physical & chemical changes
Boiling water is what kind of change? C or P? why?
Physical - water molecules stay water molecules they just have more energy.
Convert 130.5g of Boron into moles.
12.07 moles
Which element ends in the electron configuration 3p4?
Sulfur
How many hearts does an octopus have?
3
How many electron shells does Gallium have?
Ga is in Period 4, which means it has 4 electron shells
In what year was the first Apple iPhone released?
2007
What is greatest in mass: 23.5 moles of aluminum, 15.7 moles of titanium, or 11.7 moles of copper?
23.5 mol Al = 632.15 g
15.7 mol Ti = 750 g
11.7 mol Cu = 742.9 g
How many neutrons does Phosphorus have?
Neutrons = Mass - Protons
31 g/mol - 15 = 16 Neutrons
Balance:
CH4 + O2 = CO2 + H2O
CH4 + 2O2 = CO2 + 2H2O
What are 3 metalloids?
Boron, Silicon, Germanium, Arsenic, Antimony, Tellurium, Polonium
Chemical or Physical?
KNO3(s) --> K+(aq) + NO3-(aq)
Physical -- it dissolved
What is the most-watched YouTube video of all time?
Baby Shark Dance
Which famous city was the site of the signing of the Declaration of Independence in 1776?
Philadelphia, PA
When ionic compounds are added to water, they dissolve. This is a physical change. If you were to read a chemical equation on paper, what would you see that tells you a compound has dissolved?
The symbol would be (aq), which stands for aqueous
NaCl(s) + H2O(L) = Na(aq) + Cl(aq) + H2O(L)
What are two properties of the elements in group 17?
1) Nonmetals
2) Highly reactive
3) Have 7 valence electrons
4) High electronegative (meaning they like to steal electrons from others)
CH4(g) + 2O2 --> CO2(g) + 2H2O(g) + 245KJ
Chemical or physical? What does KJ stand for and what does it tell you?
Chemical, KJ = kilojoules, which tells you the reaction releases heat
A compound is found to contain 36.8% Nitrogen and 63.2% Oxygen by mass. What is the empirical formula of this compound?
Moles N = 2.63
Moles O = 3.95
N2O3
Nitrogen has the electron configuration 1s22s22p3. What is the electron configuration for calcium?
1s22s22p63s23p64s2
State this equation aloud:
KOH + H3PO4 = H2O + K3PO4
potassium hydroxide and phosphoric acid react to form water and potassium phosphate
What is the only planet in our solar system that rotates clockwise on its axis?
Venus
A group of chemistry students were conducting a lab to investigate the the change that takes place when potassium chlorate (KClO3) gets heated and decomposes. They noticed that when the reaction is completed, the mass of the products have decreased. What do you think causes this decreased mass? Extra 300 pts if you can name the products!
KClO3 decomposes into KCl and O2. Because a gas is formed, the mass on the scale has decreased as the oxygen has escaped into the air.
2Fe + 3H2SO4--> 1Fe2(SO4)3 + 3H2
This reaction started with 10g Fe. How many grams of H2 were released?
10g Fe x 1mol/55.85g = 0.179 mol Fe
0.179 x 3/2 (ratio) = 0.269 mol H2
0.269 mol H2 x 2g/1mol = 0.537g H2
What is the formula for ammonium sulfate?
(NH4)2SO4
NH4 has a +1 charge and SO4 has a -2 charge
Write and balance the equation:
Iron (III) Oxide + Carbon(s) --> Fe(s) + CO2
2Fe2O3 + 3C --> 4Fe + 3CO2
Which two groups have the greatest reactivity?
Group 1 has one electron to share and Group 17 needs 1 electron to make a full outer shell.