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2 years ago

Can we cover the earth with one mole of pennies? Explain.

Chemistry

1 answer:

mezya [45]2 years ago

4 0

Answer:

No we can’t cover the earth with one mole of pennies

Explanation:

We can’t cover the earth with one mole of pennies due to the fact that making this possible will require the flattening and extra expansion before it covers the whole surface.

The extra expansion and flattening with result in the loss of intermolecular forces and won’t remain as a solid and form other states of matter which won’t be able to cover the surface.

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the density of glycerin is 1.26 g/cm3. How many pounds/foot3 is this ? use the conversion rates of 454g/1 pound and 28,317cm3/1f

lyudmila [28]

Answer:

78.6 lb/ft³

Step-by-step explanation:

Let's do this in steps.

1. Convert grams to pounds

D = (1.26 g/1 cm³) × (1 lb/454 g)

= 2.775 × 10⁻³ lb/cm³

2. Convert cubic centimetres to cubic feet

D = (2.775 × 10⁻³ lb/1 cm³) × (28 317cm³/1 ft³)

= 78.6 lb/ft³

6 0

2 years ago

Brass is a substitutional alloy consisting of a solution of copper and zinc. A particular sample of red brass consisting of 79.0

Bas_tet [7]

Answer: The molality and molarity of zinc in the solution is 4.07 m and 28.11 M respectively.

Explanation:

Solute is the substance which is present in smaller proportion in a mixture and solvent is the substance which is present in larger proportion in a mixture.

We are given:

(m/m) % of Cu = 79 %

This means that 79 g of copper is present in 100 grams of alloy.

(m/m) % of Zn = 21 %

This means that 21 g of zinc is present in 100 grams of alloy.

As, zinc is present in smaller proportion. So, it is solute and copper is the solvent.

Calculating molality of zinc:

To calculate molality of the zinc, we use the equation:

$Molality=\frac{m_{solute}\times 1000}{M_{solute}\times W_{solvent}\text{ in grams}}$

where,

$m_{solute}$ = Given mass of solute (Zinc ) = 21 g

$M_{solute}$ = Molar mass of solute (Zinc) = 65.3 g/mol

$W_{solvent}$ = Mass of solvent (copper) = 79 g

Putting values in above equation, we get:

$\text{Molality of Zinc}=\frac{21\times 1000}{65.3\times 79}\\\\\text{Molality of zinc}=4.07m$

Calculating molarity of zinc:

To calculate volume of a substance, we use the equation:

$\text{Density of substance}=\frac{\text{Mass of substance}}{\text{Volume of substance}}$

Density of solution = $8740kg/m^3=\frac{8740kg\frac{1000g}{1kg}}{1m^3\times \frac{10^6cm^3}{1m^3}}=\frac{8740g}{1000cm^3}=8.740g/cm^3$

(Conversion factors used are: 1 kg = 1000 g & $1m^3=10^6cm^3$ )

Mass of solution = 100 g

Putting values in above equation, we get:

$8.740g/cm^3=\frac{100.0g}{\text{Volume of zinc}}\\\\\text{Volume of zinc}=11.44cm^3$

To calculate the molarity of solution, we use the equation:

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

We are given:

Molar mass of zinc = 65.3 g/mol

Volume of solution = $11.44cm^3=11.44mL$ (Conversion factor: $1cm^3=1mL$ )

Mass of zinc = 21.0 g

Putting values in above equation, we get:

$\text{Molarity of zinc}=\frac{21\times 1000}{65.3\times 11.44}=28.11M$

Hence, the molality and molarity of zinc in the solution is 4.07 m and 28.11 M respectively.

4 0

3 years ago

Give me two sources of air pollution

Liula [17]

Answer:

Explanation:

Types of Sources

There are four main types of air pollution sources: mobile sources – such as cars, buses, planes, trucks, and trains. stationary sources – such as power plants, oil refineries, industrial facilities, and factories. area sources – such as agricultural areas, cities, and wood burning fireplaces.

6 0

2 years ago

Which of the following statements is typically true for a catalyst? I. The concentration of the catalyst will go down as a react

gladu [14]

Answer: II. The catalyst provides a new pathway in the reaction mechanism.

III. The catalyst speeds up the reaction.

Explanation:

Activation energy is the extra energy that must be supplied to reactants in order to cross the energy barrier and thus convert to products.

A catalyst is a substance which increases the rate of a reaction by taking the reaction through a different path which involves lower activation energy and thus more molecules can cross the energy barrier and more molecules convert to products.

The catalyst itself does not take part in the chemical reaction and gets regenerated as such at the end of the reaction without getting consumed.

3 0

2 years ago

A gas vessel is charged with a mixture of pcl3(g) and cl2(g), which is allowed to equilibrate at 450 k. at equilibrium the parti

VikaD [51]

Answer is: Kp = 66,586.
Chemical reaction: PCl₃(g) + Cl₂(g) ⇔ PCl₅(g).
Kp - equilibrium constants expressed in terms of partial pressures of gases.
Kp = p(PCl₅) ÷ p(PCl₃) · p(Cl₂). p-partial pressure.
Kp = 1,67 atm ÷ 0,132 atm · 0,190 atm
Kp = 66, 586 1/atm. Favors product.

4 0

2 years ago