Answer:
2
Explanation:
4s2 has 2 valence electrons
Valence shell is the shell which is the outermost shell, that is filled in the last, before valence shell is penultimate shell. Therefore 2 valence electron are there in the valence shell.
What is element?Element generally consist of atoms or we can say atoms combine to form element. Atoms of an element is always same, means all the properties of all atoms of one type of element is same.
From our question the electronic configuration of element is given as
1s²2s²2p⁶3s²3p⁶4s²
Valence electron is the one which is present in the outermost shell or orbit. So, form above electronic configuration we can say that 4 is the outermost shell and in this shell 2 electron is present. Therefore 2 electron are there in the valence shell as valence electron.
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Which statement best describes a covalent bond?
a
A chemical bond in which no electrons are shared.
b
A chemical bond that involves sharing a pair of electrons between
atoms in a molecule.
с
A chemical bond in which four or more electrons are shared.
A chemical bond in which one atom loses an electron to form a
d positive ion and the other atom gains an electron to form a negative
ion.
Answer:
B
Explanation:
Option B best describes covalent bonds.
Under what condition will the result of an experiment based on a hypothesis most likely lead to a new experimentation?
Answer:
When the results do not match the experimenter's predictions.
Explain how signals are processed and stored by the brain.
Answer:
this is the answer
Explanation:
Neurons communicate with each other by sending chemical and electrical signals. Each neuron is connected with other neurons across tiny junctions called “synapses”. Impulses rush along tiny fibres, like electrical wires, from one neuron to the next. Electrical impulses travel through neurons.
The Thermal Energy
The thermal energy of an object is the total kinetic energy of its particles. An object's
thermal energy depends on the mass of the object, its temperature, its state of matter,
and its chemical composition. Larger objects have more thermal energy than smaller
objects of the same material and density at the same temperature. A liquid substance
has more thermal energy than the same mass of the substance in its solid form.
9. Suppose you have two identical objects made of the same mass of the same material.
If one object is 20 °C warmer than the other, which object has more thermal energy?
Thermal Energy is directly proportional to the temperature
Or
[tex]\\ \sf\longmapsto Thermal\: Energy\propto Temperature [/tex]
So if temperature increases the thermal Energy also increases.
An object which is 20°C warmer than other has more thermal energy
balanced equation for the reaction between gallium and nitric acid. any spammers will be reported only correct answers
Answer:
Ga + 6HNO3 → Ga(NO3)3 + 3NO2 + 3H2O
Explanation:
Gallium has an ionic charge of 3+, so three nitrate ions are needed to balance it out.
Suppose you are performing a precipitation titration to study the K sp of zinc(II) iodate, Z n ( I O 3 ) 2 . The literature value of K sp is 3.9 × 10 − 6 . If you use 0.200 M K I O 3 as the titrant, what concentration of I O 3 − (in M) do you predict will be needed to start precipitation in a 0.229 M solution of Z n ( N O 3 ) 2 ?
The predicted concentration of IO₃⁻ needed to start the precipitation titration is 1.703 × 10⁻⁷ M
The dissociation of zinc (II) iodate can be expressed as:
[tex]\mathbf{Zn (IO_3)_2 \to Zn^{2+} + 2IO_3^-}[/tex]
Given that the solubility product constant Ksp value = 3.9 × 10⁻⁶
For the above dissociation,
[tex]\mathbf{Ksp = [Zn^{2+ }] [IO_3^-]^2}[/tex]
Since [tex]\mathbf{ [Zn^{2+ }] = [Zn(NO_3)_2] = 0.229 \ M}[/tex]
∴
[tex]\mathbf{3.9\times 10^{-8} =(0.229) \times [IO_3^-]^2}[/tex]
[tex]\mathbf{ [IO_3^-]^2 = \dfrac{3.9\times 10^{-8} }{(0.229)}}[/tex]
[tex]\mathbf{ [IO_3^-]^2 = 1.703 \times 10^{-7} \ M}[/tex]
Therefore, we can conclude that the initial predicted concentration of IO₃⁻ needed to start the precipitation titration is 1.703 × 10⁻⁷ M
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Which unit is 10,000 times LARGER than the MICRO unit?
Answer:
Micro means 0.000001. So 10,000 times larger than that is the Centi unit, which is 0.01
2. Why was sud production used to assess the effectiveness of the synthesized soaps?
Answer:
Soap is effective as a cleaning agent because it is amphiphilic; it is partly polar and partly nonpolar. ... The sodium ion of the soap is replaced by one of these new ions, and the resulting salt is no longer soluble.
