How many significant figures are in the measurement 12.4 kg

Marcel just purchased 1.69 grams of iron fillings in order to make living putty for his 6 year old niece. how many moles of iron are made in his sample?

An animal cell loses the ability to convert energy stored in food to energy that the cell can use. which of the cell's organelles has stopped working? a.the mitochondria b.the nucleus c.the vacuoles d.the endoplasmic reticulum

How is energy related to the change of state represented by the model? atoms gain energy as a solid changes to a liquid. atoms gain energy as a solid changes to a gas. atoms lose energy as a solid changes to a liquid. atoms lose energy as a solid changes to a gas.