Convection currents in the mantle are what causes the movement of tectonic plates. As the extremely hot molten material from the mantle rises toward the crust, it cools enough to become denser and sink back into the hotter area of the mantle.
Answer:
A safety pin
Explanation:
Rubber, plastic and food are all non-metals, meaning they are poor conductors of heat and electricity. However, safety pins are made up of steel - a metal - making them good conductors.
Answer: The mass of the sample will be 1417.7 grams.
Explanation:
We are given:
This means that 1 mole of NaCl has an enthalpy of fusion of 30.2 kJ
1 mole of NaCl has a mass of 58.44 grams.
So, 30.2 kJ of heat is require for a mass 58.44 grams of NaCl
So, 732.6 kJ of heat will be required for = 
= 1417.65 grams of NaCl.
Hence, the mass of NaCl sample will be 1417.7 grams.
The researcher may first weight the beaker with water and then start to heat the water to a constant temperature, for example 30 °C and then start adding salt and stirring. He should add salt slowly until solid salt starts to become visible and the solution starts becoming cloudy. When this happens, he should quickly weigh the beaker. The increase in mass is the mass of salt dissolved at that temperature.
The procedure is then repeated but at an increased temperature until 5-6 temperatures have been tested.
