Answer:
A. Whatever is in the water, it moves. Even if a block is placed in there, it would move by sinking to the bottom. If a plastic bag was placed in there, it wouldn't sink but move a little.
<span>There's a trend in electronegativity. The bottom left of periodic table is the lowest (0.7) and the upper right is the highest (4.0). The most polar is the greatest difference in electronegavity.
hbr- 1~ , hi- 0.5~ ,hcl - 1.3~ , hf-1.8 so,hf is the answer</span>
<span>A is the correct answer. Tying back long hair and loose clothing is important so they don’t dangle in flames or liquids that could dissolve or bleach them, for example. The other choices - consuming food and drink from lab wares, touching hot objects without gloves on and inhaling odors - are examples of very unsafe procedures. </span>