All categories

2 years ago

A 20.0 gram sample of an element contains 4.95 x 1023 atoms. what is the element?

1 answer:

7 0

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

You might be interested in

Complete each equation with a number that is true. 5 * _ =15

natali 33 [55]

The answer is 3. As 5 * 3 = 15.

Is there any other equations I may be able to help you with? :)

5 0

3 years ago

Read 2 more answers

A 2.87 g sample of carbon reacts with hydrogen to form 3.41 g of car fuel. What is the empirical formula for the car fuel?

olga_2 [115]

CH₇ is the empirical formula of the car fuel.

Explanation:

To find the empirical formula we use the following algorithm.

First divide each mass the the molar weight of each element:

for carbon 2.87 / 12 = 0.239

for hydrogen 3.41 / 2 = 1.705

And now divide each quantity by the lowest number which is 0.239:

for carbon 0.239 / 0.239 = 1

for hydrogen 1.705 / 0.239 = 7.13 ≈ 7

The empirical formula of the car fuel is CH₇.

I have to tell you that in reality this formula is wrong because is not possible to exist. However the algorithm for finding the empirical formula is right, the problem may reside in the amounts of carbon and hydrogen given.

Learn more about:

empirical formula

brainly.com/question/5297213

#learnwithBrainly

5 0

2 years ago

What is the molality of a solution when 0.50 moles glucose is dissolved in 750 g of water?

xxMikexx [17]

Answer:

0.67mol/Kg

Explanation:

The following were obtained from the question:

Mole of solute = 0.50mol

Mass of solvent = 750g = 750/1000 = 0.75Kg

Molality =?

Molality = mole of solute /mass of solvent

Molality = 0.5/0.75

Molality = 0.67mol/Kg

3 0

2 years ago

A 112 gram sample of an unknown metal was heated from 0.0C to 20.0C. The sample absorbed 1004 J of energy. What was the specific

worty [1.4K]

Answer:

The specific heat of the sample unknown metal is approximately 0.45 J/g °C.

General Formulas and Concepts:
Thermodynamics

Specific Heat Formula: $\displaystyle q = mc \triangle T$

m is mass (g)
c is specific heat capacity (J/g °C)
ΔT is the change in temperature

Explanation:

Step 1: Define

Identify variables.

m = 112 g

ΔT = 20.0 °C

q = 1004 J

Step 2: Solve for c

Substitute in variables [Specific Heat Formula]: $\displaystyle 1004 \ \text{J} = (112 \ \text{g})(c)(20.0 \ ^{\circ} \text{C})$
Simplify: $\displaystyle 1004 \ \text{J} = (2240 \ \text{g} \ ^\circ \text{C})c$
Isolate c: $\displaystyle c = 0.448214 \ \text{J} / \text{g} \ ^\circ \text{C}$
Round [Sig Figs]: $\displaystyle c \approx 0.45 \ \text{J} / \text{g} \ ^\circ \text{C}$

∴ specific heat capacity c is equal to around 0.45 J/g °C.

---

Topic: AP Chemistry

Unit: Thermodynamics

5 0

2 years ago

With the correct choice of acid, acid hydrolysis of ethanamide could produce A) ethanoic acid and ammonium chloride. B) ethanoic

Stells [14]

Answer:

A) Ethanoic acid and ammonium chloride.

Explanation:

Amides go through acid hydrolysis to produce carboxylic acid and ammonia by heating in aqueous acid. The acid hydrolysis reaction is produced through the nucleophilic addition of water to the protonated amide, then comes the transference of a proton from the oxygen to the nitrogen to make nitrogen a better leaving group, and finally, the subsequent elimination (see attachment).

In this case, the products formed with the reaction of ethanamide and aqueous HCl will be ethanoic acid and ammonium chloride.

7 0

3 years ago