An experiment is performed to study how the change in some variables affects other related variables.
I can't see the diagrams but I can give you general answers for each statement.
1) We define a good experiment as an experiment where only one variable is tested at the time, this is because this allows the scientists to isolate the impact of that variable in the experiment.
"Since only one variable was changed in this experiment, this is called a good experiment."
2) The independent variable is the variable that the scientists can change in an experiment, in this case, we know that she does change the hours of light that each plant gets, so we can conclude that the independent variable is the time of light exposition that each plant gets.
"The independent variable in this experiment is the time of light exposition"
3) The dependent variable in an experiment is the variable that reacts to the changes in the independent variable, it usually is the thing that the scientist wants to study. In this case, we know that she is studying the floration times of tobacco plants, so:
"The dependent variable in this experiment is the flowering time of tobacco plants"
4) Controlled variables are, in principle, independent variables, that are fixed for the whole experiment. We can't see the controlled variables because there are no graphs, but we can think about what we should fix in this type of experiment.
The temperature: All the plants should grow in the same temperature, as it can affect the flowering times.
The humidity: The humidity also could impact on the flowering of the plants, so we need to fix it for the 5 plants.
The strain: All 5 tobacco plants need to be from the same genetics, we know that different genetics from different parts of the world may react differently to changes in light or temperature, so the strains need to be equal.
Substrates: All the plants should be on the same substrate, so she can be sure that all the plants are getting exactly the same nutrients from the soil.
These are just some examples, if you were designing this experiment, you would see that there are a lot of variables that need to be controlled.
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Which of the following is NOT a density formula?
Density = mass/volume
Density = volume/mass
mass = density x volume
volume = mass/density
Evidence for the Big Bang Theory
Group of answer choices
The amount of Lead and Iron in the Universe
Discovery of the Cosmic Background Radiation
Stars are like fires from the explosion
Answer:
2nd one
Explanation:
Big bang echo other ones make no sense.
Can someone help me pls, I do not know how to do this. i am trying to help a friend as well
Answer:
Your answer is 5 x 10⁵
I hope it's helps you
Answer:
[tex]thank \: you[/tex]
What is the molecular formula of sulphuric acid and ammonia compound by criss cross method
Answer:
H2SO4 AND NH3
Explanation:
I hope it will help you
Answer:
Explanation:
H2SO4 AND NH3
why does copper Cu (I) have a short lifespan
Answer:
Copper (Cu), chemical element, a reddish, extremely ductile metal of Group 11 (Ib) of the periodic table that is an unusually good conductor of electricity and heat. Copper is found in the free metallic state in nature.
Explanation:
hope this helps:)
Which methods separate a mixture according to the size of the particles?
A. distillation and evaporation
B. filtration and chromatography
C. filtration and evaporation
D. distillation and chromatography
Answer:
Only one of these methods separates compontents based on size.
The answer is filiration and chromatography.
Explanation:
which statement correctly contrasts science and psuedoscience
Answer:
The correct answer is Science is objective, whereas pseudoscience is subjective. Pseudoscience includes beliefs, theories, or practices that have been or are considered scientific, but have no basis in scientific fact. This could mean they were disproved scientifically, can't be tested or lack evidence to support them.
Explanation:
hope its help
thank you
explain dehydrogenation
Answer:
Dehydrogenation is the process by which hydrogen is removed from an organic compound to form a new chemical (e.g., to convert saturated into unsaturated compounds).
Calculate the number of moles for 50.7 g of hydrogen gas
Answer: 50.7 moles
Explanation:
given mass/ molecular mass
= 50.7/1
=50.7
Answer:
[tex]\boxed {\boxed {\sf 25.1 \ mol \ H_2}}[/tex]
Explanation:
We are asked to calculate the number of moles in 50.7 grams of hydrogen gas. To do this, we will use the molar mass or the mass of 1 mole of a substance. These values are found on the Periodic Table because they are equivalent to the atomic masses, but the units are grams per mole instead of atomic mass units.
