Chemistry, Water, pH. Exam 1

What is the maximum number of electrons that can reside in the second and third electron shell of an atom?

8

The sodium atom contains 11 electrons, 11 protons, and 12 neutrons. What is the mass number of sodium? A. 23 B. 11 C. 34 D. 22

A 23 because we add the number of protons with the number of neutrons

To be scientifically valid, a hypothesis must be A. testable and falsifiable. B. part of a theory. C. controlled. D. reasonable.

A because a hypothesis must be able to be tested by scientific research, meaning what you are testing must be physical and not supernatural

Contrast a molecule and a compound

A molecule is two or more atoms held together by a covalent bond. They can be the same or different elements. A compound is when you have 2 different elements bonded together (water is both a molecule and a compound)

Non-polar covalent and example

A non-polar covalent bond is a covalent bond in which the electrons are shared equally between the atoms. It is the same as a regular covalent bond. Ex: A bond between two Hydrogen molecules.

Proton

A positively charged atomic particle with a mass of 1 amu

Define Compound, give examples

A substance consisting of two or more elements that are chemically combined. Ex: h2o (water), co2 (carbon dioxide)

Ecosystem

A system formed by the interaction of a community of organisms with their physical environment

organelle

A tiny cell structure that carries out a specific function within the cell

community

All the different populations that live together in an area

Hypothesis

An educated guess; a testable prediction about the outcome of a specific study

Radioactive Isotope

An isotope whose nucleus decays spontaneously, giving off particles and energy.

Define Matter

Anything that has mass and takes up space

2. In salt, what is the nature of the bond between sodium and chlorine? A. nonpolar covalent B. hydrophobic C. ionic D. hydrogen E. polar covalent

C, because sodium has a positive charge, and chlorine has a negative charge which attracts them to each other

What is the difference between reactants and products of a chemical reaction?

Chemical reactions are when two or more molecules combine to create a new product where as reactants are consumed during chemical reactions and they serve as a substance that increases the rate of a chemical reaction. (serves as a catalyst)

Describe 3 ways in which radioactive isotopes ca be used to help and/or harm humans.

1. They are like "biological spies". They can be used as diagnostic tools in medicine. 2 They can be tracked in the body so we can come up with diagnoses for sicknesses such as Alzheimer's and cancer 3. It can break chemical bonds and can cause unusual bonds to form in the human body if the radiation is not dosed properly

What is the maximum number of electrons that can reside in the first electron shell of an atom?

2

atom

the smallest particle of an element that retains all of the properties of the element

Define Element and give examples

type of pure substance that cannot be broken down into simpler substances. Ex: Oxygen (O), Hydrogen (H), Carbon (C), (Sodium (Na).

control groups

used in studies for comparison; they do not receive the 'treatment' (e.g, they receive the placebo)

Which of the following lists the steps of the scientific method in their proper order? A. question, observation, hypothesis, prediction, experiment B. observation, question, prediction, hypothesis, experiment C. observation, question, hypothesis, experiment, prediction D. observation, question, hypothesis, prediction, experiment

D because you observe something, you have a question about it, form a hypothesis, make a prediction of the outcome, and then experiment

A bevy of quail (a group in one area), the coyote that is stalking them thinking about dinner, and the nest of sticks and some rocks in which their eggs are laid comprise a(n): A. population B. organism C. ecosystem D. community E. biosphere

D, because they are different populations living in one area interacting with each other

What is replication?

Doing the same study again; increases confidence that the outcomes is a 'real' pattern

Using the simplified period table at the end of the exam (last page): (9 points total) sketch the following atoms (2 points) for each, make sure that you note the correct number of protons, neutrons, and electrons (3 points) next to each completed sketch, tell me whether this atom is likely to react (and if it did, with what other type of atom). EXPLAIN your answers (4 points)

Draw Fluorine (F) and Argon (Ar)

What is another name for an ionic compound?

Electrovalent compound

Isotope

Elements that can have different numbers of neutrons in the nucleus. (They have different numbers because neutrons contribute to the weight of an atom)

What is going on in a hydrogen bond?

Hydrogen is attracted to a more electronegative atom. One end of the molecule will be slightly positive (S+) and the other end will be slightly negative (S-). One end of the S+ side of one molecule can be attracted to a S- side of another molecule, and that attraction/bond is the hydrogen bond.

What are a few trace elements that are important for the human diet, and what do they do to your body?

