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3 years ago

Explain how cells can only come from pre-existing cells. How does that work ?

Chemistry

1 answer:

AysviL [449]3 years ago

4 0

Answer:

Cells can only be formed by division of pre-existing cells. [Students should be aware that the 64 codons in the genetic code have the same meanings in nearly all organisms, but that there are some minor variations that are likely to have accrued since the common origin of life on Earth

Explanation:

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You are managing a city that needs to upgrade its disinfection basin at your 40 MGD surface water drinking water treatment plant

nignag [31]

Solution :

According to Chick's law

$\frac{N_t}{N_0}=e^{-k'C^n t}$

where, t = contact time

c = concentration of disinfectant

k' = lethality coefficient = 4.71

n = dilution coefficient = 1

4 log removal = % removal = 99.99

$\frac{N_t}{N_0}=\frac{\text{bacteria remaining}}{\text{bacteria initailly present}}$

= 1 - R

= 1 - 0.9999

Now for plug flow reactor contact time,

$\tau =\frac{V}{Q} =\frac{75000}{40 \times 10^6}$

= 0.01875 days

= 27 minutes

For CSTR, $\tau =\frac{V}{Q} =\frac{150000}{40 \times 10^6}$

$=3.75 \times 10^{-3}$ days

= 5.4 minute

There are 3 reactors, hence total contact time = 3 x 5.4

= 16.2 minute

Or $\frac{N_t}{N_0}=e^{-k'C^n t}$

or $(1-0.9999)=e^{-4.71 \times C \times t}$

∴ C x t = 1.955

For PFR, $t_1 = 27$ min

∴ C $=\frac{1.955}{27}$ = 0.072 mg/L

For CSIR, $t_2=16.2$ min

$C=\frac{1.955}{16.2} = 0.1206$ mg/L

∴ Chlorine required for PFR in kg/day

$=\frac{0.072 \times 40 \times 10^6 \times 3.785}{10^6}$ (1 gallon = 3.785 L)

= 18.25 kg/day

Therefore we should go for PFR system.

3 0

3 years ago

Help this is so confusing like

melamori03 [73]

zoom in a bit more thanks

5 0

3 years ago

Read 2 more answers

SOLVE FAST....⚡⚡⚡

Rina8888 [55]

Answer:

thanks for the points

Explanation:

have a nice day

6 0

3 years ago

If eggs are so fragile, how do they actually protect the growing bird?

Step2247 [10]

Although birds' eggs appear to be fragile, they are in fact extremely robust. The oval shape applies the same rules of engineering as an arched bridge; the convex surface can withstand considerable pressure without breaking.

6 0

3 years ago

Think about your morning from when you wake up until you arrive at school. Describe the forms of energy you encounter or use dur

denis-greek [22]

Answer:

When sleeping the energy exhibited is Potential energy. When I wake up and I’m preparing for the day I use kinetic energy which is the energy exhibited during motion.

Eating before leaving the house means I used chemical energy for replenishment of nutrients to aid the performance of more activities for the day. The food eaten and the physical activities also give rise to thermal energy which is why we sweat.

3 0

3 years ago