Creating a Positive Learning Environment for Everyone Be respectful of your classmates Save conversation for clicker portions of lecture Put cell phones in “airplane” mode Turn off tablets Close laptops

Announcements Pre-laboratory Assignment due at the beginning of lab tomorrow (pg. 48 of lab book). Nuts and bolts activity due tomorrow in lab Online HW 4 (Type II) due tomorrow by 7:00pm. Online HW 5 (Type I) due Monday 10/23 and (Type II) due Wednesday 10/25. Mid-term grades posted (first exam score only)

Lab Tomorrow Two Acid-Base Reactions: HCl(aq) + NaOH(aq) → NaCl(aq) + H2O H2SO4(aq) + 2NaOH(aq) → Na2SO4(aq) + 2H2O

Clicker #1 Which will be expected to produce the highest temperature change? Reaction (in lab tomorrow): H2SO4 + 2NaOH  2H2O + Na2SO4 A) 3 moles H2SO4 and 2 moles NaOH B) 1 mole H2SO4 reacts with 2 moles NaOH C) 1 mole H2SO4 reacts with 4 moles NaOH D) All will produce the same temperature change 2 mol H2O

Clicker #2 Consider the following reaction: N2(g) + 3H2(g) → 2NH3(g) The image to the right shows substances present in the reaction container before the reaction. What is present in the container after the reaction? Assume each particle represents 1 mole. A) 2 moles NH3, 1 mole N2 B) 4 moles NH3, 1 mole N2 C) 2 moles NH3, 3 moles H2 D) 4 moles NH3, 3 moles H2 D) 4 moles NH3 only

Example #1 If 15.0 mg of P2O5 was produced in this reaction, what masses of P4 and KClO3 were required?

Clicker #3  

Example #2 Assume you have 5.00 g of Mg and 10.0 g of CO2 available. You allow them to react to form solid magnesium oxide and carbon. Determine the masses of both products produced. Determine the mass of excess reactant. Prove that mass has been conserved.

Clicker #4 What should be the total mass present after the reaction is complete? A) 1.24 g B) 5.00 g C) 9.54 g D) 10.0 g E) 15.0 g

Example #2 Assume you have 5.00 g of Mg and 10.0 g of CO2 available. You allow them to react to form solid magnesium oxide and carbon. Determine the masses of both products produced. Determine the mass of excess reactant. Prove that mass has been conserved.

Clicker #5 When comparing what you’re given to a balanced chemical equation, you must be in units of A) moles B) grams C) molarity D) Any unit can be directly related to a balanced chemical equation.

Clicker #6 What is true about a limiting reactant? It is always the reactant with the smallest coefficient. It is always the reactant that starts with the smallest number of moles. It is always the reactant that runs out first. It is always the reactant that is remaining after the reaction. It is always the reactant that has the largest coefficient.