J.J Thomson is credited with discovering the electron: T/F
TRUE
Two isotopes of the same element can have a different number of protons:T/F
FALSE
Two isotopes of the same element can have a different number of electrons: T/F
TRUE
The symbol for magnesium is Mn : T/F
FALSE
As5+ has 33 protons and 28 electrons : T/F
TRUE
The answer to the following mathematical operation (18.5-11.4) has three significant figures: T/F
FALSE
A homogeneous mixture can be made by completely dissolving salt into water : T/F
TRUE
It is impossible to round 45,629.54 to three significant figures : T/F
FALSE
The density of a pure compound changes depending on how much liquid is present: T/F
FALSE
A mass of 456.2 g of brass (72% copper, 28% zinc) contains 328.5 g zinc: T/F
FALSE
An increase of 1°F corresponds to an increase of 1.8°C : T/F
FALSE
A hypothesis will predict the outcome of all future experiments : T/F
FALSE
Perform the following calculations and indicate the results to the correct number of significant figures:
1.24 x 3.796 =
4.70704 = 4.71
Perform the following calculations and indicate the results to the correct number of significant figures.
4.17 + 13.1 + 6.14 =
23.41 = 23.4
Perform the following calculations and indicate the results to the correct number of significant figures.
(14.35 – 7.12) x (12.3 + 3.58) =
7.23 x 15.88 = 114.8124 = 115
convert to standard:
1.403 x 103
1403
covert to standard:
2.85 x 10-4
0.000285
covert to standard:
1.67 x 10-2
0.0167
convert to scientific notation:
1.259 x 103
1259
convert to scientific notation:
4.6 x 10-3
0.0046
convert to scientific notation:
2.10006 x 101
21.0006
523 nm to m
523nm x 10^{-9}m = 5.23 x 10-^{7} m
1nm
219 K to°F
°C = 219-273 =54°C
°F= (-54 x 1.8) +32= -65.2°F
66 mi/hr to km/s
66mi x 1.609km x 1hr x 1min = 0.029km/s
hr 1.0mi 60min 1sec
1 year to seconds (Scientific Notation)
1yr X 365.2days X 24hr X 60min X 60s=3x10^{7}s
1yr 1day 1hr 1min
Magnesium has three naturally occurring isotopes 24Mg (78.99%), 25Mg (10.00%), and 26Mg (11.01%). What is the isotopic mass of 25Mg if the mass of 24Mg is 23.985 amu and the mass of 26Mg is 25.983 amu?