An experiment occurs when we want to study the relationship between the dependent and the independent variable. We know that the independent variable is the variable that is manipulated in the experiment and the dependent variable variable is the variable that undergoes a change as we change the independent variable.
It must be known that an experiment is the only way that we could be able to establish a cause and effect relationship. In other words, the results of an experiment tell us categorically if the effect owes to a supposed cause as was captured in the hypothesis of the experiment.
In this case we have the following in this experiment;
The independent variable is the use or absence of the test guide
The dependent variable is the overall performance in the academic year
The control group is the group that did not use the test guides
The experimental group is the group that used the test guides
The constants are the method of instruction, the structure of the test and the difficulty of the test.
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Missing parts;
The local high school recently passed a rule reducing how much teachers can count homework as part of a student's grade. Consequently, a larger portion of the students stop doing their homework. A teacher there decides to conduct an experiment. All of his classes get an optional "test guide" to help them study for their tests. He allows two classes to use the "test guides" (that they must fill in and complete) on their exams. He hypothesizes that students will complete the test guides and learning will occur from filling them out. In his other 2 classes, the teacher does not allow students to use test guides on the exam, and consequently very few of them filled them out. After the 2017-2018 year is over, he wants to compare scores between the 4 classes on the final exam to see if allowing students to use test guides during each test throughout the year improved their later overall performance.
Independent Variable: _____________________________ Dependent Variable: ___________________________________
Experimental Group: _______________________________ Control Group: _________________________________________
3 constants: ______________________________________________________
Which reactions performed in the experiment
involved chemical changes?
crushing calcium carbonate
mixing calcium carbonate and HCI
boiling water
heating copper (II) sulfate pentahydrate
separating iron filing and sulfur
mixing potassium iodide and lead nitrate
combining magnesium and HCI
burning the candle
DONE
Mixing calcium carbonate and HCl
Heating copper sulfate pentahydrate
Mixing potassium iodide and lead nitrate
Combining magnesium and HCl
Burning the candle.
The crushing of limestone is a bodily trade it no longer alters the chemical composition of the limestone. The heating of limestone is a chemical trade the limestone decomposes into two other materials, lime and carbon dioxide. both ended in gas formation. both ended in shade change.
Rust is not anything however Iron Oxide is a brand new substance shaped out of the response. The color of the floor of the iron additionally modifications. hence, rusting of iron is a chemical trade. Rusting is an instance of chemical exchange. A chemical property describes the ability of a substance to go through a particular chemical alternate. The chemical belonging of iron is that it is miles capable of combining with oxygen to form iron oxide, the chemical call of rust. like several steel carbonates, calcium carbonate reacts with acidic solutions to supply carbon dioxide gas.
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3. In a chemical reaction, the final amount of the products is determined by the
A. Universal Gas Law
B. catalysts involved
C. air pressure
D. temperature
E. limiting reactant
Match each electron configuration to the correct element. Use the periodic table to determine the number of electrons that each element has. Drag the tiles to the correct boxes to complete the pairs. Tiles [Kr] 5s2 4d10 5p2 1s2 2s2 2p6 3s2 3p5 1s2 2s2 2p6 3s2 3p6 4s2 3d10 [Ar] 4s2 3d6
[Kr]5s₂4d₁₀5p₂, 1s₂2s₂2p₆3s₂3p₅, 1s₂2s₂2p₆3s₂3p₆4s₂3d₁₀, [Ar]4s₂3d₆ are electronic configuration of tin (Sn), Chlorine (Cl), Zinc (Zn), Iron (Fe) respectively.
The distribution of electrons in an element's atomic orbitals is described by the element's electron configuration. Atomic electronic configurations are written using a standard notation that arranges all atomic subshells that contain electrons in a sequential order.Filling of atomic Orbitals are done by following principles: Aufbau principle, Pauli exclusion principle, and Hund's rule.The theory states that electrons fill up in the following order: 1s, 2s, 2p, 3s, 3d, 4p, 5s, 4d, 5p, 6s, 4f, 5d, 6p, and 7s, 5f, 6d, 7p....[Kr]5s₂4d₁₀5p₂
Tin
Number of electrons = 50
1s₂2s₂2p₆3s₂3p₅
Chlorine
Number of electrons = 17
1s₂2s₂2p₆3s₂3p₆4s₂3d₁₀
Zinc
Number of electrons = 30
[Ar]4s₂3d₆
Iron
Number of electrons = 26
Hence, these electronic configuration are of Tin, chlorine, zinc, and Iron.
