In which circumstance would a researcher need to first establish an operational definition in order to objectively assess its variable?
a.
researching the effects of salt on systolic blood pressure
b.
researching the effects of coffee on energy levels
c.
researching the effects of magnesium on the average number of hours of slept at night
d.
researching the effects of water on the metabolic rate
An operational definition is the statement of procedures the researcher is going to use to measure a specific variable.
Why do researchers use operational definitions of their terms?Researchers can explain in detail what they mean when they use a phrase by using an operational definition. Operational definitions are typically measurable and concrete. This method of defining variables enables others to assess the validity of the study. Operationalization is the procedure in question.
The variables you'll utilize as indicators and the methods you'll employ to observe or measure them are both included in your operational definitions. No matter how solid your conceptual definition may be, you need an operational definition since without one, you cannot measure anything.
Operational variables, also known as operationalizing definitions, describe how you'll quantify and define a particular variable when it's applied to your research. This makes it possible for a different psychologist to duplicate your findings and is crucial in establishing.
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When dominant traits are present they cover up or hide recessive traits
True or false
Answer:
True
Explanation:
If dominant traits are there, then they take over. Periot
An aqueous sodium chloride solution is made using 148g of sodium chloride diluted to a total solution volume of 1,490mL. Calculate the molality of the solution. Do not include units in your answer
The molality of the solution is 1.89 mol/kg
What is molality?
Molality is defined as the number of moles of solute per kilogram of solvent. To calculate the molality of the aqueous sodium chloride solution, we need to first calculate the number of moles of sodium chloride in the solution, and then determine the mass of water in the solution.
The molar mass of sodium chloride (NaCl) is 58.44 g/mol. Therefore, the number of moles of NaCl in the solution is:
148 g / 58.44 g/mol = 2.53 mol
The mass of water in the solution is the total mass of the solution minus the mass of the solute:
Mass of water = Total mass of solution - Mass of NaCl
Mass of water = 1490 mL x 1 g/mL - 148 g
Mass of water = 1342 g
The mass of water in kilograms is:
Mass of water (kg) = 1342 g / 1000 g/kg = 1.342 kg
Therefore, the molality of the solution is:
Molality = 2.53 mol / 1.342 kg ≈ 1.89 mol/kg
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Which treatment(s) will help remove contaminants from minerals or from the pipes carrying water from a source? you can select more than one (Water Contamination Gizmos) **ONLY ANSWER IF YOU ACTUALLY KNOW ❗️❗️**
answer choices:
Sedimentation
Disinfection
Filtration
Coagulation
Sedimentation, filtration, and coagulation are the treatments that will help remove contaminants from minerals or from the pipes carrying water from a source.
Sedimentation is a process in which suspended particles settle out of water. It is one of the most basic techniques for removing particles from water. As particles settle, they become trapped in the bottom of a container or settle to the ground in an outdoor setting
Filtration is a method of removing particles from a fluid. It is a physical or chemical separation method that separates solids from fluids (liquids or gases) by adding a medium through which only the fluid can pass.
Coagulation is the process of using chemicals to remove contaminants from water. By creating a chemical reaction, coagulation destabilizes particles and causes them to clump together. This helps to remove the contaminants from the water.
Disinfection is the process of eliminating or destroying pathogens that cause infection. Disinfection eliminates harmful microorganisms by destroying or inactivating them. The disinfectant is a chemical or physical agent that is used to destroy or inactivate harmful microorganisms.
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different between a bird and a rat
Explanation:
Rats and mice are both rodents, so look similar - the biggest difference is their size. Rats are larger and heavier while mice have smaller slender bodies. Mice also have long slender tails (for their body size) covered in hair compared to rat tails which are shorter, thicker and hairless
Jailah needs a replacement for lithium for a science experiment. She tries silicon, but it does not work. Using what you know about patterns in the periodic table, which advice would you give Jailah?
