1.11 + 1.12 Health and Safety + Liquids and Solutions

Question 1

Name some hazards in a lab.

Answer 1

toxic chemicals,
heat sources/flammable substances,
mechanical equipment,
pathogens

Question 2

Hazards can be presented from s___, o___ and e___ in a lab.

Answer 2

substances, organisms, equipment

Question 3

What is risk?

Answer 3

the chance of harm arising from a hazard

Question 4

What is a dilution?
A serial dilution involves repeated dilutions from a ___ solution.

Answer 4

Reducing the concentration of a solution
Stock

Question 5

What’s the difference between a linear and a log dilution?

Answer 5

Linear dilutions differ by an equal interval, like 0.1 (eg 0.1, 0.2, 0.3 molL-1)
Log dilutions differ by a factor of 10. (eg 0.01, 0.1, 1, 10)

Question 6

How can can colorimeters be used to find the concentration of coloured solutions?

Answer 6

by measuring the absorption of light.

Question 7

Colorimeters can be used to find the ___ of colourful compounds in solution by measuring the a___ of ___ through a sample.

Answer 7

Concentration, absorbance, light

Question 8

What is transmission of light?

Answer 8

The % of light that passes through a sample

Question 9

When determining the concentration of an unknown sample, the ___ of a series of ‘___’ of known concentration are recorded using a ____.
The unknown can then be determined after a ___ ___ is plotted.

Answer 9

absorbance, ‘standards’, colorimeter.
standard curve/calibration graph.

Question 10

What are the two most common protein standards?

Answer 10

BSA and gamma globulin

Question 11

To produce a standard curve, a ___ should be added to (known/unknown) concentrations of ___ solutions.

Answer 11

dye, (known), protein.

Question 12

The ___ of each solution is then measured using a ___, with a filter that is ____ to the solution (ie has an ___ colour wavelength).

Answer 12

absorbance, colorimeter, complementary, (opposite)

Question 13

Then, a graph can be plotted with c___ on the x-axis and a___ on the y-axis.
The x-axis always has the (independent/dependent) variable.

Answer 13

concentration, absorbance.
(Independent)

Question 14

What is pH?
What is a pH buffer?

Answer 14

A logarithmic scale of Hydrogen ion concentration.
A solution whose concentration does not change when adding a small amount of acid or alkali.

Question 15

Which two things must you do before using a colorimeter?

Answer 15

1. select a filter, that is complementary to the solution
2. Calibrate the colorimeter with a blank solvent (whichever solvent that was used when making the solutions)