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3 years ago

What did the periodic table help scientists discover?

Chemistry

2 answers:

noname [10]3 years ago

6 0

Answer:

Would be letter C

Elements not yet known

Natalija [7]3 years ago

4 0

Answer:

A_________________________

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Phosphorus pentachloride reacts with water to form hydrochloric acid and phosphoric acid. How many total moles of acid are forme

klio [65]

Answer:

0,13 moles of acid are produced

Explanation:

The reaction of the problem is:

PCl₅ + 4H₂O → 5HCl + H₃PO₄

Based on the reaction, 1 mole of PCl₅ produces 6 moles of acid (5 moles of HCl + 1 mole of H₃PO₄).

The molecular mass of PCl₅ is:

1P = 30,97g/mol + 5Cl = 5×35,45g/mol = 208,24 g/mol

That means 4,5g of PCl₅ are:

4,5g PCl₅×(1mol / 208,24g) = 0,0216 moles of PCl₅. As 1 mole of PCl₅ produces 6 moles of acid, 0,0216 moles of PCl₅ produce:

0,0216 moles PCl₅ × (6 moles acid / mole of PCl₅) =

0,13 moles of acid are produced

I hope it helps!

3 0

3 years ago

) Do you think the pH of 1,0 M tri-methyl ammonium (CH3)3NH+, pKa = 9.80, will be higher or lower than that of 1.0 M phenol, C6H

Elanso [62]

Answer:

1. The pH of 1.0 M trimethyl ammonium (pH = 1.01) is lower than the pH of 0.1 M phenol (5.00).

2. The difference in pH values is 4.95.

Explanation:

1. The pH of a compound can be found using the following equation:

$pH = -log([H_{3}O^{+}])$

First, we need to find [H₃O⁺] for trimethyl ammonium and for phenol.

Trimethyl ammonium:

We can calculate [H₃O⁺] using the Ka as follows:

(CH₃)₃NH⁺ + H₂O → (CH₃)₃N + H₃O⁺

1.0 - x x x

$Ka = \frac{[(CH_{3})_{3}N][H_{3}O^{+}]}{[(CH_{3})_{3}NH^{+}]}$

$10^{-pKa} = \frac{x*x}{1.0 - x}$

$10^{-9.80}(1.0 - x) - x^{2} = 0$

By solving the above equation for x we have:

x = 0.097 = [H₃O⁺]

$pH = -log([H_{3}O^{+}]) = -log(0.097) = 1.01$

Phenol:

C₆H₅OH + H₂O → C₆H₅O⁻ + H₃O⁺

1.0 - x x x

$Ka = \frac{[C_{6}H_{5}O^{-}][H_{3}O^{+}]}{[C_{6}H_{5}OH]}$

$10^{-10} = \frac{x^{2}}{1.0 - x}$

$1.0 \cdot 10^{-10}(1.0 - x) - x^{2} = 0$

Solving the above equation for x we have:

x = 9.96x10⁻⁶ = [H₃O⁺]

$pH = -log([H_{3}O^{+}]) = -log(9.99 \cdot 10^{-6}) = 5.00$

Hence, the pH of 1.0 M trimethyl ammonium is lower than the pH of 0.1 M phenol.

2. The difference in pH values for the two acids is:

$\Delta pH = pH_{C_{6}H_{5}OH} - pH_{(CH_{3})_{3}NH^{+}} = 5.00 - 1.01 = 4.95$

Therefore, the difference in pH values is 4.95.

I hope it helps you!

7 0

4 years ago

Which chemical change ? A.boiling B.freezing C.burning D.melting

fredd [130]

ANSWER:

the answer is burning as it is a chemical change emaning that the substance changes chemically, the other choices are exp of physical changing meaning they stay the same substance but change physically

~batmans wife dun dun dun...aka ~serenitybella

5 0

3 years ago

Read 2 more answers

At this temperature, 0.300 mol H 2 0.300 mol H2 and 0.300 mol I 2 0.300 mol I2 were placed in a 1.00 L container to react. What

Alekssandra [29.7K]

Answer:

The concentration of HI present at equilibrium is 0.471 M.

Explanation:

5 0

4 years ago

Help pleaseeeeeeeeeee

hichkok12 [17]

Answer:

D 1 and 3 only I am not sure

Explanation:

6 0

3 years ago