Answer:
First, the microwaves transmit kinetic energy to the water molecules of the food, heating the water molecules. Only, those that are not very deep into the food.
Second, the hot water molecules transmit heat by conduction to the other parts of the food.
Explanation:
1) Microwaves are a form of electromagnetic radiation. The same as any wave, they carry energy.
2) The wave length of microwaves are in the range of 0.001 mm to 1 m (shorter than radio waves and longer than infrared)
3) The microwaves of an oven, used to heat food, have a wave length aroun 12 cm.
4) The microwaves transmit energy to the water molecules in the food, by increasing the kinetic energy of water molecules. As result, the water molecules get hotter. Microwaves only penetrate about 1 cm inside the food (a potato for example) and from that the heat is transferred by conduction to the inner parts of the food.
Explanation:
Sodium metal reacts rapidly with water to form a colourless basic solution of sodium hydroxide (NaOH) and hydrogen gas (H2). The reaction continues even when the solution becomes basic. The resulting solution is basic because of the dissolved hydroxide.
Answer:
a) Limiting: sulfur. Excess: aluminium.
b) 1.56g Al₂S₃.
c) 0.72g Al
Explanation:
Hello,
In this case, the initial mass of both aluminium and sulfur are missing, therefore, one could assume they are 1.00 g for each one. Thus, by considering the undergoing chemical reaction turns out:

a) Thus, considering the assumed mass (which could be changed based on the one you are given), the limiting reagent is identified as shown below:

Thereby, since there 1.00g of aluminium will consume 0.0554 mol of sulfur but there are just 0.0156 mol available, the limiting reagent is sulfur and the excess reagent is aluminium.
b) By stoichiometry, the produced grams of aluminium sulfide are:

c) The leftover is computed as follows:

NOTE: Remember I assumed the quantities, they could change based on those you are given, so the results might be different, but the procedure is quite the same.
Best regards.