Iron: important for energy processing and carries oxygen Calcium: important for bone health and muscle contractions Sodium and potassium: involved in nerve signaling

Name and describe the three main subtonic particles that make up an atom

Protons: have a positive charge Neutrons: no charge Electrons: have negative charge

Atomic weight

The number of neutrons: Mass number - atomic number

Mass number

The number of protons + the number of neutrons

What is an atom?

The smallest unit of matter with characteristics of a particular element

Protocol

The steps that a scientist follows in an experiment

What is an atomic number?

The umber at the top of a symbol. It is the number of protos that an atom has. This defines which element it is.

Write the structural formula: Urea CH4N2O = CO(NH2)2 Glycerol C3H8O3 = C3H5(OH)3

Urea: H H H / / / O = C - N -N / H Glycerol: H / H O H / / / O - C - C - C -O / / / / / H H H H H

What is a chemical reaction?

When two or more molecules combine to generate a new produce Ex: there is an amount of potential energy that is stored within the bonds between atoms, chemicals with more energy are less stable, making them more likely to react. So like H2O, 2 hydrogens react with one oxygen which creates water

Polar covalent and example

a type of bond that forms when electrons are not shared equally Ex. H2O because there are more hydrogen atoms than there are oxygen

compound

contains at least two different elements

organ system

group of organs that work together to perform a specific function (cardiovascular, cognitive)

organisms

living things

What are ionic bonds made up of?

metals and non-metals

How much do protons and neutrons weight (separately)

one atomic mass unit

Sample size

the number of participants in a study

Valence electron

the outermost negative particles in an atom; the ones that contribute to an atom's reactivity

What are the steps/rules of atomic structures?

1. Chain the carbons together to create a "backbone" 2. Add nitrogen to the carbon chains 3. add oxygen to the carbon chain 4. add hydrogens wherever they will fit.

After reading the paragraph, answer the question(s) that follow. The National Institutes of Health (NIH) set up a study to determine whether large doses of vitamin C would shorten the length of time it takes to recover from a cold. Three thousand volunteers were split into two groups. For two weeks, members of Group A took 3,000 mg of vitamin C daily. Group B received 3,000 mg of a placebo. At the end of the two-week period, the researchers inserted live cold viruses directly into the noses of all the volunteers. The volunteers in both Group A and B continued to take their daily pills. All the volunteers got colds, and there was no significant difference in the length of time the colds lasted. Which was the experimental group? A. Group A only B. Group B only C. all 3,000 volunteers D. the researchers that inserted the cold virus

A because they are the ones getting the experimental drug

organ

A collection of tissues that carry out a specialized function of the body (heart, liver, brain, etc.)

Molecule

A group of atoms bonded together, they live in cells

population

A group of individuals that belong to the same species and live in the same area

tissue

A group of similar cells that perform the same function. (the stuff that covers your muscles)

Define electronegativity

Atom's ability to attract and hold electrons. Ex: F (Fluorine) is more electronegative than N (Nitrogen) because N needs to fill three electron spaces in its valence shell while F only needs to fill one electron space in its valence shell.

What are the levels of organization?

Atom, molecule, organelle, cell, tissue, organ, organ system, organism, population, community, ecosystem, biosphere

Ionic bond and example

Attraction between two oppositely charged ions. NaCl (Sodium Chloride/table salt): When sodium gives it's extra electron to chlorine to fill out the valence shell of Cl. Making the new charge of Na(-) and Cl(+)

A hypothesis is: A. a widely accepted idea about a phenomenon. B. a proposed explanation for a set of observations. C. the same as a theory. D. an explanatory idea that is broad in scope and supported by a large body of evidence.

B

A theory is A. an idea that has been proven. B. an explanation of an idea that is broad in scope and supported by a large body of evidence. C. a concept in the early stages that still needs to be tested. D. a description of a belief that invokes the supernatural.

B because a theory is a general statement that is backed up by a large sum of evidence from multiple researchers

Which of the following is an example of inductive reasoning? A. You hypothesize that your car battery is dead after it does not start one morning. B. Through years of field observations, researchers have determined that introduction of new female changes the behavior of a male gorilla. C. After microscopic examination, a pathologist orders follow-up biochemical tests to determine whether a large mass found in the intestine is a tumor. D. Researchers conduct a study to determine the efficacy of a weight-loss drug

B because it is a generalized conclusion that can be drawn from a large number of observations

Biosphere

Consists of all life on Earth and all parts of the Earth in which life exists, including land, water, and the atmosphere.

