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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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Which contains the greatest mass of oxygen: 0.75 moles of ethanol ( C2H5OH ), 0.60 mole of formic acid ( HCO2H ), or 1.0 mole of
Luda [366]

Answer:

In conclussion, 0.60 moles of HCOOH contains the greatest mass of O

Explanation:

Let's make some rules of three, to solve this problem:

1 mol of ethanol has 2 moles of C, 6 moles of H, and 1 mol of oxygen

Therefore, 0.75 moles of ethanol must have 0.75 mol of oyxgen

Let's convert the moles to mass → 0.75 mol . 16 g/ 1 mol = 12 g

1 mol of formic acid has 2 moles of H, 1 mol of C and 2 mol of oxygen

0.60 moles of formic acid must have  (0.6 .2) / 1 = 1.2 mol of O

If we convert the amount to mass → 1.2 mol . 16 g/ 1mol = 19.2 g

1 mol of water has 1 mol of oyxgen

Therefore, we have 1 mol of oxygen with a mass of 16 g.

In conclussion, 0.60 moles of HCOOH contains the greatest mass of O

7 0
3 years ago
Read 2 more answers
Question 1
Salsk061 [2.6K]

Answer:

Part A:

"360 grams of NaCl can be dissolved in 1 L water. So, 2000 grams sugar can be dissolved in 1 L water then we can say that the solubility of salt is lesser in water as to sugar and both heightened by increasing the temperature. If we make a batch of 800 L we can add sugar, 1600 kg at 25 0c. We can add salt is 288 kg at 25 0c and the ingredient tomato is having low solubility."

Read more at Answer.Ya.Guru – https://answer.ya.guru/questions/8061-describe-the-sequence-of-adding-ingredients-to-make-the-recipe.html

Part B:

'Manufacturers can generate new value minimize cost and increase operational stability by focusing on 4 broad areas; Management, Supply Circle, Product Design, and Value Recovery.'

Read more at Answer.Ya.Guru – https://answer.ya.guru/questions/2807911-what-changes-could-be-made-to-optimize-the-manufacturing-process.html

4 0
3 years ago
Why there are only seven crystal systems??? why not other number
Anastasy [175]
<span>In crystallography, the terms crystal system, crystal family, and lattice system each refer to one ... In total there are seven crystal systems: triclinic, monoclinic, orthorhombic, ..... A polar crystal possess a "unique" axis (found in no other directions) such ... lattices in three dimensions; each can apply in one lattice system only.</span><span>
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6 0
3 years ago
A 10.0 mL sample of 0.25 M NaOH(aq) is titrated with 0.10 M HCl(aq) (adding HCl to NaOH). Determine which region on the titratio
Anna11 [10]

Answer:

1) After adding 15.0 mL of the HCl solution, the mixture is before the equivalence point on the titration curve.

2) The pH of the solution after adding HCl is 12.6

Explanation:

10.0 mL of 0.25 M NaOH(aq) react with 15.0 mL of 0.10 M HCl(aq). Let's calculate the moles of each reactant.

nNaOH=\frac{0.25mol}{L} .10.0 \times 10^{-3} L=2.5 \times 10^{-3}mol

nHCl=\frac{0.10mol}{L} \times 15.0 \times 10^{-3} L=1.5 \times 10^{-3}mol

There is an excess of NaOH so the mixture is before the equivalence point. When HCl completely reacts, we can calculate the moles in excess of NaOH.

                    NaOH       +       HCl       ⇒       NaCl      +         H₂O

Initial          2.5 × 10⁻³         1.5 × 10⁻³               0                      0

Reaction    -1.5 × 10⁻³        -1.5 × 10⁻³          1.5 × 10⁻³          1.5 × 10⁻³

Final            1.0 × 10⁻³               0                 1.5 × 10⁻³          1.5 × 10⁻³

The concentration of NaOH is:

[NaOH]=\frac{1.0 \times 10^{-3} mol }{25.0 \times 10^{-3} L} =0.040M

NaOH is a strong base so [OH⁻] = [NaOH].

Finally, we can calculate pOH and pH.

pOH = -log [OH⁻] = -log 0.040 = 1.4

pH = 14 - pOH = 14 - 1.4 = 12.6

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3 years ago
80. Calculate AHıxn for the reaction:<br><br> CaO(s) + CO2(g) → CaCO3().
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6 0
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