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Answer: screen shot below.
Explanation:
All of the following are phases of matter except *
A solid
OB liquid
OC gas
Lighting
Answer:
lighting bru
Explanation:
Given that the work function of chromium is 4.40 eV calculate the kinetic energy of electrons emitted from chromium surface that is irradiated with ultraviolet radiation of wavelength 200.0 nm.
The kinetic energy of electrons emitted from chromium surface is determined as 2.9 x 10⁻¹⁹ J.
Energy of the emitted photon
The energy of the emitted photon is calculated as follows;
E = hf
E = hc/λ
where;
h is Planck's constantc is speed of lightλ is wavelength of the photonE = (6.626 x 10⁻³⁴ x 3 x 10⁸) / (200 x 10⁻⁹)
E = 9.94 x 10⁻¹⁹ J
Work function of the chromium is joulesΦ = 4.4 x 1.6 x 10⁻¹⁹
Φ = 7.04 x 10⁻¹⁹ J
Kinetic energy of the electronE = K.E + Φ
K.E = E - Φ
K.E = 9.94 x 10⁻¹⁹ J - 7.04 x 10⁻¹⁹ J
K.E = 2.9 x 10⁻¹⁹ J
Thus, the kinetic energy of electrons emitted from chromium surface is determined as 2.9 x 10⁻¹⁹ J.
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A 25 mL sample of matter has a density of 7.9 g/ml., What is the mass of the substance?
Answer:
197.5 grams
Explanation:
To find the mass (g) of the sample, you need to multiply the given volume (mL) by the denisty. You can use the denisty to convert between mL and g because the denisty is a ratio which represents the mass of the sample per every 1 mL. The ratio should be arranged in a way that allows for the cancellation of units (mL should be in the denominator).
Denisty = 7.9 grams/ 1 mL
25 mL 7.9 grams
----------------- x ---------------------- = 197.5 grams
1 mL
**The final answer is not written with the proper sig figs.
4521 kg into milligrams
Answer:
5421 kg = 5421000 mg
Explanation:
Hope this helps!
Answer:
4521 kg = 4521000000 milligrams
Hope this helps :)
Which of the following processes requires more heat energy?
a. raising the temperature of 100. g of water by 10.0 °C
b. raising the temperature of 100. g of aluminum by 10.0 °C?
Raising the temperature of 100 grams of water by 10.0 C is one of those processes which requires more heat energy.
What degree of heat can 100 grams of water withstand?30.514KJ is the amount of heat can 100 grams of water withstand.
Water has a volume of 100 milliliters and weighs 100 grams. (100°C - 27°C) is the temperature difference, which equals 73°C. Water has a specific heat of 4.18 J/g/°C, thus we can apply the calculation below to determine how much energy is required. The necessary energy is equal to 30.514KJ for 100g at 73°C and 4.18 J/g/°C.
What happens to water's thermal energy as it transforms from a liquid to a solid state?Once all of its thermal energy is gone, water freezes, changing from a liquid to a solid. In our daily lives, these kinds of occurrences constantly occur. Puddles, ponds, lakes, and even parts of oceans freeze when the water gets cold enough. In colder climates, the surface water on Earth freezes and solidifies.
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2.5 g Ti, 1.7 g F2
Express your answer using two significant figures
The theoretical yield of titanium tetrafluoride is 2.79 g
What is the theoretical yield?We know that the theoretical yield is the yield of the product that we can obtain from the stoichiometry of the problem. We now have to go back to the reaction equation and write;
[tex]Ti(s) + 2F_{2} (g) --- > TiF_{4} (s)[/tex]
Number of Ti = 2.5g/48 g/mol = 0.052 moles
Number of moles of F2 = 1.7 g/38 g/mol 0.045 moles
If 1 mole of Ti reacts with 2 moles of F2
0.052 moles reacts with 0.052 moles * 2 moles/1 mole
= 0.10 moles
We can see that F2 is the limiting reactant
If 2 moles of F2 1 mole of [tex]TiF_{4}[/tex]
0.045 moles of F2 produces 0.045 moles * 1 mole/2 moles
= 0.0225 moles
Mass of titanium tetrafluoride = 0.0225 moles * 124 g/mol
= 2.79 g
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What is the density of a metal block that has a mass of 250.00 grams and the length is 16.25 cm, the width is 2.30 cm, and the height is 6.00 cm?
