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Yuri [45]
3 years ago
9

Why is it important to do further investigations to determine if a chemical change really occurred?

Chemistry
1 answer:
KatRina [158]3 years ago
5 0

Answer:

x

Explanation:

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Which of the following is not a reason why chemical bonds are important
velikii [3]
What are the followings?
4 0
3 years ago
Determine the oxidation number for nitrogenin
iris [78.8K]

Answer:

1(a) N = 3

(b) N = 0

(c) N = 5

(d) N = -2

(2) Molecular formula for benzene is C6H6

Explanation:

1(a) N02 1-

N + (2×-2) = -1

N-4 = -1

N = -1+4 = 3

(b) N2

2(N) = 0

N = 0/2 = 0

(c) NO2Cl

N + ( 2×-2) + (-1) = 0

N - 4 - 1 = 0

N - 5 = 0

N = 0+5 = 5

(d) N2H4

2(N) + (4×1) = 0

2N + 4 = 0

2N = 0 - 4 = -4

N = -4/2 = -2

(2) Molcular mass of benzene = 78g/mole = (6×12g of carbon) + (6×1g of hydrogen) = 72+6 = 78g/mole

Therefore, molecular formula for benzene is C6H6

7 0
3 years ago
What is a daughter cell
Leno4ka [110]
The cells that result from the reproductive division of one cell during mitosis or meiosis
6 0
3 years ago
Read 2 more answers
there is a total of seventeen constitutional isomers for the molecular formula c5h13n. draw the skeletal formula of all three co
MAXImum [283]
Amines are derivatives of Ammonia (NH₃) in which atleast one hydrogen atom is replaced by an alkyl group. Amines are further classifies as;

Primary Amines:
                          In primary amines the nitrogen atom is attached to two hydrogen atoms and one alkyl group.

Secondary Amines:
                             In secondary amines the nitrogen atom is attached to two alkyl groups and one hydrogen atom.

Tertiary Amines:
                         In tertiary amines the nitrogen atom is attached to three alkyl groups, hence it has no hydrogen atom.

Below are three isomers of tertiary amines with molecular formula C₅H₁₃N.

5 0
4 years ago
5. What concentration of acid must be added to change the pH of 1 mM phosphate buffer from 7.4 to 7.3 (pKas of the phosphate buf
mr_godi [17]

Explanation:

According to the Henderson-Hasselbalch equation, the relation between pH and pK_{a} is as follows.

               pH = pK_{a} + log \frac{base}{acid}

where,     pH = 7.4 and pK_{a} = 7.21

As here, we can use the pK_{a} nearest to the desired pH.

So,      7.4 = 7.21 + log \frac{base}{acid}

             0.19 = log \frac{base}{acid}

            \frac{base}{acid} = 1.55

1 mM phosphate buffer means [HPO_{4}] + [H_{2}PO_{4}] = 1 mM

Therefore, the two equations will be as follows.

           \frac{HPO_{4}}{H_{2}PO_{4}} = 1.55 ............. (1)

  [HPO_{4}] + [H_{2}PO_{4}] = 1 mM ........... (2)        

Now, putting the value of [HPO_{4}] from equation (1) into equation (2) as follows.

             1.55[H_{2}PO_{4}] + [tex][H_{2}PO_{4}] = 1 mM

                        2.55 [H_{2}PO_{4}] = 1 mM

                             [H_{2}PO_{4}] = 0.392 mM

Putting the value of [H_{2}PO_{4}] in equation (1) we get the following.

                     0.392 mM + [HPO_{4}] = 1 mM

                          [HPO_{4}] = (1 - 0.392) mM

                              [HPO_{4}] = 0.608 mM

Thus, we can conclude that concentration of the acid must be 0.608 mM.

7 0
3 years ago
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