All categories

2 years ago

Which of the following sign does not indicate that a chemical change has happened .

Chemistry

1 answer:

Sever21 [200]2 years ago

4 0

Answer:

A.)

Explanation:

A change in state may seem like a chemical reaction, but it is actually a physical change. "A change in state" is basically saying that the appearance of whatever the item is, is taking a change physically. Whether this item was going through some examples of a physical change, which would be:

melting (solid to liquid), evaporation (liquid to gas), condensation (gas to liquid), freezing (liquid to solid), deposition (gas to solid), and sublimation (solid to gas).

A change in color, odor, taste, chemical compound, and temperature all represent a chemical reaction, because these are all things that are happening within the the item that is being given the product of a chemical change.

Think of it this way: internal changes within the product: chemical. External changes within the product: physical.

I hope this helps.

You might be interested in

Consider the following reaction at a high temperature. Br2(g) ⇆ 2Br(g) When 1.35 moles of Br2 are put in a 0.780−L flask, 3.60 p

UNO [17]

Answer : The equilibrium constant $K_c$ for the reaction is, 0.1133

Explanation :

First we have to calculate the concentration of $Br_2$ .

$\text{Concentration of }Br_2=\frac{\text{Moles of }Br_2}{\text{Volume of solution}}$

$\text{Concentration of }Br_2=\frac{1.35moles}{0.780L}=1.731M$

Now we have to calculate the dissociated concentration of $Br_2$ .

The balanced equilibrium reaction is,

$Br_2(g)\rightleftharpoons 2Br(aq)$

Initial conc. 1.731 M 0

At eqm. conc. (1.731-x) (2x) M

As we are given,

The percent of dissociation of $Br_2$ = $\alpha$ = 1.2 %

So, the dissociate concentration of $Br_2$ = $C\alpha=1.731M\times \frac{1.2}{100}=0.2077M$

The value of x = 0.2077 M

Now we have to calculate the concentration of $Br_2\text{ and }Br$ at equilibrium.

Concentration of $Br_2$ = 1.731 - x = 1.731 - 0.2077 = 1.5233 M

Concentration of $Br$ = 2x = 2 × 0.2077 = 0.4154 M

Now we have to calculate the equilibrium constant for the reaction.

The expression of equilibrium constant for the reaction will be :

$K_c=\frac{[Br]^2}{[Br_2]}$

Now put all the values in this expression, we get :

$K_c=\frac{(0.4154)^2}{1.5233}=0.1133$

Therefore, the equilibrium constant $K_c$ for the reaction is, 0.1133

7 0

3 years ago

What happens to the rate of dissolution as the temperature is increased in a gas solution?

Nina [5.8K]

Answer:

The rate decreases

Explanation:

When we dissolve a gas in a water, the process is exothermic. This implies that heat is evolved upon dissolution of a gas in water.

Recall from Le Chateliers principle that for exothermic reactions, an increase in temperature favours the reverse reaction. The implication of these is that when the temperature of the gas is increased, less gas will dissolve in water.

Hence increase in temperature decreases the rate of solubility of a gas in water.

8 0

3 years ago

In the electrolysis of molten libr, which product forms at the cathode?

Ira Lisetskai [31]

Sodium metal forms at the cathode

6 0

3 years ago

C como Se define una cuenca hidrogatica Ayudaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa

sladkih [1.3K]

Answer:

Una cuenca es un área de tierra que drena todos los arroyos y la lluvia a una salida común, como la salida de un embalse, la boca de una bahía o cualquier punto a lo largo del canal de un arroyo.

Explanation:

Espero que esto ayude a marcar el MÁS CEREBRAL !!!

7 0

3 years ago

Explain the chemistry behind global warming in 3-5 sentences

Oliga [24]

Answer:

When factories mass produce something it produces smoke. That smoke can be harmful to something called the ozone layer. The ozone layer is part of earth's atmosphere that protects us from the suns burning heat. When that layer is damaged the sun's heat burns through heating up the world and melting ice causing the water levels to rise. All of this can make working conditions less safe, cause more flooding, and have the sun cause cancer.

8 0

3 years ago