Laboratory Techniques and Measurements

Flashcards based on laboratory measurements, procedures, and calculations dealing with density, uncertainty, measurements, and titrations.

Counts are __: there is no uncertainty.

exact

Measurements always involve some degree of __.

uncertainty

The last reported digit in a measurement is __.

estimated

Precision is a measure of the __ of a result from replicate determinations.

reproducibility

Uncertainty is the range a data value may have because the last digit of the data value was __.

estimated

The uncertainty in the value of a number should be within the __ occupied by the right-most digit in a recorded value.

decimal place

Significant figures should be reported using the certain digits plus one __ digit.

estimated

The departure of a data value from the true or accepted value is referred to as __.

error

To compute the percent error, the formula is: percent error = (__ divided by accepted value) x 100.

(measured value - accepted value)

If the true or accepted value is known, then __ can be calculated to assess accuracy.

percent error

Water at 19.7 °C has a density of __ g/mL according to the provided data.

0.998265

When reporting average values, it is better to report the __ than any individual measurement.

mean

The methods for separating mixtures are based on differences in their __ properties.

physical

Decantation separates a liquid from a __.

solid

The process of separating a solid from a liquid using filter paper is called __.

filtration

The formula for calculating the mass percent of water in a hydrate is: % water = (__)/(mass of hydrate) x 100.

(mass of water lost)

The number of moles of water lost is calculated using the molar mass of water, which is __ g/mol.

18.0

The equation relating the concentration of acetic acid (HAC) to the standardized NaOH solution in a titration is: HAC + __ → NaC2H3O2 + H2O.

NaOH

If you have 6.00 mL of vinegar and it reacts with a certain volume of NaOH, to find the concentration of acetic acid, you first need to find the __ of NaOH used.

moles

In titrations, one mole of __ is required to neutralize one mole of acetic acid.

NaOH

The main objective of a titration is to find the unknown concentration of an analyte by using a solution of __ concentration.

known