Recipe Calculators (AKA the 'Moles to Anything Page')
The following calculators determine measurements for chemical recipes.
- This calculator is designed to output mass measurements when you insert your desired molarity.
- This calculator is designed to output volume measurements when you insert your desired molarity. It assumes you already have solutions of known molarity.
- This calculator is designed to output volume measurements when you insert your solution's molarity and solute's molecular mass. It assumes you already have solutions of known molarity.
- This calculator is designed to output volume measurements when you insert your desired molarity and solute's molecular mass. It assumes you already have solutions of known mass/volume percent.
- This calculator is designed to output mass measurements when you insert your desired percent mass and solute's molecular mass.
- This calculator is designed to convert between mass percent and parts per million, billion, or trillion.
- This calculator outputs the mass of a molecule, given the names and amounts of each element present.
Information about chemistry concentration.
- Concentrations can be expressed in numerous units. Some of these units can be a source of confusion.
- For example, when working in air concentration 1 ppm = 1 volume/106 volumes or 10-6 atm/1 atm.
- However, when working in liquid concentration 1 ppm = 1 gram of solute/106 grams of solvent.
- To avoid confusion, the terms ppmv and ppmw are commonly used to designate part per million by volume and part per million by weight respectively.
Following are definitions of commonly used units and calculators to convert one concentration to another
- Molarity (M)
- This unit of conversion relates the number of moles of solvent to a liter of solution.
- Molarity = moles of solvent/Liter of solution
- For instance: 2.5 moles of dissolved particles in 5 Liters of liquid solution constitute a 0.5 mol/L (or M) solution (0.5 molar solution)
- Molality (m)
- This unit of conversion relates the number of moles of solvent to a kilogram of solution.
- Molality = moles of solvent/Kg of solution
- For instance: 2.5 moles of dissolved particles in 5 Kg of solution constitute a molality of 0.5 mol/Kg (or m) (0.5 molal solution).
- Weight Percentage (w/w%)
- This unit of concentration is often used for concentrated solutions of acids and bases. It is defined as the weight of solute times 100 divided by the total weight and is often abbreviated as w/w%.
- w/w% = grams of solute x 100 / (grams of solvent + grams of solute)
- For example: if a label indicates a concentration of 25% by mass, then it contains 25 grams of solute and 75 grams of solvent.
- Volume Percentage (v/v%)
- This unit of concentration is most useful when liquid-liquid solutions are prepared. It is defined as the volume of solute times 100 divided by the total volume and is often abbreviated as v/v%.
- v/v% = volume of solute x 100 / (volume of solvent + volume of solute)
- For example: if a label indicates a concentration of 25% by volume, then it contains 25 mL of solute and 75 mL of solvent.
- Weight Percentage 2 (w/v%)
- This unit of concentration is the least specifically named, but the most common when diluting solvents in liquid. If w/w%, w/v% or v/v% is not specified, then w/v% is assumed.
- w/v% = grams of solute/100mL solution
- For example: if a label indicates a concentration of 2.5%, then it contains 2.5 grams of solute per every 100 mL of solution.
- Parts Per Million (ppm)
- This unit is a way of expressing very dilute concentrations of substances. Just as per cent means out of a hundred, so parts per million or ppm means out of a million. ppm is commonly used to describe very small amounts of contaminants.
- Solubility is an important property to consider when thinking about mixing two or more substances together. The solubility of a solute is the maximum quantity of solute that can dissolve in a certain quantity of solvent at a given temperature. Solubility is expressed as a maximum concentration.
- The main factors that affect solubility are
- The chemical properties of the solute and solvent (i.e. molecular size and polarity)
- Pressure (for gaseous solutes)
- Temperature: Generally, an increase in the temperature of the solution increases the solubility of a solid solute. A few solid solutes, however, are less soluble in warmer solutions. For all gaseous solutes, solubility decreases as the temperature of the solution rises.
- When a solution at equilibrium can not hold any more solute, it is said to be saturated. Under special conditions, solutions may hold more solute than the solvent can normally dissolve. This is called supersaturation.
- Dissolution is how a solution is formed when a solute dissolves in a solvent. Generally polar molecules will dissolve in polar solvents and non-polar molecules will dissolve in non-polar solvents (like dissolves like). The polar molecules have a positive and a negative end to the molecule. When the solvent molecule is also polar, positive ends of solvent molecules attract negative ends of solute molecules. Polar solvents can generally dissolve solutes that are ionic. The negative ion of the substance being dissolved is attracted to the positive end of a neighboring solvent molecules while the positive ion of the solute is attracted to the negative end of the solvent molecule.
- The main factors that affect the rate of dissolution are
- Particle size: When a solute dissolves, the action takes place only at the surface of each particle. When the total surface area of the solute particles is increased, the solute dissolves more rapidly. Breaking a solute into smaller pieces increases its surface area and hence its rate of solution.
- Agitation: With liquid and solid solutes, stirring brings fresh portions of the solvent in contact with the solute, thereby increasing the rate of solution.
- Solute Concentration: When the solute concentration in the solution is low, the rate of dissolution is higher. As the solution approaches the saturation point, the rate of dissolution lowers.
- Temperature: For liquids and solid solutes, increasing the temperature increases the saturation point and dissolution rate. For gaseous solutes, however, the reverse is true. An increase in temperature decreases both solubility and rate of dissolution.
Definition --- all plastic=polymer but not all polymer=plastic (ex: some biological and inorganic molecules)large molecule with repeating units (monomer)linear/branched
Photoresists (SU8 = epoxy polymer = thermoset)