Question

4 multiple choice 2 points which substance(s) in the original sample is insoluble and unreactive? sio₂ nacl caco₃ sio₂ and nacl caco₃ and nacl caco₃ and sio₂ sio₂ and nacl and caco₃ 5 multiple choice 2 points following the evaporation of water from the nacl filtrate and 15 minutes in the drying oven, the mass of the beaker and residue was 52.34 g. re - drying for another 10 minutes resulted in a mass of 53.14 g for the beaker and residue. has the beaker and residue been dried to a constant mass? yes no

Explanation:

For question 4, silica ($SiO_2$) is insoluble in water and many common reagents under normal conditions. Sodium - chloride ($NaCl$) is soluble in water, and calcium - carbonate ($CaCO_3$) can react with acids. For question 5, when a substance is dried to a constant mass, re - drying should not cause a significant change in mass. Here, the mass changed from 52.34 g to 53.14 g, indicating it was not dried to a constant mass.

Answer:

1. A. $SiO_2$
2. B. No