Answer:
The scientists and all test subjects involved in the investigation work for the company that sells the medication.
Explanation:
The options are as below:
A. The investigation compared a group that took the medication to a control group that did not take the medication.
B. The scientists and all test subjects involved in the investigation work for the company that sells the medication.
C. The weight loss medication worked for 95 out of the 100 test subjects, while only 15 of the 100 control subjects lost weight.
D. The weight loss results were replicated by scientists conducting a study at an independent institution
The correct option would be that the scientists and all test subjects involved in the investigation work for the company that sells the medication.
When selecting the test subjects for research, the selection must be as random as possible so as to ensure an unbiased outcome and increase the reliability of the research.
Limiting the test subjects to those that work in the company that sells the medication will generally reduce the reliability of the outcome because of element of bias that can be introduced either knowingly or unknowingly.
The test subjects must have been selected from the general population of target users for the medication and not limited to just the employees of the manufacturing company.
Correct option: B
Which of the following properties would helium have?
A. Closely packed and structured particles
B. Fills entire container
C. Definite volume
D. Definite shape
Reset Selection
Answer:
B
Explanation:
It is a gas and therefore according to particle model of matter it has large spaces between them and does not have a definite shape
Among the following properties, Helium would fills entire container. Hence Option (B) is correct.
What is States of Matter ?
A “state of matter” is a way to describe the behaviour of atoms and molecules in a substance.
There are three common states of matter: Solids – relatively rigid, definite volume and shape. In a solid, the atoms and molecules are attached to each other. They vibrate in place but don't move around.
Helium is a gas in nature and thus fills entire container.
Therefore, Among the following properties, Helium would fills entire container. Hence Option (B) is correct.
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An aerospace engineer is designing a rocket to have three stages. Which is
not a reasonable explanation for this decision?
A. To simplify the design of the rocket
O B. To decrease the mass of the rocket as it flies
C. To take advantage of the lesser amount of thrust needed in space
D. So the rocket only carries necessary mass
Answer:
A. To simplify the design of the rocket.
Explanation:
3 stage rockets require huge amounts of fuel when launched in order to last the entire voyage.
As the rocket flies, some compartments may be detached and fall away from the rocket, decreasing its mass (eliminating B, as it is reasonable). This is done so that the rocket only carries necessary mass, which doesn't include the used up rocket parts (eliminating D, as it is reasonable). When the rocket finally reaches space, the decrease in gravity means less thrust is needed, which is an important thing to take note of while designing the rocket (eliminating C, as it is reasonable).
A three stage rocket is very complex and has many features and mechanisms that are complicated to add and deal with. Giving a rocket, three stages is not a simplification, so A is the answer.
A. To simplify the design of the rocket
What is the best design for a rocket?At supersonic speeds (faster than the velocity of sound), the great shape is a narrower and sharper point. Rockets with a bigger diameter have greater drag because there's greater air being driven out of the manner.
Designing A Rocket In Six Easy Steps is given below
Step One: Know What Your Rocket Needs to Do. Step Two: Establish Mission Parameters. Step Three: Call in Experts. Step Four: Start Drawing. Step Five: Whittle Down the Possibilities. Step Six: Pick the Best Design.Learn more about rocket here: https://brainly.com/question/17833361
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When a single salt crystal is added to a cool liquid, large crystals form. Which statement about the original cool liquid is correct?
A) The liquid is a heterogeneous mixture because the crystals can be easily separated from the liquid
B) The liquid is a pure substance because it was made up of a single compound
C) The liquid is a pure substance because it was uniform before the crystal was added
D) The liquid is a homogenous mixture because the substance that formed the large crystals was uniformly dissolved
The liquid is a homogeneous mixture because the substance that formed the large crystals was uniformly dissolved.
A solution is composed of a solute and a solvent. A solution is a typical example of a homogeneous mixture.
We define a solution as any combination of solute and solvent. A solution can be regarded as a homogeneous mixture since the solute is uniformly distributed throughout the solution. The solute and solvent constitutes one phase.
When a salt crystal is added to the solution, crystallization is induced and large crystals of solute form.
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A salt crystal is a cubic form of sodium chloride that is closely bounded together by the reaction of sodium and chlorine ions during electrovalent bonding.
Taking a look at a heterogeneous mixture;
It refers to the mixtures that are not thoroughly mixed and uniform in composition.
On the other hand, homogeneous mixtures are formed when a substance i.e. solute (here, it is the salt crystal) is being added to a cool liquid(solvent) is thoroughly mixed.
