Answer: B.
Explanation:
When the electron changes levels, it decreases energy and the atom emits photons. The photon is emitted with the electron moving from a higher energy level to a lower energy level. The energy of the photon is the exact energy that is lost by the electron moving to its lower energy level.
Hope this helps!
Jamal is 8 miles away from his house. He rides his bike home toward home at a speed of 12 mph..
How far away from home is he after a half hour?
Answer: 2miles
Explanation:if he’s going 12 miles in one hour, in half an hour he would’ve made it 6 miles. 8-6=2
Answer: b. 2 miles
Explanation:
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Given the data below, what substance does not show a reaction for any of the tests? Hint: (+)= reaction occurred, (-)= no reaction
unknown
salt
Corn starch
Gelatin
Answer:
Salt
Explanation:
It has all -
Which statement best defines potential enregy?
A. Potential energy is stored energy.
B. Potential energy is energy that can change over time.
C.Potential energy is the energy of motion.
D. Potential energy is the type of energy a roller coaster uses.
Answer:
A. Potential energy is stored energy
Explanation:
Answer:
A
Explanation:
i have the same question
1. An atom has 57 neutrons and 42 protons. How many electrons will this atom have if it
neutral?
57
44
42
40
Answer:
42
Explanation:
Because the proton number or atomic number is equal to electron number.
Answer:
42
In order for it to be neutral there must be the same amount of protons and neutrons
Have a nice day! :)
1. Compare and contrast the characteristics of metals and nonmetals.
2. Describe the electrochemical series and why it’s important in understanding metals.
3. Describe the theory of ionization in regard to acids and bases.
4. Identify the role of indicators.
Answer:
1. Both metals and nonmetals are types of elements and can be involved in chemical reactions. Some of their differences are highlighted in the chart below.
Metals:
Appearance; Shiny.
Conduct heat or electricity; Yes.
Malleable or ductile; Yes, both and has great mechanical strength.
Form stable compounds; Forms stable compounds with acids; also forms oxides; replaces hydrogen in acids or water; combine with nonmetals; often becomes positive.
Nonmetals :
Appearance; Not shiny .
Conduct heat or electricity; Not well .
Malleable or ductile; Brittle and not easily molded into shapes .
Form stable compounds; Oxides usually give acid reactions in water; often becomes negative
2. The electrochemical series is an arrangement of metals in such order that any metal in the list is displaced from its compounds by any metal above it, but displaces any metal below it. The higher up the list a metal is, the greater its activity. Knowing a metal’s placement on this chart can help you understand the activity of the metal, especially in regard to its ability to displace hydrogen in acids. Any items on the list far above hydrogen will do a good job at displacing it, those near it won’t do such a good job, and those below it won’t displace it from acids at all.
3. When placed in water, acids dissociate and form free hydrogen ions, which determine the properties of acids. The number of hydrogen ions determines the strength of an acid. Strong acids dissociate to a large degree and produce a large number of hydrogen ions. Weak acids dissociate to only a slight degree.
When placed in water, bases dissociate and form free hydroxyl ions, which determine the properties of bases. Strong bases dissociate to a great degree and produce a large number of hydroxyl ions. Weak bases dissociate to only a slight degree.
When free hydrogen ions and free hydroxyl ions are removed from solutions of acids and bases, then the acidic and basic properties disappear. This is what happens when acids and bases are mixed together in proper proportion; the hydroxyl ion will unite with the hydrogen ion to form water. The resulting salt product is neutral.
4. Indicators are used to help determine the pH value of an unknown solution. These are often papers that turn a certain color at certain pH values.
Metals are good conductors of heat and electricity but the non-metals are not.
Compare metals and non-metalsMetals are good conductors of electricity and heat whereas non-metals are poor conductors of heat and electricity. Metals have high density while on the other hand, non-metals have low density. Metals are malleable and ductile whereas non-metals are brittle.
So we can conclude that metals are good conductors of heat and electricity but the non-metals are not.
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14. How do you describe an atom in which the number of protons is equal
to the number of electrons?
A foam square has a mass of 25 g and a volume of 90 mL. What is the density?
Answer:
The answer is 0.28 g/mLExplanation:
The density of a substance can be found by using the formula
[tex]density = \frac{mass}{volume} \\ [/tex]
So we have
[tex]density = \frac{25}{90} = \frac{5}{18} \\ = 0.277777...[/tex]
We have the final answer as
0.28 g/mLHope this helps you
which of these elements is most likely to be magnesium the most metallic of all samples?
