Chemistry Midterm Study Guide Answer Key PDF

Chemistry Midterm Review Answer Key What is Qualitative vs Quantitative data? Qualitative data refers to data that does not involve numbers (color, size, texture, audio recording) while quantitative data which refers to data that is numerical and measurement based. What are groups 1, 2, 17, and 18...

Chemistry Midterm Review Answer Key What is Qualitative vs Quantitative data? Qualitative data refers to data that does not involve numbers (color, size, texture, audio recording) while quantitative data which refers to data that is numerical and measurement based. What are groups 1, 2, 17, and 18 called? 1- Alkali Metals 2- Alkali Earth Metals 17- Halogens 18- Noble Gases Define: Malleability- the ability of a material to be hammered into a thin sheet Conductivity- the ability of a material to transfer heat or electricity well Luster- science word for science Precision- how close multiple measurements are to each other Accuracy- how close a measurement is to the true or accepted value Ductility- the ability of a material to be stretched into thin wires Atomos- means “indivisible” Law of Conservation of Mass- mass/matter is neither created nor destroyed in an ordinary chemical reaction Group- elements in the same vertical columns on the periodic table. Group number tells you the number of valence electrons Period- elements in the same horizontal row Aufbou Principle- an electron occupies orbitals in order from lowest energy to highest energy Pauli Exclusion Principle- no two electrons within the same atom can have the exact same set of four quantum numbers Hund’s Rule- when filling a set of orbitals each should be occupied by one electron (arrow) before any orbital is doubly occupied and all electrons (arrows) in the singly occupied orbitals must have the same spin (direction) Which is an example of an element? Anything from the periodic table, O, Ca, K List the 7 SI units of measurement and what they measure Time- seconds Length/distance- meter Mass- kilograms Electric current- ampere Temperature- Kelvin Amount of a substance- mole Luminous intensity- candela Express this number 82,680,000 in scientific notation 8.268 x 107 remember the decimal has to be behind the first non zero number and the exponent is based on how many time you had to move the decimal Express this number 2.31 x 10-6 in standard notation.00000231 How many meters are in a kilometer? Kilo- 1000, hector- 100, deka- 10, base (meter) 1, deci- 1/10, centi- 1/100, kilo- 1/1000 1000 meters in a kilometer Why are atoms electrically neutral (what two particles are responsible for the charge) The positively charged particles (protons) are the same amount as the negatively charged particles (electrons) Atoms of the same elements have the same_____(number of protons/atomic number)______ How do you determine number of neutrons in an atom? You subtract the mass and the proton number (atomic number) How many neutrons are in the Oxygen-16 isotope? The number after the hyphen (16) represents the atomic mass which you subtract the atomic number-8 from. 16 – 8 = 8 What is the highest energy state of an atom? Excited State What is the lowest energy state of an atom? Ground State What are the shapes (2nd Q#) associated with each orbital? (s,p,d,f) S-0, P-1, D-2, F-3 What are the possible orientations (3rd Q#) for each orbital? S: 0 P: -1, 0, 1 D: -2, -1, 0, 1, 2 F: -3, -2, -1, 0, 1, 2, 3 What is released when an electron goes from the excited stated back down to the ground state? A quanta of energy What does the principle quantum number (n) indicate? 2- Principle Quantum Number (quantum number 1) tells you the ENERGY LEVEL 3- Angular Momentum Quantum Number (quantum number 2) tells you the SHAPE 4- Magnetic Quantum Number (quantum number 3) tells you the ORIENTATION of the shape 5- Spin Quantum Number (quantum number 4) tells you the possible SPIN STATE The electron configuration below represents a ground-state atom of which element? 1s22s22p63s23p6 Argon What is the difference between a mixture and a compound? A mixture is a physical combination, meaning there is no change to the identity of the substances and they can be separated through physical means. A compound is a chemical combination where a new product is produced and the substance can no longer be separated by physical means although they can still be separated through chemical means. List 3 examples of physical changes and 3 examples of chemical changes: Physical: change in state of matter, change in shape, change in temperature (expected change, fire heats up, ice cools down) Chemical: production of new substance, unexpected change in temperature (2 room temperature liquids mix and get hot) unexpected color change (2 clear liquids mix to turn bright yellow) Write an example of a hypothesis: If-then testable statement: IF I play different genres of music to my plants THEN they will grow at different rates State a part of Dalton’s theory that is untrue and explain how it was disproved. 2 parts of Dalton’s theory are incorrect: Atoms are indivisible: atoms are now understood to be divisible into smaller base parts such as protons, neutrons, and electrons All atoms of an element are alike: atoms of an element can have different masses because of differing numbers of neutrons such as Carbon-12, Carbon-13, and Carbon-14. They are all types of Carbon with the difference being the number of neutrons giving them different masses. What is an isotope? Isotopes are atoms of the same element with different masses because of differing numbers of neutrons. Calculations/Problems: How many mm are in 3.23 m? 3.23 m l 1000 mm 1m = 3230 mm. How many significant figures are in the following numbers? a. 101- 3 b. 1111- 4 c. 10000- 1 1. Non-zero numbers are always significant 2. Zeros between non-zero numbers are always significant 3. Zeros to the left of non zero numbers are not significant 4. All zeros after non zero numbers are significant if there is a decimal point somewhere in the number Calculate the molar mass for the following compounds: a. CO2 b. BaCO2 c. Fe2(CO4)3 44. 009 g/mol 197.34 g/mol 351.68 g/mol What is the wavelength of a wave with a frequency of 3.12 x 10 14Hz? C=λv 3.0 x 108 = λ (3.12 x 1014) 3.0 x 108 = 9.615 x 10-7 C= 3.0 x 108 (3.12 x 1014) What is the Energy of a photon with a frequency of 5.76 x 10 5Hz? E=hv E= (6.626 x 10-32)(5.76 x 105)= 3.816 x 10-26 h= 6.626 x 10-32 Write the unabbreviated electron configuration for the following elements: a. Phosphorus b. Vanadium 1s² 2s² 2p⁶ 3s² 3p³ 1s22s22p63s23p64s23d3 Write the abbreviated (noble gas) electron configuration for the following elements: a. Strontium b Antimony [Kr] 5s2 [Kr] 5s24d105p3 Identify the quantum numbers for the following: a. Carbon b. Zinc 2, 1, 0, ½ 3, 2, 2, -½ Identify the element using the following quantum numbers: b. 4,2,-1,-1/2 b. 2,1,0,1/2 Cobalt Carbon List the discovery, model, and device (if applicable) for the following scientists Dalton: Atomism, the idea that there is a fundamental particle that all matter is composed of. Thomson: Discovered the electron leading to the plum pudding model. He used the Cathode Ray to make this discovery. Rutherford: Discovered the nucleus through the gold foil experiment leading to the nuclear model Bohr: Discovered that the electrons move around the nucleus in orbits leading to the solar system model