Which statement describes the appearance of a
temperature-vs.-time graph?
O A horizontal line shows that the temperature
increases at a constant rate over time.
O A vertical line shows that the temperature
decreases at a constant rate over time.
Horizontal lines where the temperature is
constant during phase changes connect
upward-sloping lines where the temperature
increases.
Horizontal lines where the temperature
increases are connected by upward-sloping
lines where the temperature is constant for
each phase.

it means there are 3 atoms of oxygen

answer : one can design an experiment using a liquid and an additive that can be added to the liquid and observe the chemical changes in the reaction species.

one would need a beaker which is filled with a known amount of the liquid in which thermometer is placed to measure the temperature changes; after addition of the additive to the liquid solution one can note down the temperature change and find whether the reaction is endothermic or exothermic in nature. by subtracting the initial temperature value with the final temperature one can find the temperature changes.

various combinations of liquid and additive can be used. liquid in this case can be a known quantity of water and additives can be epsom salt or without epsom salt the experiment can be conducted to notice the changes. water and ice, hydrogen peroxide and dry yeast, vinegar and baking soda,etc.

1. a)c-14 has two more protons

2. d)they have different numbers of protons, neutrons, and valence electrons; they are all gases at room temperature.

3. c) iron and nickel.