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3 years ago

Please help I’ll mark brainliest!

Chemistry

2 answers:

IRISSAK [1]3 years ago

8 0

I believe you got the correct answer D.

I actually looked up the problem on quizlet. It reads, “because each element has a different set of emission colors from the emission spectrum. They have different energy level spacing and when the electrons get excited, they go to different energy levels because of the different spacing.”

If u want to view where I got this answer from, go to quizlet and type up Flame Test Lab. There should be 8 terms in the set.

Anyways, I hope that this helps! Have a wonderful day :)

Anni [7]3 years ago

6 0

Answer:

D because excited electrons fall back.....

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What is the mass of 5.30×1021 platinum atoms?

DedPeter [7]

(5.08 * 10^21) / (6.022 * 10^23) = 0.0084357 moles * 195.084 g/mol = 1.65 g Atomic mass of platinum = 195.084 g/mol Avogadro's number = 6.022 * 10^23 so here you go

3 0

4 years ago

Calculate the equilibrium concentration of H 3 O H3O in a 0.20 M M solution of oxalic acid. Express your answer to two significa

Black_prince [1.1K]

Answer: The equilibrium concentration of $H_3O^+$ ion is $8.3064\times 10^{-2}M$

Explanation:

We are given:

Molarity of oxalic acid solution = 0.20 M

Oxalic acid $(H_2C_2O_4)$ is a weak acid and will dissociate 2 hydrogen ions.

The chemical equation for the first dissociation of oxalic acid follows:

$H_2C_2O_4(aq.)+H_2O\rightleftharpoons H_3O^+(aq.)+HC_2O_4^-(aq.)$

Initial: 0.20

At eqllm: 0.20-x x x

The expression of first equilibrium constant equation follows:

$Ka_1=\frac{[H_3O^+][HC_2O_4^{-}]}{[H_2C_2O_4]}$

We know that:

$Ka_1\text{ for }H_2C_2O_4=0.059$

Putting values in above equation, we get:

$0.059=\frac{x\times x}{(0.20-x)}\\\\x=-0.142,0.083$

Neglecting the negative value of 'x', because concentration cannot be negative.

So, equilibrium concentration of hydronium ion = x = 0.083 M

The chemical equation for the second dissociation of oxalic acid:

$HC_2O_4^-(aq.)+H_2O\rightarrow H_3O^+(aq.)+C_2O_4^{2-}(aq.)$

Initial: 0.083

At eqllm: 0.083-y 0.083+y y

The expression of second equilibrium constant equation follows:

$Ka_2=\frac{[H_3O^+][C_2O_4^{2-}]}{[HC_2O_4^-]}$

We know that:

$Ka_2\text{ for }H_2C_2O_4=6.4\times 10^{-5}$

Putting values in above equation, we get:

$6.4\times 10^{-5}=\frac{(0.083+y)\times y}{(0.083-y)}\\\\y=-0.083,0.0000639$

Neglecting the negative value of 'x', because concentration cannot be negative.

So, equilibrium concentration of hydronium ion = y = 0.0000639 M

Total concentration of hydronium ion = [x + y] = [0.083 + 0.0000639] = 0.0830639 M

Hence, the equilibrium concentration of $H_3O^+$ ion is $8.3064\times 10^{-2}M$

7 0

3 years ago

A sample of calcium carbonate weighs 2.1 kilograms (kg). There are 1,000 grams (g) in 1 kg, and 1 Times. 109 nanograms (ng) in 1

TiliK225 [7]

Answer:

2.1 x 10¹²ng

Explanation:

Mass of the calcium carbonate given is:

2.1kg

We need to take this mass to nanogram, ng.

Since :

1000g = 1kg

10⁹g = 1ng

So;

1kg = 1000 x 10⁹ = 10¹²ng

So;

2.1kg will give;

Since

1kg gives 10¹²ng

2.1kg will give 2.1 x 10¹²ng

5 0

3 years ago

The air we breathe is a(n) _____.

ddd [48]

Gas thank me later bro

8 0

3 years ago

Read 2 more answers

A solution is 0.10 M in Pb(NO3)2 and 0.10 M in AgNO3. Solid NaI is added until the second solid compound is on the verge of prec

nekit [7.7K]

Answer:

The compound which will precipitate first will be AgI with $2.9X10^{-4}$

Explanation:

In order to precipitate a salt solution the ionic product of salt must exceed the solubility product.

Given:

Ksp of AgI = $1.5X10^{-16}$

Ksp of PbI2= $1.5X10^{-9}$

As Ksp of AgI is very low it will precipitate faster than lead iodide.

Now, higher the concentration of AgI solution taken faster its precipitation.

In the given choice the highest concentration solution of AgI is $2.9X10^{-4}$

4 0

3 years ago