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photoshop1234 [79]
3 years ago
13

What is the formula to find the area of circle​

Chemistry
1 answer:
Advocard [28]3 years ago
6 0

Answer:

A= π * r *2

Explanation:

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PLEASE HURRY THIS IS TIMED!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
AURORKA [14]

Answer:

if i remember correctly i beleive its A  1.8 x 10^24

but im not for sure  also i think you forgot the 24

Explanation:

5 0
3 years ago
You need to prepare at 2.0 mL sample of a diluted drug for injection. The total amount of the drug to be injected in this 2.0 mL
pav-90 [236]

Answer:

a) The concentration of drug in the bottle is 9.8 mg/ml

b) 0.15 ml drug solution + 1.85 ml saline.

c) 4.9 × 10⁻⁵ mol/l

Explanation:

Hi there!

a) The concentration of the drug in the bottle is 294 mg/ 30.0 ml = 9.8 mg/ml

b) The drug has to be administrated at a dose of 0.0210 mg/ kg body mass. Then, the total mass of drug that there should be in the injection for a person of 70 kg will be:

0.0210 mg/kg-body mass * 70 kg = 1.47 mg drug.

The volume of solution that contains that mass of drug can be calculated using the value of the concentration calculated in a)

If 9.8 mg of the drug is contained in 1 ml of solution, then 1.47 mg drug will be present in (1.47 mg * 1 ml/ 9.8 mg) 0.15 ml.

To prepare the injection, you should take 0.15 ml of the concentrated drug solution and (2.0 ml - 0.15 ml) 1.85 ml saline

c) In the injection there is a concentration of (1.47 mg / 2.0 ml) 0.735 mg/ml.

Let´s convert it to molarity:

0.735 mg/ml * 1000 ml/l * 0.001 g/mg* 1 mol/ 15000 g = 4.9 × 10⁻⁵ mol/l

3 0
3 years ago
Which of the following is a way of purifying water?
Finger [1]
What are the answers choices?
4 0
4 years ago
How many grams of Fe2+ are there in 0.003109 moles of Fe2+?
Sergio [31]

Answer: 0.174 g

Explanation:

First of all understand that charge on an atom like here 2+ will not vary molar mass. because ions are formed by loss or gain of electrons and electrons do not contribute to the mass of an atom or ion. so losing or gaining electron doesnt create any difference.

molar mass of Fe, i.e. mass of 1 mole of Fe is 56 g. So, mass of 1 mole of Fe2+ will also be 56 g.

given is 0.003109 moles of Fe2+,

Use maths,

1 mole of Fe2+ weighs 56 g

So, 0.003109 moles will weigh = (56 g / 1 mol ) x 0.003109 = 0.174 g.

7 0
3 years ago
Why did workers form labor unions?
USPshnik [31]

Answer:

Labor unions were created in order to help the workers with work-related difficulties such as low pay, unsafe or unsanitary working conditions, long hours, and other situations. ... Sometimes the unions organized strikes in order to try to change the conditions of the workers.

Explanation:

5 0
3 years ago
Read 2 more answers
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