The temperature of a sample of iron with a mass of 10.0 kg changed from 50.4°C to 25.0°C. The specific heat of iron is 0.444 J/kg*C. What is the amount of energy required to change the temperature like this?

In which situation has the independent variable for the experiment been changed? check all that apply. changed from counting the number of duckweed at day 0 and day 14 to counting them every day changed from testing duckweed growth in beakers to testing duckweed growth in large outdoor tanks changed from testing the effect of ph on duckweed growth to testing the effect of light levels on duckweed growth changed from testing the effect of acid ph on duckweed growth to testing the effect of basic ph on duckweed growth

Anybody wanna ? (picture included? )

Critical mass is the of material required to produce a chain reaction. a.) minimum amount b.) atomic mass c.) precise amount d.) maximum amount