Questions On Chemistry

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Question 1: pH can be described as a measure of acidity or basicity (Alkalinity) of a solution. It is exactly equal in amount to the negative log of the concentration of hydronium(H3O+) ions. Due to the negative log relationship, increased hydronium ions transform to lower pH. When we add it to water, an acid releases hydrogen ion. Hydrogen ions in water unite with the water molecules to form hydronium ions, thereby lowering the pH and increasing the acidity of water. Water exposed to air is gentle in nature acidic because it absorbs small quantities of CO2 from the atmosphere. The CO2 breaks down to carbonic acid to undergo dissociation to release hydrogen ions into water, lowering the pH. Prior to that, acid added to water increases …show more content…
Scientists used the new definition to explain more bases, such as ammonia (NH3). Subsequently, bases are proton acceptors, when ammonia was seen accepting an H+ and creating an ammonium ion (NH4+), it could be labeled as a base. If it got the H+ from a water molecule, then the water (H2O) was the proton donor. According to Brønsted an acid is a substance from which a proton (H+ ion) can be removed. Essentially, an acid donates protons to bases. On the other hand, a base is a substance to which a proton (H+) can be added. Basically, a base accepts protons from …show more content…
A 10 liter stock of 10x PBS can be prepared by dissolving
800 g NaCl, 20 g KCl, 144 g Na2HPO4 · 2H2O, 24 g KH2PO4, 8 L of distilled water.
After complete mixing, top up final solution to 10 L. The pH of the 10X stock is will be approximately 6.8, but when diluted to 1x PBS it should change to 7.4 On dilution, the resultant 1x PBS should have a final concentration of 137 mM NaCl, 10 mM Phosphate, 2.7 mM KCl, and a pH of 7.4.

Question 12:
An autoclave is used to sterilizing surgical equipment, laboratory instruments, pharmaceutical items, and other materials. It can sterilize solids, liquids, an unfilled space, and instruments of different shapes and sizes. Prior to that, many autoclaves are used to sterilizing apparatus and supplies by subjecting them to having a high barometric pressure saturated steam at 121 °C (249 °F) for around 15–20 minutes depending on the size of the load and the contents. Question 13:
1 liter of 1X PBS, can be prepare as follows:
i. Start with 800 ml of distilled water ii. Add 8 g of NaCl. iii. Add 0.2 g of KCl. iv. Add 1.44 g of Na2HPO4.
v. Add 0.24 g of KH2PO4. vi. Adjust the pH to 7.4 with

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