Rules for Writing Scientifically
Follow these general scientific rules when writing lab reports.
1) Write in a passive voice.
a) Example: I poured 5 mL of water into the beaker.
b) Turn it into this: 5 mL of water was added to the beaker.
2) Write in the past tense.
a) Example: In this week’s experiment, the density of a solid, liquid, and gas will be
determined.
b) Turn it into this: This week, the density of a solid, liquid, and gas was determined.
3) Put a space in between values and units.
a) Example: The molar mass was found to be 27.5g/mol
b) Turn it into this: The molar mass was found to be 27.5 g/mol
c) Exception: With temperature that has degree symbols
i) No: 37 °C
ii) Yes: 37°C
4) Show the zero in the ones place when using a value -1 < x < 1.
a) Example: Mass of unknown = .375 g
b) Turn it into this: Mass of unknown = 0.375 g
5) Show all units when doing calculations. Units help to clarify what is going on in your
calculation—units will allow me to give you partial credit if the calculation is incorrect!
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a) Example: 500 ∗ 1000 = 0.5
b) Turn it into this: 500 𝑚𝐿 ∗
1𝐿
= 0.5 𝐿
1000 𝑚𝐿
6) The terms “weigh” and “weight” are not synonymous with mass. Mass is the amount of
material that is in a sample. This is measured using the SI unit of kg (using the metric
system, it can be measured in g, mg, g, etc). While weight is the measure of a force acting
on a certain amount of mass. Weight has SI units of N (the newton – the abbreviation is
capital while the full name is lower case).
a) Example: The unknown sample was weighed and found to have mass of 55.29 g
b) Turn it into this: The mass of the unknown sample was found to be 55.29 g
7) Chemicals and elements are not capitalized.
a) Example: 10 mL of Hexane was added to the flask
b) Turn it into this: 10 mL of hexane was added to the flask
8) Use parenthesis to indicate the amount of a compound being used.
a) Example: 10 mL of hexane was added to the flask.
b) Turn it into this: Hexane (10 mL) was added to the flask.
Northeastern University | CHEM 2312 | Spring 2020 | 1
9) Use superscripts and subscripts
a) Example: The nitrate anion, NO3- reacted with water, H2O.
b) Turn it into this: The nitrate anion, NO3- reacted with water, H2O.
10) When making a table, put shared units over to the margins in parentheses
a) Example:
Mass
Trial 1
Trial 2
27.74 g
27.91 g
Trial 1
Trial 2
27.74
27.91
b) Turn it into this:
Mass (g)
11) Label tables and put titles under them that describe what is being presented
a) Example:
Mass (g)
Trial 1
Trial 2
27.74
27.91
Trial 1
Trial 2
27.74
27.91
b) Turn it into this:
Mass (g)
Table 1. The mass of the unknown compound in the two trials.
12) Use abbreviations for units
a) Example: The mixture was heated to 55 degrees Celsius.
b) Turn it into this: This mixture was heated to 55°C.
13) When electron pushing, arrows start at the electron dense region (this can be a bond, a lone
pair, or a radial) and move to the electrophile (usually a positive charge or neutral atom).
Electron pushing shows the movement of electrons, not the movement of atoms.
a) Example:
b) Turn it into this:
Northeastern University | CHEM 2312 | Spring 2020 | 2