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inn [45]
4 years ago
11

What is the pH of a 40.0 40.0 mL solution that is 0.11 0.11 M in CN − CN− and 0.21 0.21 M in HCN HCN ? The K a Ka for HCN is 4.9

× 10 − 9
Chemistry
1 answer:
cluponka [151]4 years ago
6 0

Answer:

pH=8.03

Explanation:

From the Henderson-Hasselbalch equation:

we know that

pH = pKa + log (base / acid)

plugging the values from the question we can write

pH = 8.31 + log (0.11 / 0.21)

pH = 8.31-0.280

pH=8.03

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leonid [27]
Hello!

The observation that would provide the best evidence that a chemical reaction occurred is that The baking soda and hydrochloric acid combined, and bubbles formed.

When baking soda (NaHCO₃) and Hydrochloric Acid (HCl) combine, the following reaction happens:

NaHCO₃ + HCl → NaCl + H₂O + CO₂(g)↑

The gaseous Carbon Dioxide (CO₂) generated in this reaction is the responsible for the bubbles. The releasing of this gas is an evidence that a chemical reaction occurred between NaHCO₃ and HCl.

Have a nice day!
3 0
4 years ago
Which is the smallest number?
My name is Ann [436]

Answer:

What I came up with was D equaling out to be 42

Explanation:

Im assuming you just do the math

A. 3.5 x 104 = 364

B. 2.4 x 103 = 247.2

C. 1.4 x 10^2_2 = 280

D. 4.9 x 10-7 = 42

I hope I helped.

5 0
4 years ago
Hi everyone can anyone help with this, the question and diagram is in the pic thx!
seraphim [82]

Answer:

QP

Explanation:

P has 9 electrons.

Electronic Configuration : 2, 7

Valence electrons : 7

P needs 1 electron to get stable electronic configuration.

Q has 3 electrons.

Electronic Configuration : 2, 1

Valence electrons : 1

P needs to loose 1 electron to get stable electronic configuration.

Q donates 1 electron,

Q -----> Q+ + 1 e-

P gains 1 electron,

P + 1 e- -----> P-

Q+ + P- -----> QP

This is an ionic compound.

8 0
3 years ago
A 20.0 gram sample of an element contains 4.95 x 1023 atoms. what is the element?
Sonja [21]
You will want to find how many grams are in a whole mole so you know which element it is. To do this, find out how much of a mole you have.

4.95 x 10^23 atoms / 6.022 x 10^23 atoms (one whole mole of any element) = .8219860511 or ~82% of 1 mole

Now we know that, find what to multiply 20 g by to get the rest of the mole.

1 mole / .8219860511 mole = 1.216565657

20 g x 1.216565657 = ~24.33 g / mol

Now that you have grams per mole, you can look at the periodic table and the molar masses to see which this number is closely aligned.

Your answer is Magnesium (Mg), which has a molar mass of 24.305 g


7 0
3 years ago
How many moles are there in 35.2g of Gold?
ki77a [65]

Explanation:

196.96655

maybe

5 0
3 years ago
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