Problems with simple wording

1. How would you make 750 ml of a 0.1M NaCl solution? (FW 58.44)

2. How would you make 100 ml of a 1% NaCl solution?

3. How would you make 75ml of a 1% NaCl solution from a 5% stock solution?

4. How would you make 1.5 l of a 0.05M NaCl solution from the solution in #1

5. How would you make 150 ml of a 50mM NaCl solution from the solution in #1

Problems In-Content

1. For staining mitochondria, a 0.025% (w/v) Janus Green B solution is needed. How would you prepare this from the 1.0 g/L stock solution of Janus Green B that we used for Lab #1?

2. Triton X-100 is a nonionic detergent (a liquid). How would you make 100 ml of a 2% (v/v) Triton X-100 solution?

3. For the homogenization of spinach leaves and the isolation of chloroplasts, a Tris-NaCl buffer is used. The buffer is 0.35 M NaCl-0.02 M Tris, pH 7.5. The directions state to dissolve 5.11 g NaCl and 0.61 g tris(hydroxymethyl) aminomethane (TRIZMA base) in distilled water to make 250 ml of solution; adjust to pH 7.5 with 6 M HCl. [MWs: NaCl, 58.5; Trizma, 121.1]. Show that the amounts of NaCl and Trizma are correct.

4. For the homogenization of cauliflower and the isolation of mitochondria, a mannitol grinding medium is used. This is a sugar (mannitol) solution in a phosphate buffer. The final concentrations are 0.3 M D-mannitol-0.02 M phosphate buffer. The directions state: dissolve 27.33 g D-mannitol, 0.41 g KH₂PO₄, 1.21 g K₂HPO₄ in distilled water to make 500 ml of solution. Adjust to pH 7.2 with 1 N KOH.

A. As in #3 above, show that these directions are correct. [MWs: D-mannitol, 182.2; KH₂PO₄, 136.09; and K₂HPO₄, 174.18].