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kirza4 [7]
3 years ago
13

If scientists want to determine if a skin cream is effective against fighting acne, what would be the independent variable?

Chemistry
1 answer:
lina2011 [118]3 years ago
6 0

Answer:skin cream

Explanation:

the independent variable is the variable that is always changed or manipulated. in this case the skin cream is the independent variable.

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Explain why molecules of water were attracted to the negatively charged plastic tube while molecules of cyclohexane were not. Dr
mihalych1998 [28]

Answer:

See attached

Explanation:

Structural geometry is the key to understanding particle-particle interactions on a physical levels. Suggest a review of molecular geometry and states of matter for a more in depth understanding. Doc                                                

5 0
3 years ago
Why is it so important in an ideal simple experiment to change only one variable from trial to trial?
RideAnS [48]
Because if you change two things then you do not know which one has affected or altered the dependent variable.  if you only change one then you know what exactly changed and why
3 0
3 years ago
An organic compound is 61.5% C, 2.56% H and 35.9% N by mass. 2.00 grams of this gas is entered into a 300.0 mL flask and heated
pashok25 [27]

Answer:

C₄H₂N₂

Explanation:

First we<u> calculate the moles of the gas</u>, using PV=nRT:

P = 2670 torr ⇒ 2670/760 = 3.51 atm

V = 300 mL ⇒ 300/1000 = 0.3 L

T = 228 °C ⇒ 228 + 273.16 = 501.16 K

  • 3.51 atm * 0.3 L = n * 0.082atm·L·mol⁻¹·K⁻¹ * 501.16 K
  • n = 0.0256 mol

Now we<u> calculate the molar mass of the compound</u>:

  • 2.00 g / 0.0256 mol = 78 g/mol

Finally we use the percentages given to<em> </em><u>calculate the empirical formula</u>:

  • C ⇒ 78 g/mol * 61.5/100 ÷ 12g/mol = 4
  • H ⇒ 78 g/mol * 2.56/100 ÷ 1g/mol = 2
  • N ⇒ 78 g/mol * 35.9/100 ÷ 14g/mol = 2

So the empirical formula is C₄H₂N₂

6 0
3 years ago
Helpppppppppppppppppppppppppppppppppp
Alborosie

Answer:

the drops of liquid are coming from the decreases. they are formed as the motion of the water particles in the air gas. this change in motion cause air in the air to change from a liquid to a water

5 0
3 years ago
Read 2 more answers
What is the volume of a balloon of gas at 842 mm Hg and -23° C, if its volume is 915 mL at a pressure of 1,170 mm Hg and a tempe
garik1379 [7]
Answer:
             V₂  =  1070 mL or 1.07 L

Solution:

Data Given;
                  P₁  =  1170 mmHg

                  V₁  =  915 mL

                  T₁  =  24 °C  +  273 K  =  297 K

                  P₂  =  842 mmHg

                  V₂  =  ?

                  T₂  =  - 23 °C  +  273 K  =  250 K

According to Ideal gas equation,

                       P₁ V₁ / T₁  =  P₂ V₂ / T₂

Solving for V₂,

                       V₂  =  P₁ V₁ T₂ / P₂ T₁

Putting Values,

                       V₂  = (1170 mmHg × 915 mL × 250 K) ÷ (842 mmHg × 297 K)

                       V₂  =  1070 mL or 1.07 L
5 0
3 years ago
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