When energy changes from one form to another, some energy is always changed to a. sound. b. light. c. electricity. d. heat.

The answer is D) Heat

When energy changes from one form to another, some energy is always changed to heat.

Please mark a brailiest ^-^

When energy changes from one form to another, some energy is always changed to Heat.

Which means the answer is D. (Heat)

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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%