.2 g/1.8 mL

d = 7.9 g/mL

5 0

3 years ago

I am not sure i am thinking A and C

SIZIF [17.4K]

Answer:

I think so too

Explanation:

4 0

3 years ago