On which land masses did Lystrosaurus live?

Apiece of metal with a length of 1.42 cm was measured using four different instruments. which of the following measurements is the most accurate?

For the reaction c6h14(g) & longrightarrow; c6h6(g) + 4h2(g), δp(h2)/δt was found to be 2.5 x 10-2 atm/s, where δp(h2) is the change in pressure of hydrogen. determine δp(c6h14)/δt for this reaction at the same time.

What type of chemical bond is formed between two atoms of bromine 1. metallic 2. hydrogen 3. ionic 4. covalent