lab final 1 Flashcards
scientific method steps
questions, observations, hypotheses, testing, testing, conclusions, etc
dependent variable goes on __ axis
y
independent variable goes on __ axis
x
____ data is presented in a line figure
continuous
___ data is presented in a histogram or bar graph
discrete
where does a figure description go?
under the figure
it should have enough information where a reader can understand the figure just by reading the description
introduction section:
-background
-purpose
-hypothesis
methods section:
-basic procedures
-important changes in procedures
results section:
-tables/figures AND headings
-written description
discussion section
-do results match hypothesis
_meaning of hypothesis
-possible errors
-new hypothesis
-major conclusions
function of a spectrophotometer?
A spectrophotometer is an instrument that measures the amount of photons (the intensity of light) absorbed after it passes through sample solution. With the spectrophotometer, the amount of a known chemical substance (concentrations) can also be determined by measuring the intensity of light detected.
absorbance vs transmittance?
Transmittance refers to the amount of light that passes completely through the sample and strikes the detector. Absorbance is a measurement of light that is absorbed by the sample.
what is a “blank”?
A blank is a sample that contains everything except for the analyte of interest.
what are enzymes are why are they important?
enzymes are biological catalyst that speed up chemical reactions by reducing activation energy.
What are enzyme substrates?
Enzymes are proteins that act upon substrate molecules and decrease the activation energy necessary for a chemical reaction to occur by stabilizing the transition state.
what are enzyme products?
The substrate goes through a chemical reaction and changes into a new molecule called the product
what are enzyme activators?
chemicals that bind to an enzyme to increase its activity
what are enzyme inhibitors?
chemicals that bind to an enzyme to decrease its activity
how do we measure the rate at which an enzyme works?
determine the rate at which substrate is used OR determine the rate at which product is formed
Why do some fruits turn brown when they are cut?
The substrates react with one another within the active site of the enzyme. The products formed by this reaction are benzoquinone and water; since benzoquinone has a brown color, you can see that the reaction has taken place. This is called the fruit browning reaction.
What are Catechol Oxidase, Catechol, and Benzoquinone?
catechol oxidase: enzyme
catechol: substrate
benzoquinone: product
How does TLC work?
thin layer chromatography separates pigments from each other n
on-polar compounds move up the plate most rapidly , whereas polar substances travel up the TLC plate slowly or not at all.
mobile phase vs stationary phase
The silica gel is the stationary phase. The mobile phase is a suitable liquid solvent or mixture of solvents.
- Why do scientists repeat experiments?
lets you see patterns and trends in your results