Answer:
B
Explanation:
Just did it on usa test prep
The element which is most likely to be magnesium is the element with the electronic configuration same as magnesium.
What is an element?It is defined as a substance which cannot be broken down further into any other substance. Each element is made up of its own type of atom. Due to this reason all elements are different from one another.
Elements can be classified as metals and non-metals. Metals are shiny and conduct electricity and are all solids at room temperature except mercury. Non-metals do not conduct electricity and are mostly gases at room temperature except carbon and sulfur.
The number of protons in the nucleus is the defining property of an element and is related to the atomic number.All atoms with same atomic number are atoms of same element.
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Calculate the density of an object with mass = 30.50 g and a volume = 2.20 cm^3
Answer:
The answer is 13.86 g/cm³Explanation:
The density of a substance can be found by using the formula
[tex]density = \frac{mass}{volume} \\ [/tex]
From the question
mass = 30.5 g
volume = 2.2 cm³
We have
[tex]density = \frac{30.5}{2.2} \\ = 13.863...[/tex]
We have the final answer as
13.86 g/cm³Hope this helps you
Does changing the number of protons change the identity of the element you have built ?
Answer: Yes.
Explanation:
the number of protons in the nucleus determines an element's identity. Chemical changes do not affect the nucleus, so chemical changes cannot change one type of atom into another. The number of protons in a nucleus does change sometimes, however. The identity of the atom, therefore, changes.
A metal block, 2.0cm x 2.5cm x 3.0cm, has a mass of 40.5g. What is the density of the sample? What type of metal is the metal block composed of?
Aluminum - 2.699
Copper - 8.92
Iron - 7.874
Lead - 11.43
Nickel - 8.908
Tin - 7.265
Zinc - 7.14
Answer:
The block is made up of aluminum.
density = 2.7 g/cm³
Explanation:
Given data:
Dimension of metal block = 2.0 cm×2.5 cm× 3.0 cm
Mass of block = 40.05 g
Density of block = ?
Which metal is this = ?
Solution:
Density:
Density is equal to the mass of substance divided by its volume.
The symbol used for density is called rho. It is represented by ρ. However letter D can also be used to represent the density.
Units:
SI unit of density is Kg/m3.
Other units are given below,
g/cm3, g/mL , kg/L
Formula:
D=m/v
D= density
m=mass
V=volume
Volume of block = 2.0 cm×2.5 cm× 3.0 cm = 15 cm³
d = m/v
d = 40.5 g/ 15 cm³
d = 2.7 g/cm³
The block is made up of aluminum.
Draw a structural formula for the alkene you would use to prepare the alcohol shown by hydroboration/oxidation.
Answer:
See explanation
Explanation:
The question is incomplete because the image of the alcohol is missing. However, I will try give you a general picture of the reaction known as hydroboration of alkenes.
This reaction occurs in two steps. In the first step, -BH2 and H add to the same face of the double bond (syn addition).
In the second step, alkaline hydrogen peroxide is added and the alcohol is formed.
Note that the BH2 and H adds to the two atoms of the double bond. The final product of the reaction appears as if water was added to the original alkene following an anti-Markovnikov mechanism.
Steric hindrance is known to play a major role in this reaction as good yield of the anti-Markovnikov like product is obtained with alkenes having one of the carbon atoms of the double bond significantly hindered.
which balances the equation Mg + O2 → MgO
Answer:
2Mg+[tex]O_{2}[/tex]→2MgO
Explanation:
The first step is magnesium + oxygen equals magnesium oxide
The second step is changing that into an equation which looks like Mg+[tex]O_{2}[/tex]→MgO
The third step is to 2*Mg and 2*O as well as the product has to be 2*Mg,2*O which gets the equation to become balanced as 2Mg+[tex]O_{2}[/tex]→2MgO
The coefficient 2 balance the given reaction. The balanced equation for the given reaction is given as [tex]\rm Mg + O_2 \rightarrow 2MgO[/tex].
A balanced equation is a mathematical representation of a chemical reaction that respects the law of mass conservation. It depicts the reactants and products of the reaction, as well as the relative amounts of each species. The unbalanced equation is [tex]\rm Mg + O_2 \rightarrow MgO[/tex]. One magnesium (Mg) atom on the left side and one on the right side, so the magnesium is already balanced. Balance the oxygen (O) atoms. On the left side, there are two oxygen (O) atoms present in the O2 molecule. On the right side, there is only one oxygen (O) atom in the MgO molecule. To balance the oxygen atoms, we need to add a coefficient of 2 in front of MgO: [tex]\rm Mg + O_2 \rightarrow 2MgO[/tex]. The balanced equation is [tex]\rm Mg + O_2 \rightarrow 2MgO[/tex].
