Understanding the Difference Between Fluid Ounces and
Net Weight Ounces

When formulating any chemical solution with different ingredients, you will sometimes work with volumetric measurements (i.e. milliliters, fluid ounces and gallons). At other times, you will work with net weight measurements (i.e. pounds, net weight ounces and grams).

Working with ingredients measured in ounces can be confusing because measurements denoted in ounces can apply to either volumetric or net weight measurements.

When an ingredient is specified by volume, it should be listed with the designation fluid ounces or an abbreviation like "fl. oz." When an ingredient is specified by weight, it should be listed with a designation like net weight ounces, "net wt. oz," or "wt oz."

W/v% and V/v%

The terms w/v and v/v are used in chemistry to describe the concentration of a solute (usually a solid) in a solvent (usually a liquid).

• w/v stands for weight per volume, and expresses the amount of solute in grams per volume of solution in milliliters. For example, a 5% w/v solution of salt means that 5 grams of salt are dissolved in 100 milliliters of water.

• v/v stands for volume per volume, and expresses the amount of a liquid in milliliters per volume of solution in milliliters. For example, a 20% v/v solution of alcohol means that 20 milliliters of alcohol are dissolved in 100 milliliters of solution.

When two liquids have the same weight but different densities, they will occupy different volumes. For example, 1 liter of water weighs the same as 1 liter of oil, but water is denser than oil, so it occupies less volume.

Therefore, if you have two liquids that weigh the same but have different densities, liquids have different volumes in the container. This is because the volume of a liquid is affected by its density, while its weight is not.

To give an example, let's say you have a container that can hold 1 liter of liquid. If you fill the container with water, it will weigh the same as if you fill it with oil, but the volume of the oil will be less than that of the water because oil is less dense than water. This means that you will have more oil in the container by volume than water, even though they both weigh the same.

In summary, w/v and v/v are used to describe the concentration of a solute in a solvent in terms of weight or volume. When two liquids have the same weight but different densities, they will occupy different volumes in a container.

Crystal Clear  designates its ingredients sold by volume with the abbreviation "fl oz." Products sold by weight are generally designated with the abbreviation "wt oz."

Aren't Liquids Always Measured in Fluid Ounces and Aren't Dry Goods Always Measured By Weight?

Not always. Liquids such as fixed oils and chemical solutions are expressed in w/v% and v/v%  are sometimes measured by weight. Some dry goods, such as salts, sugars and herbs, are measured by volume such as 1 cup (8 fluid ounces).

One Fluid Ounce of an Ingredient is Not Equivalent to One Net Weight Ounce of the Same Ingredient

To ensure that you replicate a formulation or recipe accurately, it's important not to confuse fluid ounces with ounces denoted by weight (net weight ounces). For example: we sell our chlorine dioxide solutions by net weight. 4 wt. ounces of our Sodium chlorite has a molecular weight of 90.45 this means their is 9.045g/L it is much denser than our Hydrochloric Acid which has a molecular weight of 36.46 or 3.646 g/L so it will occupy more space than that of part A sodium chlorite solution. Part B Citric acid solution C-50 will also occupy more space in the bottle making it look fuller than that of part a Sodium Chlorite solution.  is much greater in quantity in comparison to the total quantity when using a measuring cup and filling it with 4 fl ounce.