Answer:
Option d) 3 only is the right answer
8. Jill conducted an experiment to investigate which plant food would make her
plants grow faster. She tried four different plant foods on plants of the same
type and age. Jill concluded that the plant that was fed Brand A grew the
fastest. Jill did not realize that the plant that was fed Brand A also received
more sunlight. (SC.7.N.1.5.3)
What error did Jill make in her experiment?
a) She used the wrong kind of plant.
b) She used too much plant food.
c) She did not control the variables.
I want to know how to solve this question by step by step.
Question: What is the pH value of 500ml of an aqueous solution of 0.005 mol HCl ?
The pH value of 500 mL of an aqueous solution of 0.005 mole HCl is 2
How do I determine the pH of the solution?We'll begin our calculations by obtaining the molarity of the solution. Details below:
Volume of solution = 500 mL = 500 / 1000 = 0.50 LMole of HCl = 0.005 moleMolarity = ?Molarity = mole / volume
Molarity = 0.005 / 0.50
Molarity = 0.01 M
Next, we shall obtain the concentration of the hydrogen ion, H⁺ in the solution. Details below:
HCl(aq) <=> H⁺(aq) + Cl¯(aq)
From the balanced equation above,
1 mole of HCl contains 1 mole of H⁺
Therefore,
0.01 M HCl will also contain 0.01 M H⁺
Thus, the concentration of the hydrogen ion, H⁺ in the solution is 0.01 M
Finally, we shall determine the pH of the solution. Details below:
Concentration of hydrogen ion [H⁺] = 0.01 MpH of solution =?pH = -Log H⁺
pH = -Log 0.01
pH = 2
Thus, we can conclude that the pH of the solution is 2
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2. A small block of a metal with a mass of 223.1 grams when
submerged in a beaker containing water, the water level rises to
150.0 mL as shown in the figure here. If the density of the metal
block is 7.41 g/cm³ at 22°C, then what was the original water level
in the beaker?
Water leve
150 mL
The volume of the metal block can be calculated using the density and mass of the block is 30.0 cm³
What is metal block?A metal block is a solid piece of metal that is typically used for machining and other industrial applications. It is usually made from aluminum, steel, or other metals, and can be machined into a variety of shapes and sizes depending on the application. Metal blocks are also used for casting, forging, and other manufacturing processes. Metal blocks may also be used for decorative purposes, such as sculpture or engraving. They are also used in jewelry making and engraving, as well as in medical and dental applications.
The volume of the metal block can be calculated using the density and mass of the block:
Volume = Mass/Density = 223.1 g/7.41 g/cm³ = 30.0 cm³
Since the metal block was submerged in the water, the volume of the block will be added to the volume of water in the beaker. Therefore, the original water level in the beaker can be calculated using the following equation:
Original Water Level = 150 mL + (30.0 cm³/1000 cm³/mL) = 180.0 mL
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Which statement is true about the potential energy diagram for an endothermic reaction? (5 points)
The potential energy of the products is equal to the potential energy of the reactants.
It starts at a higher energy value and ends at a lower energy value.
The energy value remains the same throughout the diagram.
Products have more potential energy than reactants.
In an endothermic reaction, potential energy of products is greater than that of the reactants. Reactants in endothermic reaction are absorbing enough heat energy to overcome this barrier potential. Hence, option d is correct.
What is an endothermic reaction?An endothermic reaction is the one in which heat energy is absorbed by the reactants from the surroundings. In endothermic reactions, the enthalpy change is positive.
The minimum energy that the reactants have to acquire for effective collision and reaction is called the activation energy. By absorbing heat energy reactants becomes more energetic and overcome this activation potential.
Therefore, in an endothermic reaction, the activation potential of products will be higher than that of the reactants . Hence, option d is correct.
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C(s) + O2(g) → CO2(g) ΔHº = -94.6 kJ
H2(g) + \scriptsize \frac{1}{2}O2(g) → H2O(l) ΔHº = -286.0 kJ
2C2H2(g) + 5O2(g) → 4CO2(g) + 2H2O (l) ΔHº = -2598.8 kJ
calculate the value of ΔHº for the final reaction:
2C(s) + H2(g) → C2H2(g) ΔHº = kJ
The value of enthalpy(ΔHº) for the final reaction (2C(s) + H₂(g) → C₂H₂(g) ) is -1932.8KJ.
