Midterm 2: Study Points Flashcards
How do you determine the number of moles in a certain amount of grams of a substance?
Divide the mass by the molar mass to obtain moles. So if you were looking for 5 grams of oxygen it would be 5/15.99 for one mole.
What is the mass in grams of 0.443 mols of calcium nitrate?
Mass=0.433moles×164.094g/mol = 71.04
What is a molecular formula? What is the empirical formula?
The molecular formula is the standard writing of the formula. Example: C6 H12 O6
The empirical formula is the lowest ration that can be made. Example C H6 O
How do you obtain the empirical formula from the percentage composition?
If given the precent of each composition. Assume you are dealing with 100grams of the product. That way, your percentage translates to grams. You then multiple the grams you have by 1 mol of the substance divided by the molar mass to find the amount of moles you have of the substance. You then divide all the substances by the mole of the smallest one.
Practice Stoichimetry. Remember to go from moles of substance A to moles of substance B
What is a limiting reaction?
Usually one reactant will be completely consumed before the others. the amount of product you get is controlled by the limiting reactant.
What is the difference in the cis and trans function of Pt(NH3)2CI2?
The cis isomer is a powerful chemotherapy drug while the trans isomer has no value as a chemotherapy drug
What is the new definition of the mole?
Their new definition is based on a specified number of elementary entities. Until now, a
mole has been defined with reference to a specified mass.
IUPAC’s new definition describes the mole as containing exactly 6.02214076 x 1023 (the
Avogadro constant) elementary entities.
Textbooks published from 1971 onwards are likely to define a mole as the mass of
substance containing the same number of fundamental units as there are atoms in exactly 12.000 g of 12C.
The new definition stresses that moles are to do with counting entities rather than
measuring the mass of a sample of something else.
What is the role of electrolytes in the body?
In the body, electrolytes fulfill a
number of vital roles in maintaining fluid balance and pH, membrane potentials, muscular functions, and nervous
conduction, and they serve as cofactors in many enzyme-mediated reactions
What is a major extracellular cation in plasma?
Sodium is the major extracellular cation in plasma, and its concentration is closely related to osmotic homeostasis
Which electrolyte is involved in neuromuscular transmission?
Calcium is involved in neuromuscular transmission
Which electrolyte is a major intracellular anion?
Phosphate is the major intracellular anion
Which electrolyte is an important structural component of bone and muscle?
Magnesium is an important structural component of bone and muscle that predominates in the ICF and is
found free.
Study Figure 2A
What is the mass (g) of 0.433 moles of calcium nitrate?
What is the empirical and molecular formula for ethylene glycol (anti-freeze)?
empirical formula is ethylene glycol is CH₃O
molecular formula of ethylene glycol is C₂H₆O₂.
How many moles of N2 are made if 2.50 moles of KNO3 are used?
If 2.50 moles of KNO3 are used, 0.250 moles of
N2 are produced.
When does precipitate reactions occur?
When a positive and a negative ion strongly interact
Are the following soluble or not soluble?
Lead sulfate (PbSO4) - Not soluble
Sodium carbonate (Na2CO3) - Soluble
What is the ideal gas law?
PV = nRT
P = Pressure
V = Volume
n = Quantity of moles
T = Temperature
R = Ideal gas constant
What laws is the ideal gas law based on?
- Boyles law: the pressure of a fixed amount of gas at constant pressure is inversely proporitonal to volume
- Charles Law: The Volume of fixed amount of gas at constant pressure
- Avogrado’s Law: Volume is proportional to moles at constant pressure and temperatire
What is the volume of one mole of ideal gas at freezing point at 25 degrees celcius?
At 0°C (Freezing Point): 22.414 L/mol
At 25°C: 24.465 L/mol
