herkansing Tygo

• Natuurkunde
• Middelbare school
• vmbo b
• Leerjaar 1

The heat of combustion for spiritus is 18MJ/L.
To start up the heater you need 50 mL spiritus.
How much energy is released when igniting the heater in this way?

1. 360 kJ
2. 900 kJ
3. 360 MJ
4. 900 MJ

Convert:
800kJ = ... J

1. 800 000
2. 800
3. 0,008
4. 0,000 008

Heat of combustion

A gasburner needs 0,75 m3 of natural gas to boil a certain amount of water.
a.Calculate how much heat is released when you burn 0,75 m3 of gas.
b. How much wood do you need to release the same amount of heat?

Dad was given a barbeque.
He has a bag of coal of 10 kg. Every time you light up the BBQ you use approximately 45000 J. How many times would he be able to light up the BBQ?

A device is connected to a container with an unknown substance.
When burning some of the unknown substance you find out that you can release 53.700 J of heat when you burn 1,5 L of this substance.
What will be the unknown substance?

To be able to heat up the garage you need 144.000 J every day..
When you use a petrol heater for this, how many liters do you need to be able to heat up the garage for a year?

Calculate the efficiency

3,8 J of 6,5 J energy is converted into light in a lightbulb. What is the efficiency of the lightbulb?

1. 171%
2. 58%
3. 37%
4. 15%