Look up the molar mass of hydrogen (H).
H: 1.008 g/molNote that we are given grams of hydrogen gas. This is a diatomic molecule with 2 hydrogen atoms. The formula is H₂. Multiply the molar mass by 2 to find hydrogen gas's molar mass.
H₂ = 1.008 *2 = 2.016 g/molNow we can convert using dimensional analysis. Set up a ratio using the molar mass.
[tex]\frac {2.016 \ g \ H_2}{1 \ mol \ H_2}[/tex]
We are converting 50.7 grams to moles, so we multiply the ratio by this value.
[tex]50.7 \ g \ H_2 *\frac {2.016 \ g \ H_2}{1 \ mol \ H_2}[/tex]
Flip the ratio so the units of grams of hydrogen gas cancel.
[tex]50.7 \ g \ H_2 *\frac{1 \ mol \ H_2} {2.016 \ g \ H_2}[/tex]
[tex]50.7 \ *\frac{1 \ mol \ H_2} {2.016 }[/tex]
[tex]\frac {50.7} {2.016 } \ mol \ H_2[/tex]
[tex]25.14880952 \ mol \ H_2[/tex]
The original value of grams (50.7) has 3 significant figures, so our answer must have the same. For the number we calculated, that is the tenths place. The 4 in the hundredth place to the right tells us to leave the 1 in the tenths place.
[tex]25.1 \ mol \ H_2[/tex]
50.7 grams of hydrogen gas is equal to approximately 25.1 moles of hydrogen gas.
Please help thank you (15 points)
Answer:
A. Complete one revolution around the sun
4) A sample of sodium bromide, NaBr, has a mass percentage of sodium of 22.34%.
a) If the sample of sodium bromide were contaminated with sodium chloride, NaCl, would the mass percentage of Na in the sample be higher or lower than the pure sample? Justify your claim.
b) If the sample of sodium bromide were contaminated with sodium iodide, NaI, would the mass percentage of Na in the sample be higher or lower than the pure sample? Justify your claim
Explanation:
The trick here is to realize the every sample of sodium bromide, regardless of its mass, will contain
22.34
%
sodium by mass.
This is true because sodium and bromide always combine in definite proportions, i.e. stable ratios by mass, to form sodium bromide.
Now, a
22.34
%
percent concentration by mass means that every
100 g
of sodium bromide will contain
22.34 g
of sodium and
100 g
−
22.34 g
=
77.66 g Br
Therefore, you can say that the mass ratio that exists between sodium and bromine in any sample of sodium bromide will be
22.34 g Na
77.66 g Br
=
22.34
77.66
You can thus use this definite proportion to say that a
5.69 g
sample of sodium bromide will contain
5.69
g NaBr
⋅
22.34 g Na
100
g NaBr
=
1.271 g Na
=
¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯
∣
∣
a
a
1.27 g Na
a
a
∣
∣
−−−−−−−−−−−−−
The answer is rounded to three sig figs.
You can use the known definite proportion to find the mass of bromide present in the sample
1.271
g NaBr
⋅
77.66 g Br
22.34
g NaBr
=
4.42 g Br
This checks out because
mass of NaBr sample
5.69 g
−
mass of Na
1.27 g
=
mass of Br
4.42 g
The answers to your questions are ;
a) The mass percentage of Na in the sample will be higher in the sample
b) The mass percentage of Na in the sample will be be lower in the sample
Given that:
Mass percentage of sodium contained in sodium Bromide = 22.34%
a) Determine if the mass percentage of Na will be higher or lower when sodium Bromide is contaminated with sodium chloride
mass percentage of Na in sodium bromide
= ( mass of Na / mass of NaBr )*100
The mass of sodium in NaBr and NaCl is the same while the mass of Br is not same ( greater than ) as the mass of Cl. hence when NaBr is contaminated with NaCl the total mass of in percentage NaBr will decrease. and This decrease in mass of NaBr will lead to a decrease/lower mass percentage of Na in the sample
b) When NaBr is contaminated with NaI
The mass of Na is the same in NaBr and NaI while the mass of I is not the same ( greater than ) as the mass of Br, therefore the total mass will increase and the increase in the Total mass in percentage will lead to an increase/higher value of Na in the given sample.
hence the mass percentage of Na will decrease when NaBr is contaminated with NaCl while the mass percentage of Na will increase when NaBr is contaminated with NaI
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Take a look at your rubbing alcohol at home. What is its main composition?
