A certain element is composed of two isotopes, having the mass and abundance shown below.  What is the average atomic mass unit (amu) for this element?     Mass  Abundance Isotope 1:  6.0 amu      7.59% Isotope 2:  7.0 amu     92.41% (Hint: Atomic mass = Σ(mass of isotope)(abundance of isotope))

Form a sentence that correctly uses ‘heat’ in it with reference to the human Martian and the Martian atmosphere as night begins. 

Many missions have looked for evidence of past life on Mars.  Some scientists maintain that not only did life exist on Mars in the past, it still exists today, likely hidden away under the surface.  If you were to be making observations of potential living things on Mars, what are three characteristics of living things would you look for? Identify and describe each.

An atom that loses an electron is _______.

From an energy standpoint, why might it be better to feed the plants directly to the colonizers, rather than feeding animals the plants which the colonizers would then eat?

An atom that gains an electron is _______.

Which has a greater total amount of thermal energy, the human at 98°F or the Martian atmosphere at -100°F?  Why?

Which system has a higher level of entropy?

We have recently discovered that Mars, like Earth, experiences periods of glaciation, or ice ages.  To understand how this might impact the ability for humans to survive long-term on Mars, scientists at NASA are developing models to understand glaciation events on Mars.  What is a model and why are they useful?  

Which picture best represents a pure element?