I NEED HELP ASAP Follow significant figures rules. Show your work (will be turned in later

Select the correct text in the passage. which sentences describe examples of sustainable living? i live in an old apartment building downtown, but my company is based in an office park on the outskirts of the city. i drive an old car that needs to be replaced. i plan to buy a hybrid for better gas mileage, but for now i am able to carpool with a couple of friends from work. the drive to the office park is about 45 minutes each way, but we do get to work in a modern building. the architects just received a leed certification for the design.

Find the number of grams of hcl needed to react completely with .50 moles of magnesium.

Explain what happens at the saturation point when adding salt to water at room temperature.