Which of the following is not an example of a chemical change?

How much does the mass of 12.65-g sample of copper(II) nitrate hexahydrate decrease when heated?

garik1379 [7]

There is 103 percent of water in hydrate

4 0

2 years ago

Tollens’ test, also known as silver-mirror test, is a qualitative laboratory test used to distinguish between an aldehyde and a

Makovka662 [10]

Explanation:

Tollens' reagent is prepared by using two-step process : -

Step 1:

Silver oxide is formed by mixing aqueous silver nitrate with base like sodium hydroxide. The reaction is shown below as:

$AgNO_3 + NaOH &\rightarrow AgOH + NHO_3 \nonumber \\ 2AgOH &\rightarrow Ag_2O + H_2O$

Step 2

Ammonia solution is drop-wise added until all the silver oxide dissolves to form the reagent. The reaction is shown below as:

$Ag_2O + 4NH_3 + H_2O \rightarrow 2Ag(NH_3)_2^+ + 2OH^-$

3 0

3 years ago

Which season will the northern hemisphere experience if the axis of Earth is tilted away from the sun?

pashok25 [27]

the answer would be winter because the north would be facing away from the son therefor making the northern states cold.

8 0

3 years ago

Read 2 more answers

What does AS> O mean?

Vlad1618 [11]

Answer:

ΔS> 0 means Letter A

Explanation:

Processes that involve an increase in entropy of the system (ΔS > 0) are very often spontaneous; however, examples to the contrary are plentiful. By expanding consideration of entropy changes to include the surroundings, we may reach a significant conclusion regarding the relation between this property and spontaneity. In thermodynamic models, the system and surroundings comprise everything, that is, the universe, and so the following is true:

\displaystyle \Delta {S}_{\text{univ}}=\Delta {S}_{\text{sys}}+\Delta {S}_{\text{surr}}

5 0

3 years ago

1. Mg2+ and Ca2+ are in the same group on the periodic table. In terms of electronic

finlep [7]

Answer:

Se detailed explanation.

Explanation:

Hello,

In this case, since both magnesium and calcium ions are in group IIA, we can review the following similar properties:

- Since both calcium and magnesium are in group IIA they have two valence electrons, it means that the both of them have two electrons at their outer shells.

- They are highly soluble in water when forming ionic bonds with nonmetals such as those belonging to halogens and oxygen's family.

- Calcium has 18 electrons and magnesium 10 which are two less than the total protons (20 and 12 respectively) since the both of them have lost two electrons due their ionized form.

- Their electron configurations are:

$Ca^{20}=1s^2,2s^2,2p^6,3s^3,3p^6,4s^2\\\\Mg^{12}=1s^2,2s^2,2p^6,3s^2$

It means that the both of them are at the $s$ region since it is the last subshell at which their electrons are.

Best regards.

8 0

3 years ago