A scientist wants to test the effectiveness of a medicine in treating
headaches. He puts the medicine into cookies and then tells his subjects to
lie down and have a cookie when they have a headache. He asks them to give
him feedback about how well these relaxation techniques work to cure their
headaches. What rule of ethics does this experiment break?
O A. The subjects are not informed that they are taking a medicine.
B. It is likely to harm his subjects.
C. The scientist is taking the work of others by reviewing the
subjects' feedback.
D. It is testing more than one variable at the same time.
Calculate the percentage composition of SrBr2
Answer:
64.6% of Br and 35.4% of Sr
Explanation:
The percentage composition is obtained defining the percentage in mass of each atom in a molecule.
To solve this question we must find the mass of each atom in 1 mole:
Molar mass Br: 79.904g/mol
Molar mass Sr: 87.62g/mol
The molar mass of SrBr2 is:
79.904g/mol*2 + 87.62g/mol =
159.808g/mol + 87.62g/mol =
247.428g/mol
The percentage of Br is:
79.904g/mol*2 = 159.808g/mol / 247.428g/mol * 100
= 64.6% of Br
And percentage of Sr is:
87.62g/mol / 247.428g/mol * 100
= 35.4% of Sr
Will mark brainliest!!!
Can someone please help me with this???
Calculate the pH at the equivalence point for titrating 0.200 M solution of benzoic acid with 0.060 M NaOH. Ka for benzoic acid is 6.3 x10^-5
Answer:
[tex]pH=8.43[/tex]
Explanation:
Hello there!
In this case, since the reaction between benzoic acid and sodium hydroxide is carried out in a 1:1 mole ratio, it is possible to calculate the moles of sodium benzoate salt that are produced due to the neutralization as show below:
[tex]n_{salt}=0.2mol/L*1L=0.2mol[/tex]
We can assume that the volume of benzoic acid is 1 L and therefore the used volume of NaOH is:
[tex]V_{NaOH}=\frac{0.200M*1L}{0.060M}=3.33L[/tex]
Which means that the total final volume is 4.33 L and the concentration of the resulting basic salt is:
[tex][salt]=\frac{0.2mol}{4.33L}=0.046M[/tex]
Next, since the salt is C6H5COONa, we can see it is ionized in Na+ cations and C6H5COO- anions, but just the latter is able to react with the water in the solution in order to undergo the following reaction:
[tex]C_6H_5COO^-+H_2O\rightleftharpoons C_6H_5COOH+OH^-[/tex]
Whose equilibrium expression, it terms of Kb, due to the release of OH- ions, is:
[tex]Kb=\frac{[C6H5COOH][OH^-]}{[C6H5COO^-]}[/tex]
And can be written in terms of x, Kw and Ka:
[tex]\frac{Kw}{Ka} =\frac{x*x}{0.046M-x} \\\\\frac{1x10^{-14}}{6.3x10^{-5}}=1.59x10^{-10}= \frac{x^2}{0.046M-x}[/tex]
And because Kb<<<<<1 we can neglect the x on the bottom to get:
[tex]1.59x10^{-10}= \frac{x^2}{0.046M}[/tex]
Whereas x is computed as follows:
[tex]x=\sqrt{1.59x10^{-10}*{0.046M} =2.7x10^{-6}M[/tex]
Which is actually equal to the concentration of OH- ions so that we can calculate the pOH prior to the pH:
[tex]pOH=-log(2.7x10^{-6})=5.57[/tex]
And therefore the pH as shown below:
[tex]pH=14-5.57\\\\pH=8.43[/tex]
Which makes sense since this sodium benzoate is a basic salt.
Regards!
Explain how the iron pipes change into rust?
3C6H206
How many atoms are there? Help ASAP!
Answer:
the answer to this is 74 :)
Describe what is wrong with this sentence:
"When you kick a soccer ball, you create new
kinetic energy!"
Answer:
You transfer kinetic energy from you foot to the ball.
Explanation:
Energy cannot be created or destroyed.
Answer:
hi..,......
.....hsjnsgzgkskshbs
Many different parts of the brain work together to encode, store, and retrieve information as needed. The diagram below indicates three parts of the human brain that are involved in information storage.
Image courtesy of FDA
Which of these terms best describes the process by which the brain stores information that can be retrieved at a later time?
A.
memory
B.
stimulation
C.
nerve specialization
D.
sensory reception
Please help me
Answer:
Are memories stored in just one part of the brain, or are they stored in many different parts of the brain? Karl Lashley began exploring this problem, about 100 years ago, by making lesions in the brains of animals such as rats and monkeys. He was searching for evidence of the engram: the group of neurons that serve as the “physical representation of memory” (Josselyn, 2010). First, Lashley (1950) trained rats to find their way through a maze. Then, he used the tools available at the time—in this case a soldering iron—to create lesions in the rats’ brains, specifically in the cerebral cortex. He did this because he was trying to erase the engram, or the original memory trace that the rats had of the maze.
