You are making a temperature measurement with a lab thermometer. The increments (markings) are 1°C. You see that the temperature is about 1/3 of the way from 21°C to 22°C. How would you record this temperature? How many significant figures does it have? In what place value is the smallest certain digit? In what place value (tens, ones, tenths, etc.) is the uncertain digit?

One of the hopes for solving the world's energy problem is to make use of the fusion reaction 21h +31h --> 42he + 10n + energy how much energy is released when 1 mol of deuterium is fused with 1 mol of tritium according to the above reaction? the masses of the atoms and the neutrons are as follows: 21h = 2.0140 amu 31h = 3.01605 amu 42he = 4.002603 amu 10n = 1.008665 amu. the speed of light is 2.9979 x 108 m/s.