Soap seems to be amphiphilic, or partially polar as well as partially nonpolar, it works well as a cleaning agent. Several of these newfound ions take the place of such soap's sodium ion, rendering the salt insoluble.
What is Soap?Long chain fatty acids are salts of sodium and potassium that have a cleaning effect in the water. referred as soap They should be used as cleaning agents to get rid of oil and filth from garments and skin. As an illustration, stearic, oleic, as well as palmitic acids are used to create sodium stearate, sodium oleate, respectively sodium palmitate.
What is cleaning agent?Cleaning agents, often known as hard-surface cleansers, are things that are used to get rid of debris from surfaces, such as dust, stains, foul odors, and clutter. Health, aesthetics, odor removal, and stopping the transfer of dirt and toxins to oneself or others will be among the goals of cleaning products.
Because soap can serve as an emulsifying agent, it would be a superior cleanser. An emulsifier has the ability to mix two immiscible liquids together.
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How many photons are produced in a laser pulse of 0.593 J at 671 nm?
Explanation:
May kwento po ba yan o yan na talaga
Identify key concepts/terminologies about solutions or concentration of solutions
PLS HELP ASAP!!
identify keys concepts/terminologies about solutions or concentration of solutions.
Answer:They are the two basic solution concentration terms that you need to know.We always need to keep an account of the amount of solute in a solution.The amount of solute in the solvent is what is called the concentration of a solution.In chemistry,we define concentration of solution as the amount of solute in a solvent.
Explanation:Depending upon amount of solute present,it is called a dilute, concentrated or a saturated solution.Different substances in a given solvent have a different solubilities at the same temperature.The most common method for expressing the concentration of a solution is the percentage method
#Carry On Learning :)Two students are identifying a sample of tap water.
Student A says that tap water is a mixture, while
Student B says that it is a compound. Which student
is correct? Justify your answer.
Tap water is a mixture not compound due to presence of many substance.
Tap water is an example of mixture not compound because in tap water, water is not available in pure form, it has many substances mix with water and those substances make no bond with water.
It has dissolved compounds like calcium carbonate, magnesium and fluoride. Different elements or compounds are physically combined rather than chemically linked together so we can conclude that student A is correct that tap water is a mixture.
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Identify whether the following changes would generally increase or decrease the reaction rate. (3 points)
• Increasing the concentrations of reactants (0.5 point):
• Increasing the temperature (0.5 point):
• Increasing the pressure (0.5 point):
• Shining light on the reaction (0.5 point):
• Increasing the activation energy (0.5 point):
Answer: (1) increase(2) increase (3) increase (4) increases(5) decrease
Explanation:so basically anything you do will make the reaction go faster except like increasing the activation energy for example
The correct answers are as follows
Increase Increase Increase Increase DecreaseWhat is Reaction rate?It is the measure of the change in concentration of the reactants or the change in concentration of the products per unit time.The speed of a chemical reaction is the change in concentration of a substance divided by the time interval during which this change is observed.
What will happen to reaction rate if we do the following?The reaction rate will increase on Increasing the concentrations of reactants.The reaction rate will increase on Increasing the temperature. The reaction rate will increase on Increasing the pressure.The reaction rate will increase on Shining light on the reaction.The reaction rate will decrease on Increasing the activation energy .
Hence Except Activation energy the reaction rate will increase
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For the formula shown, how many sulfur atoms are represented?
Answer:
Your answer would be 6
Answer:
1 it is 1
Explanation:
What is epoxy?
………………..
Answer:
Epoxy is the family of basic components or cured end products of epoxy resins.
Respiration describes the process that living cells use to release energy by combining sugar and oxygen. The primary chemical changes that happen during respiration are shown in the equation below.
C6H12O6 + 6O2 ---> 6CO2 + 6H2O + energy
Which statement correctly compares the reactants and products of the equation?
A.
The mass of the reactants is less than the mass of the products.
B.
The mass of the reactants is greater than the mass of the products.
C.
The mass of the reactants is the same as the mass of the products.
D.
The number of reactant molecules is greater than the number of products.
Answer:
C the mass of the reactant molecules is the same as the mass of the product
Fruit juice when boiled taste sweeter than sucrose because
Answer :see explanation
Explanation:
the sweet carbohydrate in fruit is not sucrose , it is fructose.
and fructose tastes sweeter than sucrose
fructose and glucose minus water equals sucrose
and fructose is sweeter than glucose
How are elements in the same family in the periodic table alike?
