11. Why are there high and low tides on Earth? A. They are due to changes in the moon's tilt on its axis.
B. They are due to the gravitational pull between Earth and the moon.
C. They are due to the magnetic force between Earth and the moon.
D. They are due to changes in the moon's speed every month.

d: the voltage of the secondary coil is less than that of the primary coil.

im not suree sorry if wrong

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%