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myrzilka [38]
3 years ago
7

How many significant figures are there in the following numbers: 10.78, 6.78, 0.78? If these were pH values, to how many signifi

cant figures can you express the [H]? Explain any discrepancies between your answers to the two questions.
Chemistry
1 answer:
Ksivusya [100]3 years ago
3 0

Answer:

10.78 → 4 significant figures, pH = 10.78 → [H⁺] = 1.66ₓ10⁻¹¹ M

6.78 → 3 significant figures, pH = 6.78 → [H⁺] = 1.66ₓ10⁻⁷ M

0.78 → 2 significant figures, pH = 0.78 → [H⁺] = 0.166 M

pH always can be expressed by at least 4 significant figures. The [H⁺], can be expressed by, at least 3 significant figures

Explanation:

Significant figures are the numbers of a measurement that have certainty plus a doubtful number (it is associated with the uncertainty in the measurement). For example, if we measure a paper with a ruler and the ruler measures up to centimeters we can say that the paper is 7.5 cm long, with which we know that the paper is 7 cm + 0.5 cm which we associate with uncertainty. In this case we talk about two significant figures. If the sheet measured 7.57 cm we would already be talking about a more precise measurement and in this case with 3 significant figures.

10.78 → 4 significant figures

6.78 → 3 significant figures

0.78 → 2 significant figures

To determine [H⁺], we apply 10^-pH

10⁻¹⁰°⁷⁸ = 1.66ₓ10⁻¹¹ M

10⁻⁶°⁷⁸ = 1.66ₓ10⁻⁷ M

10⁻⁰°⁷⁸ = 0.166 M

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Which element has a mass number of 32?
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Suppose NAD is unavailable because NADH cannot be oxidized due to a mutation in the NADH dehydrogenase (Complex I). If FAD could
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Answer:

FAD substitution will produce 28 ATP instead of 36.

Explanation:

NAD and FAD are coenzymes involved in reversible oxidation and reduction reactions. These compounds are also known as electron carriers. However NADH produce 3 electrons in electron transport chain and FADH2 produce 2 electron beacuase it transfer the electrons to second complex in ETC.

Normal prduction of ATP from glucose;

2 cytoplasmic NADH formed in glycolysis         Each yields 2 ATP   +4

2 NADH formed in the oxidation of pyruvate Each yields 3 ATP         +6

2 FADH2 formed in the citric acid cycle         Each yields 2 ATP         +4

6 NADH formed in the citric acid cycle             Each yields 3 ATP         +18

2 ATP from glycolysis                                                                                   +2  

2 ATP from citric acid cycle                                                                          +2                            

                                                                    Net yield ATP +36

C6H12O6 + 6 CO2 + 36 ADP + 36 Pi ⇒6 CO2 + 6 H2O + 36 ATP

If we replace the NAD with FAD the total ATP production would be.

2 cytoplasmic FADH2 formed in glycolysis          Each yields 2 ATP            +4

2 FADH2 formed in the oxidation of pyruvate   Each yields 3 ATP    +4

2 FADH2 formed in the citric acid cycle            Each yields 2 ATP    +4

6 FADH2 formed in the citric acid cycle                  Each yields 2 ATP   +12

2 ATP from glycolysis                                                                                    

+2

2 ATP from citric acid cycle                                                                            +2

                                                                  <u>Net yield ATP +28</u>

C6H12O6 + 6 CO2 + 28ADP + 28 Pi ⇒6 CO2 + 6 H2O + 28 ATP

7 0
3 years ago
What molecule is needed to digest milk?
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4 0
2 years ago
Group the following electron configurations in pairs that would represent similar chemical properties at their atoms;
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<u>Answer:</u> Pairs are:  (a) and (d), (b) and (f), (c) and (e)

<u>Explanation:</u>

In a periodic table, elements are arranged in 18 vertical columns known as groups and 7 horizontal rows known as periods.

Elements arranged in a group show similar chemical properties because of the presence of same number of valence electrons.

Valence electrons are defined as the electrons which are present in the outermost shell of an atom. Outermost shell has the highest value of 'n' that is principal quantum number.

For the given options:

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The given electronic configuration is:  1s^22s^22p^63s^2

The number of valence electrons in the given configuration are 2

  • <u>For b:</u>

The given electronic configuration is:  1s^22s^22p^63s^3

The number of valence electrons in the given configuration are [2 + 3] = 5

  • <u>For c:</u>

The given electronic configuration is:  1s^22s^22p^63s^23p^64s^23d^{10}4p^6

The number of valence electrons in the given configuration are [2 + 6] = 8

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The given electronic configuration is:  1s^22s^2

The number of valence electrons in the given configuration are 2

  • <u>For e:</u>

The given electronic configuration is:  1s^22s^22p^6

The number of valence electrons in the given configuration are [2 + 6] = 8

  • <u>For f:</u>

The given electronic configuration is:  1s^22s^22p^63s^23p^3

The number of valence electrons in the given configuration are [2 + 3] = 5

Electronic configuration of (a) and (d) will form a pair, (b) and (f) will form a pair, (c) and (e) will form a pair and will have similar chemical properties.

Hence, the pairs are:  (a) and (d), (b) and (f), (c) and (e)

4 0
3 years ago
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