[tex]▪▪▪▪▪▪▪▪▪▪▪▪▪ {\huge\mathfrak{Answer}}▪▪▪▪▪▪▪▪▪▪▪▪▪▪[/tex]
The Correct choice is ~ C
They have the same number of electron shells~
Explanation:
option C is correct.....
What’s the frequency of radiation that has a wavelength of 13 um, about the size of bacterium?
Answer:
2.3)X10^13-Hz
Explanation:
What’s the frequency of radiation that has a wavelength of 13 um, about the size of bacterium?
a micro meter is 10^-6 meter
frequency of light times wavelength = c the speed of light 3X10^8 M/sec
so
frequency times 13 X10^-6 =3X10^8 M/
so
FR3EQUENCY = 3X10^8/13X10-6
=(30/13)10^13 =2.3)X10^13-Hz
7 X
6
*1. The internal energy with a system associated with the motion of particles and that can be added to a substance is called_____.
A. Thermal energy
B. Electrostatic forces
C. Temperature
D. Kinetic energy
•
•
•
*2. Which statement describes the effect of adding more energy to a system, assuming a phase change does not occur?
A. The particles within the system will have greater motion, and the temperature will decrease.
B. The particles within the system will have greater motion, and the temperature will increase.
C. The particles within the system will have less motion, and the temperature will increase.
D. The particles within the system will have less motion, and the temperature will decrease.
•
•
•
*3. Which statement correctly describes how attractions that hold particles break?
A. Attractions due to electrostatic forces. When particles have low enough energy, these forces can no longer keep particles together.
B. Attractions due to gravitational forces. When particles have low enough energy, these forces can no longer keep particles together.
C. Attractions due to gravitational forces. When particles move fast enough, these forces can no longer keep particles together.
D. Attractions due to electrostatic forces. When particles move fast enough, these forces can no longer keep particles together.
•
•
•
*4. Which statement explains why a rubber band analogy is not a perfect comparison for bonds in a substance when considering phase changes?
A. For a phase change from liquid to gas, the bonds break completely and particles can move independently of each other.
B. For a phase change from liquid to gas, the bonds do not break completely and the particles can still slide past each other.
C. For a phase change from solid to liquid, the bonds break completely and particles can move independently of each other.
D. For a phase change from solid to liquid, the bonds do not break completely in the particles can still slide past each other.
•
•
•
*5. The boiling point of benzene is 80°C. Which pair of samples will have the same average kinetic energy as benzene molecules?
A. Two samples of liquid benzene, one at 70°C in the other at 80°C.
B. A sample of liquid benzene at 70°C and a sample of gaseous benzene at 90°C.
C. Two samples of gaseous benzene, one at 80°C in the other at 90°C.
D. A sample of liquid benzene at 80°C and a sample of gaseous benzene at 80°C.
Answer:
1. thermal energy
2. the particles within the system will have greater motion, and the temp will increase.
3. attractions occur due to electrostatic forces. when particles move fast enough, these forces can no longer keep particles together.
4. for a phase change from a solid to liquid, the bonds do not break completely and particles call still slide past each other.
5. a sample of liquid benzene at 80°C and a sample of gaseous benzene at 80°C
Explanation:
hope this helps
Temperature is a measure of the average kinetic energy of molecules.
The particles of a substance are in constant random motion. As more thermal energy is added to the particles, the motion of the particles increases. If more energy is added to a system during phase change, the particles within the system will have greater motion, and the temperature will increase.
Attractions between particles is greater when the kinetic energy of molecules decreases. Therefore, a statement that correctly describes how attractions that hold particles break is; "attractions due to electrostatic forces. When particles move fast enough, these forces can no longer keep particles together."
The rubber analogy is commonly used to describe covalent bonds where stretching of bonds occur. This analogy is not apt in describing phase changes because for a phase change from a solid to liquid, the bonds do not break completely and particles call still slide past each other.
The average kinetic energy of molecules depend on temperature hence a sample of liquid benzene at 80°C and a sample of gaseous benzene at 80°C will have the same average kinetic energy.
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A mining company is looking for ways to save money on the process they use to discover new mineral resources while also reducing the impact that the mining process has on the environment.
Which improved technology would
best achieve this goal?
O fracking
O drilling technology
O extraction technology
O geological Surveying
Answer:
extraction technology.....
Magnesium metal is reacted with hydrochloric acid to produce hydrogen gas. A sample of hydrogen gas is collected over water in a eudiometer at 28.0°C. The atmospheric pressure is 786 mmHg. Determine the pressure (in atm) of the hydrogen gas produced.
