A cold can of soda is taken out of the refrigerator. It slowly warms up until it is at room temperature. Once the soda has warms up, it has more thermal energy than it had in the refrigerator. Where did this additional thermal energy come from?

See explanation

Explanation:

We know that the thermal energy of a substance largely depends on the temperature of the body. This implies that the hotter a substance is, the greater its thermal energy and vice versa.

When you bring a cold can of soda out of the refrigerator, the molecules of air at room temperature gradually loose energy to the can and condense around it. This transfers thermal energy from the air particles to the molecules in the cold can of soda and the soda warms up pretty soon!

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

metric time was an attempt to create a standard unit of time based off of 10, but it never took off an is not included in the metric system (si)