Answer:
C
Explanation:
Jailah should try an element from the same group as lithium.
What group elements have similar properties?
The elements are those in the same group or column of the periodic table that have mostly similar chemical properties. Elements are placed in vertical groups that have the same valence electrons and similar chemical properties.
On the periodic table, the vertical columns are called groups because of their similar chemical behavior. All the members of a group (1 to 18) of elements have similar chemical properties.
Since Lithium, sodium, and potassium are all Group 1A metals, they all have most similar chemical properties. The electronic configuration of the lithium is 1s²2s¹. Lithium has one electron in its outermost shell. All the elements in group 1 have one electron in their valence shell.
Therefore, she should replace lithium with an element of group 1 of the periodic table.
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how do one get this solution
-log10 (2* 10^-2)
The result of the computation when you follow the steps is 1.699.
A logarithm is a mathematical function that represents the exponent or power to which a specific base must be raised to obtain a given number. In simpler terms, it answers the question: "To what power must we raise a base number to obtain a certain value?"
What you should do is that on your calculator, you could press the logarithm key and then put in the value that has been shown and then the result would be displayed on your calculator.
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Magnesium velocity acceleration
Nobody answering my questions what the answer givng brainliest
Answer: I think it’s B. Because as you can see from the picture there are layers
Explanation:
I think but just in case ask for a second opinion
Answer:
C. Air bubbles
Explanation:
Cant be A because.... you cant freeze a tempreature
Cant be B because... organism types cant show precipitation patterns.
Cant be D because....well it could be D, but there isnt a way to prove humans increased the tempreature
ITS C hope it helps :)
I also got this question before
Determine if the particle undergoes alpha, beta or gamma
The particle decay process described as 226 88 Ra → 222 Rn + He 86 involves the emission of a helium nucleus (He), which consists of two protons and two neutrons. This type of emission is known as alpha decay. Option A.
Alpha decay occurs when a radioactive nucleus releases an alpha particle, resulting in the emission of high-energy helium nuclei. In this case, the radium-226 (Ra) nucleus decays into radon-222 (Rn) by emitting an alpha particle. The resulting helium nucleus (He) is the emitted alpha particle.
Alpha particles have a positive charge and are relatively large and heavy. They are composed of two protons and two neutrons, which gives them a helium-like structure. Due to their size and charge, alpha particles have limited penetrating power and are typically stopped by a few centimeters of air or a sheet of paper.
Therefore, the correct answer A. alpha radiation.
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The compound butanol has the following structural formula.
A string of 4 C atoms are bonded above, left, and below to H. The right-hand end is bonded to O, which in turn is bonded to H.
Which of these is a structural isomer of butanol?
A string of 4 C atoms are bonded above, below, left and right to H.
A string of 4 C atoms is bonded above, below, left, and right to H, except the second C, which is bonded below to O, which is bonded below to H.
A string of 4 C atoms is bonded above, below, left, and right to H, but the chain is interrupted between the first and second C, which are bonded to an O between them.
A string of 4 C atoms is bonded above, below, and left to H, except the last C has no H below and is double-bonded to an O to the right.
The structural formula of butanol is C4H9OH. It consists of a chain of four carbon atoms, with a hydroxyl (-OH) group attached to one of the carbon atoms. Butanol has several structural isomers, which have the same molecular formula but different structural formulas.
A structural isomer is a compound that has the same molecular formula as another compound but has a different arrangement of its atoms. A string of 4 C atoms are bonded above, below, left, and right to H, except the second C, which is bonded below to O, which is bonded below to H is a structural isomer of butanol.
This is called butan-2-ol. The structural formula of butan-2-ol is CH3CH(OH)CH2CH3. In this isomer, the hydroxyl group is attached to the second carbon atom in the chain, whereas in butanol, the hydroxyl group is attached to the first carbon atom in the chain.
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If your equation includes 7(CrO4)2, how many Cr's are there?
