Scientific Math & Moles
How many significant figures are in the number 15000
2
What is the mole ratio of glucose, C6H12O6, to oxygen, O2?
C6H12O6 + 6O2 --> 6CO2 + 6H2O
1 mol C6H12O6/6 mol O2
Which type of substance will probably dissolve in nonpolar hexane?
something else nonpolar
A bathroom cleaner recommends wearing rubber gloves. The cleaner is slippery and turns red litmus blue. The cleaner is probably...
a base
What is the process by which solid turns to liquid?
melting
What is 0.0345 written in Scientific Notation?
3.45 x 10-2
What is the volume of 0.5 moles of Nitrogen gas (N2) at STP? (1 mol = 22.4 L)
(0.5)(22.4/1) = 11.2 L
What is the molarity of a solution containing 2.0 mol of KCl dissolved in 2.5L of water? (M=mol/L)
0.8
The formula H2SO4 can be classified as which type of compound?
acid
Heat always flows in which direction?
hot to cold
What is the molar mass of NH3?
17 g/mol
How many moles of water are in 45 g of water? (molar mass = 18.0 g/mol)
45g(1mol/18.0g) = 2.5 mol
What type of bond is found in H2O?
polar covalent
An arrhenius base produces which ion as the only negative ion in an aqueous solution?
OH-1
How can you tell if a reaction is exothermic?
feels warm/heat is released/temperature increases
What is the molar mass of KNO3?
101.1 g/mol
What is the volume of 2.00 mol of CO2 at STP? (1 mol = 22.4L)
2 mol(22.4L/1mol) = 44.8 L
The area below a curve on a solubility graph means the solution is ________.
unsaturated
What is the pOH for a solution with a pH of 8.21? (pH + pOH = 14)
5.79
The boiling point of ethanol is 78.3oC. What is the boiling point in Kelvins? (K=oC+273)
351
How many molecules are in 1 mole of water?
6.02x1023
Given 2 HCl + Mg(OH)2 → 2 H2O + MgCl2, how many moles of HCl are needed to react with 2.4 moles of Mg(OH)2?
(2.4 mol Mg(OH)2)(2mol HCl/1mol Mg(OH)2) = 4.8 mol HCl
When 0.05L of 3.0M solution is diluted to 0.15L, what is the new molarity? (M1V1=M2V2)
1 M
In a sample of orange juice the [H+] concentration is 7.94x10-4M. What is the pH? (pH = -log[H+])
3.10
How does solubility for a gas change as temperature increases?