The pressure of hydrogen gas produced is 0.997 atm
Using the standard table of temperature and water vapour pressure;
At 28.0°C, the water vapour pressure = 28.3 mmHgThe pressure of hydrogen gas (H₂) collected over water is:= [tex]\mathbf{P_{moist\ gas } = 786 mmHg}[/tex]Recall that:
[tex]\mathbf{P_{moist \ gas} = P_{dry \ gas} + P_{water vapor}}[/tex]
where;
the dry gas = hydrogen gas[tex]\mathbf{ P_{dry \ gas} = P_{moist \ gas} - P_{water vapor}}[/tex]
[tex]\mathbf{ P_{dry \ gas} = (786- 28.3) mmHg}}[/tex]
[tex]\mathbf{ P_{dry \ gas} = (757.7) mmHg}}[/tex]
We know that 1 atmospheric pressure = 760 mmHg
∴
757.7 mmHg will be:
[tex]\mathbf{=\dfrac{757.7 \ mmHg \times 1 \ atm}{760 \ mmHg}}[/tex]
= 0.997 atm
Therefore, we can conclude that the pressure of hydrogen gas produced is 0.997 atm
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what is chemical reaction ?
Identify the general features of an amino acid. Which part is responsible for the unique properties of each amino acid
Answer:
Every amino acid also has another atom or group of atoms bonded to the central atom known as the R group. This R group, or side chain, gives each amino acid proteins specific characteristics, including size, polarity, and pH.
Explanation:
The R group is another atom or group of atoms that is attached to the core atom in every amino acid. This R group, or side chain, provides each amino acid protein with unique properties such as size, polarity, and pH.
Amino acids are chemical molecules that are used to construct proteins. Proteins are vital macromolecules in living organisms, serving a variety of functions including enzymatic catalysis, structural support, transportation, immunological response, and others. A polypeptide chain is formed by linking amino acids in a precise sequence, which subsequently folds into a three-dimensional structure to make a functioning protein.
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what other solvent could have been used?
What other solvent could have been used?
water (universal solvent)acetonemethanolacetic acidethyl acetate4. A student performs four trials of an investigation to determine the boiling point of water. How should the student handle the results?
A. The student should take the average of the minimum and maximum value of the results.
B. The student should use the value that is closest to 100ºC.
C. The student should use the maximum value of the results.
D. The student should take the average of the results from all four trials.
Answer:
i think its D
Explanation:
In order to get maximum accuracy, student should take average of results from all four trials.
What is accuracy?Accuracy in terms of chemistry can be defined as to how close a measurement is to the true value.There are three types of accuracy:
1) Point accuracy-It means accuracy is present at that point of scale only.It does not give any information about the accuracy of the instrument.
2)Percentage of true value--It is the accuracy which is determined by identifying accuracy of the instrument and comparing it with the measured true value.
3)Percentage of scale range- It is the accuracy which determines accuracy of the measurement.
Accuracy in case of instruments is neglected up to ±0.5 percent.Accuracy of measurements can be increased by taking multiple measurements and taking into account human errors.
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What is heat of reaction? Tell me In a short description?
Answer:
The Heat of Reaction (also known and Enthalpy of Reaction) is the change in the enthalpy of a chemical reaction that occurs at a constant pressure. It is a thermodynamic unit of measurement useful for calculating the amount of energy per mole either released or produced in a reaction.
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You have 2.567 grams of water. What is the volume of water(use correct units)
Answer:
2.567 mL
Explanation:
Which diagram best illustrates the difference between distance and
displacement?
Answer:
It is the one that has start and finish and a compass on it...I am sorry I can share images for some reason. And underneath the compass, it says 1.0 Mile. It also has a compass in the bottom right-hand corner.
Explanation:
I just took the quiz and got it correct!
Indicate the general type of reaction represented in each the reactions: The starting material is a 6 membered ring with an internal alkene between carbons 1 and 2. The product is a six membered ring with a bond to X on carbon 1 and a bond to Y on carbon 2. What type of reaction is Reaction A
The reaction as described is an addition reaction in which a saturated product is obtained.
The information we have from the question is that; the starting material is a 6 membered ring with an internal alkene between carbons 1 and 2. The product is a six membered ring with a bond to X on carbon 1 and a bond to Y on carbon 2.
We know that an addition reaction is one in which a molecule is added across the double bond to yield a saturated product. The reaction A described has to do with he addition of a molecule XY to a six member alkene to obtain the saturated product as described.
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