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3 years ago

One mole of copper equals about how many atoms?

2 answers:

8 0

One mole of copper equals 6.02 × 10^23 atoms. The answer is letter C. This follows the Avogaro’s law wherein 1 mole of a substance is equal to 6.02 x 10^23 atoms, formula units or molecules. This is applicable to all substances.

telo118 [61]3 years ago

6 0

Answer: The correct answer is Option c.

Explanation:

According to mole concept:

1 mole of an element or compound contains $6.022\time 10^{23}$ number of particles.

The number is called as Avogadro's number.

We are given:

One mole of a copper element

This element will have the Avogadro's number of particles which is $6.02\times 10^{23}$

Hence, the correct answer is Option c.

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KonstantinChe [14]

Answer: There are 0.5 grams of barium sulfate are present in 250 of 2.0 M $BaSO_{4}$ solution.

Explanation:

Given: Molarity of solution = 2.0 M

Volume of solution = 250 mL

Convert mL int L as follows.

$1 mL = 0.001 L\\250 mL = 250 mL \times \frac{0.001 L}{1 mL}\\= 0.25 L$

Molarity is the number of moles of solute present in liter of solution. Hence, molarity of the given $BaSO_{4}$ solution is as follows.

$Molarity = \frac{mass}{Volume (in L)}\\2.0 M = \frac{mass}{0.25 L}\\mass = 0.5 g$

Thus, we can conclude that there are 0.5 grams of barium sulfate are present in 250 of 2.0 M $BaSO_{4}$ solution.

7 0

3 years ago

If i initially have 4.0 l of a gas at a pressure of 1.1 atm, what will the volume be if i increase the pressure of 3.4 atm?

ddd [48]

The volume of a gas that its pressure increase to 3.4 atm is calculated as follows

By use of boyles law that is P1V1=P2V2
V1=4.0 L
P1=1.1 atm
P2=3.4 atm
V2= P1V1/P2

(1.1 atm x 4.0 L)/3.4 atm= 1.29 L

4 0

3 years ago

Determine the volume of fluid in the graduated cylinder shown.

alexgriva [62]

Answer:

47.3 ml

Explanation:

The graduated cylinder is shown in the image attached.

Now we have to take a good look at the cylinder, the lines between 45 and 50 are 46, 47, 48 and 49. Even though the points in between two lines weren't graduated but we can intelligently guess the correct volume by observing the upper meniscus of the liquid. Hence the answer.

8 0

3 years ago

Read 2 more answers

The half-life of cesium-137 is 30 years. suppose we have a 200-mg sample.

Assoli18 [71]

a) To find the mass after t years:

we will use this formula:

A = Ao / 2^n

when A =the amount remaining

and Ao = the initial amount

and n = t / t(1/2)

by substitution:

∴ A = 200 mg/ 2^(t/30y)

b) Mass after 90 y :

by using the previous formula and substitute t by 90 y

A = 200mg/ 2^(90y/30y)

∴ A = 25 mg

C) Time for 1 mg remaining:

when A= Ao/ 2^(t/t(1/2)

so, by substitution:

1 mg = 200 mg / 2^(t/30y)

∴2^(t/30y) = 200 mg by solving for t

∴ t = 229 y

7 0

4 years ago

A solution with a hydrogen ion concentration of 3.25 × 10-2 m is ________ and has a hydroxide concentration of _______

Romashka-Z-Leto [24]

To know the acidity of a solution, we calculate the pH value. The formula for pH is given as:

pH = - log [H+] where H+ must be in Molar

We are given that H+ = 3.25 × 10-2 M

Therefore the pH is:

pH = - log [3.25 × 10-2]

pH = 1.488

Since pH is way below 7, therefore the solution is acidic.

To find for the OH- concentration, we must remember that the product of H+ and OH- is equivalent to 10^-14. Therefore,

[H+]*[OH-] = 10^-14 
[OH-] = 10^-14 / [H+]

[OH-] = 10^-14 / 3.25 × 10-2

[OH-] = 3.08 × 10-13 M

Answers:

Acidic

[OH-] = 3.08 × 10-13 M

6 0

3 years ago