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3 years ago

Can someone help me with these. I don’t understand how to answer them or do the work

Chemistry

1 answer:

ICE Princess25 [194]3 years ago

6 0

How am I supposed to help you if there's not picture of what the problem is

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What is the pH of a solution which is 0.600 M in dimethylamine ((CH3)2NH) and 0.400 M in dimethylamine hydrochloride ((CH3)2NH2C

Viefleur [7K]

Answer:

pH = 11.05

Explanation:

It is possible to answer this question using Henderson-Hasselbalch formula:

pH = pka + log₁₀ [A] / [HA⁺]

Where A in this case is weak base (dimethylamine) and conjugate acid (HA⁺) is dimethylamine hydrochloride.

As Ka= Kw / Kb = 1x10⁻¹⁴ / 7.4x10⁻⁴ = 1.35x10⁻¹¹ And pKa is -log Ka = 10.87 pH of the solution is:

pH = 10.87 + log₁₀ [0.600] / [0.400]

pH = 11.05

I hope it helps!

3 0

3 years ago

Which of the following is the displacement from point P to point W?

IRINA_888 [86]

C represents the displacement ONLY if it is the VECTOR arrow from P to W.
Usually if the arrow on the diagram has JUST a letter listing, that letter stands for the SIZE or LENGTH of the VECTOR arrow. In order to have the letter represent the VECTOR, itself, it must have a symbol of a "half arrow" placed above it.

4 0

3 years ago

Help?

Ahat [919]

Answer:

$KClO_3$

Explanation:

Hello!

In this case, as we know the mass of the total sample, we can first compute the mass of oxygen:

$m_O=22.9g-7.33g-6.65g=8.92g$

Next, we compute the moles of each element:

$n_K=\frac{7.33g}{39.9g/mol}= 0.184mol\\\\n_{Cl}=\frac{6.65g}{35.45g/mol}=0.188mol \\\\n_O=\frac{8.92g}{16.00g/mol} =0.5575mol$

Now, we divide the moles by 0.184 moles, the fewest ones, to obtain:

$K=\frac{0.184}{0.184}=1.0 \\\\Cl=\frac{0.187}{0.184}=1.0\\\\O=\frac{0.5575}{0.184} =3.0$

Therefore, the empirical formula is:

$KClO_3$

Regards!

3 0

3 years ago

I need help with this question

scoray [572]

It’s C I think Idrk

3 0

3 years ago

Read 2 more answers

How many moles of H2 are in a flask with a volume of 2500 mL at a pressure of 30.0 kPa and a temperature of 27oC?

quester [9]

Answer:

0.0300 moles of H₂

Explanation:

The original equation is PV = nRT. We need to change this to show moles (n).

n = $\frac{PV}{RT}$

It's important to convert your values to match the constant (r) in terms of units.

30.0 kPa = 0.296 atm

2500 mL = 2.50 L

27 °C = 300 K

Now, plug those values in to solve:

n = $\frac{(0.296)(2.50)}{(0.0821)(300)}$ - for the sake of keeping the problem clean, I didn't include the units but you should just to make sure everything cancels out :)

Finally, you are left with n = 0.0300 moles of H₂

4 0

3 years ago