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What is your carbon footprint?
the amount of carbon dioxide you use when recycling
the amount of oxygen put into the atmosphere due to your consumption of fossil fuels
the amount of carbon dioxide and oxygen in the atmosphere at any given time
the amount of carbon dioxide put into the atmosphere due to your consumption of fossil fuels
Answer:
c. .....................
Answer: the amount of carbon dioxide put into the atmosphere due to your consumption of fossil fuels
Your carbon footprint is the amount of carbon dioxide and other carbon compounds emitted, because of your use of fossil fuels.
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You just got a free ticket for a boat ride, and you can bring along
2 friends! Unfortunately, you have 5 friends who want to come along.
Answer:
10
Explanation:
Khan Academy
Two liters of hydrogen gas are stored at a
pressure of 100 kPa. If the temperature
does not change, what will the volume
of the gas be when the pressure is
decreased to 25 kPa?
Answer:
the volume will expand
Explanation:
gas under pressure contracts, and expands with a lesser pressure
The volume of the hydrogen gas at 25 kPa is 8 Liters.
Explanation:
Given:
At constant temperature, 2 liters of hydrogen gas at 100kPa pressure.
To find:
The volume of the hydrogen gas at 25kPa.
Solution:
The initial pressure of the hydrogen gas =[tex]P_1=100 kPa[/tex]
The initial volume of the hydrogen gas at 100 kPa =[tex]V_1=2 L[/tex]
The final pressure of the hydrogen gas =[tex]P_2=25 kPa[/tex]
The final volume of the hydrogen gas at 25kPa = [tex]V_2=?[/tex]
Using Boyles law:
[tex]P_1V_1=P_2V_2\\100kPa\times 2 L=25 kPa\times V_2\\V_2=\frac{100 kPa\times 2L}{25 kPa}=8L[/tex]
The volume of the hydrogen gas at 25 kPa is 8 Liters.
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Light travels at a speed of 3.00 x 100 ^10 cm/s. What is the speed of light in kilometers/hour?
Answer:
1.1 x [tex]10^{9}[/tex] km/h
Explanation:
Here we need to do two conversions- one from centimetres to kilometres and one from seconds to hours.
To get from cm to km- we divide by 100 000 since there are 100 000 cm in a km.
To get from seconds to hours we divide by 3600 since there are 3600 seconds in an hour
[tex]\frac{3*10^{10}cm/100000 }{1second/3600} =1.1*10^{9} km/h[/tex]
What is the volume, in liters, of 1.40 mol of oxygen gas at 20.0°C and 0.974 atm?
Answer:
V = 34.55 L
Explanation:
Given that,
No of moles, n = 1.4
Temperature, T = 20°C = 20 + 273 = 293 K
Pressure, P = 0.974 atm
We need to find the volume of the gas. It can be calculated using Ideal gas equation which is :
PV=nRT
R is gas constant, [tex]R=0.08206\ L-atm/mol-K[/tex]
Finding for V,
[tex]V=\dfrac{nRT}{P}\\\\V=\dfrac{1.4\times 0.08206\times 293}{0.974 }\\\\V=34.55\ L[/tex]
So, the volume of the gas is 34.55 L.
I hate chemistry please help
Answer:
Love it because Love it
Explanation:
Does anybody understand this I’m stuck
Answer:
it's the first one
Explanation:
can you help me too
How many total atoms of element X are represented below?
Consider the reaction below. 2 Upper N Upper H Subscript 3 (g) Baseline double headed arrow Upper N Subscript 2 (g) Baseline + 3 Upper H Subscript 2 (g). What is the most likely effect to the forward reaction if there is an increase in pressure on this reaction? The reactant surface area increases. The reaction rate decreases. The reaction is not affected at all. The reaction stops completely.
Answer:
The increase in pressure of the reacting system will increase the formation of NH₃
Explanation:
The given parameters are;
2NH₃ (g) ⇄ N₂ (g) + 3H₂ (g)
The number of molecules in the reactant side of the equation = 2 molecules
The number of molecules in the product side of the equation = 1 + 3 = 4 molecules
Avogadro's law states that equal volume of all gases at a given temperature and pressure contains equal number of molecules
Therefore, given that the number of molecules of the product are twice the number of molecules of the reactant, the volume of the product is twice the volume of the reactant
If the pressure is increased, at constant temperature by Boyles law, the volume will be reduced, favoring the formation of the low volume occupying NH₃
Therefore, the reverse reaction (formation of NH₃) will preferably occur.
