Frequently Asked Questions
- Where can Material Safety Data Sheets (MSDS) be obtained for ScholAR Chemistry chemicals?
- Can Lab Grade chemicals be used for high school chemistry experiments?
- Can an aqueous solution of Magnesium Chloride, MgCl2(aq), be prepared from the hydrated salt — Magnesium Chloride Hexahydrate?
- The chemical 1,6-hexanediamine (#97107XX) was received as a solid mass in a liquid reagent bottle. Is this normal?
- How can a 0.1 M Sodium Sulfate solution be prepared from Sodium Sulfate powder (# 9434706)?
- How can a Phenolphthalein Indicator solution be prepared from Phenolphthalein powder?
- Which indicator can be used to detect the formation of dissolved carbon dioxide gas in water, CO2(aq)?
- What is the procedure for preparing a starch solution in water?
- Can a chemical be used after its age exceeds the shelf life listed in your catalogs?
- What is the procedure for preparing Agar media from the Agar Bacteriological Powder (#94435XX)?
1.) Where can Material Safety Data Sheets (MSDS) be obtained for ScholAR Chemistry chemicals?
Every ScholAR Chemistry chemical is shipped with an MSDS attached to the chemical container. If a chemical is received in a single box, the MSDS will be inside the box. MSDS for ScholAR chemicals can also be accessed through this website by browsing the chemical category. Each chemical has a downloadable MSDS in PDF format.
2.) Can Lab Grade chemicals be used for high school chemistry experiments?
Yes. ScholAR Chemistry Lab Grade chemicals are high purity chemicals that are suitable for most K-12 experiments and demonstrations. ScholAR Chemistry Reagent Grade chemicals are recommended for analytical and research work.
3.) Can an aqueous solution of Magnesium Chloride, MgCl2(aq), be prepared from the hydrated salt — Magnesium Chloride Hexahydrate?
Yes, the hexahydrate can be dissolved in water to form MgCl2(aq). The Molar Mass of the hexahydrate, 203.31 g/mol, must be used to calculate the amount of solid required.
4.) The chemical 1,6-hexanediamine (#97107XX) was received as a solid mass in a liquid reagent bottle. Is this normal?
Yes, 1,6-hexanediamine is a solid at room temperature with a melting point of 39–42 degrees Celsius. When you are ready to use it, warm the bottle in a hot water bath until the solid melts. The correct volume or mass of material can then be poured out of the bottle.
5.) How can a 0.1 M Sodium Sulfate solution be prepared from Sodium Sulfate powder (# 9434706)?
A 0.1 Molar solution contains 0.1 mole of dissolved solute, sodium sulfate in this case, per Liter of solution. To prepare a 0.1 M Na2SO4(aq) you will need to weigh out 14.2 g of Na2SO4 powder (0.1 M x 142.04g/mol) and dissolve it in enough water to make 1 L of solution. We recommend the solution be prepared in a volumetric flask, if available.
6.) How can a Phenolphthalein Indicator solution be prepared from Phenolphthalein powder?
Phenolphthalein powder is soluble in alcohol but almost insoluble in water. A 1% solution can be prepared by dissolving 1 g of Phenolphthalein powder into 100 mL of 2-propanol 70% solution (#9508506). Caution: the indicator solution will be flammable.
7.) Which indicator can be used to detect the formation of dissolved carbon dioxide gas in water, CO2(aq)?
CO2(aq) reacts with water to form carbonic acid, H2CO3(aq), which lowers the pH of the water. Bromothymol Blue (BTB) 0.5% aqueous indicator solution (#9447202) works well for detecting the resultant drop in pH. This comes in a 30-mL dropper bottle for easy dispensing. BTB is blue above pH 7 and yellow below pH 6. One drop of 0.5% BTB mixed with 100 to 200 mL of water will give a very light blue colored solution. Upon bubbling CO2 gas through the water, the solution color will change to yellow.
8.) What is the procedure for preparing a starch solution in water?
To prepare a 5% starch solution, SLOWLY add 5 g of soluble starch (#94691XX or #94690XX) to 100 mL of water while stirring the water. The resultant solution will be viscous.
9.) Can a chemical be used after its age exceeds the shelf life listed in your catalogs?
We recommend that chemical purchasing be planned out so the chemicals are used up within their normal shelf life. Chemicals should always be dated 'when received' and 'when the container is opened (seal broken) for the first time'. The appearance and quality of each chemical should always be inspected before using it. The expected Appearance and Odor of each ScholAR Chemistry chemical is listed in Section III of the MSDS.
10.) What is the procedure for preparing Agar media from the Agar Bacteriological Powder (#94435XX)?
To prepare sterile agar media:
- To make the agar solution, add 23.3g of the bacteriological agar powder to a 2L beaker. Add 1000 mL of water.
- Place the beaker on a hot plate and stir while heating.
- Let the mixture come to a boil. Let the mixture boil for 5 minutes.
- Cover the beaker with foil. Carefully take the heated mixture and autoclave for 15 minutes at 121 degree Celsius.
- Remove the sterile agar from the autoclave (do not let the mixture cool).
- Pour the sterile agar onto plates. Leave plate covers ascew to allow steam to escape.
- Once plates have begun to set, cover plates and allow to cool. Store plates upside down in refrigerator until use. (exp date of 3 months)
- When the plates are utilized, one plate is not treated with bacteria but is added to the incubator with the treated plates. The untreated plate serves as a control plate. If colonies develop on the control plate during the incubation process, the plate media is suspect and the experiment must be terminated.