Intro: Math and Measurement
Which measurement contains a total of two significant figures?
(1) 51.0 (3) 0.051
(2) 0.510 (4) 50
(3) 0.051
The average kinetic energy of water molecules decreases when
1) H2O(l) at 337 K changes to H2O(l) at 300. K
Which subatomic particle(s) are found in regions called orbitals?
electrons
The chemical properties of calcium are most similar to the chemical properties of
1) Ar 3) Mg
2) K 4) Sc
3) Mg
What is Ms. Marble's favorite show?
The Office
In an experiment, a student found that the percent of oxygen in a sample of KClO3 was 62%. If the accepted value was 39.3%, the experimental percent error is
57.8%
A sample of lead at 10K is placed in contact with a sample of iron at 25K. State the direction of heat transfer.
Heat transfers from the iron to the lead.
How many electrons are in an S-2 ion?
18
Two gaseous forms of oxygen are diatomic oxygen, O2, and ozone, O3. These two forms of oxygen have
(1) the same molecular structure and the same properties
(2) the same molecular structure and different properties
(3) different molecular structures and the same properties
(4) different molecular structures and different properties
(4) different molecular structures and different properties
Who is Ms. Marble's favorite musical artist?
T-Swift
A student calculates the density of an unknown solid. The mass is 10.04 grams, and the volume is 8.21 cubic centimeters. How many significant figures should appear in the final answer?
3
Which substance cannot be broken down by chemical means?
1. aluminum
Explain, in terms of electrons, the change in radius when a calcium atom becomes a calcium ion
The radius of a calcium ion is smaller because the calcium atom lost one electron.
A Ca ion is smaller because it has one less occupied electron shell.
Compare the electrical conductivity of an alkali metal at STP with the electrical conductivity of a halogen at STP.
Metals conduct electricity better than halogens.
A halogen is a poor conductor compared to an alkali metal.
The metal is better.
Would Ms. Marble choose goldfish or cheez its?
goldfish
Convert 102 pm to m
1.02x10-10
or
0.000000000102 (9 zeros)
How much heat energy is required to change 10 grams of water from 20K to 90K?
2926 J
What were Rutherford's two conclusions from his gold foil experiment?
1. the atom is mostly empty space
2. there is a small, dense, positively, charged center = aka the nucleus
Explain, in terms of electrons, why the halogens are all placed in the same group on the Periodic Table.
All halogen atoms have 7 valence electrons in the ground state.
They have atoms with the same number of outermost shell electrons.
They each need one more electron to achieve a stable octet
What is Ms. Marble's daughter's name?
Charlotte/Charlie
A student measures the mass and volume of a piece of aluminum. The measurements are 25.6 grams and 9.1 cubic centimeters. The student calculates the density of the aluminum. What is the percent error of the student’s calculated density of aluminum?
4%
A sample of helium gas has a volume of 900. milliliters and a pressure of 2.50 atm at 298 K. What is the new pressure when the temperature is changed to 336 K and the volume is decreased to 450. milliliters?
5.64 atm
Describe, in terms of both electrons and energy states, how light is produced.
Light is produced when electrons fall from higher energy states to lower energy states (from excited to ground)
Explain, in terms of atomic structure, why the noble gas neon is an unreactive element.
Neon has a full outermost shell of electrons
Neon's valence electron shell is full
Neon's outermost occupied electron shell is full
When is Ms. Marble's birthday?
WEDNESDAY, 11/22/90