Answer:
It is a mixture of denatured alcohol, water, and agents added to make the alcohol unpalatable to drink.
Iron has a density of 7.86 g/cm3. Calculate the volume (in dL) of a piece of iron having a mass of 4.59 kg .
A graduated cylinder is filled with 20ml of water. A rock is dropped in to the graduated cyclinder and the volume of water rises to 30ml
inside the graduated cylinder. The mass of the rock is 23g. What is the density of the rock?
2.3g/ml
0.77g/ml
5g/ml
1.15g/ml
Answer:
[tex]\boxed {\boxed {\sf 2.3 \ g/mL}}[/tex]
Explanation:
We are asked to find the density of a rock. Density is the substance's mass per unit volume. The formula for calculating density is:
[tex]\rho= \frac{m}{v}[/tex]
The mass of the rock is 23 grams. The volume was found using water displacement. A known amount of water was measured, the rock was added to the graduated cylinder, and the water level was recorded again. The volume is the difference between the final and initial water level. The graduated cylinder originally had 20 milliliters and the water rose to 30 milliliters.
volume = final water level - initial water level volume = 30 mL - 20 mLvolume = 10 mLNow we know the mass and the volume.
m= 23 g v= 10 mLSubstitute the values into the formula.
[tex]\rho= \frac{ 23 \ g }{30 \ mL}[/tex]
Divide.
[tex]\rho= 2.3 \ g/mL[/tex]
The density of the rock is 2.3 grams per milliliter.
Please solve these two QUESTION .
its my ASSIGNMENT
Explanation:
It is the total mass of protons and neutrons in an individual atom or isotope. Since, Atomic Mass is total mass of protons and neutrons in an individual atom or isotope and not the actual weight of an Atom.
this means that it exists in the form of isotopes and is generally in fraction.
draw a diagram to show what happened to the particle, when a liquid cools to a solid?
And do follow if you appreciate it
Which of the following can be referred to as a d7 ion? * O Cu4+ o Mn 4+ O O O Ni4+ O None of the above .
Transition metals are known to have incompletely filled d- orbitals. For this reason, they are commonly referred to as the d- block. Cu4+ is a d7 ion.
An ion is formed when electrons are lost from or gained in a neutral atom.
An ion is a positively or negatively charged chemical specie. Chemical species form ions by loss or gain of electrons.
An atom is neutral if it has equal number of protons and electrons. When an atom has lost electrons, it forms a positive ion.
Copper has electronic configuration; 1s2 2s2 2p6 3s2 3p6 4s2 3d9. When four electrons are lost, its electronic configuration now becomes;
1s2 2s2 2p6 3s2 3p6 3d7.
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Which pair of reactants for a Grignard reaction does not give 2-phenylbutan-2-ol after an aqueous workup?
An certain element Y has two naturally occurring isotopes, 6Y (isotopic mass = 6.015123 amu) and 7Y (isotopic mass = 7.016005 amu). If the atomic mass of the element is 6.9412 amu. What is the percent abundance of 6Y?
Do not include the symbol "%" in your answer.
Report the correct answer to three significant figures
The percentage abundance of 6Y is 0.102.
An Isotope refers to two or more atoms that has the same atomic number but different mass numbers.
We have been informed from the question that the atomic mass of the element is 6.9412 amu.
