BIOLAB [DENSITY, pH + BUFFERS, & CARBOHYDRATES]

What is relatively consistent across different samples and is often considered a characteristic property?

Density of a Pure Substance

What specifications usually accompany density measurements?

Temperature and Pressure

This is often used to indicate how “heavy” a substance feels.

Density

Mathematically, how can density be expressed as?

d = m / V

How is density usually expressed in units?

Grams per millimeter (g/mL) for LIQUIDS

Grams per cubic centimeter (g/cm³) for SOLIDS

Gram per liter (g/L) for GASES

Theoretical density of pure water at room temperature.

1.00 g/mL (or 1.00 g/cm³)

Standard unit for the density of liquids.

Grams per milliliter (g/mL)

Standard unit for the density of solids.

Grams per cubic centimeter (g/cm³)

Standard unit for the density of gases.

Grams per liter (g/L)

Formula for Percentage Error.

% Error = | Theoretical Value - Experimental Value / Theoretical Value | x 100

The proper technique for reading liquid volume in a graduated cylinder.

Read the scale at eye level at the bottom of the liquid meniscus curve.

What is the purpose of the water displacement method?

To determine the volume of an irregularly shaped solid by measuring the volume of water displaced.

The volume formula for a rectangular wooden block.

V = l x w x h, where l is length, w is width, and h is height.

How do you calculate the volume of an irregular solid using the Water Displacement Method?

Volume of solid = Final water level - Initial water level

Density of water:
Mass of cylinder = 100.00 g

Combined mass = 118.60 g

Volume = 20.0 mL

0.93 g/mL (calculated as 118.60 g - 100.00 g / 20.0 mL = 18.60 g / 20.0 mL)

Density of liquid sample: