1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
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

You might be interested in
Is mixing baking soda and vegetable oil a chemical change or physical change and WHY? PLEASE HELP
skelet666 [1.2K]
It’s a chemical change
3 0
2 years ago
Read 2 more answers
When ash, cinders, and bombs build up in a steep pile around a volcano’s vent, the result is a
Verdich [7]
Im pretty sure a cinder-cone volcano 
8 0
2 years ago
One gram of liquid benzene is burned in a bomb calorimeter. The temperature before ignition was 20.826 C, and the temperature af
Licemer1 [7]

Answer:

fH = - 3,255.7 kJ/mol

Explanation:

Because the bomb calorimeter is adiabatic (q =0), there'is no heat inside or outside it, so the heat flow from the combustion plus the heat flow of the system (bomb, water, and the contents) must be 0.

Qsystem + Qcombustion = 0

Qsystem = heat capacity*ΔT

10000*(25.000 - 20.826) + Qc = 0

Qcombustion = - 41,740 J = - 41.74 kJ

So, the enthaply of formation of benzene (fH) at 298.15 K (25.000 ºC) is the heat of the combustion, divided by the number of moles of it. The molar mass od benzene is: 6x12 g/mol of C + 6x1 g/mol of H = 78 g/mol, and:

n = mass/molar mass = 1/ 78

n = 0.01282 mol

fH = -41.74/0.01282

fH = - 3,255.7 kJ/mol

4 0
3 years ago
Three mixtures were prepared from three very narrow molar mass distribution polystyrene samples with molar masses of 10,000, 30,
8_murik_8 [283]

Answer:

(a). 46,666.7 g/mol; 78,571.4 g/mol

(b). 86950g/mol; 46,666.7 g/mol.

(c). 86950g/mol; 43,333.33 g/mol

Explanation:

So, we are given the molar masses for the three samples as: 10,000, 30,000 and 100,000 g mol−1.

Thus, the equal number of molecule in each sample = ( 10,000 + 30,000 + 100,000 ) / 3 = 46,666.7 g/mol.

The average molar mass = [ ( 10,000)^2 + (30,000)^2 + 100,000)^2] ÷ 10,000 + 30,000 + 100,000 = 78,571. 4 g/mol.

(b). The equal masses of each sample = 3/[ ( 1/ 10,000) + (1/30,000 ) + (1/100,000) ] = 20930.23 g/mol.

Average molar mass = ( 10,000 + 30,000 + 100,000 ) / 3 = 46,666.7 g/mol.

(c). Equal masses of the two samples = (0.145 × 10,000) + (0.855 × 100,000)/ 0.145 + 0.855 = 86950g/mol.

The weight average molar mass = 1.7 + 10,000 + 100,000/ 1.7 + 1 = 43,333.33 g/mol.

6 0
3 years ago
A sample of helium gas occupies a volume of 152.0 mL at a pressure of 717.0 mm Hg and a temperature of 315.0 K. What will the vo
kozerog [31]

Answer:

0.581 L  or  581 mL

Explanation:

As stated in the question, the combined gas law is (P1*V1/T1) = (P2*V2/T2)

Write down the amounts you are given.

V1 = 0.152 L (I was taught to always convert milliliters to liters)

P1 = 717 mmHg

T1 = 315 K

V2 = ?

P2 = 463 mmHg

T2 = 777 K

The variable that is being solved for is final volume. Fill in the combined gas law equation with the corresponding amounts and solve for V2.

(717 mmHg*0.152 L) / (315 K) = (463 mmHg*V2) / (777 K)

0.346 = (463*V2) / (777)

0.346*777 = (463*V2) / (777)*777

268.842 = 463*V2

268.842/463 = (463*V2)/463

V2 = 0.581

Pressure and volume are indirectly proportional. This checks out because the volume increased while pressure decreased. Volume and temperature are directly proportional. This checks out because both volume and temperature increased. This is a good way to check your answers. You can also solve each side of the combined gas law equation to see if they are both the same.

6 0
2 years ago
Other questions:
  • In the energy pyramid, if a primary producer is consumed by a first-level consumer, and that first-level consumer is consumed by
    6·1 answer
  • Which of the following is the best definition of nodes?
    5·2 answers
  • Hcl and 1-isopropylcyclohexane formation
    13·2 answers
  • The electronegative of phosphorus is
    11·2 answers
  • Which expression has a value of 10
    8·1 answer
  • Silver has a density of 10.5 g/cm³, and gold has a density of 19.3 g/cm³. Which would have a greater mass, 5 cm³ of silver or 5
    13·1 answer
  • Name 3 ores for metals and which metal they yield?​
    7·1 answer
  • Could you help answer these two question
    15·1 answer
  • How will the reaction rate of the SN1 reaction change if the electrophile is switched from the tertiary electrophile to a second
    8·1 answer
  • If another hydrogen of c2h5cl is replaced by a chlorine atom to yield c2h4cl2, how many isomers would result?
    11·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!