Chem Lab Final

Question 1

scientific method

Answer 1

approaches to acquire knowledge by observing phenomena

Question 2

hypothesis

Answer 2

tentative and testable explanation of an observation

Question 3

calibrate

Answer 3

use a standard with a known true value
Ex: calibrate a balance with a 50kg weight because we know its 50 kg!

Question 4

accuracy

Answer 4

agreement between an experimentally measured value and the true value

Question 5

precision

Answer 5

the extent to which repeated measurements of the same variable agree

Question 6

two types of experimental error

Answer 6

1. systematic error (can be rectified often)
2. random error (related to precision and affects reproducibility)

Question 7

what do you use if you need an accurate volume measurement?

Answer 7

graduated cylinder

Question 8

what do you use an erlenmeyer flask

Answer 8

heating, stirring, storage, many other liquid handling needs

Question 9

qualitative vs quantitative

Answer 9

qual: sight, sound, touch, smell, taste
quant: reading precise numbers from piece of equipment

Question 10

sig figs

Answer 10

if you use something that requires reading measurements, estimate next digit.

working with digital number, no additional digit needed

Question 11

percent error

Answer 11

comparison between true value of data (from literature)

Question 12

non-Newtonian fluid

Answer 12

substance where viscosity changes when stress is applied

Question 13

density

Answer 13

mass/volume

Question 14

c = delta*v

Answer 14

c = speed of light
delta = wavelength
v = frequency

Question 15

range of white light

Answer 15

400nm - 800nm

Question 16

what energy transitions will produce photons in the visible range of wavelengths

Answer 16

nf = 2 and ni=3,4,5,6

Question 17

spectrometer

Answer 17

instruments used to quantify the phenomena of light, spectroscopy

Question 18

Spectroscope

Answer 18

measures spectrum of light and splits light into various components to produce spectral lines

Question 19

spectral lines

Answer 19

provide information about intensity and wavelength of diverse spectral lines

Question 20

calibration curve

Answer 20

defines relationship between an instrument’s response and the property we want to measure, instrument response on x-axis and desired property on y-axis

Question 21

three primary bonds

Answer 21

covalent: valence electrons share atoms
ionic: atom donates another
metallic bonding: bonds between metals in a lattice