Specific Heat Calculations What you need to know

Specific Heat Calculations

What you need to know • • • Heat Formula: Q = mcp∆T Q – heat transferred (J) m- mass (g or kg) Cp - specific heat capacity (J/g·C° or J/kg·C°) ∆T - temperature change (C°)

Question 1 • Heat Formula: Q = mcp∆T • • Specific heat capacity of water – 4. 186 J/g C 0 Temperature change of the water – 10 C 0 Mass of water – 60 grams Find the heat transferred - ? • Multiply each value to find heat transferred.

Question 2 • Heat Formula: Q = mcp∆T • A copper mass is placed in water and changes the water’s temperature from 60 0 C to 55 0 C. The water has a mass of 50 grams and a specific heat capacity of 4. 186 J/ g 0 C • What was the amount of heat transferred from the water to the copper mass? Known Equation Substitution Q=? m = 50 g cp = 4. 186 J/g°C ΔT = 55°C-60°C = -5°C Q = mcp∆T Q=(50)(4. 186)(-5) Solve

Question 3 • • • Formula for specific heat: cp = Q/m∆T Heat transferred – 30 Joules Mass of substance – 100 grams Change in temp. - 10 0 C Find the specific heat of this substance • Multiply mass by change in temperature, then divide Heat transferred by the result.

Question 4 • A substance with a mass of 10 grams is heated to 100 0 C. The substance is placed in cold water and reaches equilibrium with the water at 50 0 C. The amount of heat transferred from the substance to the water is 500 Joules. Calculate the specific heat capacity of the substance Known Equation Substitution Q = 500 J m = 10 g cp = ? ΔT = 50°C-100°C = -50°C cp = Q/m∆T cp=500/(10*-50) Solve