Answer:
The cell membrane is the outer layer of the cell. The primary function of the cell membrane is to regulate what substances enter and leave the cell. The cell membrane is selectively permeable, or "semi-permeable", meaning that the membrane only allows certain substances to enter or leave the cell.
Explanation:
already had this question and this is the correct answer
The correct answer to this question is this one:
find the energy of one photon:
<span>E=h*<span>c/λ
</span></span>
divide the energy given by the energy of one photon of that wavelength
What I've done so far is convert wave length to m and energy to j.
E photon = h * x / wave length
E = (6.626 x 10^-43)(3.00 x 10^8) / 587 ^ -9 = 3.38 x 10 ^18 J
3.38 x 10 ^18 J x 1000 kj / 1 j = 3.37 x 10 ^ 16 Kj
609 kJ/ 3.37 x 10 ^ 16 Kj = 1.81 x 10 ^ 16
E = (6.626 x 10^-34)(3.00 x 10^8) / 587 ^ -9 = 3.38 x 10 ^19 J
3.38 x 10 ^19 J x 1000 kj / 1 j = 3.37 x 10 ^ -16 Kj
609 kJ/ 3.37 x 10 ^ 16 Kj = 1.81 x 10 ^ 18 but the answer is 1.81 × 10^24 photons
3.38 x 10 ^-19 J
should be negative
then 3.38 x 10 ^18 J x 1kJ/1000 J
you're converting from J to kJ.. just like meters to kilometres, you wouldn't multiply you would divide
B) Physical. No matter how much of something there is, it is still considered that thing. They still have the same physical properties, just in a higher proportion. A larger amount of something would make it react differently to different catalysts, as well as chemically.
Answer:
B. Better ways to recycle plastics
Explanation:
A chemist might choose to study better ways to recycle plastics because there may be certain types of chemicals that can disintegrate the plastic..
Answer:
Volume of the sulfuric acid (25cm³), same mass of each metal (1g)
Explanation:
In an experiment, the CONTROL VARIABLE also known as constant is the variable that is kept unchanged for all groups in an experiment. This is done in order not to influence the outcome of the experiment.
In this case, students are trying to investigate the reactivity of four different metals. They added 1 g of each metal to 25cm³ of sulfuric acid and recorded the temperature change. Based on the explanation of control variable above, the VOLUME OF SULFURIC ACID (25cm³) and the MASS OF EACH METAL (1g) are the CONTROL VARIABLES because they are the same or unchanged in this experiment.
