Persistent chlorinated hydrocarbon pesticides persist in the environment and accumulate in the foods chain causing harmful effects on the environment including posing a threat to humans health in the long term. Nonpersistent organophosphate pesticides are more toxic than the former but degrade after a short life span. Therefore they cause immediate harm in case one is in contact with them.
The fact that they do not accumulate in the environment, they are more favourable than chlorinated hydrocarbon pesticides. Chlorinated hydrocarbon pesticides will affect several generations due to their accumulation in the environment. However they don't need to be re-applied hence are less expensive
<span>there is less vegetation to help water soak int the ground</span>
The effect of a catalyst is to increase the speed of the reaction, this is the speed at which reactants, A and B, are consumed, ant the product, C, is produced.
Given that when C is produced the solution bubbles, the bubbles are an indication of progression of the reaction.
The greater the speed of reaction, the earlier the reaction will end and the earlier the bubbles will stop.
So the student can identify the catalyst because the bubbles will stop first.
Answer: <span>The test tube that stops bubbling first contains the catalyst.</span>
Answer:
The heat given off by Earth's core is circulated through mantle convection.
Explanation:
Heating materials usually causes them to <em>expand</em>; as they become hotter, they also become less dense. Convection describes the transfer of heat from hot areas of liquids and gases to cooler ones. This causes the heated, less dense material to rise and more dense material to fall, as it’s pulled by gravity. Super-heated metal forming Earth’s central core heats rock in the mantle; the hot and cool rock slowly rise and sink- this circulation process is called mantle convection.
Gravity (defined as: the force that attracts a body toward the center of the earth or toward any other physical body having mass)