If your equation includes 7(CrO4)2, how many O's are there?
If an equation includes 7(CrO₄)₂, the numbers of Cr's and O's atoms that are there are 14 and 56 respectively.
How to calculate number of atoms?The number of atoms present in a chemical compound can be calculated by multiplying the subscript of the particular element by any coefficient.
According to this question, 7 moles of chromate with the chemical formula; (CrO₄)₂ is given. The number of oxygen and chromium atoms in this compound can be calculated as follows:
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WHAT IS THE CONCENTRATION, IF A SOLUTION IS PREPARED BY DISSOLVING 90ML OF HYDROGEN PEROXIDE IN ENOUGH WATER TO MAKE 3000ML OF SOLUTION
Answer:
30%
Explanation:
Chemical concentrations are general defined as the ratio between amount of solute (Less amount compound, hydrogen peroxide) and amount of solvent or solution (More amount, water).
For example, volume/volume percentage -(V/V%)- is defined as 100 times the ratio between volume of solute (90mL of hydrogen peroxide) and volume of solution (300mL of solution), that is:
V/V% = 90mL / 300mL * 100 =
30%
PLEASE HELP QUICKLY!!!
HI gas is removed from the system
at equilibrium below. How does the
system adjust to reestablish
equilibrium?
51.8 kJ + H₂(g) + 1₂(g) = 2HI(g)
A. The reaction shifts to the right (products) and the concentrations
of I, and H₂ decrease.
B. The reaction shifts to the left (reactants) and the concentrations
of H₂ and I increase.
C. The reaction shifts to the right (products) and the concentrations
of I, and H₂ increase.
D. The reaction shifts to the left (reactants) and the concentration of
HI increases.
Answer:
A. The reaction shifts to the right (products) and the concentrations of I and H₂ decrease.
Explanation:
If gas is removed from the system at equilibrium, the system will try to compensate for the loss by shifting the reaction in a direction that produces more gas molecules. This is known as Le Chatelier's principle, which states that a system at equilibrium will respond to a disturbance by shifting in a way that minimizes the effect of the disturbance.
In this case, since gas is being removed from the system, the reaction will shift to the side that produces more gas molecules. Looking at the balanced equation, we can see that 2HI(g) has a greater number of gas molecules compared to H₂(g) and I₂(g). Therefore, the system will shift to the right (products) to produce more HI(g) and reestablish equilibrium.
Amines and amides are organic compounds that contain nitrogen. Amines are ammonia derivatives, in which at least one hydrogen atom is replaced by an organic substituent. Methylamine is a simple amine in which one of the hydrogen atoms of ammonia is replaced by a methyl group:
Answer:
Following are the solution to the given question:
Explanation:
Write the following in standard notation:
5.1874 x 102
Answer:
529,1148
Step-by-step explanation:
5,1874 × 102
= 5,1874 × 102,0
= 529,1148
Conclusion:
Result of 5,1874 × 102 is 529,1148.
\( \)
Answer:
529.1148
Explanation:
5.1874 × 102
= 102 × 5.1874
= 529.1148
Which of the following has the highest melting point?
Responses
H2O
HCl
NH3
H2S
Answer:
H2O
Explanation:
H2O melts at 0 Celsius while everything else melts at a lower degree temp
Aloud is an astronomer. He is trying to find evidence that a galaxy has supermassive black hole at its center. What should he look for? A. Neutron star B quasar C pulsar D black matter
Aloud is trying to find evidence that a galaxy has supermassive black hole at its center. He should look for the black matter in the center of the Earth. Thus, the correct option is D.
What is the Black matter?Black matter or dark matter is composed of the particles which do not absorb, reflect, or emit light rays, so they cannot be detected by observing electromagnetic radiations. Dark matter is the material which cannot be seen directly through the eyes.