Enthalpy change: what is it?A system's enthalpy is its heat capacity. A reaction's enthalpy change is roughly equivalent to how much energy is lost or gained throughout the reaction. If the enthalpy of the system decreases over the reaction, the reaction is preferred.
C(s) + O₂(g) → CO₂(g) ΔHº = -94.6 kJ --- (1)
H₂(g) + O₂(g) → H₂O(l) ΔHº = -286.0 kJ ---(2)
2C₂H₂(g) + 5O₂(g) → 4CO₂(g) + 2H₂O (l) ΔHº = -2598.8 kJ ---(3)
The value of ΔHº for the final reaction,
2C(s) + H₂(g) → C₂H₂(g)
ΔH₄° = 2× ΔH₂º + ΔH₃º - ΔH₁º
ΔH₄° = 2× -286.0 + ( -2598.8) - (- 94.6)
ΔH₄° = 2× -286.0 -2598.8 + 94.6
ΔH₄° = 666 - 2598.8
ΔH₄° = -1932.8KJ.
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Are all antigens foreign substances?
No, not all antigens are foreign substances.
An antigen is any substance that can trigger an immune response, including the production of antibodies. Some antigens are naturally present in the body and are called "self" antigens which are usually not harmful, but in some cases, the immune system can mistakenly recognize them as foreign and attack them which can lead to autoimmune diseases.
Antigens bind together with antibodies and promote the elimination of harmful pathogens present in the body. They alert other parts of the immune system to take over which helps to neutralize the threat from pathogens.
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When compared to the keto form, the enol form of which of the following compounds is most stable?
1
II
III
IV
V
Which compound's? H is the least acidic?
nitroethane
propanenitrile
propanal
N,N-dimethylacetamide
acetone
Rank the compounds from strongest acids to weakest. To rank items as equivalent, overlap them.
To solve this we must be knowing each and every concept related to tautomerization. Therefore, out of keto and enol form, keto form is mot stable.
What is tautomerization?Tautomers are two structural isomers that are readily inconvertible and vary in the relative locations of their atoms while being in dynamic equilibrium. Tautomers essentially function as structural isomers.
Tautomerization is the term used to describe the tautomerization phenomena. Tautomerization includes the exchange of protons and electrons between molecules. Out of keto and enol form, keto form is mot stable.
Therefore, out of keto and enol form, keto form is mot stable.
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The half-life of Po-218 is three minutes. How much of a 2.0 gram sample remains after 15 minutes? Suppose you wanted to buy some of this isotope, and it required half an hour for it reach you. How much should you order if you need to use 0.10 gram of this material?
(2)(½^(15/3)) = 0.0625 (5 half-lives) 102.4 grams order
What is the half-life of an isotope?A radionuclide's half-life is the amount of time it takes for half of its radioactive atoms to decay. A good rule of thumb is that you will have less radiation than 1% of the original amount after seven half-lives.Knowing an element's alpha, beta, or gamma decay can help someone properly protect their body from excessive radiation. Within one half-life, the amount of radioactive nuclei present at any particular time will be reduced to half.Each radioisotope has a set half-life that can be anywhere between a few milliseconds (for example, 215At at 0.1 milliseconds) and billions of years (e.g.,238U at 4.468 billion years). Both stable and radioactive isotopes can exist for an element.The period of time needed for something to go from 50% to 50%To learn more about half-life of an isotope refers to:
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Use the data in the table below to calculate the heat of vaporization (AHvap) in kJ/mol of pinene.
Vapor Pressure
(torr)
760
515
340
218
135
Temperature
(K)
429
415
401
387
373
kJ/mol
Use the value of AHyap determined in Part 1 to calculate the vapor pressure of pinene (in torr) at room temperature (23°C)
760
torr
Answer:
41 kJ/mol4 torrExplanation:
Given pinene has a (temperature, vapor pressure) relation (K, torr) = {(373, 135), (429, 760)}, you want the heat of vaporization in kJ/mol and the vapor pressure at room temperature (23 °C).
Clausius–Clapeyron EquationThe Clausius–Clapeyron equation can be used to find the heat of vaporization:
[tex]\ln{P}=-\dfrac{\Delta H_{\text{vap}}}{R}\left(\dfrac{1}{T}\right)+C[/tex]
Solving for ∆H, we find ...
