0.22g of carbon dioxide are dissolved in 400 cm3 of pure water. Calculate the concentration in mol/dm3 of the
solution produced.

0.0125mol/dm³

Explanation:

Given parameters:

Mass of carbon dioxide  = 0.22g

Volume of water  = 400cm³

Unknown:

Concentration in mol/dm³ =  ?

Solution:

Concentration is the amount of solute dissolved in a solvent.

The formula is expressed as;

    Concentration  =  

Number of moles  =

       Molar mass of CO₂   = 12 + 3(16) = 44g/mol

Number of moles  =   = 0.0005mol

Now,

             1000cm³  = 1dm³

             400cm³ =  = 0.4dm³

Insert the parameters and solve;

     Concentration  =  = 0.0125mol/dm³

d. temperate deciduous forest

when 25.0 ml of 0.700 mol/l naoh was mixed in a calorimeter with 25.0 ml of 0.700 mol/l hcl, both initially at 20.0 °c, the temperature increased to 22.1 °c. the heat capacity of the calorimeter is 279 j/°c.

the equation for the reaction is:

naoh + hcl → nacl + h₂o

moles of hcl = 0.0250 l hcl ×

0.700

mol hcl

1 l hcl = 0.0175 mol hcl

volume of solution = (25.0 + 25.0) ml = 50.0 ml

mass of solution = 50.0 ml soln ×

1.00

ml soln

= 50.0 g soln

δt=t2-t1

= (22.1 – 20.0) °c = 2.1 °c

the heats involved are

heat from neutralization + heat to warm solution + heat to warm calorimeter = 0

q1+q2+q3=0

nδh+mcδt+cδt=0

0.0175 mol ×

δh

+ 50.0 g × 4.184 j·g⁻¹°c⁻¹ × 2.1 °c + 279 j°c⁻¹ × 2.1 °c = 0

0.0175 mol ×

δh

+ 439.32 j + 585.9 j = 0

0.0175 mol ×

δh

= -1025.22 j

δh=1025.22j0.0175 mol= -58 600 j/mol = -58.6 kj/mol