Answers To 2023-2024 Chem328 Review HW For Sig Figs And Fundamental Principles Of Chemistry

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Answers to 2023-2024 Chem328 Review HW for Sig Figs and Fundamental Principles of Chemistry homework handout.

1) Matter ( I call them particles) and Energy

2) All substances are composed of particles that are in constant motion and sometimes collide/interact.

3a) Conservation of Mass - In a physical process and/or chemical reaction, mass is neither created nor destroyed (i.e. has to be conserved/accounted for).

3b) Conservation of Energy - In a physical process and/or chemical reaction, energy is neither created nor destroyed (i.e. has to be conserved/accounted for). Also called First Law of Thermodynamics

4) Coulomb's Law ( I called it Coulombic Force, CF).

5) When particles collide, they can either
a) stay same - called physical change or
b) reorganize/rearrange - called chemical change (also called chemical reaction).


7) Less energy but higher CF to nucleus (conversely an electron in a higher energy level, further away from nucleus, has more energy but has a lower CF to nucleus)

8) Release/give off valence electron (ve-) (because these ve- tend to be in higher energy level so less CF to nucleus).

9) Keep or gain ve- (because these ve- tend to be in lower energy levels so more CF to nucleus).

10) Intramolecular forces are forces that hold the "particle together" whereas Intermolecular forces are between particles (for molecules only now). There are three Intramolecular forces:

a) Metallic bond is when two or more metal elements get close to each other. (all elements release ve-
b) "Ionic bond" is when a metal and non-metal elements get close to each other.(transfer ve-)
c) Covalent bond is when two non-metal elements (can have more than 2) get close to each other. (share ve-)

Answers to Question 11, 12, and 13 on separate sheet

14)Distribution of electrons. Unevenly distributed electrons cause polar molecules whereas "overall/on average" distributed electrons cause non-polar molecules.

15) Activation energy (Eac) is the minimum amount of energy for a set of reactants to form a set of products.

16) Besides Activation energy (Eac), the particles must be in the spacial orientation (close enough to collide and in correct 3-D location compared to other reacting particles). Of course, Effective collision (EC) of reactants cause products to be made.

17) Kinetics

18) In a reversible reaction, the products can have Effective collision causing products to rearrange back into reactant particles whereas an irreversible reaction products can NOT rearrange back into reactant particles.

19) False ( A BAD WORDED QUESTION since the first (Eac) needs to be absorbed by an Exothermic reaction but no other since the further set of reactants can use the releasing energy for their (Eac) so no more outside energy is needed).

20) Value of item and measuring device explanation (i.e. what scale to use)

21) Precision

22) Kg

23) Your choice from notes

24) Kelvin

25) mol (not mole that is the name)

26) Ion (since ion is a charge element that either released or gained a ve-, there must be cation and anion. That is what the "formula unit" explains include elements/ions and how many of each)

27) 4

28) 3.0E2g or 3.0X102g
29) 3E2g or 3X102g
30) 3.00E2g or 3.00X102g

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Last edited September 26, 2023 10:23 am (diff)