Tutor profile: Jessie S.

A. What are the three main parts of an atom? B. Which of these can be changes without creating a different element? What do you create when you do change the amounts of these "parts" of an atom?

A. Protons (positively charged), neutrons (neutral charge) and electrons (negatively charged). B. Protons are the defining feature of an atom, they have a set number in each element. Neutrons can be increased or decreased, creating isotopes. These isotopes occur in nature and don't change the type of element they make-up. Electrons can be removed or added to an atom to create a charged atom called an ion. An atom with extra electrons will have a negative change (anions) and atoms with reduced electrons will have a positive charge (cations).

A. What are the key properties of water that make it unique and essential for life? B. Chose one of these properties and explain why it is important.

A. Key properties include its polarity, being a universal solvent, high heat capacity, high heat of vaporization, cohesion, adhesion and lower density when frozen. B. Polarity - this means that the molecules have a slight and opposite charge on each end, allowing weak bonding (hydrogen bonding), which causes cohesion (image the molecules clumping as they are attracted to the slight charges on each other) and adhesion, when the water molecules stick to other surfaces. Adhesion allows for water to stick to the insides of the vascular systems of plants and be pulled upwards during transpiration. Without polarity, this capillary action would not be possible.

12x+ 4(6/3)^3 = 68, solve for x

12x+ 4(6/3)^3 = 68, solve for x 12x+ 4(2^3) = 68 12x+ 4(8) = 68 12x +32 = 68 12x = 36 x = 3