[tex]\Delta H_{\text{vap}}=-\dfrac{R\cdot\ln{\dfrac{P_1}{P_2}}}{\dfrac{1}{T_1}-\dfrac{1}{T_2}}\\\\\\\Delta H_{\text{vap}}=-\dfrac{8.314\cdot\ln{\dfrac{760}{135}}}{\dfrac{1}{429}-\dfrac{1}{373}}\approx 41052.8[/tex]
The heat of vaporization of pinene is about 41 kJ/mol.
Vapor pressureRearranging the above equation to give P1, we have ...
[tex]\ln{\dfrac{P_1}{P_2}}=-\dfrac{\Delta H_\text{vap}}{R}\left(\dfrac{1}{T_1}-\dfrac{1}{T_2}\right) \\\\\\P_1=P_2\cdot e^{-\frac{\Delta H_\text{vap}}{R}\left(T_1^{-1}-T_2^{-1})}[/tex]
Using the same P2 and T2 as above, we find the vapor pressure at room temperature (296.15 K) to be ...
P1 ≈ 4.349 . . . . . torr
The vapor pressure of pinene at room temperature is about 4 torr.
What is the ratio between the numbers 30 and 90
What is the molecular weight of H2O
Answer:
18.015
Explanation:
Using the periodic table of the elements to find atomic weights, we find that hydrogen has an atomic weight of 1, and oxygen's is 16. In order to calculate the molecular weight of one water molecule, we add the contributions from each atom; that is, 2(1) + 1(16) = 18 grams/mole.
an oxygen atom, the number of nucleons is 16. What is its atomic mass?
Answer:
oxygen-16 is a stable isotope of oxygen, having 8 neutrons and 8 protons in its nucleus. It has a mass of 15. u
Please help me I really need the help
Thermal energy is the sum of all the potential and kinetic energy of the atoms within a system that is responsible for its temperature.
How to conclude the Electro negativity?Friction transforms other forms of energy into thermal energy. Atoms are the building blocks of matter. Atoms are composed of subatomic particles called protons, neutrons, and electrons.Periodic trends are patterns on the periodic table that illustrate elements’ characteristics.Significant trends are atomic radius, metallic reactivity, electronegativity, electron affinity, and ionization energy.
Atomic radius and metallic reactivity trends: They increase when they move down a group and left across a period.Electronegativity, electron affinity, and Ionization energy trends: They increase when they move up a group and right across a period.
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What is the hybridization of all the atoms (other than hydrogen) in each of the following species?
Drag the appropriate items to their respective bins.
The hybridization of C in HCN is sp because, carbon is triple bonded to the nitrogen. Hybridization of N in HCN is also sp. Hybridization of nitrogen in NH₄ is sp³.
What is hybridization?When tow atoms combines to form a molecules, the energy of individual atomic orbitals redistribute to form hybrid orbitals of equivalent energy. The type of hybridization s based on the on the involvement of s, p or d orbitals of the atom.
In HCN, carbon is triple bonded to nitrogen. Here, both s and p orbital contribution is 50%. Hence, both C and N in HCN in sp hybridized.
In NH₄, the nitrogen is sigma bonded to each hydrogen and the hybridization of N is sp³ here since, 3 p orbitals of nitrogen and one s orbital are involved.
In CH₃-, C is sp² hybridized and in CH₃⁺ , C is sp³ hybridized. The C in C(CH₃)₄ is also sp³ hybridized where carbon involves sigma bonds with the methyl groups.
N in NH₃ is sp³ hybridized. Oxygen in water is sp² hybridized. When water abstracts one more proton forming H₃O⁺ , oxygen forms sp³ hybridized orbitals.
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A student placed four magnets of equal size and mass each the same distance from an electromagnet. She turned the electromagnet on and then quickly turned it off. The diagram below shows how far each magnet traveled toward the electromagnet when the circuit was closed.
four magnets near an electromagnet
What is the order of the magnets by strength from strongest to weakest?
magnet W
magnet X
magnet Y
magnet Z
You have to put them in order
Four magnets near an electromagnet What is the order of the magnets by strength from strongest to weakest. magnet W,magnet X,electromagnet,magnet Y,magnet Z.
