Answer:
Number 4 is an example of a chemical reaction
Explanation:
heThe chalk is reacting with the vingear which is creating a new substance. The new substance is the gas that the reaction gives off.
We determine the percent by mass of water in the compound by dividing the mass of water by the total mass. The total mass of Na2SO4.10H2O is equal to 322 g. The mass of water is 180 g.
percent by mass of water = (180 / 322)*(100 %) = 55.9%
Uranium-235 would be more useful for dating in Cambrian time because Cambrian time was 540 million years ago while the half life of carbon-14 is only 5,730 years
Hope this helps
When gases get cooler the molecules slow down or lose energy and condense so the volume in the tire or soccer ball would decrease and may feel flatter