Dark matter play an important role in the formation of galaxies. Many researchers use the astronomical surveys to build maps of the location where dark matter in the universe is found based on how the light from the distant galaxies bends as it travels to us.
Thus, the matter which fall into a black hole arranges itself in the shape of a disk which is thick at the outer edge, while it is thin along the inner ring of the disk.
Therefore, the correct option is D.
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is diphenylamine a solid, liquid, or a gas at room temperature
Answer:
Solid
Explanation:
Diphenylamine has a melting point of 127.4 F or 53 C so at room temperature ~70 F or 21 C its a solid.
Which of the following is an incorrect representation for a neutral atom?
36Li
613C
3063Cu
1530P
This representation suggests that the element is phosphorus (P) with a mass number of 30, which is incorrect. The correct mass number for phosphorus is approximately 30.97. The incorrect representation for a neutral atom is 36Li
To determine the correct representation for a neutral atom, we need to consider the atomic number (Z) and mass number (A) of the element. The atomic number represents the number of protons in the nucleus, while the mass number represents the sum of protons and neutrons.
Let's analyze the given representations:
36Li:
This representation suggests that the element is lithium (Li) with a mass number of 36, which is incorrect. The correct mass number for lithium is approximately 6.94.
613C:
This representation suggests that the element is carbon (C) with a mass number of 13, which is correct. Carbon has different isotopes, and 13C represents one of its stable isotopes.
3063Cu:
This representation suggests that the element is copper (Cu) with a mass number of 63, which is correct. Copper has different isotopes, and 63Cu represents one of its stable isotopes.
1530P:
This representation suggests that the element is phosphorus (P) with a mass number of 30, which is incorrect. The correct mass number for phosphorus is approximately 30.97.
Therefore, the incorrect representation for a neutral atom is 36Li, as it does not match the known properties of lithium.
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What is the volume of 67.1g of ethyl alcohol, which has a density of 0.79 g/mL?
Answer:
\(84.94\ \text{mL}\)
Explanation:
\(m\) = Mass of ethyl alcohol = \(67.1\ \text{g}\)
\(\rho\) = Density of ethyl alcohol = \(0.79\ \text{g/mL}\)
\(V\) = Volume of ethyl alcohol
Density is given by
\(\rho=\dfrac{m}{V}\\\Rightarrow V=\dfrac{m}{\rho}\\\Rightarrow V=\dfrac{67.1}{0.79}\\\Rightarrow V=84.94\ \text{mL}\)
The volume of ethyl alcohol is \(84.94\ \text{mL}\).
Predict the order of elution if you were to attempt to separate using column chromatography on silica gel and with a gradient eluent system starting with petroleum ether and slowly increasing MTBE % over time.
Answer:
Follows this order: B=> A => C.
Explanation:
NB: kindly check the attachment for the diagram of compounds A, B and C.
Elution is a very important concept in chromatography separation techniques. It deals with the use of eluent in the removal of an adsobate from an adsorbent. The principle behind Elution is just about how polar the solvent is.
So, in this question Compound B will go with the Elution first because of its polarity. Compound B has lesser polarity as compared to Compounds A and B.
Compound A will then elutes second because of its polarity too as resonance increases its polarity.
Last, compound C elutes because it has the highest polarity which is caused by electronegative atoms.
What is the molarity of a solution that contains 0.75 mol Naci in 3.0 L of solution? Select one: O a. 4.0 M O b. 2.3 M O d. 3.8 M O d. 0.25 M Clear my choice
Answer:
\(\boxed {\boxed {\sf D. \ 0.25 \ M}}\)
Explanation:
Molarity is a measure of concentration in moles per liter.
\(molarity= \frac{moles \ of \ solute}{ liters \ of \ solution}\)
The solution contains 0.75 moles of sodium chloride and has a volume of 3.0 liters.
moles of solute = 0.75 mol NaCl liters of solution = 3.0 LSubstitute these values into the formula.
