How much energy is needed to increase the temperature of 500g of lead from 20 degrees celcius to 45. The specific heat heat capacityof lead is 128J/kg/degrees celcius

just work with the units you have

500g = .5 kg
Your temp change is 25°C

.5kg * 25°C * 128J/kg-°C = 1600J

If you keep units in mind, you will be better able to determine how they combine.

To calculate the energy needed to increase the temperature of a substance, you can use the formula:

Q = mcΔT

Where:
Q is the energy (in Joules)
m is the mass of the substance (in grams)
c is the specific heat capacity of the substance (in J/kg/°C)
ΔT is the change in temperature (in °C)

First, convert the mass from grams to kilograms:
m = 500g / 1000 = 0.5 kg

Next, substitute the given values into the formula and calculate the energy:
Q = (0.5 kg) * (128 J/kg/°C) * (45 °C - 20 °C)

Q = (0.5 kg) * (128 J/kg/°C) * (25 °C)

Q = 1600 Joules

Therefore, the energy needed to increase the temperature of 500g of lead from 20°C to 45°C is 1600 Joules.