From the given information, we are being told that when this single salt crystal is added to the cool liquid, large crystals are formed.
This implies that the formation of large crystals is brought about by the action of crystaliization rendering the liquid to be a homogeneous mixture.
We can therefore conclude that the correct statement about the original cool liquid is in Option D.
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Was is meant by the term suprenatural? Does science deal with the supernatural?
A. The term supernatural literally means (within nature) Science deals with the supernatural because it works within nature, not above it
B. The term supernatural literally means (above nature) Science does not deal with the supernatural because it works within nature, not above it
C. The term supernatural literally means (within nature) Science does not deal with the supernatural because it works above nature, not within it
D. The term supernatural literally means (above nature) Science deals with the supernatural because it also works with nature, not within it
Answer:
it's option D
Scientists from different fields are trying to understand how the global climate is reacting to the changes caused in nature, and by human activities. They have come up with conflicting interpretations. Which of these is the most likely outcome of differences in interpretations made by scientists on the issue of global climate?
Answer:
New ideas would be created and tested
Explanation:
All old ideas would be discarded.
Scientific evidence would be weakened.
New ideas would be created and tested.
The limitations of science would be evident.
In science, old ideas are usually improved or modified and not entirely discarded. The old ideas form the basis for new ideas after extensive reviews. Differences in the interpretations made by scientists on any particular phenomenon give rooms for reviews. The reviews often generate new ideas or hypotheses and these can be tested using relevant experimental procedures according to the scientific method.
Hence, the correct answer would be that new ideas would be created and tested.
If each geometric shape represents a different type of atom, and atoms that are touching have chemically bonded with each other, which best describes this model? * 1. An element 2. A compound 3. A homogeneous mixture of two compounds 4. A heterogeneous mixture of two compounds 5. A homogeneous mixture of four elements 6. A heterogeneous mixture of four elements
Answer:
The correct option is;
3. A homogeneous mixture of two compounds
Explanation:
An homogeneous mixture is one where the components of the mixture are evenly dispersed such that the individual components cannot be seen to be isolated and distinguishable and having a constant composition of the constituents
The image displays three atoms (red circle, cyan triangle, and orange rectangle). The red circle appear to be bonded in pairs while the cyan triangles are bonded to the orange rectangles making a total of two compounds
The arrangement of the compounds in the mixture appear to be very evenly distributed to suggest an homogeneous mixture
The visibility of the compounds should be for an illustrative purpose.
Match the chemical equation with the correct reaction type:
Column A
Column B
1.
Fe +52 - Fe253
2.
Pb(NO3)2 + K2CrO 4 PbCrO 4 +KNO3
a. single replacement
b. double replacement
C. decomposition
3.
H2 + N2 + NH3
d. combustion
4.
Fe + CuCl2 - FeCl2 + Cu
e synthesis
5.
KCIO3 -KCI + O2
6.
Mg + HCI-H2 + MgCl2
7.
C3Hg + O2 CO2 + H2O
8.
Zn + HCI - ZnCl2 + H2
9.
NH3-N2 + O2
10.
AgNO3 + Cu Cu(NO3)2 + Ag
f70X
1.
Fe +52 - Fe253
SYNTHESIS REACTION
A synthesis reaction occurs when two or more reactants combine to form a single product.
2.
Pb(NO3)2 + K2CrO 4 PbCrO 4 +KNO3
DOUBLE REPLACEMENT
A double-replacement reaction exchanges the cations (or the anions) of two ionic compounds.
3.
H2 + N2 + NH3
SYNTHESIS REACTION
A synthesis reaction occurs when two or more reactants combine to form a single product.
4.
Fe + CuCl2 - FeCl2 + Cu
SINGLE REPLACEMENT
A single-displacement reaction, is a chemical reaction in which one element replaces an/other element in a compound.
Note. An element can only replace an element that it is higher than in the electrochemical series or an element that is less reactive than itself.
5.
KCIO3 -KCI + O2
DECOMPOSITION REACTION
A decomposition reaction is a reaction in which a compound breaks down into two or more simpler substances.
Most times this type of reaction requires an in put of energy.
It is usually an endothermic reaction as heat is mostly absorbed.
6.
Mg + HCI-H2 + MgCl2
SINGLE REPLACEMENT
A single-displacement reaction, is a chemical reaction in which one element replaces an/other element in a compound.
Note. An element can only replace an element that it is higher than in the electrochemical series or an element that is less reactive than itself.
7.
