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jarptica [38.1K]
3 years ago
14

What event marks the beginning of Earth's current era?

Chemistry
2 answers:
Firlakuza [10]3 years ago
4 0
It’s B a mass extinction

uysha [10]3 years ago
3 0
B. We are in the cenzoic era so what previously had happen to cause the life we live today was a huge mass extinction.... hope this helps!!
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The pyruvate dehydrogenase complex catalyzes the oxidative decarboxylation of pyruvate to form acetyl‑CoA. E1 , E2 , and E3 are
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It’s B Thiamine puro pyrophosphate (TPP)
4 0
3 years ago
Temperature can weather rocks because A heat can cause minerals to oxidize B. most rocks do not absorb heat evenly C. water cont
Zina [86]

Answer:

c

Explanation:

water contracts when it freezes

5 0
3 years ago
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• We obtained the above 10.00-mL solution by diluting a stock solution using a 1.00-mL aliquot and placing it into a 25.00-mL vo
garik1379 [7]

Answer:

a) The relationship at equivalence is that 1 mole of phosphoric acid will need three moles of sodium hydroxide.

b) 0.0035 mole

c)  0.166 M

Explanation:

Phosphoric acid is tripotic because it has 3 acidic hydrogen atom surrounding it.

The equation of the reaction is expressed as:

H_3PO_4 \ + \ 3NaOH -----> Na_3 PO_4 \ + \ 3H_2O

1 mole         3 mole

The relationship at equivalence is that 1 mole of phosphoric acid will need three moles of sodium hydroxide.

b)  if 10.00 mL of a phosphoric acid solution required the addition of 17.50 mL of a 0.200 M NaOH(aq) to reach the endpoint; Then the molarity of the solution is calculated as follows

H_3PO_4 \ + \ 3NaOH -----> Na_3 PO_4 \ + \ 3H_2O

10 ml            17.50 ml

(x) M              0.200 M

Molarity = \frac{0.2*17.5}{1000}

= 0.0035 mole

c) What was the molar concentration of phosphoric acid in the original stock solution?

By stoichiometry, converting moles of NaOH to H₃PO₄; we have

= 0.0035 \ mole \ of NaOH* \frac{1 mole of H_3PO_4}{3 \ mole \ of \ NaOH}

= 0.00166 mole of H₃PO₄

Using the molarity equation to determine the molar concentration of phosphoric acid in the original stock solution; we have:

Molar Concentration =  \frac{mole \ \ of \ soulte }{ Volume \ of \ solution }

Molar Concentration = \frac{0.00166 \ mole \ of \  H_3PO_4 }{10}*1000

Molar Concentration = 0.166 M

∴  the molar concentration of phosphoric acid in the original stock solution = 0.166 M

6 0
3 years ago
If you had a 0.5 M KCl solution, how much solute would you have in moles, and what would the solute be?
Svetradugi [14.3K]

Answer:

37.25 grams/L.

Explanation:

  • Molarity (M) is defined as the no. of moles of solute dissolved per 1.0 L of the solution.

<em>M = (no. of moles of KCl)/(volume of the solution (L))</em>

<em></em>

∵ no. of moles of KCl = (mass of KCl)/(molar mass of KCl)

∴ M = [(mass of KCl)/(molar mass of KCl)]/(volume of the solution (L))

∴ (mass of KCl)/(volume of the solution (L)) = (M)*(molar mass of KCl) = (0.5 M)*(74.5 g/mol) = 37.25 g/L.

<em>So, the grams/L of KCl = 37.25 grams/L.</em>

6 0
3 years ago
Select the correct answer. The gas in a sealed container has an absolute pressure of 9.25 atmospheres. If the air around the con
N76 [4]

Answer:

Explanation:

8.25 atm

7 0
3 years ago
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