Round to the correct number of significant figures. Do not include the unit in the answer.
The density of a metal block that has a mass of 250.00 grams and the length is 16.25 cm, the width is 2.30 cm, and the height is 6.00 cm is 1.11.
What is density?Density can be defined as the measurement of how tightly a material is pecked together. It is defined as mass per unit volume.
Its SI unit is g/cm3 .
Density can be expressed as
Density = mass/ volume
Volume of metal block = length x width x height
= 16.25 x 2.30 x 6.00
= 224.3 ml
Density = 250.0 / 224.3 g/ml
= 1.11 g/ml
Thus, the density of a metal block that has a mass of 250.00 grams and the length is 16.25 cm, the width is 2.30 cm, and the height is 6.00 cm is 1.11.
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While camping, you make a snack over a campfire. You roast a marshmallow over the campfire until it is browned and put it between some chocolate and graham crackers. When you take a bite, you notice that the chocolate and marshmallow have melted slightly.
Which statement correctly identifies a part of this process as a physical or a chemical change?
A. The melting of the chocolate is a chemical change
B. The digestion of the food is a physical change
C. The toasting of the marshmallow is a chemical change
D. The burning of the wood for the campfire is a physical change
The answer is C. The toasting of the marshmallow is a chemical change.
Why?
Based on the other options:
A.) The melting of the chocolate ISNT a chemical change. It's a physical change.
B.) The digestion of food is NOT a physical change. It's a chemical change.
D. The burning of the wood for the campfire is NOT a physical change. It's a chemical change.
Physical Change: Doesn’t change the composition of the matter. However, its physical appearance and properties can change.
Chemical Change: During chemical changes, the matter that you start with isn’t the matter you end up with.
One example of an estuary is
Responses
A The Atlantic Ocean.the Atlantic Ocean.
B Lake Superior.Lake Superior.
C the Potomac River.the Potomac River.
D the Chesapeake Bay.
NO SPAMS OR I WILL REPORT YOU AND BAN YOU IMMEDIATLEY
Answer: D I PROMISE
Explanation:
IVE TOOK THE TEST AND ITS D
Emission and absorption line spectra both provide evidence for which of the following:
a. the existence of isotopes
b. the existence of energy levels within the atom
c. the existence of sub-atomic particles
d. the existence of ions
B. The emission and absorption line spectra both provide evidence for the existence of energy levels within the atom.
What is emission of line spectrum?
An emission of line spectrum occurs when energy is added to an atom due to difference in energy level.
An emission line will appear in a spectrum if the source emits specific wavelengths of radiation.
What is absorption line spectrum?An absorption spectrum occurs when light passes through a cold, dilute gas and atoms in the gas absorb at characteristic frequencies due to difference in energy level.
Thus, the emission and absorption line spectra both provide evidence for the existence of energy levels within the atom.
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1000 in² = ? yd.
Could sb help me out
Answer:
um 27 yards..............
Will mark BRAINLYEST
When you place your hand in water it appears to be larger. explain why this happens
Answer:
because the water is like a magnified glass Its on your hand and your hand apears bigger
Explanation:
Which subatomic particle is used to identify the atom, as it never changes?
Protons
Electrons
Neutrons
Nucleus
I need some help with crush advise. So basically i have a crush on this dude but i don't think he know me we are not in the same class but we see each other at morning time and recess by the way he is Vietnamese and he is cute. If you have some advice. ( PLEASE TELL ME) please don't just steal the points, really help me out
Answer:
Go for it!
Explanation:
You only live once, seriously just go up and talk to him. Say something like, "Hey, you seemed cool I just wanted to say hi. Do you have an ig?" :) you won't regret it.