C3Hg + O2 CO2 + H2O
COMBUSTION REACTION
Combustion reaction is a high-temperature exothermic redox chemical reaction between a fuel (example propane C3H8) and an oxidant, usually atmospheric oxygen, that produces oxidized, often gaseous products.( mostly C02)
It can also be referred to as burning.
Combustion reaction is one of the chemical characteristics of hydrocarbons.
8.
Zn + HCI - ZnCl2 + H2
SINGLE REPLACEMENT
A single-displacement reaction, is a chemical reaction in which one element replaces an/other element in a compound.
Note. An element can only replace an element that it is higher than in the electrochemical series or an element that is less reactive than itself.
9.
NH3-N2 + O2
DECOMPOSITION REACTION
A decomposition reaction is a reaction in which a compound breaks down into two or more simpler substances.
Most times this type of reaction requires an in put of energy.
It is usually an endothermic reaction as heat is mostly absorbed.
10.
AgNO3 + Cu Cu(NO3)2 + Ag
f70X
SINGLE REPLACEMENT
A single-displacement reaction, is a chemical reaction in which one element replaces an/other element in a compound.
Note. An element can only replace an element that it is higher than in the electrochemical series or an element that is less reactive than itself.
What is the equilibrium constant of aA+bB cC +dD?
Explanation:
{c}^C . {d}^D / {a}^A . {b}^B
List down the observations made by Rutherford during the gold foil experiment.
Answer:
1) The volume occupied by an atom is composed of mainly empty space
2) Atoms have a very small, relatively dense, central nucleus that is positively charged
3) The region around the nucleus of an atom are orbited by negatively charged electrons in a the same fashion planets orbit around the Sun.
Explanation:
The selection of gold for the gold foil experiment was due to its ability to be rolled into extremely thin sheets such that it was expected for alpha particle to perforate or pass through the foil.
calculate the pH of 500cm3 of 0.2mol/dm3 Ca(OH2), assume complete ionisation
Answer:
The pH of 500 cm³, 0.2 mol/dm³, Ca(OH₂) is ≈ 13.6
Explanation:
The given parameters are;
Concentration of the calcium hydroxide, Ca(OH₂) = 0.2 mol/dm³
Volume of the calcium hydroxide, Ca(OH₂) = 500 cm³
Given that the calcium hydroxide, Ca(OH₂), undergoes complete ionization in water, complete dissociation, we have;
Ca(OH₂) ⇄ Ca²⁺ + 2 OH⁻
Therefore, we have;
2 moles of [OH⁻] for each mole of Ca(OH₂) which gives the concentration of [OH⁻] as
[OH⁻] = 2 × 0.2 ≈ 0.4 mol/dm³
The pH is given by the formula
pH = 14 + ㏒₁₀ [OH⁻]
pH = 14 + ㏒₁₀ (0.4) = 14 - 0.3979 = 13.6021 ≈ 13.6
The pH of the 500 cm³ 0.2 mol/dm³ Ca(OH₂) ≈ 13.6.
Cho 17,7 gam kim loại Fe tác dụng với dung dịch HCl loãng, dư thu được V lít khí H2
a) Viết PTHH và tính giá trụ của V
b) Cho lượng Fe ở trên tác dụng với dung dịch H2SO4 đặc nóng, dư thấy thoát ra V1 lít khí SO2. Viết PTHH và tính giá trị của V1
Answer:
A
Explanation:
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ХА
19
Which two major parts of the Earth system does this photo most clearly
show?
O A. Atmosphere
B. Biosphere
c. Cryosphere
PREVIOUS
Answer:
B. Biosphere.
Explanation:
what are two consents in this experiment
The number of cricket chirps
The temperature of each container
The kind of containers used
The number of crickets in each container
Answer:
the number of crickets in each container
Explanation:
to participate in the experiment you will have to know the crickets in the container
Water has __________ than other liquids such as ethanol , reflecting its capacity to absorb large amounts of heat. View Available Hint(s)for Part A lower specific heat a lower heat of vaporization a higher boiling point a lower capacity for forming hydrogen bonds less surface tension
Answer:
a high boiling point
Explanation:
Water has a high boiling point because it is held together by stronger molecular forces compared to ethanol
PLEASE PLEASE HELP!! A pipe drips at 155mL/day- convert this rate to gallons/day (1gal=3.785L)
1 mL =[tex]10^{-3}[/tex] L
so $155$ mL =$155\times10^{-3}$ L
Now, $1$ gallon = $3.785$ L , or $1$ L= $\frac1{3.785}$ gallons
so $155\times10^{-3}$ L= $155\times10^{-3}\times \frac{1}{3.785}=40.95\times 10^{-3}$ gallons
and this is for each day, so just divide by 1 (day) to get the ratw gallons/day
i.e. $40.95\times 10^{-3}$ gal/day
name of the compound Br8P4
Answer:
4-phospho,Bromooctane
hurry
A solution:
A. is a mixture that is made when a solid dissolves and combines with a liquid.
B. is the amount of a substance that will combine with another substance before they begin to chemically combine.
C. is the amount of a substance that will dissolve in 1 dm3 of water at 25 C .
D. is two or more substances that are combined together but not chemically joined.
Reset Selection
Answer:
b is the correct answer ok
A solution is made up of solute and solvent. It is an addition of two or more substances to each other that combines physically and chemically. Thus, option B is correct.
What is a solution?A solution is the mixture of solutes that can be more than one in a solvent that has the same composition all over (homogenous). A solution comprises two main elements called a solute and a solvent.
A solute is the part of the solution that has been added to the solvent for desolvation. On the other hand, the solvent is the substance that dissolves the solute in them to make a solution.
The homogenous mixture or the solution can be created by mixing salt and water, sugar and water, mercury in amalgamated zinc, coffee, vinegar, etc.
Therefore, option B. a solution is the addition of the substances that combine physically.
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One day, you decide to pop some popcorn. You put the bag in the microwave, but after a couple of minutes of cooking it is clear the popcorn is not popping. Why did this happen? What steps could you take to help locate the problem?
Question #13
What causes the low pressure zones around the equator?
Hint: How does air move at a low pressure zone? Why does
air move that way? What happens at the equator that would
cause air to move that way?
Answer:
Warm equatorial air rises higher into the atmosphere and migrates toward the poles. This is a low-pressure system. At the same time, cooler, denser air moves over Earth's surface toward the Equator to replace the heated air. ... This happens because Earth's rotation generates what is known as the Coriolis effect
1 atm is equal to
O 1 mmHg
• 14.7 mmHg
• 76 mmHg
© 760 mmHg
Answer:
C 760 mm of hg
because this is the atmospheric pressure at sea level
Give two examples of neutralization
Answer:examples for neutralization - treating indigestion,treatment for insect bites.hope it help you
Explanation:
Which of the following is NOT the property of a non-metal? A. Non-rigid structure B. Not ductile C. Low density D. Malleable
Answer:
The answer is D.
Explanation:
Malleable is the property of metal not non-metal.
Answer:
malleable
Explanation:
because a non metal cannot be harmmed into sheetsCH4 + 2O2 → CO2 + 2H2O In the chemical reaction, if 10 moles of H2O are produced, moles of CO2 are also produced
Answer:
The correct answer is 5 moles of CO2 are produced.
Explanation:
The given reaction:
CH₄ (g) + 2O₂ (g) ⇔ CO₂ (g) + 2H₂O (g)
The given reaction is an illustration of a combustion reaction. Any reaction in which a substance is burnt in excess of oxygen to generate water and carbon dioxide is termed as a combustion reaction. From the given equation, it is clear that the moles of the formation of the products are in the ratio 1: 2, that is, if 10 moles of H₂O is produced, the production of 5 moles of CO₂ will be produced.
Let us multiply, the given equation with 5 we get,
5CH₄ + 10O₂ ⇔ 5CO₂ + 10H₂O
Hence, it is clear that with the formation of 10 moles of H₂O, formation of 5 moles of CO₂ will also take place.
If the red car travels from 50 m to -25 m in 5 seconds, what is its velocity?
Answer:
V = 14m/s
Explanation:
velocity is the rate of change in displacement
V = (change in displacement)/time
V = (50 - (-20) )/5
V = (70)/5
V = 14m/s
For the set of ionic compounds, CaSO4, CaCO3, Ca(OH)2, choose the correct characterization of their solubilities in water from the response list. Group of answer choices None of the three salts are soluble. All three salts are soluble. Two of the three salts are soluble. One of the three salts is soluble.
Answer:
None of the three salts are soluble.
Explanation:
According to the solubility rule, the carbonates and sulphates of group two elements are insoluble in water.
All three substances mentioned possess very low solubility in water and can be said to be slightly soluble in water. If we compare them with other ionic substances that dissolve readily in water, we can rightly say that they are insoluble in water.
Hence all three substances are insoluble in water.
