A
Analytical chemistry is primarily concerned with:
determining the composition of matter
Analyte refers to:
the chemical being measured
A method that measures how much of a substance is present is called
Quantitative
Which factor most strongly influences random error in measurements?
environmental fluctuations
Is chemical synthesis part of the analytical process?
No
Which method is most suitable for determining metal ions at ppm levels?
Atomic absorption spectroscopy
Identify the type of error: A student accidentally records 25.0 mL instead of 2.50 mL in their lab notebook
Gross Error
A reagent used in the analysis contains an unknown impurity that reacts with the analyte.
Method Error
An interferent affects an analytical measurement by:
producing a signal similar to that of the analyte
This phrase means you’re doing something confidently… even if it’s a little unhinged.
Doing it for the plot
A pipette delivers slightly less volume than indicated because of a manufacturing defect
Instrument Error
Identical samples analyzed on different days give slightly different results due to uncontrolled temperature changes
Random Error
This artist made Gen Z romanticize being sad in lowercase.
Bellie Eilish
Complete the lyrics of the song, “For Good”, from the musical, “Wicked.”
“Like a comet pulled from orbit, as it passes a ___
Like a stream that meets a ____, halfway through the wood
Who can say if I've been changed for the better?
But because I knew you
I have been changed __ ___”
sun
boulder
for good
Identical samples analyzed on different days give slightly different results due to uncontrolled temperature changes.
Random Error
This game popularized the shortened word “sus”
Among Us
A sample of acetic acid (CH₃COOH) weighing 3.0 g is dissolved in water to make 250.0 mL of solution. Experiments show that at equilibrium, the hydrogen ion concentration is 0.012 M.
What is the change concentration of CH₃COO-?
0.012 M
An analytical method consistently reports concentrations about 6% lower than certified reference values.
Systematic Error
An analytical result consistently higher than the true value suggests:
Positive systematic error
A 0.842g sample of an impure solid containing calcium carbonate is treated with excess hydrochloric acid until the reaction is complete. During the reaction, gas and water is formed and collected. The collected gas has a mass of 0.317g and is known to be carbon dioxide.
How many moles of carbon dioxide was formed?
0.0072 mol CO2
A 0.842g sample of an impure solid containing calcium carbonate is treated with excess hydrochloric acid until the reaction is complete. During the reaction, gas and water is formed and collected. The collected gas has a mass of 0.317g and is known to be carbon dioxide.
Give the chemical equation.
CaCO3 + 2HCl→CaCl2+CO2+H2O
Identify the lie about your instructor:
- longest relationship is 4 yrs
- was backstabbed by a friend
- college party girl
Longest relationship is 4 yrs
A sample of acetic acid (CH₃COOH) weighing 3.0 g is dissolved in water to make 250.0 mL of solution. Experiments show that at equilibrium, the hydrogen ion concentration is 0.012 M.
What is the initial concentration of acetic acid?
0.1988 M
A 4.95 g sample of magnesium hydroxide reacts with excess phosphoric acid, H₃PO₄, producing magnesium phosphate and water.
Give the chemical equation
3Mg(OH)2 + 2H3PO4 --> Mg3(PO4)2 + 6H2O
Calculate the w/v % of each substance int the solution at equilibrium.
CH₃COOH = 0.1998 M
CH₃COO- = 0.012 M
H+ = 0.012 M
CH₃COOH = 1.13%
CH₃COO- = 0.07%