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lakkis [162]
3 years ago
9

Students in Ms. Winters' class were interested in testing the antibacterial strength of hand soap versus hand sanitizer. The stu

dents planned to wash their hands using the sanitizer or soap and warm water for two minutes, then dry their hands with a paper towel. The standard of comparison would be rubbing their hands vigorously for 2 minutes in warm water, without any soap or sanitizer, and then drying with a paper towel. The sanitizer advertisement claimed to kill bacteria more effectively than any soap. After washing, hands would be swabbed and then the swab applied to a culture plate and incubated. Finally, the bacterial cultures would be counted.
What would be an appropriate research question to guide this scientific investigation?
A) What method kills bacteria?
B) Under what conditions does bacteria grow best?
C) Is hand sanitizer more effective in killing bacteria than hand soap?
D) How does using hand sanitizer to kill bacteria compare to using just warm water?
Chemistry
2 answers:
Serhud [2]3 years ago
4 0
I would say <span>C) Is hand sanitizer more effective in killing bacteria than hand soap </span>
KatRina [158]3 years ago
3 0
My answer is a please tell me if I helped
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Need help ASAP... (Question from 'Observing the Bunsen Burner'). "The match head is supposed to stay unlit. What does this tell
Solnce55 [7]

Answer:

It is too hot.

Explanation:

7 0
2 years ago
What expression approximates the volume of O2 consumed, measure at STP, when 55 g of Al reacts completely with excess O2?2 Al(s)
Genrish500 [490]

Answer:

34.28 L ( 1.5*22.4 L)

Explanation:

Calculation of the moles of aluminum as:-

Mass = 55 g

Molar mass of aluminum = 26.981539 g/mol

The formula for the calculation of moles is shown below:

moles = \frac{Mass\ taken}{Molar\ mass}

Thus,

Moles= \frac{55\ g}{26.981539\ g/mol}

Moles= 2.0384\ mol

According to the reaction:-

4Al+3O_2\rightarrow 2Al_2O_3

4 moles of aluminum react with 3 moles of oxygen gas

1 mole of aluminum react with \frac{3}{4} moles of oxygen gas

2.0384 moles of aluminum react with \frac{3}{4}\times 2.0384 moles of oxygen gas

Moles of oxygen gas = 1.5288 moles

At STP,  

Pressure = 1 atm  

Temperature = 273.15 K

Using ideal gas equation as:

PV=nRT

where,

P is the pressure

V is the volume

n is the number of moles

T is the temperature

R is Gas constant having value = 0.0821 L.atm/K.mol

Applying the equation as:

1 atm × V = 1.5288 mol × 0.0821 L.atm/K.mol × 273.15 K

⇒V = 34.28 L ( 1.5*22.4 L)

7 0
3 years ago
Calculate average kinetic energy of one mole of gas at 517K
Gekata [30.6K]

In an ideal gas, there are no attractive forces between the gas molecules, and there is no rotation or vibration within the molecules. The kinetic energy of the translational motion of an ideal gas depends on its temperature. The formula for the kinetic energy of a gas defines the average kinetic energy per molecule. The kinetic energy is measured in Joules (J), and the temperature is measured in Kelvin (K).

K = average kinetic energy per molecule of gas (J)

kB = Boltzmann's constant ()

T = temperature (k)

Kinetic Energy of Gas Formula Questions:

1) Standard Temperature is defined to be . What is the average translational kinetic energy of a single molecule of an ideal gas at Standard Temperature?

Answer: The average translational kinetic energy of a molecule of an ideal gas can be found using the formula:

The average translational kinetic energy of a single molecule of an ideal gas is  (Joules).

2) One mole (mol) of any substance consists of  molecules (Avogadro's number). What is the translational kinetic energy of  of an ideal gas at ?

Answer: The translational kinetic energy of  of an ideal gas can be found by multiplying the formula for the average translational kinetic energy by the number of molecules in the sample. The number of molecules is  times Avogadro's number:

7 0
3 years ago
EDTA EDTA is a hexaprotic system with the p K a pKa values: p K a1 = 0.00 pKa1=0.00 , p K a2 = 1.50 pKa2=1.50 , p K a3 = 2.00 pK
mihalych1998 [28]

Answer:

Check the explanation

Explanation:

When,

pH = -log[H+] = 3.30

[H+] = 5.0 X 10^{-4} M

Ka1 = 1 ; Ka2 = 0.0316 ; Ka3 = 0.01 ; Ka4 = 0.002 ; Ka5 = 7.4 X 10^{-7} ; Ka6 = 4.3 X 10^{-11}

alpha[Y^-4] = [H+]^6 + Ka1[H+]^5 + Ka1Ka2[H+]^4 + Ka1Ka2Ka3[H+]^3 + Ka1Ka2Ka3Ka4[H+]^2 + Ka1Ka2Ka3Ka4Ka5[H+] + Ka1Ka2Ka3Ka4Ka5Ka6

= 1.56 X 10^{-20} + 3.12 X 10^{-17} + 2 X 10^{-15} + 4 X 10^{-14} + 1.6 X 10^{-13} + 2.34 X 10^{-16} + 2 X 10^{-23}

= 2.02 X 10^{-13}

When,

pH = -log[H+] = 10.15

[H+] = 7.08 X 10^{-11} M

Ka1 = 1 ; Ka2 = 0.0316 ; Ka3 = 0.01 ; Ka4 = 0.002 ; Ka5 = 7.4 X 10^{-7} ; Ka6 = 4.3 X 10^-11

alpha[Y^{-4}] = [H+]^6 + Ka1[H+]^5 + Ka1Ka2[H+]^4 + Ka1Ka2Ka3[H+]^3 + Ka1Ka2Ka3Ka4[H+]^2 + Ka1Ka2Ka3Ka4Ka5[H+] + Ka1Ka2Ka3Ka4Ka5Ka6

= 1.26 X 10^{-61} + 1.8 X 10^{-51} + 8.1 X 10^{-43} + 1.12 X 10^{-34} + 3.17 X 10^{-27} + 3.3 X 10^{-23} + 1.83 X 10^{-23}

= 5.12 X 10^{-23}

4 0
3 years ago
Do you round when dividing significant figures
Tatiana [17]

Answer: You multiply and divide when rounding division significant figures

Explanation: Both multiplying and dividing significant figures have the same rule. That rule is, the FINAL ANSWER of a multiplication and division problem should be rounded to the number of significant figures that is the least amount of any figures used in the multiplication or division. Let us demonstrate below.

4 0
3 years ago
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