Answer:
It is true that earth was once covered with oceans and little dry land.
Explanation:
Over the course of around four billion years, the Earth's oceans have lost about a quarter of their original mass. Today the atmosphere is rich in oxygen, which reacts with both hydrogen and deuterium to recreate water, which falls back to the Earth's surface. So the vast bulk of the water on Earth is held in a closed system that prevents the planet from gradually drying out. According to the researchers, the continents emerged relatively suddenly from an ocean that covered 95 percent of the Earth's surface. The appearance of large masses of dry land would have caused more extreme weather, changes in ocean currents and the emergence of proper seasons. In turn, these environmental changes may have led to rise in atmospheric oxygen that enabled the explosion of new life forms around 500 million years ago.
Answer: It is usually separated from tea leaves by filtration. B Because the composition of the solution is uniform throughout, it is a homogeneous mixture. A Orange juice contains particles of solid (pulp) as well as liquid; it is not chemically pure.
Answer:
False
Explanation:
Some substances don't have to be
Ca(s)+2Hcl(aq) ------>CaCl2(s)+H2(g)
Answer:
Options B and C are the two criteria that are most essential
Explanation:
When trying to develop a novel process, <u>it is important that the new process involves the use of equipment that can be operated safely by workers so as to prevent death or injury in the cause of handling this equipment</u>. If this equipment is seen not to be safe or cannot be handled safely by workers, it can/will force workers to previous or alternative methods that require more safe equipment.
Also, the process must be able to maximize the most of the reactants, i.e <u>the process must be able to convert a good percentage of the reactants into the desired product (phosphorus pentachloride) since that is the focus</u>. This will also lead to reduction of byproducts produced which could be useful or otherwise (a loss).
