Y2_T4_Practice test

• Science
• Middelbare school
• havo, vwo
• Leerjaar 2

Practice Test

Have ready:

• notebook (blanc page)
• Calculator
• Ruler/triangle
• Pen

Liquid nitrogen: (5 points)

Liquid nitrogen is often used in molecular cooking to make ice cream. Cooks will add liquid nitrogen (which is usually around -195C) to the ice cream mixture and as they mix it in the ice cream freezes, any liquid nitrogen left in the mixture evaporates into nitrogen gas which is naturally in the air around us. Liquid nitrogen has a freezing point of -210C and a boiling point of -170C.

Q1: Draw a transition diagram in your notebook. Make sure to label the phases as well as the transitions over the different parts of your graph. (3p)

Phase transitions

During a phase change the 

temperature stays constant.

The temperature will not 

change until all molecules 

have transitioned.

Q2: What phase is nitrogen at 80 K? Use a calculation to support your answer. (2p)

Biological soaps: (6 points)

Biological soaps use natural enzymes to clean the dirt from your hands or dirty clothes. The optimum temperature these enzymes is often around 40 degrees. 

Q3: What would happen if someone washes their clothes at 50C. (2p)

Q3: What would happen if someone washes their hands with cold water, which is about 10C (2p)

Most thermostat taps have a maximum setting so kids cannot burn themselves, this lock is often around 35C. Is this a good temperature for using biological soaps? (2p)

Climbers: (8 points)

This forces diagram shows a climber abseiling down a cliff. This diagram shows proper gear and ropes are of life and death importance. 

Copy the diagram into your notebook:

The climber is a block of 1 cm wide and 2 cm high.  scale: 1 cm = 50N

Fg= 800N, Ft=1000N, Ffr=100N, Fn=50N

Upload a picture of your diagram here (2p)

If a climber pushes off from the wall there are only 2 forces left at work, what are these 2 forces? (2p)

If a climber pushes off from the wall there are only 2 forces left at work, calculate the resulting force (2p)

If a climber is touching the wall all 4 forces are at work, calculate the resulting force. Round up to full numbers. (2p)

a​2​​+b​2​​=c​2​​

Study for the Test:

• study all the glossaries
• study the notes
• review all the hw exercises 

Make sure you bring:

• ruler/triangle
• calculator
• pen
• highlight marker