Question

1. Why are sharp knives more effective than dull knives? (Hint: Think about the definition of pressure.) 2. Name 6 possible units of pressure. 3. Convert 30°C to Kelvin. 4. Draw a manometer and a barometer and explain how they both work. 5. Sometimes leaving a bicycle in the sun on a hot day will cause a blowout. Why? 6. A 2.50-L volume of hydrogen measured at -196 °C is warmed to 100 °C. Calculate the volume of the gas at the higher temperature, assuming no change in pressure. Which law is this? 7. How many moles of gaseous boron trifluoride, BF3, are contained in a 434.10-ml bulb at 788.0 K if the pressure is 1.220 torr? How many grams of BF3? Which law is this? Pay attention to the units. 8. Determine the pressure of a gas in a 15-mL syringe at 10 psi when its volume is reduced from 12.5 mL to 8 mL.

Answer 1

1) Sharp knife cuts better because of very small and fine edge which has small area and therefore pressure applied becomes larger.

As, pressure is inversely proportional to area hence small the area more would be the pressure and hence sharp knife cut better than dull knife.

2) units of pressure are-

Pascal

Atm

Newton/ metre square

Bar

Torr

Psi

3) 30° C to K

= 30 + 273.15 k

= 303.15 k.

Hope this helps you