Which of these reactions are redox reactions? check all that apply.

cd + hcl → cdcl2 + h2

cucl2 + na2s → 2nacl + cus

caco3 → cao + co2

2zns + 3o2 → 2zno + 2so2

ch4 + 2o2 → co2 + 2h2o

How is 0.00235 expressed in proper scientific notation? a. 2.35 × 10-3 b. 0.235 × 10-2 c. 2.35 d. 2.35 × 103

1. suppose a reaction mixture, when diluted with water, afforded 300 ml of an aqueous solution of 30 g of the reaction product malononitrile [ch2(cn)2], which is to be isolated by extraction with ether. the solubility of malononitrile in ether at room temperature is 20.0 g/100 ml, and in water is 13.3 g/100 ml. what weight of malononitrile would be recovered by extraction with (a) three 100-ml portions of ether and (b) one 300-ml portion of ether? suggestion: for each extraction, let x equal the weight extracted into the ether layer. in part (a), the concentration in the ether layer is x/100 and in the water layer is (30 x)/300; the ratio of these quantities is equal to k 20/13.3.

Kc = 0.040 for the system below at 450oc. if a reaction is initiated with 0.40 mole of cl2 and 0.40 mole of pcl3 in a 2.0 liter container, what is the equilibrium concentration of cl2 in the same system? pcl5(g) ⇄ pcl3(g) + cl2(g)