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lara [203]
3 years ago
8

explain why it is a common laboratory procedure to heat analytical reagents and store them in a dessicated atmosphere (a sealed

environment containing a dehumidifying agent) before use.
Chemistry
1 answer:
Readme [11.4K]3 years ago
6 0

Explanation:

Most reagent forms are going to absorb water from the air; they're called "hygroscopic".  Water presence can have a drastic impact on the experiment being performed  For fact, it increases the reagent's molecular weight, meaning that anything involving a very specific molarity (the amount of molecules in the final solution) will not function properly.

Heating will help to eliminate water, although some chemicals don't react well to heat, so it shouldn't be used for all.  A dessicated environment is simply a means to  "dry."  That allows the reagent with little water in the air to attach with.

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When 1 mole of H2(g) reacts with F2(g) to form HF(g) according to the following equation, 542 kJ of energy are evolved H2(g) + F
topjm [15]

Answer: The reaction is exothermic. The value of q is  -542 kJ.

Explanation:

Endothermic reactions are defined as the reactions in which energy of the product is greater than the energy of the reactants. The total energy is absorbed in the form of heat and  for the reaction comes out to be positive.

Exothermic reactions are defined as the reactions in which energy of the product is lesser than the energy of the reactants. The total energy is released in the form of heat and  for the reaction comes out to be negative.

Thus H_2(g)+F_2(g)\rightarrow 2HF(g) evolves heat , it is exothermic in nature. The value of q is -542kJ.

7 0
3 years ago
How do two sublevels of the same principal energy level differ from each other?
dem82 [27]

Two sublevels of the same principal energy level differ from each other through shape and size.

There are mainly 4 energy level s, p, d and f.

The s level has one orbital and one orbital have two electrons. So the maximum number of electron in s sublevel is 2.

The p level has three orbital and one orbital have two electrons. So the maximum number of electron in s sublevel is 6.

The d level has five orbital and one orbital have two electrons. So the maximum number of electron in s sublevel is 10.

The f level has 7 orbital and one orbital have two electrons. So the maximum number of electron in s sublevel is 14.

They may be differ in magnetic level.

Thus, we concluded that Two sublevels of the same principal energy level differ from each other through shape and size.

learn more about energy level:

brainly.com/question/14654539

#SPJ13

3 0
1 year ago
Carbonyl fluoride, COF2, is an important intermediate used in the production of fluorine-containing compounds. For instance, it
lions [1.4K]

<u>Answer:</u> The equilibrium concentration of COF_2 is 0.332 M

<u>Explanation:</u>

We are given:

Initial concentration of COF_2 = 2.00 M

The given chemical equation follows:

                2COF_2(g)\rightleftharpoons CO_2(g)+CF_4(g)

<u>Initial:</u>          2.00

<u>At eqllm:</u>     2.00-2x          x      x

The expression of K_c for above equation follows:

K_c=\frac{[CO_2][CF_4]}{[COF_2]^2}

We are given:

K_c=6.30

Putting values in above expression, we get:

6.30=\frac{x\times x}{(2.00-2x)^2}\\\\x=0.834,1.25

Neglecting the value of x = 1.25 because equilibrium concentration of the reactant will becomes negative, which is not possible

So, equilibrium concentration of COF_2=(2.00-2x)=[2.00-(2\times 0.834)]=0.332M

Hence, the equilibrium concentration of COF_2 is 0.332 M

4 0
3 years ago
Are scientific theories all proven facts?
SSSSS [86.1K]
No! That’s why they’re called theories. Most of them have a lot of facts to back it up however the theories themselves are either proven or just hypothetical.
8 0
3 years ago
Read 2 more answers
Which statement about AHf is true?
Pachacha [2.7K]

Answer:

  • <u><em>It is positive when the bonds of the product store more energy than those of the reactants.</em></u>

Explanation:

The <em>standard enthalpy of formation</em>, <em>ΔHf</em>, is defined as the energy required to form 1 mole of a substance from its contituent elements under standard conditions of pressure and temperature.

Then, per defintion, when the elements are already at their standard states, there is not energy involved to form them from that very state; this is, the standard enthalpy of formation of the elements in their standard states is zero.

It is not zero for the compounds in its standard state, because energy should be released or absorbed to form the compounds from their consituent elements. Thus, the first choice is false.

When the bonds of the products store more energy than the those of the reactants, the difference is:

  • ΔHf =  ΔHf products - ΔHf reactants > 0, meaning that ΔHf is positive. Hence, the second statement is true.

Third is false because forming the compounds may require to use (absorb) or release (produce) energy, which means that ΔHf could be positive or negative.

Fourth statement is false, because the standard state of many elements is not liquid. For example, it is required to supply energy to iron to make it liquid. Thus, the enthalpy of formation of iron in liquid state is not zero.

3 0
3 years ago
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