What is electromagnet?
An electromagnet is a type of magnet in which the magnetic field is generated by an electric current. It usually consists of a coil of wire that is wrapped around a core of magnetic material such as iron or steel.
When an electric current passes through the wire, a magnetic field is created around the core, making it a magnet. Electromagnets are used in many different applications, such as motors, generators, and speakers.
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A chemist has one solution that is 30.% acid and another solution that is 18% acid. How much of each solution should be used to get 300. L of a solution that is 21% acid?
a. 23 L of the 30.% solution and 277 L of the 18% solution
b. 75 L of the 30.% solution and 225 L of the 18% solution
c. 131 L of the 30.% solution and 169 L of the 18% solution
d. 138 L of the 30.% solution and 162 L of the 18% solution
e. 244 L of the 30.% solution and 56 L of the 18% solution
There is a golden rule of solubility, non polar solute dissolve in non polar solvent and polar solute dissolve in polar solvent. Therefore, the correct option is option B.
What is solution?
Solution is a homogeneous mixture of two or more than two substances. A solution is a homogeneous mixture of solute and solvent molecules. Solvent is a substance that is in large amount in solution. solute is the substance which is in small amount in a solution.
There are two types of mixture that is homogeneous and heterogeneous. Solution is a homogeneous solution. The nature of solvent tells about whether the solvent is in liquid, solid or gas form.
Let amount of 30% to mix, be X
Then amount of 18% to mix = 300 - X
0.3X + 0.18(300 - X) = 0.21(300)
0.3X+ 0.18(300) - 0.18X= 0.21(300)
0.3X - 0.18X =0 .21(300) -0 .18(300)
0.12X =0 .03(300)
X=75L
Therefore, the correct option is option B.
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CHEMISTRY - DOES ANYONE KNOW HOW TO DO THIS QUESTION???
Cathode: 2 Ag+ (aq) + 2 e- → 2 Ag (s). Anode: 2 H+ (aq) → H2 (g) + 2 e-.
What is cathode ?
A cathode is an electrode in an electrical circuit from which electrons flow out. It is usually made of metal and is negatively charged. Cathodes are commonly used in electronic devices such as batteries, lamps, and vacuum tubes. In a battery,
the cathode is the terminal which provides a negative charge and is usually connected to the negative terminal of the battery. In a vacuum tube, the cathode is the source of electrons which flow through the tube to the anode, which is the positive terminal.
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What is the molecular weight of (NH4)2SO4
The molecular weight of [tex](NH_4)_2SO_4[/tex] would be 132 g/mol.
Calculation of molecular weightsThe molecular weight, otherwise known as the molar mass of substances is the sum of the molar weights of individual atoms that make up the substance.
[tex](NH_4)_2SO_4[/tex] is made up of 2 atoms of N, 8 atoms of H, 1 atom of S, and 4 atoms of O.
Molar weight of N is 14 g/molMolar weight of H is 1 g/molMolar weight of S is 32 g/molMolar weight of O is 16 g/molThus, the molecular weight of [tex](NH_4)_2SO_4[/tex] = (14x2) + (1x8) + 32 + (16x4)
= 132 g/mol
In other words, the molecular weight of [tex](NH_4)_2SO_4[/tex] is 132 g/mol.
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Why don’t different varieties of corn plants grow to the same size under similar growing conditions?
EXPLAIN Before medical images are taken, radioisotopes are often injected into a vein in a patient’s arm, or the patient drinks a solution containing the radioisotopes. Why do
you think atoms in the body usually do not emit radiation?
Answer: adioisotopes, are species of chemical elements that are produced through the natural decay of atoms. Exposure to radiation generally is considered harmful to the human body, but radioisotopes are highly valuable in medicine, particularly in the diagnosis and treatment of disease.
Explanation:
What is the density of a 1209 kg object that is 1.94 m3 in size?
Answer:
623 kgm^-3
Explanation:
Density = Mass/Volume
Mass = 1209 kg
Volume = 1.94 m^3
Density = 1209 / 1.94 kgm^-3
= 623.1958763 kgm^-3
= 623 kgm^-3 (3sf)
Please help me fill in the blanks
Sublevels are indicated by letters s, p, d, and f.
