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STALIN [3.7K]
3 years ago
15

Need help on atoms and molecules​

Chemistry
1 answer:
balu736 [363]3 years ago
7 0

1-b

2-c

3-a

4-d

5-d

6-b

7-a

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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
What is “monomer” mean?
oksano4ka [1.4K]

it is a molecule* that can be joined with other molecules that are identical to form a polymer*

key words :

a molecule:

a group of atoms bonded together, representing the smallest fundamental unit of a chemical compound that can take part in a chemical reaction.

a polymer:

a substance that has a molecular structure consisting chiefly or entirely of a large number of similar units bonded together

hope this helped, good luck in future studies !

-A

5 0
3 years ago
Quinine, an antimalarial drug, is 8.63% nitrogen. There are two nitrogen atoms per molecule. What is the molecular weight of qui
Furkat [3]

Answer:

324.18 g/mol

Explanation:

Let the molecular mass of the antimalarial drug, Quinine is x g/mol

According to question,

Nitrogen present in the drug is 8.63% of x

So, mass of nitrogen = \frac {8.63}{100}\times x

Also, according to the question,

2 atoms are present in 1 molecule of the drug.

Mass of nitrogen = 14.01 amu = 14.01 g/mol (grams for 1 mole)

So, mass of nitrogen = 14.01×2 = 28.02

These 2 must be equal so,

\frac {8.63}{100}\times x=28.02

solving for x, we get:

<u>x = 324.18 g/mol</u>

6 0
3 years ago
What determines the amount of chemical energy a substance has?
Ratling [72]


Chemical energy  is the kind of energy stored in the bonds formed by atoms and molecules in chemical compounds and elements.  This energy is  released during a chemical  reaction and  heat is often given out in the process. These kind of reactions where heat is given out as a by product are called exothermic reactions.

The major factor that determines how much chemical energy a substance has is the mass of that substance. Mass is defined as the amount of matter in a substance.

The higher  the mass of a substance, the more concentrated that substance is and subsequently the greater the number of atoms and molecules.

Logically, the higher the number of atoms and molecules  then the greater the number of bonds in that substance and subsequently the more the amount of chemical energy  stored therein.


6 0
3 years ago
The equilibrium: 2 NO2(g) \Longleftrightarrow&amp;iff; N2O4(g) has Kc = 4.7 at 100ºC. What is true about the rates of the forwar
Sergeeva-Olga [200]

Answer:

  • Initial: forward rate > reverse rate
  • Equilibrium: forward rate = reverse rate

Explanation:

2NO₂(g) → N₂O₄(g)   Kc=4.7

The definition of <em>equilibrium</em> is when the forward rate and the reverse rate are <em>equal</em>.

Because in the initial state there's only NO₂, there's no possibility for the reverse reaction (from N₂O₄ to NO₂). Thus the forward rate will be larger than the reverse rate.

7 0
3 years ago
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