Stoich And Measurement Flashcards
has only one marking; used in measuring volume precisely.
Volumetric flask
Determination of the dimensions, capacity, quantity, or extent of
something
Measurement
It is the process of obtaining the magnitude of a quantity relative to an
agreed standard.
Measurement
It is composed of a number and a unit and is meaningless without the unit.
Measurement
→ a property that is measured
→ Can be derived or fundamental
− Ex. mass, volume, length, time, temperature, pressure
Quantity
Fundamental: simplest quantities
mass, volume, length, time, temperature, pressure
Quantities (7)
Force, velocity, energy, electric current, acceleration, power
A standard quantity against which a quantity is measured
− Ex.kg,L,m,s,K,Pa
Unit
Used to describe quantities.
Unit
Kg is a unit used to describe ?
Mass
L is a unit used to describe
volume
m describes
Length
S describes
Time
describes temperature,
K
Unit of pressure
Pa
− Units in commerce
− Units: Inch, foot, pound, quart, and gallon
English System
− Used in scientific work
− Units: grams, meter, and liter
Metric System
Measurement systems should be understandable to everyone hence
the creation of ?
SI system
SI means?
“Système International d’Unités”
The internationally adopted system which defines or expresses all quantities in terms of seven basic units, the six used by chemists being:
SI system
the only unit not commonly used by chemists
Candela
basis for 1 second. The old basis of a second was observed from the pendulum.
Cesium hyperfine splitting frequency
the basis for luminous intensity.
Luminous efficacy of a specified monochromatic source
Kg stands for?
Mass
m stands for?
Length
S stands for?
Second
K stands for?
Temperature
Mol stands for?
Amount of substance
A stands for?
Electric current
fixed value; does not change
Constant
logical extension of the metric system
SI units
SI units speed
m/s
SI unit of density
kg/m3
are used with these base units and other derived units to express small or large measured quantities in terms of a few simple digits
Prefixes
1 kg = _____g
1000 g
1 milligram (mg) =_______g
0.001 g
What is the multplier of giga
10^9
What is the multplier of mega
10 ^6
What is the multplier of kilo
10^3
What is the multplier of deci
10^-1
What is the multplier of centi
10^-2
What is the multplier of milli
10^-3
results from counting objects or is part of a definition.
exact number
results from a measurement or observation and contains some uncertainty.
inexact number
Digits in a measurement that are known with certainty plus one digit that
is estimated.
Significant figures
Unit of density for solids
g/cm3
Unit of density in liquid
g/mL
Unit of density for gases
g/L
Ratio of the density of a substance to the density of water. It is one of the few unitless quantities in Chemistry.
Specific gravity
If is the density of the 𝑔/𝑚𝑙 substance the density of water that you will you use is the constant value is
1 𝑔 / 𝑚𝑙
ρ𝑠𝑢𝑏𝑠𝑡𝑎𝑛𝑐𝑒 formula
𝑠𝑝𝑔𝑟𝑥ρ𝐻2O
The specific gravity of a substance is equal to its _______, but contains no units
Density
The specific gravity of a substance is equal to its density, but contains no units
MOLES
SI unit for the amount of a chemical species
Mol
Avogadro’s
number
(6.022 × 1023)
Mass, in grams, of a substance that is numerically equivalent to the formula mass of the substance
Molar Mass
is 1/1000 of a mole
Millimole
A homogeneous mixture of two or more substances with each substance retaining its own chemical identity
SOLUTIONS
cannot identify or distinguish the individual components in a mixture
homogeneous
solution in which water is the solvent
Aqueous solution
A solution in which a substance other than water is the solvent
→Nonaqueous solution
Component of a solution that is usually present in the
greatest amount
Solvent
Component of a solution that is usually present in a lesser amount relative to that of the solvent
Solutr
A solution that contains a large amount of solute relative to the amount that could be dissolved
Concentrated solution:
A solution that contains a small amount of solute relative to the amount that could be dissolved
Dilute solution:
The process in which more solvent is added to a solution in order to lower its concentration
Dilution
How would you prepare 100 mL of 0.9% saline solution in water from a 10% saline solution?
9 mL of 10% saline solution + 91 mL of water
The amount of solute present in a specified amount of solution
PERCENT CONCENTRATION
What is the percent by mass concentration of glucose in a solution made by dissolving 5.5 g of glucose in 78.2 g of water?
6.6% (m/m)
Calculate the volume percent of solute in 30.0 mL of methyl alcohol in enough water to give 435 mL of solution.
6.90% (v/v)
How many grams of sodium chloride are needed to prepare 150 mL of 0.9% (m/v) sodium chloride?
1.35 g of NaCl
Moles of solute in a solution divided by the liters of solution
Molarity
Calculate the molarity of a solution made from 20.0 g of NaOH in 250 mL of solution. ( ) moles of solute Molarity M = liters of solution
2.00 M
The most common measure of concentration in the laboratory is?
Molarity