You work in the special effects department of a movie studio. You are
currently working on a superhero movie where the hero is very strong
and can punch through metal. For the next scene you need to replace a
6 inch by 6 inch square of a metal wall with a different material that will
crumble when the actor hits it. What could you use?
A. You could use Carbon(C)
B. You could use Potassium (k)
C. You could use Titanium (T)
D. You could use Manganese (Mn)
Answer:
The correct option is;
D. Manganese (Mn)
Explanation:
Manganese is very brittle, hard, iron like silvery-gray metal, that is difficult to melt. In air, Manganese slowly disintegrate in a similar manner to iron rusting in water
Manganese and iron have similar chemical and physical properties however manganese is more harder and more brittle than iron
A brittle material is one that easily breaks without deforming elastically
Therefore, manganese, due to its very iron like appearance and brittle nature will be suitable to replace the metal wall and crumble easily when the actor hits it.
Josefina and Raul were comparing how sound moves through various mediums and how charge moves through conducting wires. They performed experiments to find out if the factors that determine the speed of sound are the same as those that determine the flow in a circuit. What did they find? Describe two things that they found. For each, explain how the speed of sound and flow of current are affected
They found that difference occurs in the speed of both sound and charges occur due to the difference in the type of medium.
Sound and charges needs specific medium for faster movement i.e. sound moves faster in solid as compared to liquid and gas whereas charges moves faster and easily in gold due to lower resistance which is followed by copper. Sound can move from solid, liquid and gases whereas charges move only in solid metal in which free electrons are present. The speed of sound and flow of current are affected due to difference in the arrangement of atoms in solid, liquid and gas.
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If the temperature of a gas increased from 100K to 200K and the volume of a gas decreased from 20L to 10L, what is the new pressure I’d the original pressure was 100 kPa?
Answer:
400 kPa
Explanation:
using General Gas Law
[tex] \frac{100 \times 20}{100} = \frac{p \times 10}{200} [/tex]
[tex]p = 400[/tex]
The concept combined gas law is used here to determine the new pressure of the gas. The pressure of the gas obtained is 400 kPa.
What is combined gas law?The equation connecting the volume, pressure and temperature of a gas can be represented mathematically by an equation called the combined gas law. In this equation the temperature should be always in Kelvin.
The combined gas law is also defined as the ideal gas law without Avogadro's law. It is the combination of Boyle's law, Charles's law and Gay-Lussac's law. The equation is given as:
PV/T = k
Here 'P' is the pressure, 'V' is the volume, 'T' is the temperature and 'k' is a constant. The equation for two gases of different volumes and temperature is:
P₁V₁ / T₁ = P₂V₂ / T₂
Then P₂ = P₁V₁T₂ / T₁V₂
Here the new pressure P₂ is:
P₂ = 100 × 20 × 200 / 100 × 10
P₂ = 400 kPa.
Thus the new pressure is 400 kPa.
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Tips for memorizing the first 20 elements of the periodic table?
Answer:
hydrant flying with balloon, balloon has lithp letting air out, bee: really yum balloon
= = = =
hydrogen helium lithium beryllium
be bore on the balloon, balloon pops, hydrant drops and makes a car bomb
= =
boron carbon
night row general gets hurt by car bomb nearby, that general gets off boat
=
nitrogen
wearing oxygen mask, mask is full of fluride gel, then he got neon teeth
= = =
oxygen fluorine neon
(try making a story out of the elements, use your imagenation)
I will give u tips to learn whole periodic table
1. Break down the table into sections
2. Spread out the memorisation process
3. Learn the elements in a song
4. Make none sense words made from element symbols
5. Use colour to learn element groups
6. Use mnemonic device to help remember the order of elements
I am sure this will be helpful for uuu
Explanation:
Which of the following is the correct chemical formula for Ca and F? CaF Ca2F CaF2
Answer:
CaF2
Explanation:
Calcium fluoride is a solid formed by the chemical combination of Calcium (Ca) and Fluorine (F). Two molecules of fluorine (F2) and one molecule of Calcium (Ca) are needed to form the Calcium Fluoride molecule.
An ionic bond is formed between the Calcium and Fluorine atoms i.e. electrons are transferred from calcium atoms to fluorine atoms. The calcium ion is a cation with formula; Ca2+ while fluorine is an anion with formula; F-. Hence, it takes two molecules of Fluorine ion (F-) to form a relatively stable and neutral molecule with 1 molecule of Calcium ion (Ca2+).