How do write Electronic configuration?
Electron configurations have a standard notation that tells you the principle energy levels and sublevels that electrons occupy. here is Sulphur:
The atomic number of Sulphur is 16.
the electronic configuration of Sulphur is 1s2 2s2 2p6 3s2 3p4.
The 4s sublevel has lower energy than the 3d sublevel,
so, it fills next.
Which four different electron configurations are there?One orbital can house a maximum of two electrons, and there are four different types of orbitals (s, p, d, and f). More electrons can be held in the p, d, and f orbitals since they contain various sublevels. According to its location on the periodic table, each element's electron configuration is distinct.
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Rank the following fibers on the degree to which a dye will bind to the fabric and resist fading.
rank the following fibers on the degree to which a dye will bind
Answer:
polymer mear least receptive to dye
,
Find the number of moles of oxygen atoms in 3.00 mol of copper(II) sulphate pentahydrate.
Answer:
9 times Avogadro's number, because there are a total of 9 oxygen atoms in the copper sulfate hydrate being considered: 4 from the sulfate
Explanation:
No Constant Variable
A 2.00L sample of gas at STP is heated to 500K and compressed to 200 kPa. What is
the new volume of the gas?
I’ll give you all my points
The new volume of the gas will be 1.85L.
The three gas laws are what?According to Boyle's Law, as pressure lowers, gas volume grows. According to Charles' Law, when the temperature rises, the volume of the gas also rises. Avogadro's Law also states that as the amount of gas increases, so does the volume of the gas.
Given, initial volume of gas V1 = 2L
initial temp T1 = 273K
initial pressure P1 = 101.3 kPa
final temperature, T2 = 500K
Final pressure, P2 = 200 kPa
let final or new volume be V,
now for a constant moles of gas,
by using ideal gas equation,
P1×V1/T1 = P2×V/T2
101.3×2/273 = 200×V/500
202.6/273 = 2V/5
V = 0.742×5/2
V = 1.85 L
The new volume of the gas will be 1.85L.
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Why do some elements not take part in chemical bonds?
Answer:
Because there is some element which is already in an octet state and has no need to achieve it, they have a full electron in their outermost shells such as helium, argon etc.
how do you test the methods of cleaning an oil spill while not risking the lives of the organisms
Answer:
Get a controlled environment, such as a pool or even a bowl. Pour some oil in it then you can test your solutions without causing any damage.
Explanation:
what is van't hoff factor?
state the formulas to calculate " i " during association or dissociation.
tysm! :)
The relationship between the calculated concentration of a material and the actual concentration of particles is known as the Van't Hoff factor.
I is the difference between a typical or theoretical colligative quality and an observable one.
What does the connection van t Hoff factor mean?The van 't Hoff factor is the difference between the concentration of a material determined by its mass and the concentration of particles actually formed when the substance is dissolved. The van 't Hoff factor is virtually 1 for the majority of non-electrolytes dissolved in water.
What does Van t Hoff factor mean in terms of connection and dissociation?For dissociation, association, and the non-electrolyte solute, the Van't Hoff factor value is more than one, less than one, and equal to one respectively.
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What is the name of the charge that orbits the nucleus called?
Answer:
Electrons
Explanation:
"An electron is a negatively charged particle that orbits the nucleus of an atom."
"Electrons are negatively charged particles arranged in orbits around the nucleus of an atom"
O
Question 2 of 10
Which of the following values best classifies a bond between 2 atoms as
being covalent?
A. An electronegativity difference of greater than 2.7 between the
atoms
B. An electronegativity difference of greater than 1.7 between the
atoms
C. An electronegativity difference of less than 1.7 between the atoms
D. An electronegativity difference of less than 2.7 between the atoms
← PREVIOUS
SUBMIT
A bond between 2 atoms as being covalent an electronegativity difference of greater than 1.7 between the atoms.
What is bond?Bond is a debt instrument, which is issued by governments and corporations. These bonds are used to raise capital for various projects and investments. Bonds are a form of loan and investors are usually paid a fixed interest rate for lending their money. Bonds are typically issued for a fixed period of time, usually for a period of 5-30 years, and have a fixed maturity date. Investors receive interest payments at regular intervals and receive the principal amount of the bond at the end of the period.
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