Answer:
The groupings of elements in the periodic table reveal various trends, present in groups such as the alkali metals and noble gases, or the lanthanides and actinides. The periodic table can be used to find information on elements or predict the properties of as-of-yet undiscovered elements.
Explanation:
A solution has a pOH of 7. 1 at 10∘c. Then the pH of the solution given that kw=2. 93×10−15 at this temperature is 7.4 .
It is given that,
pOH of solution = 7.1
Kw =2.93×10^(-15)
Firstly, we will calculate the value of pKw
The expression which we used to calculate the pKw is,
pKw=-log [Kw]
Now by putting the value of Kw in this expression,
pKw =−log{2.93×10^(-15)}
pKw =15log(2.93)
pKw=14.5
Now we have to calculate the pH of the solution.
As we know that,
pH+pOH=pKw
Now put all the given values in this formula,
pH+7.1=14.5
pH=7.4
Therefore, we find the value of pH of the solution is, 7.4.
learn more about pH value:
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Answer: the percent composition of carbon in heptane is 83.9%
Explanation:
<u>1) Atomic masses of the atoms:</u>
<u>2) Molar mass of heptane:</u>
- C₇H₁₆: 7 × 12.01 g/mol + 16×1.008 g/mol = 100.2 g/mol
<u>3) Mass of carbon in one mole of heptane:</u>
- C₇: 7 × 12.01 g/mol = 84.07 g/mol
<u>3) Percent composition of carbon:</u>
- % = (mass in grams of C) / (mass in grams of C₇H₁₆) × 100 =
= (84.07 g/ 100.2 g) × 100 = 83.9% ← answer
Answer: 6.75 moles
Explanation:
This is a simple stoichiometry proboe. that I would set up like this:
(13.5 moles CuCI2) (1 mol I2 / 2 moles CuCi2)
That means you all you have to do for this problem is divide by 2 and cancel out the unit moles CuCI2, which leaves you with 6.75 moles I2.
Hope this helps :)
I think it’s D. Stars and planets.
