Convert between Celsius, Kelvin and Fahrenheit

Answer Key - Grade 10 Science Worksheet - Challenge Me

Circle the best answer, or write your answer on the line.

1. 1.

   Bo measures a gas at constant pressure: 30 mL at 25 °C and 35.2 mL at 75 °C. Extend the straight line to zero volume. At what temperature, to the nearest °C?

   -263 °C
2. 2.

   Jun's weather app says today's 30 °C is twice as hot as yesterday's 15 °C. Verdict?

   • Yes: 30 is double 15, so the average energy doubled
   • No: 303 K against 288 K is about 5% more average energy per molecule
   • Yes: the ratio 30 to 15 is also 2 on the kelvin scale
3. 3.

   Kira converts a 15 °C rise to Fahrenheit as 15 × 1.8 + 32 = 59 °F. What is the error?

   • The 32 should be subtracted: 15 × 1.8 − 32 = −5 °F
   • A rise skips the +32: 15 °C more is 27 °F more
   • No error: a conversion adds 32 each time
4. 4.

   Water's specific heat is 4.18 J/(g·°C). What is it in J/(g·°F), Luz?

   • 2.32 J/(g·°F), because a Fahrenheit degree is smaller
   • 7.52 J/(g·°F), found by multiplying 4.18 by 1.8
   • 4.18 J/(g·°F), because specific heat does not depend on the scale
5. 5.

   Water's triple point is 273.16 K (0.01 °C), but ice melts at 0 °C at 1 atm. Why the 0.01 °C gap, Milo?

   • The kelvin and Celsius degrees differ slightly in size near 0 °C, so 0.01 shows up
   • At 1 atm, with air dissolved, ice melts about 0.01 °C lower than at the triple point
   • The 273.16 K figure is a measuring error that has not been corrected
6. 6.

   A sealed rigid can of air is heated from 27 °C to 177 °C. How does the pressure change, Noah?

   • It rises to 1.5 times its start: 300 K to 450 K
   • It rises to 6.6 times its start, since 177 is 6.6 times 27
   • It rises by 150%, since the temperature rose by 150 degrees
7. 7.

   A sample warms from 300 K to 325 K. What is that change in °F, Pia?

   • 77 °F, found by 25 × 1.8 + 32 in the usual way
   • 45 °F: 25 K is 25 °C, and each °C is 1.8 °F
   • 125.3 °F, the final reading converted into Fahrenheit
8. 8.

   A thermometer reads 1.5 °C in ice water and 99.0 °C in boiling water at 1 atm. It reads 50.0 °C in a sample. What is the true temperature, Ren?

   • About 49.7 °C, after correcting both the offset and the degree size
   • 48.5 °C, correcting just the 1.5 °C offset
   • 50.0 °C, trusting the reading since the error looks small
9. 9.

   On scale Y (freezing 10 °Y, boiling 130 °Y), a sample warms from 40 °Y to 100 °Y. How many kelvins is that change, Tala?

   • 72 K, found by multiplying the 60 °Y change by 1.2
   • 60 K, since a degree is a degree on any scale
   • 50 K: the change is 60 °Y and 1.2 °Y equals 1 K

10. Read this first

    Reference temperatures (real data, NIST)

    point	kelvin (K)	Celsius (°C)	Fahrenheit (°F)
    absolute zero	0	−273.15	−459.67
    liquid nitrogen boils	77.36	−195.79	−320.42
    dry ice turns to gas	194.65	−78.5	−109.3
    water freezes	273.15	0	32
    a room	293.15	20	68
    water boils	373.15	100	212

11. 10.

    Liquid nitrogen boils at 77.36 K. Zee says that is 273.15 − 77.36 = 195.79 °C. What is wrong?

    • The student should add: 77.36 + 273.15 = 350.51 °C, not subtract
    • The sign: 77.36 − 273.15 = −195.79 °C, which is below zero
    • Nothing: 195.79 °C is right because nitrogen is very cold