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2 years ago

How many atoms are present in 179.0 g of iridium?

2 answers:

8 0

Avogadro's number represents the number of units in one mole of any substance. This has the value of 6.022 x 10^23 units/mole. This number can be used to convert the number of atoms or molecules into a number of moles. We do as follows:
179.0 g of iridium (1 mol / 192.217 g) ( 6.022 x 10^23 atoms / 1 mol ) = 5.61 x 10^23 atoms of iridium
Hope this answers the question.

TEA [102]2 years ago

7 0

Avogadro's number represents the number of units in one mole of any substance. This has the value of 6.022 x 10^23 units / mole. This number can be used to convert the number of atoms or molecules into number of moles. We do as follows:
179.0 g of iridium (1 mol / 192.217 g) ( 6.022 x 10^23 atoms / 1 mol ) = 5.61 x 10^23 atoms of iridium
I think this is the answer

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Aluminum has a specific heat of 0.902 j/gC. How much heat is lost when a piece of aluminum with a mass of 23.984 g cools from a

Marizza181 [45]

Answer:

Q = - 8501.99 j

Explanation:

Given data:

Specific heat of Al = 0.902 j/g.°C

Heat lost = ?

Mass of sample = 23.984 g

Initial temperature = 415°C

Final temperature = 22°C

Solution:

Specific heat capacity:

It is the amount of heat required to raise the temperature of one gram of substance by one degree.

Formula:

Q = m.c. ΔT

Q = amount of heat absorbed or released

m = mass of given substance

c = specific heat capacity of substance

ΔT = change in temperature

ΔT = 22°C - 415°C

ΔT = -393°C

Q = m.c. ΔT

Q = 23.984 g× 0.902 j/g.°C × -393°C

Q = - 8501.99 j

8 0

2 years ago

A steam turbine is a device in which high-pressure steam enters the turbine and causes blades to spin. The spinning blades have

pav-90 [236]

The answer is Some of the heat used to make the steam is transformed into work as the steam pushes against the blades to make them turn. This also observes the law of conservation in thermodynamics. The kinetic energy in the steam helps push the blades and is converted to mechanical energy. Some of the energy is lost since it is never 100% efficient.

6 0

2 years ago

Read 2 more answers

When 0.270 mol of a nondissociating solute is dissolved in 410.0 mL of CS2, the solution boils at 47.52 ∘C. What is the molal bo

grandymaker [24]

Answer:

Kb = 0.428 m/°C

Explanation:

To solve this problem we need to use the boiling-point elevation formula:

Tsolution - Tpure solvent = Kb * m

Where Tsolution and Tpure solvent are the boiling point of the CS₂ solution (47.52 °C) and of pure CS₂ (46.3 °C), respectively. Kb is the constant asked by the problem, and m is the molality of the solution.

So in order to use that equation and solve for Kb, first we calculate the molality of the solution.

molality = mol solute / kg solvent

Density of CS₂ = 1.26 g/cm³

Mass of 410.0 mL of CS₂ ⇒ 410 cm³ * 1.26 g/cm³ = 516.6 g = 0.5166 kg

molality = 0.270 mol / 0.5166 kg = 0.5226 m

Now we solve for Kb:

Tsolution - Tpure solvent = Kb * m

47.52 °C - 46.3 °C = Kb * 0.5226 m

Kb = 0.428 m/°C

3 0

2 years ago

(a) The mass density of a gaseous compound was found to be 1.23 kg m^−3 at 330 K and 20 kPa. What is the molar mass of the compo

Luden [163]

Answer:

The molar mass of the compound is:- 168.82 g/mol

The molar mass of the gas is:- 16.38 g/mol

Explanation:

(a)

Using ideal gas equation as:

$PV=nRT$

where,

P is the pressure

V is the volume

n is the number of moles

T is the temperature

R is Gas constant having value = 0.0821 L.atm/K.mol

Also,

Moles = mass (m) / Molar mass (M)

Density (d) = Mass (m) / Volume (V)

So, the ideal gas equation can be written as:

$PM=dRt$

Given that:-

Pressure = 20 kPa = 20000 Pa

The expression for the conversion of pressure in Pascal to pressure in atm is shown below:

P (Pa) = $\frac {1}{101325}$ P (atm)

20000 Pa = $\frac {20000}{101325}$ atm

Pressure = 0.1974 atm

Temperature = 330 K

d = 1.23 kg/m³ = 1.23 g/L

Molar mass = ?

Applying the equation as:

0.1974 atm × M = 1.23 g/L × 0.0821 L.atm/K.mol × 330 K

⇒M = 168.82 g/mol

The molar mass of the compound is:- 168.82 g/mol

(b)

Given that:

Pressure = 152 Torr

Temperature = 298 K

Volume = 250 cm³ = 0.25 L

Using ideal gas equation as:

$PV=nRT$

R = $62.3637\text{torr}mol^{-1}K^{-1}$

Applying the equation as:

152 Torr × 0.25 L = n × 62.3637 L.torr/K.mol × 298 K

⇒n = 0.002045 moles

Given that :

Mass of the gas = 33.5 mg = 0.0335 g

Molar mass = ?

The formula for the calculation of moles is shown below:

$moles = \frac{Mass\ taken}{Molar\ mass}$

Thus,

$0.002045\ moles
= \frac{0.0335\ g}{Molar\ mass}$

The molar mass of the gas is:- 16.38 g/mol

5 0

2 years ago

An ion with 5 protons, 6 neutrons and a charge of 3+ has an atomic number of ____.

Umnica [9.8K]

Answer:An ion with 5 protons, 6 neutrons and a charge of 3+ has an atomic number of 5

Explanation:

3 0

2 years ago

Read 2 more answers