Answer:
There are a couple of things you should do! first, you should become his friend, and be a good friend, too. Don't fl!rt with him when you first meet, or in the first couple of times you guys meet. Ask him things you are genuinely curious to know about him, don't ask generic questions such as " whats your favorite color" or make small talk. Ask him things that relate to him more like what's his full name, or where is he from. If you really are curious to know what his favorite color is, you can ask him, but make sure he knows you are genuinely curious to know, and not just making small talk. After getting to know him better, you have to ask yourself if you are still interested in him in "that" way, or interested at all, even. If the answer is yes, you still have love interest the next thing you should know is if he is single, or likes someone. When you ask him if hes single don't make it weird if he says no, just be chill. If he is single, but has a crush on someone you should ask him who. If he doesn't tell you and you guys are close already, it's probably you. After finding out all these things about him, you should wait about 2 months and then confess to him that you like him (if he has not already confessed to you) and no worries if he rejects you, rejection happens sometimes and it's totally okay. It may not feel like it right away, or even longer away but you will eventually get over him.
Explanation:
I hope these tips were helpful, and if you have any more questions please ask I'm here to help you <3
What is the volume of foil for 14.45cm times 8.55 cm times 0.550 g
The volume of foil for 14.45cm times 8.55 cm times 0.550 g is
67.95 cm^3
Volume = lenght * breadth * height
= 14.45cm * 8.55 cm * 0.550 cm
= 67.95 cm^3
Volume is the amount of space an object take upA measure of the size of a body or region in three-dimensional space.amount of space occupied by an object L x W x Hcubic centimeters is the basic unit for measuring the volume of solids and gasesvolume is a Three Dimensional existing in three dimensions; having length, width, and height.Cubic Yard is the volume of a cube is one yard on each side.Cubic Meter is the volume of a cube is one meter on each side.To know more about Volume visit :
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if you can please answer both
Answer: C & D
Explaination:
C because the atomic number increases sequentially and also the nuclear charge
D because as you're moving down a column the valance electrons does not change, only the atomic radius does.
72. A 5-mL sample of water has a mass of 5g. What is the density of water?
Answer: 1 g/ml
Explanation:
5 g / 5ml= 1 g/ml
Write the name of the alkane with six carbon atoms
Hexane is an alkane with six carbon atoms.
Hexane is an organic substance having the chemical formula C6H14. It is a straight-chain alkane containing six carbon atoms. When pure, it is an odorless, colourless liquid with a boiling point of roughly 69 °C (156 °F). It is a broadly applicable non-polar solvent that is quite safe, mainly unreactive, affordable, and easily evaporable.
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What is the molarity of a substance in which 10.8 grams per f calcium chloride is dissolved in enough water to make to make 125 mL of solution?
The moles of solute per liter of solution is measured as molarity. For instance, when table salt is dissolved in water, water serves as both the solution and the solute. Sodium chloride weights 58.44 grams per mole. 58.44 grams of sodium chloride dissolve in one liter of water to form a one molar solution, or 1M.
What is the molarity of a substance in which 10.8 grams per f calcium chloride is dissolved in enough water to make to make 125 mL of solution?
"2.7 moles"
Rearranging Molarity is determined by multiplying moles by litres.
Litres times molarity equals moles.
The amount of water in 125 g is similar to 125 ml, or 0.125 litre.
The number of moles is 0.125 x 2 = 0.25 mol since the molarity is 2.0M.
To get the answer of 10.8g, simply multiply this by the molar mass of calcium chloride, which is 110.98 g/mol.
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Which of the following values of n makes the equation n2-159=10 true?
