Tutor profile: Vivianna P.

I have a test in a week, but I don't know how to prepare for it.

Is there a way to break up the material for the test into 4 sections? On day one you can study section 1, on day two study section 2, on day 3 study section 3, on day 4 study section 4, on day 5 take a break, and on day 6 review the topics that gave you the most trouble. When you're studying try to find the method that works the best for you such as flashcards or practice problems. Write down any questions you have while studying to ask your teacher or tutor when you next see them. If this is a cumulative exam, look at your past tests and go through the questions you got wrong.

From the reaction: B2H6 + O2 -> HBO2 + H2O, what mass of O2 will be needed to burn 36.1 g of B2H6?

Step 1: Balance the chemical equation. Consider taking an "inventory" or count how many of each element are on each side of the equation. According to the Law of Conservation of Mass, mass is neither created nor destroyed in chemical reactions, so there should be the same number of each element on each side of the equation. Start balancing with B first, then H, then O: B2H6 + 3 O2 -> 2 HBO2 + 2 H2O Step 2: Find the molar mass of B2H6 and O2 by using the values on the period table of elements: B2H6 = 27.68 g/mol, O2 = 32.00 g/mol Step 3: Set up the stoichiometric equation, keeping in mind that you can cancel units by having them in the numerator and denominator: (36.1 g B2H6/1) * (1 mol B2H6/27.68g HBO2) * (3 mol O2/1 mol B2H6) * (32.00 g O2/1 mol O2) = 125 g O2 Answer: 125 g of O2 is needed to burn 36.1 g of B2H6.

Natalie was selling adult and children tickets for her school play. She sold 10 more adult tickets than children's tickets and made $190 in total. If a children's ticket cost $2 and an adult ticket cost $5, how many children's and adult tickets did she sell?

Step 1: Assign variables: a = # of adult tickets sold, c = # of children's tickets sold Step 2: Set up equations: Equation #1: a = c +10 , Equation #2: (2*c) + (5*a) = 190 Step 3: Substitute "a" in Equation #2: (2*c) + (5*(c+10)) = 190 Step 4: Simplify the left side of the equation using PEMDAS: 7c +50 = 190 Step 5: Isolate the variable "c" to one side of the equation: 7c = 140 Step 6: Solve for "c" by divided 7 on both sides: c = 20 Step 7: Plug-in "c" in Equation #1 to find "a": a = (20) + 10 = 30 Answer: Natalie sold 20 children's tickets and 30 adult tickets.