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22 Cards in this Set
- Front
- Back
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What are the general steps to the scientific method? |
1) Observations- these lead to questions; 2) Formation of a Hypothesis- tentative answer to one of our questions, multiple possible answers. Must be tested; 3) Formulation and Conduction of an experiment to test the Hypothesis- written in “if…then” form, talks about specific outcomes and events. Based on deductive reasoning; 4) Acknowledgement of the Data- Experimenter must accept data, even if it is not what was expected; 5) Formulation of a Conclusion- This will either support or refute your hypothesis |
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Distinguish between essential & trace elements. |
Essential elements (CHONPS) are elements needed in fairly large quantities for the survival of the organism. Trace elements are also necessary but in much smaller quantities. There are about 25 trace elements. |
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What is an isotope? |
Atoms that have the same atomic number (same element) but different mass (neutron) numbers. |
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What feature determines the chemical properties of an atom? |
How the electrons are arranged or configured. |
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Describe an ionic bond. |
Involves the stealing or gaining of electrons by a more electronegative form. As electrons are lost and gained, this creates ions (charged atoms). Created when oppositely charged ions are now attracted to one another. |
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Describe a covalent bond. |
2 types: non-polar and polar. The electrons are shared equally between the atoms, but when polar will be slightly charged as one side “hogs” more of the electrons. |
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Describe a hydrogen bond. |
Occurs when a hydrogen atom is bonded to a very electronegative atom (O or N), but is also attracted to another electronegative atom (O or N). Produces very slight positive and negative charges in the molecule. |
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What is an electron? |
A component of an atom which orbits the nucleus at the speed of light. These have a negative charge and contribute almost no mass to the atom. |
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What is a neutron? |
A: Neutrons have no charge (neutral) and are located in the nucleus of the atom. These contribute about 1 dalton of mass to the atom. |
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What is a proton? |
Protons have a positive charge and are located within the nucleus (center) of an atom |
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What is the atomic number? |
The atomic number is the number of protons in the nucleus (written in subscript to left of element). |
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What is the mass number? |
The mass number is equal to the number of protons plus the number of neutrons inside the nucleus (written in superscript to the left of the element). |
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What is potential energy? |
Energy associated with the position or location of matter. Associated with electrons. |
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What is kinetic energy? |
The energy associated with mass or energy in motion. Includes heat and light. |
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What are electron orbitals and how do they relate to the properties of atoms? |
Each orbital contains space where electrons may orbit. These are usually labeled 1s, 2s, 2px, 2py, 2pz, and so forth. Innermost shell orbitals are filled first, and the outer shell is the last to be filled. Whether the content of the outer shell is ‘balanced’ with an even number of electrons or not is what determines the attitude of the atom. If the atom needs to get rid of one of its electrons to be balanced it will aggressively search for another atom to ‘share’ its unpaired electron with, many times totally changing the chemical reaction. |
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Differentiate between a polar and a non-polar covalent bond. |
Nonpolar covalent bonds occur when two atoms share their electrons equally. Polar covalent bonds occur when combined atoms are not shared equally (usually when one atom is more electronegative). One side hogs the electrons so this makes one side of the molecule slightly positive and the other slightly negative. |
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What is an ion? Anion? Cation? |
An ion is a charged atom. A cation has more protons than electrons and has a positive charge. An anion has more electrons than protons and has a negative charge. |
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What is the relative strength of the 3 bonds discussed? (covalent, ionic, hydrogen) |
Covalent bonding- Strong Ionic bonding- Weaker Hydrogen bonding- Weakest |
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How can hydrogen bonds be related to polar covalent bonds? (think about water) |
Both hydrogen bonds and polar covalent bonds are charged, meaning one side will be (slightly) negative and the other will be (slightly positive). This attracts other atoms. |
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What does “specific heat” mean? |
The specific heat is the amount of energy required to raise one gram of a substance by 1 degree celcius. |
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What does “heat of vaporization” mean? |
Amount of heat needed to convert one gram of liquid into one gram of vapor. |
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Properties of water |
1) Cohesion 2) Water is a good solvent 3) Water has a high specific heat 4) Water has a high heat of vaporization 5) Water expands at freezing temperatures |
