Sig Figs/ Scientific Notation
How many significant figures are in 100 m?
What is 1 significant figure?
What is the difference between a measurement and a conversion factor?
What is: conversion factors are exact numbers while measurements are calculated?
What would happen if an electron were to be removed from a 12C atom?
What is: the atom becomes a cation?
This element has the following characteristics:
19 protons, 21 neutrons, 18 electrons, 40 amu (mass), and a +1 charge. What is the name of this ion?
What is 40K+?
mass = 40 amu
K has 19 protons
+1 charge indicates one less electron
It's Saturday night, and your friends are tailgating for a Hawkeye football game against the Purdue Boilermakers. To cook the delicious brats you brought, your friend has supplied the group with a propane gas grill. Propane gas (CH3Ch2CH3) burns in oxygen gas (O2) to produce carbon dioxide gas (CO2) and water vapor (H2O). What is the balanced chemical equation for this reaction?
What is CH3CH2CH3(g) + 5O2(g) --> 3CO2(g) + 4H2O(g)?
How many significant figures are in 3600.0 kg?
What are 5 significant figures?
To treat a bacterial infection, a doctor orders the patient to take 4 tablets per day of amoxicillin. Each tablet contains 250 mg of amoxicillin. How many grams of amoxicillin are given in 10 days?
What is 10 g?
(1000 mg/1 day) * (1 g/ 1000 mg) * (10 days/ 1 g)
(250 mg * 4 = 1000 mg = 1 g)
Chlorine (Cl) has two naturally occurring isotopes shown below:
35Cl: 34.9689 amu: 75.76% natural abundance
37Cl; 36.9659 amu: 24.24% natural abundance
Calculate the weighted average atomic mass for Cl in units of amu.
What is 35.45 amu?
(75.76/100) * 34.9689 = 26.4924
(24.24/100) * 36.9659 = 8.9605
26.4924 + 8.9605 = 35.45 amu
Answer the following questions on aluminum oxide:
What is the charge on the cation?
What is the charge on the anion?
What is the formula of the compound?
What is 3+?
What is 2-?
What is Al2O3?
Ibuprofen, an anti-inflammatory drug, has the formula C13H18O2. How many grams of ibuprofen are in 0.525 moles of ibuprofen?
What is 108 g?
molar mass of ibuprofen: 206.3 g
0.525 mol * (206.3 g/1 mol) = 108 g
What is 2900.00 L in scientific notation?
What is 2.9 * 103 L?
Determine the mass of a water sample that is heated from an initial temperature of 35 degrees C to a final temperature of 100. degrees C following addition of 1.2 kJ of heat energy.
What is 4.41 g?
q/(c * delta T) = m
1.2 kJ/(4.18 J/g degrees C * 65 degrees C) = 4.41 g
What is the abbreviated (noble gas) electron configuration of Vanadium?
What is [Ar]4s23d3?
full configuration: 1s22s22p63s23p64s23d3
What is the chemical formula for Dinitrogen pentoxide?
What is N2O5?
Water is formed by burning hydrogen gas in the presence of oxygen gas. Suppose you place 32.0 g of H2 and 45.0 g of O2 in a container and burn the mixture. What is the limiting reactant for this reaction?
What is oxygen gas?
Reaction: 2H2(g) + O2(g) --> 2H2O(g)
32.0 g H2 * (1 mol H2/2.016 g H2( * (2 mol H2O/2 mol H2) = 15.9 mol H2O
45.0 g O2 * (1 mol O2/ 31.98 g O2) * (2 mol H2O/ 1 mol O2) = 2.81 mol H2O
2.81 is less than 15.9 therefore O2 is the limiting reactant
What is 0.0010 K in scientific notation?
What is 1.0 * 10-3 K?
If something is boiling, what is the physical state change?
What is liquid to gas?
What element has the abbreviated electron configuration [Ar]4s13d5?
What is Chromium (Cr)?
What is the Lewis structure of CBr2O?
What is:
Br (3 lone pairs) single bonded to C
C has a double bond to O (2 lone pairs)
C is single bonded to Br (3 lone pairs)
24 electrons
The equation for the following reaction is below:
2H2(g) + O2(g) --> 2H2O(l)
delta H = -572 kJ
Is this reaction endothermic or exothermic?
What is exothermic?
Round 129762 s to three significant figures.
What is 1.30 * 105 s or 130000 s?
The fuel tank for a motorcycle has a capacity of 22 L. The mileage for the motorcycle is 35 miles/gallon. 1 km = 0.621 mi; 1 gal = 4 qt; 1 L = 1.06 qt. How long a trip, in kilometers, can the bikers make on one full tank of gasoline?
What is 330 km?
1 tank * (22 L/ 1 tank) * (1.06 qt/ 1 L) * (1 gal/ 4 qt) * (35 mi/ 1 gal) * (1 km/ 0.621 mi) = 328.58 - 330 km
How many unpaired electrons does S (sulfur) have?
What is 2? (6 valence electrons)
What is the electron group and molecular shape of PF3?
What is tetrahedral, trigonal planar?
A weather balloon is filled with 15.0 L of helium gas at 25 degrees C and has a pressure of 685 mmHg. This balloon is then released into the upper atmosphere where the temperature drops to -35 degrees C and the volume becomes 34.0 L. What is the final pressure exerted by the helium gas?
What is 241 mmHg?
(P1V1/T1) = (P2V2/T2)
P2 = (P1V1T2)/(V2T1)
= (685*15.0*238.15)/(298.15*25) = 241 mmHg.