Lashley did not find evidence of the engram, and the rats were still able to find their way through the maze, regardless of the size or location of the lesion. Based on his creation of lesions and the animals’ reaction, he formulated the equipotentiality hypothesis: if part of one area of the brain involved in memory is damaged, another part of the same area can take over that memory function (Lashley, 1950). Although Lashley’s early work did not confirm the existence of the engram, modern psychologists are making progress locating it. Eric Kandel, for example, spent decades working on the synapse, the basic structure of the brain, and its role in controlling the flow of information through neural circuits needed to store memories (Mayford, Siegelbaum, & Kandel, 2012).
Many scientists believe that the entire brain is involved with memory. However, since Lashley’s research, other scientists have been able to look more closely at the brain and memory. They have argued that memory is located in specific parts of the brain, and specific neurons can be recognized for their involvement in forming memories. The main parts of the brain involved with memory are the amygdala, the hippocampus, the cerebellum, and the prefrontal cortex
Answer:
memory
Explanation:
for study island
The balanced equation for the combustion of ethene is given below. If 97.7 g of oxygen is used, how much
heat energy will be produced?
C2H4+ 3O2 → 2CO2 + 2H2O + 1390 kJ
Answer:
c
Explanation:
Why is there an attraction between the two ions in this chemical bond?
Answer:
A metallic bond is a force of attraction between charged metal ions and the electrons that are in the delocalized bond, which covers the assembly of ions. A covalent bond is the force of attraction between the nuclei of atoms, and the electrons shared between them.
Explanation:
A chemical bond is a lasting attraction between atoms, ions or molecules that enables the formation of chemical compounds. The bond can be generated by electrostatic attraction between charged ions (for example, ionic bonds) or by electron sharing (for example, covalent bonds).
I hope this helps you :)
Where is most of the high-level waste stored in the United States?
salt mines
at the nuclear reactor site
mountain peaks
the ocean
volcanic fissures
Answer:
at the nuclear reactor site
Explanation:
In the United States, liquid high-level waste is stored in underground tanks pending vitrification. High-level waste is stored at the nuclear reactor site.
Such waste was created by the weapons programs of the cold war and the Manhattan project. This waste can not be vitrified as there were not enough funds for further processing.
Answer:
at the nuclear reactor site
Explanation:
Isotonic compound have high melting point. Why ? Name the ions present in CaS.
Pls answer fastly ..
Explanation:
Because a large amount of energy is required to break the strong inter-ionic attraction.
CaS => Ca2+ & S2-
Forensic biologist Manning is looking at a cell sample under the microscope. The cell she sees is oval, with a long tail or flagellum. Immediately, she knows that this is a ________ cell.
red blood
skin
sperm
plant
Answer:
Sperm Cell
Explanation:
How many moles of calcium oxide are formed when 3 moles of calcium react with oxygen?
Answer:
3 moles of calcium oxide are formed
Explanation:
Based on the reaction of Calcium Ca, with oxygen, O₂, to produce calcium oxide, CaO is:
2Ca + O₂ → 2CaO
where 2 moles of calcium produce 2 moles of Calcium oxide.
That means, if 3 moles of Ca react in presence of oxygen:
3 moles of calcium oxide are formed
dichlorine monoxide is polar or nonpolar ?
Answer:
( dichlorine monoxide ) is Polar Explanation:Answer. Answer = CF2Cl2 (Dichlorodifluoromethane) is Polar What is polar and non-polar? Cl2O ( dichlorine monoxide ) is Polar I'll tell you the polar or nonpolar list below.
PLEASE HELP
Balance this equation.
___PH3 ——-> ___ P2 + H2
Answer:
2PH3 = P2 +3H2
Explanation:
____ occurs when the vapor pressure of a liquid is equal to the external atmospheric pressure.
A. Sublimation
B. Compression
C. Boiling
D. Freezing
Answer:
Boiling
Explanation:
c.boiling
choice number 3
If you put a link, you will be reported.
Answer:
5ppm
Explanation:
there are 1 million (1,000,000) µg (micrograms or mcg) per g (gram) ("micro" means millionth). So, 4. 1 part per million (ppm) for a 1g sample is 1 µg or .
I know you said no links, but this is a converter that explained it much better than I know how to
http://www.endmemo.com/sconvert/ppmug_g.php#:~:text=%C2%BB%20Microgram%2Fgram%20Conversions%3A&text=ug%2Fg%E2%86%94ppm%201%20ug%2Fg%20%3D%201%20ppm
heres a screenshot of the site (since i understand links are awful)
A type of symbiosis where one organism benefits, while the other organism is neutral.
Mutualism
Parasitism
Commensalism
Predation
Answer:
Commensalism is a symbiotic relationship in which one species benefits while the other species is not affected. One species typically uses the other for a purpose other than food.
How many kilojoules of heat must be transferred to a 480-g aluminum pizza pan to raise its temperature from 22°C to 234°C? The specific heat of aluminum in this temperature range is 0.96 J/g.°С. Show your work.
