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Vlad1618 [11]
3 years ago
13

Why does the designed world change?

Chemistry
1 answer:
Archy [21]3 years ago
3 0
The designed world is changed regularly by inovations and new technology.
Hope I could help.
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Hydrogen reacts with chlorine to form hydrogen chloride (HCl (g), mc012-1.jpgHf = –92.3 kJ/mol) according to the reaction below.
Kobotan [32]

<u>Given:</u>

H2(g) + Cl2 (g) → 2HCl (g)

<u>To determine:</u>

The enthalpy of the reaction and whether it is endo or exothermic

<u>Explanation:</u>

Enthalpy of a reaction is given by the difference between the enthalpy of formation of reactants and products

ΔH = ∑nHf (products) - ∑nHf (reactants)

      = [2Hf(HCl)] - [Hf(H2) + Hf(Cl2)] = 2 (-92.3) kJ = - 184.6 kJ

Since the reaction enthalpy is negative, the reaction is exothermic

<u>Ans:</u> The enthalpy of reaction is -184. kJ and the reaction is exothermic

3 0
3 years ago
Read 2 more answers
For Na2HPO4:(( (Note that for H3PO4, ka1= 6.9x10-3, ka2 = 6.4x10-8, ka3 = 4.8x10-13 ) a) The active anion is H2PO4- b) The activ
Komok [63]

Answer:

Check the explanation

Explanation:

Answer – Given, H_3PO_4 acid and there are three Ka values

K_{a1}=6.9x10^8, K_{a2} = 6.2X10^8, and K_{a3}=4.8X10^{13}

The transformation of H_2PO_4- (aq) to HPO_4^2-(aq)is the second dissociation, so we need to use the Ka2 = 6.2x10-8 in the Henderson-Hasselbalch equation.

Mass of KH2PO4 = 22.0 g , mass of Na2HPO4 = 32.0 g , volume = 1.00 L

First we need to calculate moles of each

Moles of KH2PO4 = 22.0 g / 136.08 g.mol-1

                             = 0.162 moles

Moles of Na2HPO4 = 32.0 g /141.96 g.mol-1

                             = 0.225 moles

[H2PO4-] = 0.162 moles / 1.00 L = 0.162 M

[HPO42-] = 0.225 moles / 1.00 L = 0.225 M

Now we need to calculate the pKa2

pKa2 = -log Ka

       = -log 6.2x10-8

       = 7.21

We know Henderson-Hasselbalch equation

pH = pKa + log [conjugate base] / [acid]

pH = 7.21 + log 0.225 / 0.162

     = 7.35

The pH of a buffer solution obtained by dissolving 22.0 g of KH2PO4 and 32.0 g of Na2HPO4 in water and then diluting to 1.00 L is 7.35

6 0
3 years ago
A battery changes chemical energy into _____.
Sophie [7]
It turns chemical into electricity 
5 0
3 years ago
Read 2 more answers
Indicate the peptides that would result from cleavage by the indicated reagent: a. Gly-Lys-Leu-Ala-Cys-Arg-Ala-Phe by trypsin b.
Ilia_Sergeevich [38]

Answer:

a. Gly-Lys + Leu-Ala-Cys-Arg + Ala-Phe

b. Glu-Ala-Phe + Gly-Ala-Tyr

Explanation:

In this case, we have to remember which peptidic bonds can break each protease:

-) <u>Trypsin</u>

It breaks selectively the peptidic bond in the carbonyl group of lysine or arginine.

-) <u>Chymotrypsin</u>

It breaks selectively the peptidic bond in the carbonyl group of phenylalanine, tryptophan, or tyrosine.

With this in mind in "peptide a", the peptidic bonds that would be broken are the ones in the <u>"Lis"</u> and <u>"Arg"</u> (See figure 1).

In "peptide b", the peptidic bond that would be broken is the one in the <u>"Phe"</u> (See figure 2). The second amino acid that can be broken is <u>tyrosine</u>, but this amino acid is placed in the <u>C terminal spot</u>, therefore will not be involved in the <u>hydrolysis</u>.

3 0
3 years ago
What is the temperature of liquid nitrogen?
motikmotik
Really darn cold lol
6 0
3 years ago
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