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blsea [12.9K]
3 years ago
6

Sam wished to investigate how fertilizer run-off affects the growth of algae in freshwater lakes and streams. He set his experim

ent up in this way. He placed
900 ml of water into each of five 1000 ml glass beakers. To each beaker he added 5 ml of water from an aquarium which contained a large concentration of
algae. The beakers were placed under a grow light which was timed to provide 12 hours of light each day. Liquid fertilizer was added to the beakers in the
following amounts: Beaker A-8 mi fertilizer, Beaker B - 6 ml fertilizer, Beaker C - 4 ml fertilizer, Beaker D-2 mi fertilizer, and Beaker E - no fertilizer. Each
week a random sample from each of the beakers was examined under a microscope to get a count of the number of algal cells present.
What is the independent variable in this experiment?
O hours of daylight
O amount of water
O amount of fertilizer
O number of algal cells
Chemistry
1 answer:
MrMuchimi3 years ago
8 0

Answer:

amount of fertaliser--> the independant variable is the one being changed

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What challenges would you encounter with the titration if you had used apple cider vinegar or balsamic vinegar as the analyte in
Vika [28.1K]

Explanation:

Apple cider vinegar or balsamic vinegar might contain various synthetics which might  interact with or nullified the findings, whereas white vinegar comprises of acidic acid only. In fact, apple cider vinegar and balsamic vinegar are deep in appearance this would make it very difficult to determine the color. This is why it is preferable to use white vinegar in the Titration process.

3 0
3 years ago
If 12.5 grams of the original sample of cesium-137 remained after 90.6 years, what was the mass of the original sample?
myrzilka [38]

Answer:

Mass of original sample = 100 g

Explanation:

Half life of cesium-137 = 30.17 years

t_{1/2}=\frac {ln\ 2}{k}

Where, k is rate constant

So,  

k=\frac{\ln2}{t_{1/2}}

k=\frac{\ln2}{30.17}\ year^{-1}

The rate constant, k = 0.02297 year⁻¹

Time = 90.6 years

Using integrated rate law for first order kinetics as:

[A_t]=[A_0]e^{-kt}

Where,  

[A_t] is the concentration at time t

[A_0] is the initial concentration

Initial concentration [A_0] = ?

Final concentration [A_t] = 12.5 grams

Applying in the above equation, we get that:-

12.5\ g=[A_0]e^{-0.02297\times 90.6}

[A_0]=\frac{12.5}{e^{-0.02297\times 90.6}}\ g=100\ g

<u>Mass of original sample = 100 g</u>

8 0
3 years ago
Term that means to break down
astraxan [27]

Answer:

decompose

Explanation:

3 0
3 years ago
Help!!!!! Which of the following is a characteristic of reliable scientific study
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3 years ago
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How are journals helpful to scientists
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They help keep track of notes and experaments
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