Let the abundance of isotope 6Y be x
Let the abundance of isotope 7Y be 1-x
Hence;
6.9412 = 6.015123x + 7.016005(1 - x)
6.9412 = 6.015123x + 7.016005 - 7.016005x
6.9412 - 7.016005 = 6.015123x - 7.016005x
-0.102 = -1x
x = -0.102/-1
x = 0.102
Hence the percentage abundance of isotope 6Y is 0.102.
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The percentage abundance of 6Y is 7.47%
Isotopy is the phenomenon whereby two or element have the same atomic number but different mass number due to the difference in their neutron number.
We'll begin the solving as follow:
Let A represent isotope 6Y
Let B represent isotope 7Y
From the question given above, the following data were obtained:
For isotope A (6Y):Mass of A = 6.015123 amu
Abundance of A (A₀) =…? For isotope B (7Y):Mass of B = 7.016005 amu
Abundance of B (B₀) = (100 – A₀%
Relative Atomic mass of Y = 6.9412 amu
The abundance of 6Y can be obtained as follow:
[tex]RAM = \frac{MassA * A_{0} }{100} + \frac{MassB * B_{0} }{100}\\\\6.9412 = \frac{6.015123 * A_{0}}{100} + \frac{7.016005 (100 - A_{0})}{100}\\\\6.9412 = 0.06015123 A_{0} + \frac{701.6005 - 7.016005A_{0}}{100}\\\\6.9412 = 0.06015123 A_{0} + 7.016005 - 0.07016005A_{0}[/tex]
Collect like terms
[tex]6.9412 - 7.016005 = 0.06015123A_{0} - 0.07016005A_{0}\\-0.074805 = -0.01000882A_{0}[/tex]
Divide both side by –0.0100882
[tex]A_{0} = \frac{-0.074805}{-0.01000882}\\\\[/tex]
A% = 7.47%Therefore, the abundance of 6Y is 7.47%
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what is chemical change ?
[tex]\huge{ \color{violet}{ \boxed{ \color{hotpink}{Answer}}}}[/tex]
➣ Chemical ChangeIt occurs when new materials are formed by a change in the way the atoms are bonded together.Heat, light or electrical energy is often emmitted or absorbed.[tex] \: [/tex]
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Question
"Drag each tile to the correct location on the concept map", for the question.
Read the instructions for this self-checked activity. Respond to each question, and check your answers. At the end of the activity, write a brief
evaluation of your work.
Answer:
i hope this helps, also you might want to put it into your own words because this was directly from the answer key :)
Explanation:
Faustus Faustus is the protagonist of the play. He is a brilliant scholar who makes a deal with Lucifer to exchange his soul for magical power. He later regrets his decision, but it’s too late and his soul is carried away to hell.
Mephastophilis Mephastophilis is a demon that Faustus calls upon to help him with magic. He turns into Faustus's servant in his pact with the devil.
Valdes and Cornelius Valdes and Cornelius are friends of Faustus who teach him the art of black magic.
three scholars The three scholars are friends of Faustus who are concerned about his welfare.
Lucifer Lucifer (the devil) is Mephastophilis’s master. He makes a deal with Faustus.
Wagner Wagner is Faustus’s servant. He learns how to work magic from his master’s books.
clown The clown becomes Wagner's servant. He provides comic relief in the story.
good angel The good angel is a spirit that tries to get Faustus to repent.
evil angel The evil angel is a spirit that tempts Faustus to rebel against God and make a pact with the devil.
the pope The pope is the head of the Roman Catholic Church and symbolizes the religious beliefs that Faustus has abandoned.
horse-courser The horse-courser is a horse trader who purchases a horse from Faustus.
old man The old man is a mysterious figure who takes the place of the good and evil angels in the last scene of the play.
Given six molecules, identify the molecules with polar bonds and the molecules that are polar.CCl4, CH3Cl, H20, CO2, O2
Answer:
polar bonds- H2O, CO2, CH3CL,
The molecules that have polar bonds are CH₃Cl, and H₂O.
