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algol [13]
3 years ago
15

When looking at the percentage of patients whose symptoms were relieved after taking a placebo, a scientist sees a 20% success r

ate. The success rate of patients whose symptoms were relieved after taking a new composite drug was 30%. The scientist determines that the margin of error is 10%, which indicates that the new drug had no statistically significant positive effect. In which stage of the engineering process is this scientist?
A. Evaluating test results
B. Screening
C. Identifying a need
D. Looking for future improvements
Chemistry
1 answer:
9966 [12]3 years ago
6 0
A. Evaluating test results is your answer. Let me know if this is correct!
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What unknown quantity can be calculated after performing a titration? a. volume c. mass b. concentration d. density
sertanlavr [38]
C & B are switched so I'm not sure if that was a typo or not, but the answer is concentration!
3 0
3 years ago
Which option is an example of physical change?
Murljashka [212]

Answer:

They are all physical exept c

Explanation:

8 0
3 years ago
Read 2 more answers
Suppose you need to prepare 141.9 mL of a 0.223 M aqueous solution of NaCl. What mass of NaCl do you need to use to make the sol
Afina-wow [57]

Answer:

1.811 g

Explanation:

The computation of the mass need to use to make the solution is shown below:

We know that molarity is

Molarity = \frac{Number\ of\ moles}{Volume\ in\ L}

So,

Number\ of\ moles = Molarity\ \times Volume\ in\ L

= 0.223\times 0.141

= 0.031 moles

Now

Mass = moles \times Molecualr\ weight

where,

The Molecular weight of NaCl is 58.44 g/mole

And, the moles are  0.031 moles

So, the mass of NaCL is

= 0.031 \times 58.44

= 1.811 g

We simply applied the above formulas

3 0
3 years ago
Sulfur and oxygen react to produce sulfur trioxide. In a particular experiment, 7.9 grams of SO3 are produced by the reaction of
galina1969 [7]

Answer:

\%\, yield\, \, SO_3=82.29

Explanation:

First write the balance eqation of chemical reaction:

2S(s) +3O_2(g) \rightarrow 2SO_3(g)

Remember writing any chemical reaction from its  elemetal form then write the elements in their natural form i.e. how that element exists in the nature here sulphur exists in solid monoatomic form in the nature and oxygen in gaseous diatomic form.

mass of oxygen given=5gram

mole of oxygen=5/32mol=0.16mol

mass of sulpher given=6gram

mole of sulpher=6/32mol=0.19mol

from the above balanced equaion;

2 mole of sulphur reacts with 3 mole Oxygen completely

1 mole of sulphur reacts with 1.5 mole Oxygen completely

0.19 mole of sulphur reacts with 1.5\times 0.19 i.e. 0.285 mole Oxygen completely.

but we have 0.16 mole so oxygen will be the limiting reagent and sulpher will be the excess reagent

so product will depend on the limiting reagent

from the balance equation

3 mole of sulpher gives 2 mole SO_3

1 mole of sulpher will give 2/3 mole SO_3

0.16 of sulpher will give 0.12 mole SO_3

mass of SO_3=9.6gram this is theoreical production of SO_3

and

actual production of SO_3 =7.9gram

\%\, yield   \,\, SO_3=\frac{Actual \,yield}{theoretical\, yield}\times 100

\%\, yield\, \, SO_3=\frac{7.9}{9.6} \times 100=82.29

\%\, yield\, \, SO_3=82.29

3 0
3 years ago
a. Order the following liquids in order from least dense to most dense: Dish Soap, Rubbing Alcohol, Milk, Corn Syrup.
Anettt [7]

dish Soap,Corn Syrup,Rubbing Alcohol, Milk,

7 0
2 years ago
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