Answer:
97.7 kJ
Explanation:
We'll use the formula for specifc heat: Q=mcΔT
Q= heat/energy (Joules), m= mass (grams), c= specific heat (different for each substance and is usually given)
ΔT= final temperature - initial temperature
Let's check our given units and see if they're the correct, here they all are. Let's plug in what we know.
Q=mcΔT
Q=(480)(0.96)(234 - 22)
Q=(480)(0.96)(212)
Q= 97,690 J
Before we submit an answer, let's check out units. We have our answer in Joules, but we want it it kilojoules, so we'll convert it knowing that:
1000 Joules = 1 kilojoule
97,690J x [tex]\frac{1 kJ}{1000J}[/tex] = 97.7kJ
Explanation:
the answer and the working out is shown above.
Equal volumes of nitrogen and oxygen, at the same temperature and
pressure, would:
a. have the same mass
b. contain the same number of particles
C. contain different numbers of particles
d. have different kinetic energies
Equal volumes of nitrogen and oxygen, at the same temperature and pressure, would: b. contain the same number of particles.
Avogadro's law states that, equal volumes of all gas samples have the same number of atoms or molecules at the same temperature and pressure.
In Science, the Avogadro's number is typically used to determine the number of atoms or molecules that are contained in a certain mass of a chemical element.
Note: Avogadro's constant is equal to [tex]6.02 \times 10^{23}[/tex]
In conclusion, equal volumes of nitrogen and oxygen, at the same temperature and pressure, would contain the same number of particles (atoms or molecules) in accordance with Avogadro's law.
Read more: https://brainly.com/question/21280037
HELLLLLLPPPPP
What type of circuit does this figure represent?
an open series circuit
an open parallel circuit
a closed parallel circuit
a closed series circuit
Electricity and magnetism
Answer:
a closed series circuit
Answer:
An open series circuit
Explanation:
I'm late but for future people...
I took the test.
Which of the following could be described as exotic? *
a. a pair of sneakers
b. a rare type of flower
Answer:
Exotic is something that’s is unique and you can only find it or this thing in some places. The answer is the rare type of flower.
Explanation:
calculate the molar mass for BaSO4
Answer:
233.38 g/mol
Explanation:
you find the molar mass of each element and then add them up.
How would the graph differ if you were to draw a graph to compare temperature with
time taken for the reaction to take place?
Explain why all other atoms are reactive?
Answer:
The number of electrons in the outermost shell of an atom determines its reactivity. Noble gases have low reactivity because they have full electron shells. Halogens are highly reactive because they readily gain an electron to fill their outermost shell.
Hope this Helps!~
What is the molarity of a solution with 2 moles of HCl in 2000 mL?
Answer:
"1 M" will be the right solution.
Explanation:
The given values are:
Number of moles,
= 2 moles
Volume of solution,
= 2000 mL
or,
= 2 L
Now,
The molarity of the solution will be:
= [tex]\frac{Moles}{Liters}[/tex]
On substituting the values, we get
= [tex]\frac{2}{2}[/tex]
= [tex]1 \ M[/tex]
If I have 0.044 mol Ammonia (NH3) molecules, how many atoms of hydrogen do I have?
Answer:
1 Answer. Before you use log you have to multiply the answer of 8.66 mol by 6.02⋅1023 by 3 because the answer of 8.66 mol by 6.02⋅1023 gives you the number of ammonia molecules and in each molecules there are 3 hydrogen atoms present.
Explanation:
Belle’s grandfather lives in a region where the temperature drops below 0°F at night. When Belle visited her grandfather, they hiked up a hill. Belle noticed that a lot of rocks had cracks in them. She also found quite a few rocks that had split into pieces. What most likely caused the rocks in this region to weather?
Answer : Normally all molecular motions seizes at 0k which is -272oC so the temperature can't go below that
Explanation:
But, the rocks cracked because of too much expansion. Generally at night, water can be found within rocks which then evaporates during the day. And when water is cold or freezed it expands. So, as the water in the rock expands it causes an increase in size until a certain level where it can no more expand, it cracks.What causes the split of the rock is due to the expansion of water as it freezes
Answer:The answer is B
Explanation:
Como se explica o fato de o diamante e o grafite serem formados pelo mesmo elemento, o carbono, e serem materiais completamente diferentes?
Answer:
Ver explicacion
Explanation:
La capacidad de un elemento de existir en diferentes formas en el mismo estado físico se conoce como alotropía.
No es solo el carbono el que exhibe alotropía. También se sabe que el azufre y el fósforo exhiben alotropía.
Hay dos alótropos cristalinos de azufre; grafito y diamante. El grafito y el diamante difieren en la disposición de los átomos de carbono y la naturaleza de los enlaces entre los átomos de carbono en ambas sustancias.
Por lo tanto, el grafito y el diamante tienen propiedades físicas y químicas observadas completamente diferentes debido a las diferencias en la disposición de los átomos de carbono en cada sustancia, así como a las diferencias en la naturaleza de los enlaces entre los átomos de carbono en ambas sustancias.