The density of manganese is 7.21 g/cm^3 . What is the density in kg/m^3 ? (dimensional analysis)

Calculate the number of chloride ions in 6.8 g of zinc chloride

Bumek [7]

Answer:

The correct answer is 0.300 * 10^23 ions.

Explanation:

Based on the given question, there is a need to find the number of chloride ions in the mentioned 6.8 grams of zinc chloride compound.

The moles of zinc chloride (ZnCl2) is,

= mass of zinc + 2 mass of chlorine

= 65.38 + 2 (35.45)

=65.38 + 70.90

= 136.28 grams (The molecular mass of zinc is 65.38 and the molecular mass of chlorine is 35.45)

Thus, 136.28 g of ZnCl2 contains 70.90 grams of chlorine

Therefore, 6.8 grams of ZnCl2 will comprise = (70.90/136.28) * 6.8

= 3.537 g of chlorine

70.90 g of Cl comprise 6.022*10^23 chlorine, thus, 3.537 g of Cl will comprise (6.022*10^23/70.90) * 3.537

= 0.300 * 10^23 ions of chlorine.

3 0

2 years ago

What is water's density at 93 ∘C? Assume a constant coefficient of volume expansion. Express your answer with the appropriate un

Ganezh [65]

Answer:

982.5 kg/m³

Explanation:

When the temperature of a fluid increases, it dilates, and because of the variation of the volume, it's density will vary too. The density can be calculated by the expression:

ρ₁ = ρ₀/(1 + β*(t₁ - t₀))

Where ρ₁ is the final density, ρ₀ the initial density, β is the constant coefficient of volume expansion, t₁ the final temperature, and t₀ the initial temperature.

At t₀ = 4°C, the water desity is ρ₀ = 1,000 kg/m³. The value of the constant for water is β = 0.0002 m³/m³ °C, so, for t₁ = 93°C

ρ₁ = 1,000/(1 + 0.0002*(93 - 4))

ρ₁ = 1,000/(1+ 0.0178)

ρ₁ = 982.5 kg/m³

3 0

2 years ago

4. A nuclear engineer is designing a nuclear reactor for a new power plant. The reactor core will have an operating temperature

Readme [11.4K]

Sodium Chloride because its still a liquid at the 773 temperature mark

8 0

2 years ago

Which statement is TRUE regarding the macroscopic and

damaskus [11]

Answer:

Chemists make observations on the macroscopic a scale that lead to conclusions about microscopic features

Explanation:

Many important chemical observations are made on the macroscopic scale. This is because, many of the scientific equipments available are not presently able to provide direct evidence about microscopic processes. Evidences obtained from macroscopic observations could serve as important insights into the nature of certain microscopic processes.

This is evident in the study of the structure of the atom. Most of the evidences that led to the deduction of the atomic structure were obtained from macroscopic evidence but ultimately provided important information about the microscopic structure of the atom.

7 0

2 years ago

Some building materials contain small capsules filled with paraffin wax to improve the insulating properties of the materials. T

alisha [4.7K]

Answer:

(a)

From surrounding to wax

(b)

Q = 2.62 KJ

(c)

Density of a substance is defined as the no. of particles of the substance, that occur in a unit volume. So, when the substance melts, the inter-molecular attractive forces and bonds between molecules or atoms are weakened. This, increases the distance between the molecules or atoms. Hence, the no. of particles in a unit volume is decreased. As, a result of this, the density of the substance also decreases.

Explanation:

(a)

During the melting process, the solid material or substance requires energy, in order to break the bonds between its molecules or atoms.

Therefore, while the wax is melting, the net flow of thermal energy is from surrounding to the wax.

(b)

The amount of energy required to melt solid paraffin wax is given by the formula:

Q = nC

where,

Q = amount of energy

C = Molar Heat of Fusion = 48.78 KJ/mol

n = No. of Moles = Mass in gram/Molar Mass = (15.2 g)/(282.62 g/mol)

n = 0.0538 mol

Therefore,

Q = (0.0538 mol)(48.78 KJ/mol)

Q = 2.62 KJ

(c)

Density of a substance is defined as the no. of particles of the substance, that occur in a unit volume. So, when the substance melts, the inter-molecular attractive forces and bonds between molecules or atoms are weakened. This, increases the distance between the molecules or atoms. Hence, the no. of particles in a unit volume is decreased. As, a result of this, the density of the substance also decreases.

3 0

2 years ago