Why does refrigerated food stay fresh longer than food that is kept at room temperature

When determining the shape of a molecule, it is important to draw a lewis dot structure first in order to see the total number a. electrons within the moleculeb. bonding and unshared pairs around central atomc. unshared pair within the molecule( i really need it )

Asolution contains 225 g of sodium chloride, nacl, dissolved in enough water to make a 0.25 l of solution. what is the molarity of the solution?

If blood contains 150g of hemoglobin per liter of blood, how much hemoglobin would be contained in 10 ml of blood