Purple Pages Flashcards
What are the two ways scientists study science?
Experimentation and observation
What is a hypothesis?
An answer to a question which can be tested
Name and describe the basic steps of the scientific method.
- Observation of the natural world
- Forming a hypothesis
- Testing the hypothesis
What is the difference between an independent and a dependent variable?
Independent: controlled by the scientist to test their effects on
Dependant: effected by independent
How is an element different from a compound?
An element is a pure substance which cannot be broken down further compound is two or more elements in a fixed ratio
Which elements make up the greatest percentage of matter in living organisms?
Hydrogen and carbon
Which subatomic particles make up the atomic nucleus?
Neutrons and protons
If given the number of protons, neutrons and electrons of an element can you determine the atomic number and mass?
Yes atomic number is number of protons, atomic mass is protons +neutrons
What happens when isotopes decay?
The unstable isotope which decays leads to loss of energy and particles from its nucleus and forms a different isotope (spontaneous)
How can radioactive tracers be used in nuclear medicine?
Substances used to measure speed of a chemical process and or movement of a substance
What determines the reactivity of an atom?
Valence electrons
Name and describe the differences between the four types of chemical bonds.
- Ionic: transfer of electrons from one element to another (one becomes pos and the other neg)
- Covalent: sharing of electrons (not always equal depending on electronegativity- could be polar or non polar)
- Hydrogen bonds: happen between slightly positive hydrogen atoms and slightly negative other atoms
- Van der waals forces: areas of positive and negative charges which develop between non polar molecules
(The list represents strength of bond in hierarchy)
Polar
When atoms in a molecule have different electronegativities thus creating a dipole moment
Non polar
Sharing of electrons is quite even since électronégativies here are even so no dipole moment
What determines if electrons are shared equally in a covalent bond? If they are not shared equally what type
of bond is this?
Electronegativity : If not shared equally then polar covalent bond
How do hydrogen bonds form?
Through interaction between hydrogen and electronegative atoms like oxygen and nitrogen
Explain how van der Waal forces form.
They occur when two or more atoms or molecules are very close together creating regions of pos and neg charges
Why is ice less dense then liquid water?
The stable orientation of h2o molecules in ice allows those molecules to be more spaced out , thus less molecules than in liquid water
What causes the creation of surface tension on water?
Cohesion
How do ions stay separated in aqueous solutions?
Because they are covered by water molecules
How do acids and bases work in changing the pH of a solution?
They change the pH of a solution as acids increase concentration of h+ ions whereas bases increase oh- (hydroxide ions)
What is the buffering system that is used to maintain our blood pH = 7.4? How does it work?
Carbonic acid bicarbonate system allows for absorption and release of h+ ions to maintain stability of pH
What is a hydrocarbon?
A hydrogen and carbon compound
Name and draw the six main functional groups discussed in class
- Hydroxyl (-OH)
- Carbonyl( -C=O)
- Carboxyl(-COOH)
- Amino (-NH2)
- Phosphate (-PO4 2-)
- Sulfhydryl (-SH)
