Answer:
The chronic daily intake during the period of exposure is most nearly 0.012 mg/kg day.
Explanation:
Number of hours worker exposed to xylene = 
The concentration of xylene in the workplace =
The worker is inhaling air at a rate of 
.
Amount xylene inhaled by worker in an hour :
= 
Amount xylene inhaled by worker in 320 hours:
1 μg = 0.001 mg
Amount xylene inhaled by worker in 320 hours = 11.520 mg
1 day = 24 hours
Amount xylene inhaled by worker in 1 day:
Assuming 70 kg body mass, the chronic daily intake of xylene :
The chronic daily intake during the period of exposure is most nearly 0.012 mg/kg day.
The property of potential energy that distinguishes it from kinetic energy are Shape and position
(1)
The health of coral colonies
The levels of carbon dioxide in the atmosphere
This is because corals are very sensitive to changes in the ocean's properties pH being included. Warmer oceans dissolves more carbon dioxide from the atmosphere hence making the waters slightly acidic. This will affect coral resulting in bleaching. This negatively affects the marine ecosystems since corals are usually at the bottom of the energy pyramid in these ecosystems.
(2)
Chlorofluorocarbons are very harmful to the environment when released into the atmosphere. They damage the ozone layer and therefore allow more UV rays from sunlight to reach the earth’s surface. They also have a greenhouse effect causing the earth’s atmosphere to warm up. This ultimately leads to global warming and climate change.
(3)
It would allow storm systems to stall in an area
Jets streams are very significant in that they influence weather patterns across the world. They are responsible for the movement of pressure systems and global air cells and their accompanying weather patterns. Because they generally sit in between cold and warm air systems they are significant in moving these air masses around. When they are weak they cause an air system to linger including storms causing excessive flooding in an area.
(4)
Absorb and re-emit infrared radiation.
Produced by human activity
Greenhouse gases do not allow infrared radiation from the earth's surface to escape back to space. Infrared is the electromagnetic wave spectrum responsible for transferring heat energy. Therefore, when left to linger in the atmosphere, they cause the greenhouse effect. This is the reason for global warming.
(5)
Air temperature –, ice
Ocean temperature – ice, a chemical isotope of <em>foraminifera</em>
Carbon dioxide levels – a chemical isotope of <em>foraminifera</em>
Kind of plants – fossilized pollen grains
Rainfall- the rings
Answer:
D. They have the same number of protons as electrons.
Explanation:
Protons are found in the nucleus of the atom and have a positive charge while electrons orbit around the nucleus and have a negative charge. Usually, in a neutral atom of an element, the number of protons is equal to the number of electrons. This is why the atom has no charge because the positive and negative charges cancel out. When an atom loses an electron its charge turns positive while when it gains an electron its charge turns negative.
Answer: 10.62g
Explanation:
First let us generate a balanced equation for the reaction.
HCl + NaOH —> NaCl + H2O
Molar Mass of HCl= 1 + 35.5 = 36.5g/mol
Molar Mass of NaOH = 23 + 16 + 1 = 40g/mol
From the question,
Mass of HCl = 17g
Mass of NaOH = 6.99g
Converting these Masses to mole, we obtain:
n = Mass / Molar Mass
n of HCl = 17/36.5 = 0.4658mol
n of NaOH = 6.99/40 = 0.1748mol
From the question,
1 mole of NaOH requires 1mole of HCl.
Therefore, 0.1748mol of NaOH will also require 0.1748mol of HCl.
But we were told that 17g( i.e 0.4658mol) of HCl were mixed.
Therefore, the unreacted amount of HCl = 0.4658 — 0.1748 = 0.291mol
Converting this to mass, we have:
Mass of HCl = n x molar Mass
Mass of HCl = 0.291 x 36.5
Mass of HCl = 10.62g
Therefore the left over Mass of HCl is 10.62g