What are polar bonds?A polar bond is a type of covalent bond where the electron is unequally distributed.
This unequal distribution is due to the electronegativity difference of the attached atoms in the molecule.
A lewis structure of the molecule is studied to determine whether the compounds are polar and non-polar.
The molecule CCl₄: has one carbon atom at the center and the chlorine surrounds the carbon from all four sides, so even if there is a difference in the electronegativity the net dipole movement gets balanced from all four sides, so it is not a polar bond.
The molecule CH₃Cl
Similar to the CCl₄, hydrogen, and chlorine is surrounding the carbon, the three sides are hydrogen and one side is chlorine, so there is a net dipole movement and so it is a polar bond.
The molecule H₂O: The dipole movement of Hydrogen and oxygen are both in opposite directions and of different magnitude hence it will have a net dipole movement and so it is polar.
The molecule CO₂ and O₂ have net dipole movements as zero so are not polar compounds.
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Density is defined as the mass of a substance divided by its volume, or D=M/V. Calculate the
volume of 119.9 grams of a substance that has a density of 0.8 g/mL
Answer: 149.9 ml
Explanation: Do as the formula suggests: D = M/V
0.8 g/ml = 119.9 grams/V
V = (119.9 grams)/(0.8 grams/ml) = 212.8 ml
Note how the grams cancel and the ml moves to the top.
Which of the following does the atomic number of an atom represent? (1 point)
o the number of neutrons in the atom
O the number of particles outside the nucleus of the atom
O the number of protons in the atom
o the number of particles in the nucleus of the atom
Explanation:
the atomic number is the number of protons in the atom
True or false
an astronomer studies the universe beyond Earth.
Answer:
More generally, astronomy studies everything that originates beyond Earth's atmosphere. Cosmology is a branch of astronomy that studies the universe as a whole. Astronomy is one of the oldest natural sciences. The early civilizations in recorded history made methodical observations of the night sky.
1°C rise in temperature is equal to a rise of
Answer:
1°C rise in temperature is equal to a rise of 59°F
Answer:
Hence 1℃ rise in temperature is equal to the rise in 59℉.
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If I have a bottle of compound X at a pressure of 45 atm and temperature of 100 °C, what will happen if I raise the temperature to 400 °C?*
Answer:
55/350
Explanation:
because the answer is in the middle of 50and 400
4-hydroxyl and 5- hydroxyl aldehydes exist primarily as a cyclic hemiacetals.draw the structures formed from 4-hydroxyl butanal
2. Which of the following is the reason that ionization energy generally increases from left to right across the first period of the periodic table?
(A) As the atomic number increases, the electrons are harder to remove.
(B) Ionization energy increases as the atomic number increases in a period.
(C) As the atomic number increases, more electrons are
added to the atoms, thus increasing the electron-electron repulsions.
(D) As the atomic number increases, more protons in the
nucleus cause an increase in the effective nuclear charge,
making it harder to remove the electrons.
Answer:
The correct answer is D
Explanation:
more protons in the nucleus cause an increase in effective nuclear charge ,
write on the principle and other application of a named instrument employed in unlocking frozen joints.
We have that the bone file from our research below
The is a very important tool in unlocking frozen joints by using its
Pull stroke
Serrated edges etc
And its also used in the field of dentistry.
Before we pick an instrument to focus on we first have to under stand what a frozen joints is
Frozen Joint,
Frozen Joint, which is also refereed to as adhesive capsulitis, is a situation whereby ones joints are stiff and they experience pain in the joint.
We focus on the
Bone file( principle)
It is made of a pull stroke which is designed to aid the removal of bones,they are also designed with serrated edges which are used in many different ways one of which is to smooth bones out in order to disinfect a given area
Bone file
This can also be used in the field of dentistry.
it puts into use it variant functions to make the work of a dentist easy
In conclusion
The Bone file is a very important tool in unlocking frozen joints by using its
Pull stroke
Serrated edges etc
And its also used in the field of dentistry.
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