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snow_lady [41]
3 years ago
6

Calculate the average atomic mass of chromium. It's composition is: 83.79% with a mass of 51.94 Amy; 9.50% with a mass of 52.94

amu; 4.35% with a mass of 49.95 amu; 2.36% with a mass of 53.94 amu.
Chemistry
1 answer:
Lana71 [14]3 years ago
8 0
Youve gotta multiply the percentages by the masses. Like here
(.8379)(51.94)
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14. 60. g of NaOH is dissolved in enough distilled water to make 300 mL of a stock solution. What volumes of this solution and d
zepelin [54]

The question is incomplete, the complete question is attached below.

Answer : The volumes of stock solution and distilled water will be, 20 mL and 80 mL respectively.

Explanation : Given,

Mass of NaOH = 60 g

Volume of stock solution = 300 mL

Molar mass of NaOH = 40 g/mol

First we have to calculate the molarity of stock solution.

\text{Molarity}=\frac{\text{Mass of }NaOH\times 1000}{\text{Molar mass of }NaOH\times \text{Volume of solution (in mL)}}

Now put all the given values in this formula, we get:

\text{Molarity}=\frac{60g\times 1000}{40g/mole\times 300mL}=5mole/L=5M

Now we have to determine the volume of stock solution and distilled water mixed.

Formula used :

M_1V_1=M_2V_2

where,

M_1\text{ and }V_1 are the molarity and volume of stock solution.

M_2\text{ and }V_2 are the molarity and volume of diluted solution.

From data (A) :

M_1=5M\\V_1=20mL\\M_2=1M\\V_2=?

Putting values in above equation, we get:

5M\times 20mL=1M\times V_2\\\\V_2=100mL

Volume of stock solution = 20 mL

Volume of distilled water = 100 mL - 20 mL = 80 mL

From data (B) :

M_1=5M\\V_1=20mL\\M_2=1M\\V_2=?

Putting values in above equation, we get:

5M\times 20mL=1M\times V_2\\\\V_2=100mL

Volume of stock solution = 20 mL

Volume of distilled water = 100 mL - 20 mL = 80 mL

From data (C) :

M_1=5M\\V_1=60mL\\M_2=1M\\V_2=?

Putting values in above equation, we get:

5M\times 60mL=1M\times V_2\\\\V_2=300mL

Volume of stock solution = 60 mL

Volume of distilled water = 300 mL - 60 mL = 240 mL

From data (D) :

M_1=5M\\V_1=20mL\\M_2=1M\\V_2=?

Putting values in above equation, we get:

5M\times 60mL=1M\times V_2\\\\V_2=300mL

Volume of stock solution = 60 mL

Volume of distilled water = 300 mL - 60 mL = 240 mL

From this we conclude that, when 20 mL stock solution and 80 mL distilled water mixed then it will result in a solution that is approximately 1 M NaOH.

Hence, the volumes of stock solution and distilled water will be, 20 mL and 80 mL respectively.

5 0
2 years ago
A hydrogen bond can occur between:
Readme [11.4K]

A hydrogen bond occurs between a hydrogen from one molecule and an oxygen from another molecule. Option D

<h3>What is the hydrogen bond?</h3>

The hydrogen bond is one that is responsible for association in molecules. It occurs when hydrogen is covalently bonded to a highly electronegative element such as oxygen, nitrogen or Sulphur.

Thus, a hydrogen bond occurs between a hydrogen from one molecule and an oxygen from another molecule. Option D

Learn more about hydrogen bonding:brainly.com/question/10904296?

#SPJ1

5 0
2 years ago
Which one of the following will change the value of anequilibrium constant?
IRINA_888 [86]

Answer:

d. changing temperature

Explanation:

The thermodynamic equilibrium constant K is defined as a quantity characterizing the equilibrium of a chemical reaction. For a reaction where concentrations are in equilibrium:

aA + bB ⇄ cC + dD

The equilibrium constant is:

k = \frac{[C]^c[D]^d}{[A]^a[B]^b}

Thus, the equilibrium constant will change if:

a. Varying the initial concentration of reactants . FALSE. The k constant doesn't depend of initial concentrations but concentration in equilibrium does.

b. Adding other substances that do not react with any of thespecies involved in the equilibrium . FALSE. The equilibrium constant just depends of substances that are involved in the equilibrium

c. Varying the initial concentration of products . FALSE. Again, equilibrium constant doesn't depend of initial concentrations.

d. Changing temperature . <em>TRUE. </em>As a thermodynamic constant, k depends of temperature thus:

K = e^(-dG/RT)

e. Changing the volume of the reaction vessel. FALSE. The changing in the volume of the reaction vessel will change just the initial concentrations of the reactants.

I hope it helps!

6 0
2 years ago
What would you multiply "grams of barium" by to get the units "moles of barium" ?
solmaris [256]
Moles = weight in grams / molecular weight.

So I would divide the "grams of barium" by its molecular weight (which is 137.3) to get "moles of barium". :)
6 0
3 years ago
Urgent!!! Need answers!!!!??
vampirchik [111]

Answer:

Explanation:

What is the identity of the atom shown?

Answer:

Chlorine

Explanation:

An atom consist of electron, protons and neutrons. Protons and neutrons are present with in nucleus while the electrons are present out side the nucleus.

All these three subatomic particles construct an atom. A neutral atom have equal number of proton and electron. In other words we can say that negative and positive charges are equal in magnitude and cancel the each other. For example if neutral atom has 6 protons than it must have 6 electrons. The sum of neutrons and protons is the mass number of an atom while the number of protons are number of electrons is the atomic number of an atom.

In given picture it can be seen that there are 17 protons and 18 neutrons are present with in nucleus it means atomic mass is 35 amu and 17 electrons are present out side the nucleus it means its atomic number of 17.

The atomic number of chlorine is 17 and mass number is 35.5 amu thus the given atom is of chlorine.

Elements in the same group/family of the periodic table are similar in what way?

Answer:

D. They have the same number of valence electrons.

Explanation:

The elements in the same group have similar properties due to same number of valance electrons. For example

Consider the group two. It is alkaline earth metals's group. It consist of six members Beryllium, Magnesium, Calcium, Strontium, Barium and radium. All these have two valance electrons.

Electronic configuration of Beryllium:

Be = [He] 2s²

Electronic configuration of Magnesium:

Mg = [ Ne] 3s²

Electronic configuration of Calcium:

Ca = [Ar] 4s²

Electronic configuration of Strontium:

Sr = [Kr] 5s²

Electronic configuration of Barium:

Ba = [ Xe] 6s²

Electronic configuration of radium:

Ra = [Rn] 7s²

7 0
3 years ago
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