How much heat does it take to melt 2.5 kg of lead when it is at its melting point (m. p. = 327.5°c; hf = 2.04 × 104 j/kg)?

6.2 × 10^1 j

8.2 × 103 j

5.1 × 10^4 j

1.7 × 10^7 j

it takes 2.52 × 10^5 j of heat to melt 4.00 kg of a substance. according to the table, what is the substance?

copper

iron

silver

gold

which of the following would you use to calculate the heat released when a liquid freezes?

heat of fuheat of vaporization

heat of condensation

heat of solidification

how much heat is required to completely boil away 0.200 kg of water (hv = 2.26 × 103 kj/kg)?

4.52 × 10^2 kj

2.26 × 10^3 kj

4.52 × 10^3 kj

1.13 × 10^4 kj

If a planet rotates 360 degrees during a 24 hour time period, what does that tell us about the planet? a. the middle of the planet is in darkness b. the seasons on the planet vary every day. c. the planet runs on a 12-hour time clock. d. the temperature on the planet varies daily.

Does the temperature affect the solubility of sugar and salt in water? if it does tell me like different temperatures with different solubilities so i can sketch down a graph

13. calculate the initial concentration (before precipitation) of carbonate ions after the addition of each 0.05 ml of solution b to the 1.00 l beaker of solution a. divide the work among group members and write the answers in the table in model 3. assume the volume change as solution b is added is negligible. 14. notice the initial concentrations of zn2+ - and cu2+ in the table in model 3. a. explain how these were obtained from the data in model 2. b. as solution b is added and precipitates form, do these initial concentrations change? 15. use the data in model 2 to indicate the presence of precipitate (either znco3 or cuco3) after each 0.05 ml addition of solution b in model 3. 16. use the initial concentrations of carbonate ions and zinc ions to calculate the reaction quotient, qsp for the zinc carbonate scenarios in model 3. divide the work among group members and write the answers in the table in model 3. 17. use the initial concentrations of carbonate ion and copper(ii) ions to calculate the qsp for the copper(ii) carbonate scenarios in model 3. divide the work among group members and write the answers in the table in model 3.