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3 years ago

6

A student is testing water to know which is best for cleansing purposes with soaps. He would find that the cleansing action of s

oaps is best when he uses water obtained from
A. Rain
B. Tap
C. Hand pump
D. Pond

1 answer:

8_murik_8 [283]3 years ago

6 0

The answer is rain water because it is distilled and distilled water is best for this process

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What is the first way in which biology researchers present the results of their latest research?

antoniya [11.8K]

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3 years ago

How many grams of CO₂ can be produced from the combustion of 2.76 moles of butane according to this equation: 2 C₄H₁₀(g) + 13 O₂

Vilka [71]

Answer:

485.76 g of CO₂ can be made by this combustion

Explanation:

Combustion reaction:

2 C₄H₁₀(g) + 13 O₂ (g) → 8 CO₂ (g) + 10 H₂O (g)

If we only have the amount of butane, we assume the oxygen is the excess reagent.

Ratio is 2:8. Let's make a rule of three:

2 moles of butane can produce 8 moles of dioxide

Therefore, 2.76 moles of butane must produce (2.76 . 8)/ 2 = 11.04 moles of CO₂

We convert the moles to mass → 11.04 mol . 44g / 1 mol = 485.76 g

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3 years ago

Water boils at 100°C at sea level. If the water in this experiment did not boil at 100°C, what could be the reason?

RSB [31]

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While heating two different samples, of
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3 years ago

4. What are the characteristics of<br> the particles of matter?

mojhsa [17]

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3 years ago

Epinephrine (adrenaline) is a hormone secreted into the bloodstream in times of stress. It contains 59.0% C, 7.15% H, 26.20% O,

vichka [17]

Answer:

C9H13O3N

Explanation:

Take the atomic mass of C=12.0, H=1.0, O=16.0 and N=14.0.

We can draw a chart (please view this on desktop so to avoid spacing errors):

Let the mass of Epinephrine be 100g.

C H O N

mass(g) : 59 7.15 26.2 7.65

no. of moles : 59/12 =4.9167 7.15/1 = 7.15 26.2/16=1.6375 7.65/14=0.5464

(n.o.m. = mass/molar mass)

Ratio: 4.9167/0.5464 =9 7.15/0.5464=13 1.6375= 3 0.5464/0.5464 =1

(divide the n.o.m. by the smallest n.o.m., which is 0.5464 in this case, take the whole numbers)

So, the empirical formula will be: C9H13O3N

But this is still not yet the molecular formula. We have to ensure the molar mass is 183g/mol. Multiply the empirical formula by n.

So, let the molecular formula of Epinephrine be (C9H13O3N)n.

12x9n + 1x13n + 16x3n + 14n = 183

108n + 13n + 48n + 14n = 183

183 n = 183.

n = 1

Hence, the molecular formula is C9H13O3N.

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3 years ago