For the reaction shown, identify the oxidation half-reaction and the reduction half-reaction. KNO3 → KNO2 + O₂ Which pair of half-reactions represents the balanced half-reactions? N5+ + 2e →N³+ 0² →0₂ + 4e 2N5+ + 4e¯ → 2N³+ 20²- → 0₂ +4e 4N5+ 2e4N³+ 20² → 20₂ + 4e¯
N5+ + 2e →N³
here Nitrogen gains electron so, its reduction half-reaction
20²- → 0₂
here oxygen loss electron so, its oxidation half-reaction
20² → 20₂ + 4e¯
here oxygen loss electron so, its oxidation half-reaction
2N5+ + 4e¯ → 2N³
here nitrogen gains electron so, its reduction half-reaction
When an atom loses electrons, it is said to be oxidising; when it acquires electrons, it is said to be reduced. A redox reaction occurs when both of these reactions take place at the same time.When a molecule oxidises, it implies it either gives or loses electrons to another molecule. As a result, the reaction between a molecule of oxygen and a molecule of hydrochloric acid may be shown below. Because it has to combine with hydrogen to create a proper molecule, the oxygen molecule in this process is unstable. Four extra hydrogen molecules are available for disposal in the hydrogen chloride molecule. Thus, although the hydrochloric acid transforms into chlorine gas, all of the hydrogen from the acid unites with the oxygen molecule to form water.To know more about oxidation visit : https://brainly.com/question/13003361
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32. Describe how scientific notation makes it easier to
work with very large or very small numbers.
Scientific notation makes it easier to work with very large or very small numbers because it makes a very small or large number into a shorter one.
How scientific notation makes it easier to work with very large or very small numbers?Scientific notation makes it easy to compare numbers that have very large values because all the zeroes have been replaced with small number which can be read easily. In scientific notation, numbers with a greater exponent are bigger than numbers with a small or less exponent because higher exponent shows the larger value and smaller value represents smaller value. So that's why scientific notation make easier to write or read a very large or small number.
So we can conclude that Scientific notation makes it easier to work with very large or very small numbers because it makes a very small or large number into a shorter one.
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Question 19
When the reaction here goes in the backwards direction what is acting as the base?
H3O+ PH3 PH4* + H₂O.
OPH₂*
O H₂O
OPH₂
O H₂O*
1.5 p
Round the answer of the following calculation to the correct number of significant figures;
3700 20.1 x 5.60 x 0.0407
The calculation gives the product 17000 to 2 significant figures
What are significant figures in a calculation?Significant figures in a calculation or a number refers to the number of non-zero numbers that are present in a number.
If the number contains a decimal point, the number of non-zero numbers before the decimal point gives the number of significant figures.
However, if a zero occurs between non-zero numbers, it is considered significant.
Significant figures are used in approximation to indicate to what point a set of numbers become significant.
In a calculation, the number significant figure is determined by the number which has the lowest number of significant figures.
In the given calculation, the lowest significant figure is in the numbers 3700 and 5.60
3700 × 20.1 × 5.60 × 0.0407 = 17000 to 2 significant figures
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(PLEASE HELP)"The most abundant isotope of Hydrogen has a mass of 1 amu. Therefore, the average atomic mass on the periodic table for Hydrogen will be 1 amu." Using the terms isotopes, abundance, average atomic mass and weighted mass to explain why this misconception is incorrect and why the abundance(amount) of each isotope of the element affect the average atomic mass.
The statement the most abundant isotope of Hydrogen has a mass of 1 amu is wrong.
What is the average atomic mass?The average atomic mass could be obtained as the sum of the products of the percentage abundance of each of the hydrogen isotopes and the mass of the isotope.
We know that every element has isotopes. In every sample of the atom, there are various isotopes of the element. Thus the average atomic mass must take into account the masses of all these isotopes.
As such, the statement the most abundant isotope of Hydrogen has a mass of 1 amu is wrong.
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How I can convert 7 Ms to s
Answer:
Divide the time value by 1000
Explanation:
7 Ms = 0.007s
The density of copper is 8.92g/cm³. If a 10.00g sample is placed in a graduated cylinder that
contains 15.0mL of water, what is the total volume?
The total volume of sample with given density and mass of copper is 16.815 cm³.
Equation :volume of copper = mass / density
v = 10.00g / 8.92g/cm³
v = 1.121 cm³
So to calculate total of volume of given sample,
Total volume = Volume of copper x Volume of water
V = 1.121 x 15.0
V = 16.815 cm³
What is volume ?A solid shape's capacity is measured using volume, a three-dimensional quantity. It implies that a closed figure's volume determines how much three-dimensional space it can occupy. A derived unit called the cubic meter (m3) serves as the SI unit of volume. The cubic decimeter is referred to as a "liter" (L) (dm3).
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