In our lab prep space, we have the following solutions and powders: Sodium citra

Question

In our lab prep space, we have the following solutions and powders:

Sodium citrate (FW = 43.7 g/mol)

SDS powder (FW = 288.38 g/mol)

0.5 M EDTA

IPTG powder (FW = 238.3 g/mol)

20 mg/mL X-gal solution

1000X ONPG

Premade LB

Premade LB agar

0.5 mM Colchicine

50X gel running buffer

Agarose powder

95% ethanol

100 mg/mL Ampicillin

10X BamHI restriction enzyme digestion buffer

milliQ water

dimethylformamide (DMF)

Please explain and show work!

16) . (B-gal) You need to make more of the 20 mg/ml X-gal stock, but somebody put an almost empty jar back on the shelf – there is only 8 mg of X-gal left. How much water would you add to use the rest of the powder up before buying more?

17) 17. (DNA isolation) Holy cow, everything is almost gone. You want to make a large quantity of 0.2 M sodium citrate, but there is only 0.5 g on the shelf. How much could you make?

18) . (B-gal) For ONPG, we use a 1000X stock - what is the concentration (in M) of the 1000X stock if the working (1X) concentration is 0.013 M?

Explanation / Answer

A16) You will add 8mg of XGAL to 400uL of water to make 20mg/ml solution.

A17) With 0.5g of sodium citrate, you can make 57.21 mL solution with concentration 0.2M.

A18) Concentration for 1000x would be 0.013M x 1000 = 13.0M..

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