What are the ways that heat moves?
heat moves from a cold object to a warm object.

heat only moves through air currents.

heat only moves through conduction and radiation.

heat moves through conduction, convection, and radiation.

Heat moves through conduction, convection, and radiation.

Explanation:

Hello,

In this case, heat transport is possible via conduction, convection and radiation which are defined as follows:

- Conduction: it happens when two or more objects have different temperatures and they are touching each other, thus, the energy is transferred from the hot to the cold object. For example, we can warm our hands by touching hot receptacles or objects.

- Convection: it occurs when a flowing fluid gets in contact with a surface at a different temperature, causing the heat transfer from the hot to cold region. For instance, when the air is freezing, it cools us down as we "provide" heat to it.

- Radiation: it occurs when a heat body transfers energy to its surroundings  by the creation of heatwaves which are released due to the temperature difference with its surroundings.

Best regards.

1. for the first question, we must find the mass of the anhydrous salt, mgso₄. the molar mass for mgso₄·7h₂o is 246.47 g/mol, while that of mgso₄ is 120.37 g/mol.7.834 g mgso₄·7h₂o * 1 mol mgso₄·7h₂o/246.47 g * 1 mol mgso₄/1 mol mgso₄·7h₂o * 20.37 g mgso₄/mol = 0.647 g mgso₄

2. mass of water = mass of sample - mass of anhydrous salemass of water = 7.834 - 0.647 = 7.19 gpercent water in hydrate = 7.19/7.834 * 100 = 91.74%