All categories

2 years ago

18) Calculate the molarity

Chemistry

1 answer:

Sloan [31]2 years ago

4 0

Answer:

B. 0.92 M

Explanation:

Molarity of a solution = number of moles (n) ÷ volume (V)

According to the information provided in this question;

mass of NaCl = 42g

Volume of water = 780mL

Using mole = mass/molar mass

Molar mass of NaCl = 23 + 35.5 = 58.5g/mol

mole = 42/58.5

mole (n) = 0.72mol

Volume (V) = 780 mL = 780/1000 = 0.780 L

Hence, molarity = n/V

Molarity = 0.72/0.780

Molarity = 0.923 M

You might be interested in

Nitrogen gas (112 g) reacts with hydrogen gas to produce 40.8 g of ammonia according to the following

Lemur [1.5K]

Answer:

%yield of NH₃ = 30%

Explanation:

Actual yield of NH₃ = 40.8g

Theoretical yield = ?

Equation of reaction

N₂ + 3H₂ → 2NH₃

Molar mass of NH₃ = 17g/mol

Molarmass of N = 14.00

2 molecules of N = 2 * 14.00 = 28g/mol

Number of moles = mass / molar mass

Mass = number of moles * molar mass

Mass = 1 * 28.00 = 28g of N₂ (the number of moles of N₂ from the equation is 1).

From the equation of reaction,

28g of N₂ produce (2 * 17)g of NH₃

28g of N₂ = 34g of NH₃

112g of N₂ = x g of NH₃

X = (112 * 34) / 28

X = 136g of NH₃

Theoretical yield = 136g of NH₃

% yield = (actual yield / theoretical yield) * 100

% yield = (40.8 / 136) * 100

% yield = 0.3 * 100

% yield = 30%

8 0

3 years ago

How do different bridge designs react to stong winds

anastassius [24]

Depending on how the design is, The bridge will sway, bounce, or move in some way. If the bridge was too stiff the winds would destroy the bridge and cause it to crumble and fall.

Hope that answer works for you! :)

3 0

3 years ago

The change of matter from a gas state to a liquid state

lara [203]

Condensation ..when gas cool down into liquid statr its called condensation..

5 0

3 years ago

How can waves transfer energy without transporting matter from one place to another?

vichka [17]

Answer:

When a wave is present in a medium (that is, when there is a disturbance moving through a medium), the individual particles of the medium are only temporarily displaced from their rest position.

Explanation:

3 0

2 years ago

Read 2 more answers

The chemical symbol of several elements are given below. Determine the atomic number of each element. Chemical Atomic Number Sym

spayn [35]

Explanation:

Atomic number is defined as the number of protons or electrons that are present in a neutral atom.

Atomic number = number of protons = number of electrons

Mass number is defined as the sum of number of protons and neutrons that are present in an atom.

Mass number = Number of protons + Number of neutrons

The isotopic representation of an atom is: $_Z^A\textrm{X}$

where,

Z = Atomic number of the atom

A = Mass number of the atom

X = Symbol of the atom

For A:

1) Fe

The atom given to us is iron. It is present in Group 8 and period 4 of the periodic table. The atomic number of iron is 26

2) Be

The atom given to us is beryllium. It is present in Group 2 and period 2 of the periodic table. The atomic number of beryllium is 4

3) Kr

The atom given to us is krypton. It is present in Group 18 and period 4 of the periodic table. The atomic number of iron is 36

For B:

1) $_{24}^{53}\textrm{Cr}$

Atomic number = Number of protons = Number of electrons = 24

Mass number = 53

Number of neutrons = 53 - 24 = 29

The number of protons, electrons and neutrons for the given element are 24, 24 and 29 respectively

2) $_{44}^{103}\textrm{Ru}$

Atomic number = Number of protons = Number of electrons = 44

Mass number = 103

Number of neutrons = 103 - 44 = 59

The number of protons, electrons and neutrons for the given element are 44, 44 and 59 respectively

3) $_{30}^{67}\textrm{Zn}$

Atomic number = Number of protons = Number of electrons = 30

Mass number = 67

Number of neutrons = 67 - 30 = 37

The number of protons, electrons and neutrons for the given element are 30, 30 and 37 respectively

For C:

1) Atomic number = 14; Mass number = 28

The element having atomic number '14' is Silicon

The isotopic symbol of the element is $_{14}^{28}\textrm{Si}$

The symbol of the element is 'Si'

2) Atomic number = 18; Mass number = 40

The element having atomic number '18' is Argon

The isotopic symbol of the element is $_{18}^{40}\textrm{Ar}$

The symbol of the element is 'Ar'

3) Atomic number = 19; Mass number = 39

The element having atomic number '19' is Potassium

The isotopic symbol of the element is $_{19}^{39}\textrm{K}$

The symbol of the element is 'K'

5 0

3 years ago