\(molarity= \frac{ 0.75 \ mol \ NaCl}{3.0 \ L}\)
\(molarity= 0.25 \ mol \ NaCl/L\)
Molarity has the molar (M) as its unit. 1 molar is equal to 1 mole per liter.
\(molarity= 0.25 \ M \\)
The molarity of the solution is 0.25 Molar and Choice D is correct.
A chemist mixes 28.5 g of water with 95.6 g of acetic acid and 24.0 g of acetone. Calculate the percent by mass of each component of the solution T-shirt each of your answers entries has the correct number of significant digits component: water mass %?Acetic acid mass %?Acetone mass %?
We have to know first the total mass of the solution, so we sum all the mass given:
Water: 28.5 g
Acetic acid: 95.6 g
Acetone: 24 g
Total mass: 28.5 g + 95.6 g + 24 g = 148.1 g
Now, the percent by mass is defined like:
\(\text{Percent by mass = }\frac{\text{Mass of solute}}{\text{Mass of solution}}\times100\)Then we divide each solute by the total mass of the solution and multiply by 100:
Water:
\(\frac{28.5g}{148.1g}=19.2\)Acetic acid:
\(\frac{95.6g}{148.1g}=64.6\)Acetone:
\(\frac{24g}{148.1g}=16.2\)So, the answer will be:
Water mass 19.2%
Acetic acid mass 64.6%
Acetone mass 16.2%
1) In the nuclear equation below, what does the letter X represent? Show your work.
In aqueous solution, 5.2 mg of iron(III) chloride reacts with excess ammonium hydroxide.A. Write and kalance the equation, including phasesB. Is this a limiting reactant problem? Why or why not?C. Calculate the moles of each product that are formedD. Calculate the grams of each product that are formedI already answered part a and b. I need help on part c and d.
With a balanced reaction, we can determine the moles of products. The balanced equation will be:
FeCl3 + 3NH4OH → Fe(OH)3 + 3NH4Cl
They says that NH4OH is in excess, so, the limiting reactant will be FeCl3 and we will do all the calculations with this reactant.
We have to calculate the moles of FeCl3, we will use the molar mass:
\(\begin{gathered} molFeCl_3=5.2mg\times\frac{1g}{1000mg}\times\frac{1molFeCl_3}{MolarMass,gFeCl_3} \\ molFeCl_3=5.2mg\times\frac{1g}{1,000mg}\times\frac{1molFeCl_3}{162.2gFeCl_3}=3.2\times10^{-5}molFeCl_3 \end{gathered}\)Now, to calculate the moles of the products we must take into account the product/reactive ratios, for this we are guided by the coefficients that accompany the molecules.
Ratio Fe(OH)3 to FeCl3 = 1/1
Ratio NH4Cl to FeCl3 = 3/1
Moles of each product
Moles of Fe(OH)3
\(molFe(OH)_3=3.2\times10^{-5}molFeCl_3\times\frac{1molFe(OH)_3}{1molFeCl_3}=3.2\times10^{-5}molFe(OH)_3\)Moles of NH4Cl
\(molNH_4Cl=3.2\times10^{-5}molFeCl_3\times\frac{3molNH_4Cl}{1molFeCl_3}=9.6\times10^{-5}molNH_4Cl\)The grams of each product we will find by multiplying the moles by the molar mass. So we have.
g of Fe(OH)3
\(\begin{gathered} gFe(OH)_3=3.2\times10^{-5}molFe(OH)_3\times106.87g/molFe(OH)_3 \\ gFe(OH)_3=3.4\times10^{-3}g=3.4mg \end{gathered}\)g of NH4Cl
\(\begin{gathered} gNH_4Cl=molNH_4Cl\times MolarMassNH_4Cl \\ gNH_4Cl=9.6\times10^{-5}molNH_4Cl\times53.491g/molNH_4Cl=5.1\times10^{-3}g=5.1mg \end{gathered}\)Select all answer choices that would result in units of moles.
