(CO2) (O2) (He) (N2) (CH4) (Imagine these are balloons with the specified gas inside)

Above are five identical balloons, each filled to the same volume at 25°C and 1.0 atm

Which balloon contains the molecules with the greatest average speed? Which has the Lowest average speed?

Highest speed: He

Lowest speed: CO2

Explanation:

The rms speed (average speed) of the molecules/atoms in an ideal gas is given by:

where

R is the gas constant

T is the absolute temperature of the gas

M is the molar mass of the gas, which is the mass of the gas per unit mole

From the equation, we see that at equal temperatures, the speed of the molecules in the gas is inversely proportional to the molar mass: the higher the molar mass, the lower the speed, and vice-versa.

In this problem, we have 5 gases:

(CO2) (O2) (He) (N2) (CH4)

Their molar mass is:

CO2: 44 g/mol

O2: 16 g/mol

He: 4 g/mol

N2: 14 g/mol

CH4: 16 g/mol

The gas with lowest molar mass is Helium (He): therefore, this is the gas with greatest average speed.

The gas with highest molar mass is CO2: therefore, this is the gas with lowest average speed.

the answer is true.

as given the equation is

2al + 6 hcl > 2 alcl3 + 3 h2(g)

as per equation two moles of aluminum reacts with six moles of hcl to give two moles of alcl3 and three moles of hydrogen gas

given: three moles of al are present and 7 moles of hcl

for three moles of aluminum nine moles of hcl will be required

however as 7 moles of hcl are present so the limiting reagent is hcl

hcl is going to decide the number of moles of product formed

when six moles of hcl are present = 3 moles of h2 are formed

when one mole of hcl is present == 3/6 mole sof h2 will be formed

when 7 moles of hcl are present = 3 x 7/ 6 moles of h2 will be formed = 3.5 moles of h2