T or F: 32Phosphorus has 15 protons, 32 neutrons, and 15 electrons.

F Phosphorus has 15 protons, 17 neutrons, and 15 electrons

T or F: An ionic bond occurs when two atoms share one or more electrons pairs so that both of their outer shells are filled.

F. A covalent bond occurs when two atoms share. An Ionic bond happens when an addition or subtraction of electrons to even outer shells

T or F: A Carbon (C) atom has 5 electrons in its outer shell and so can form 3 covalent bonds.

F. Carbon has 6 electrons and 6 Protons and it can form 4 covalent bonds

T or F: Trace elements are types of atoms that the body needs only a small amount of because they are not very important for body function.

F. Trace elements are essential for life but required in extremely minute amounts.

T or F: Magnesium is likely to form an ionic bond with Chlorine if the two are found in the same place. Magnesium will lose 2 electrons and become an Mg 2- ion and two chlorines will each gain one electron to become CL+ ions.

F. When Magnesium forms an ionic bond with Chlorine, Mg completes its octet by becoming Mg 2+, and Cl completes its octet by becoming Cl-.

T or F: Radioactive isotopes release particles as they break down. This radioactivity is always harmful to humans. (e.g., when a nuclear power plant releases radioactivity by mistake).

F. While radioactive isotopes CAN be harmful to humans in uncontrolled exposures, they can also be helpful in treatments. For example, it can be helpful for curing thyroid cancer cells, but a radioactive power plant explosion is harmful to humans.

What are the 4 elements that are the most abundant elements in living things?

H (Hydrogen), O (Oxygen), Nitrogen (N), Carbon (C)

What is H.O.N.C and how many bonds can they form?

H(ydrogen) = 1 bond O(xygen) = 2 bonds N(itrogen) = 3 bonds C(arbon) = 4 bonds

Neutron

No charge, but has a mass of 1 amu

Examine the structure below. H H H / ./ / C — N — C // I / O O H Is this a correct molecular structure? (I.e., could the atoms behave this way)? Explain your response. Be SPECIFIC... if there's something wrong, show me exactly where it is. (3 points)

No, this structure is not correct for many reasons. First starting with the fact that the Carbons are not chained together to create a "backbone", also, Nitrogen can only form 3 bonds, not 4. Lastly, the Oxygen that is connected to the Nitrogen is supposed to be connected to the other carbon instead of the Nitrogen.

What are covalent (molecular) bonds made up of?

Non-metals

cell

The basic unit of structure and function in living things

Describe how the number of electrons in the outer shell affects the reactivity of the atom.

They contribute to how an element/atom behaves. Atoms wit a full outer shell do NOT interact with other atoms. Atoms without a full outer shell DO interact with other atoms which results in chemical bonds.

4

This atom can form up to _____ single covalent bond(s)

T or F: Scientific theories are general statements that are based on the outcome of many studies in which the theory was proved. They can be used to make predictions about specific events.

True

T or F: Table salt, water, and carbon dioxide (CO2) are all compounds.

True

covalent bond example

Two or more atoms share electrons. Atoms don't lose or gain more electrons, but they share the electrons. (it symbolized by a straight line) H2 = 2 hydrogens that stick together to complete each other's valence shells. CH4 or O2

Answer the following questions about this synopsis of a scientific study: A study examined the ability of a new medication to reduce the symptoms of malaria. 80 people who had malaria were included in the study. 40 people received the new medication; the other 40 received a placebo. The researchers hypothesized that malaria symptoms would be significantly reduced in people who received the medication compared to people who received the placebo. At the end of 1 week, the peoples' symptoms were evaluated, and the two groups were compared. There was no difference in symptoms between the two groups.: a) what was/were the dependent variable(s)? b)What was/were the independent variable(s)? c) What was the experimental group? d) what was the control group?

a) the malaria symptoms b) the medication for the malaria symptoms c) the group that received the malaria medication d) the group that receives the placebo.

What is the abbreviation for an atomic mass unit?

a.m.u

What is an ion

an atom in which the number of protons does NOT equal the amount of electrons; an atom with a new charge

deductive reasoning

applying general rule to a specific situation. It's like a funnel affect Ex: All huskies are loud. My friend has a husky. Therefore, her husky is loud.