The molar mass of nitrogen (n2) is 28.02 g/mol. what is the mass, in grams, of 4.60 mol of n2?

The correct answer is 129 grams.  

On the basis of the given data, the molar mass of nitrogen is 28.02 g/mol, the moles of nitrogen given is 4.60 mol. There is a need to calculate the mass of nitrogen.  

In order to calculate the mass, the formula to be used is:  

moles = mass (g) / molar mass (g/mol)

Now by putting the values we get,  

4.60 mol = mass / 28.02 g/mol

mass = 4.60 mol × 28.02 g/mol

mass = 128.892 g or 129 g

Thus, the mass of 4.60 mol of nitrogen is 129 g.  

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