a) RT/PV
b) PV/RT
c) mass ÷ molar mass
d) molar mass ÷ mass
e) molar mass × mass
f) molarity ÷ volume
g) volume ÷ molarity
h) molarity × volume
The correct options that will result in mole are option B, C, and H
How do i know which options will result in mole?To know the options that will result in mole, do the following:
Ideal gas law states as follow:
PV = nRT
Where
P is the pressure V is the volumen is the number of moleR is the gas constantT is the temperaturePV = nRT
Make n the subject by dividing both sides by RT
n = PV / RT (option B)
Mole, mass and molar mass are related according to the following formula:
Mole = mass / molar mass (option C)
Molarity is defined as mole per unit volume as shown below:
Molarity = mole / volume
Make mole the subject by cross multiplying.
Mole = Molarity × volume (option H)
Thus, from the above illustrations, we can conclude that the correct options which will result in mole are option B, C, and H
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Which of the following equations is balanced?
Answer:
wheres the image
Explanation:
You can determine from the table earlier in this lesson that the energy stored in a gallon of gasoline is actually 65 times greater than the energy stored in a stick of dynamite. However, the energy in a stick of dynamite is released all in one instant, while the energy from a gallon of gasoline is usually released in a more controlled manner. Why is the rate at which energy is output from a system important?
Answer:
Explanation:
Safety: The rate of energy release determines how quickly and explosively the energy is released. In the case of the stick of dynamite, the rapid and instantaneous release of energy can cause a violent explosion. On the other hand, the controlled release of energy from gasoline allows for safer and more manageable energy output, reducing the risk of accidents and minimizing potential harm.
Efficiency: The rate at which energy is output affects the efficiency of a system. In many practical applications, such as engines or power generation, it is desirable to convert energy into useful work as efficiently as possible. Controlling the rate of energy release allows for a more efficient conversion of energy, minimizing waste and maximizing the desired output.
Control and Functionality: Different systems require energy to be released at specific rates to perform their intended functions. For example, in an internal combustion engine, the controlled and timed release of energy from fuel allows for the synchronized movement of engine components, resulting in the desired mechanical work. Controlling the rate of energy output ensures that a system operates effectively and performs its intended function.
Environmental Impact: The rate at which energy is output can also impact the environment. In processes that release energy too rapidly or uncontrollably, such as certain combustion reactions or explosions, there can be significant environmental consequences, including air pollution, damage to ecosystems, and the release of harmful byproducts. Controlling the rate of energy release allows for better management and mitigation of these environmental impacts.
Overall, the rate at which energy is output from a system is crucial for safety, efficiency, control, functionality, and environmental considerations. By regulating and optimizing the rate of energy release, we can ensure that energy is utilized effectively and responsibly in various applications.
How many atoms are in 12 g of Carbon-12 (12C)?
There are approximately 6.022 × 10^23 atoms in 12 grams of Carbon-12 (12C).
The number of atoms in a given amount of a substance can be calculated using Avogadro's number, which represents the number of atoms or molecules in one mole of a substance. Avogadro's number is approximately 6.022 × 10^23.
Carbon-12 is a specific isotope of carbon, with an atomic mass of 12 atomic mass units (amu). One mole of Carbon-12 has a mass of 12 grams. Since one mole of any substance contains Avogadro's number of particles, in the case of Carbon-12, it contains 6.022 × 10^23 atoms.
Therefore, if we have 12 grams of Carbon-12, which is equal to one mole, we can conclude that there are approximately 6.022 × 10^23 atoms in this amount of Carbon-12.
In summary, 12 grams of Carbon-12 contains approximately 6.022 × 10^23 atoms. Avogadro's number allows us to relate the mass of a substance to the number of atoms or molecules it contains, providing a fundamental concept in chemistry and enabling us to quantify and understand the microscopic world of atoms and molecules.
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