Answer:
The answer is B
Explanation:
The other answer is incorrect. The correct Answer is B
Trust Me
A piece of wood that measures 2.7 cm x 5.5 cm x 3.9 cm has a mass of 84 g what is the density of the wood
The density of the wood : 1.45 g/cm³
Further explanationDensity is a quantity derived from the mass and volume
Density is the ratio of mass per unit volume
With the same mass, the volume of objects that have a high density will be smaller than objects with a smaller type of density
The unit of density can be expressed in g/cm³ or kg/m³
Density formula:
[tex]\large {\boxed {\bold {\rho ~ = ~ \frac {m} {V}}}}[/tex]
ρ = density
m = mass
v = volume
Volume of the wood[tex]\tt V=2.7\times 5.5\times 3.9=57.915~cm^3[/tex]
density[tex]\tt \rho=\dfrac{m}{V}\\\\\rho=\dfrac{84~g}{57.915~cm^3}=\boxed{\bold{1.45`g/cm^3}}[/tex]
Write a balanced equation for the complete oxidation reaction that occurs when ethane burns in air
Alkanes are saturated hydrocarbons that have single bonds in chains
General formula for alkanes :
[tex]\tt \large{\bold{C_nH_{2n+2}}[/tex]
Hydrocarbon combustion reactions (specifically alkanes)
[tex]\large {\box {\bold{C_nH _ (_2_n _ + _ 2_) + \dfrac {3n + 1} {2} O_2 \Rightarrow nCO_2 + (n + 1) H_2O}}}[/tex]
So that the burning of ethane with air (oxygen):
[tex]\tt C_2H_6+\dfrac{7}{2}O_2\rightarrow 2CO_2+3H_2O[/tex]
2C₂H₆ (g) + 7O₂ (g) ⟶ 4CO₂ (g) + 6H₂O (ℓ)
or we can use mathematical equations to solve equilibrium chemical equations by giving the coefficients for each compound involved in the reaction
C₂H₆ (g) + aO₂ (g) ⟶ bCO₂ (g) + cH₂O (ℓ)
C : left 2, right b ⇒ b=2
H: left 6, right 2c⇒ 2c=6⇒ c= 3
O : left 2a, right 2b+c⇒ 2a=2b+c⇒2a=2.2+3⇒2a=7⇒a=7/2
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Click Oil Basics and use the information to complete this passage that discusses how plastic production affects society.
The production of plastics makes life
{answer} , so it benefits society. On the other hand, the production of plastics causes air and water {answer} , so it also harms society.
Answer:
easier and pollution
Explanation:
I just had this question and got it right
Can you explain what vsepr stand for in your own word?
pls help ill mark as brainliest :)
Q7. Pb + O2 PbO2
Is this combustion, single replacement, double replacement, synthesis, or decomposition
Answer:
This is a synthesis reaction.
Explanation:
Two elements are bonded together to form (synthesize) a new compound.
If air temperature decreases, then
wave height will decrease
ocean temperature will also decrease the same amount
ocean temperature will also decrease, but not as much
ocean temperature will also decrease, but a greater amount
wave height will increase
Answer:
ocean temp
Explanation:
If air temperature decreases, then wave height will decrease and ocean temperature will also decrease, but not as much.
What is ocean temperature ?The water's temperature at the surface is known as the ocean surface temperature. Depending on the measuring technique, the term "surface" might signify anything from 1 millimeter to 20 meters below the sea's surface.
Due to changes in solar radiation and the physical characteristics of water, the temperature of ocean water fluctuates depending on location, both in terms of latitude and depth.
Water contracts and gets denser as it cools. The density of water is influenced by temperature and salinity, and as a result, water moves up or down through the ocean's strata and circulates as currents.
Thus, option B is correct.
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Identify the law that explains the following observation:
Nitrogen Dioxide can be formed by reacting 14 grams of
nitrogen with 32 grams of oxygen.
Answer:
Proust's law of definite proportion
Explanation:
The law of constant proportion states that the components elements of a given chemical compound combine with each other in a fixed mass ratio when the compound is produced by any given process
Therefore, from the question, the chemical formula for Nitrogen Dioxide is NO₂, where the molar mass of nitrogen, N = 14
The molar mass of oxygen, O = 16
Given that one molecule of NO₂, contains one atom of nitrogen and two atoms of oxygen, one mole of NO₂ will contain 14 grams of nitrogen and 32 grams of oxygen, according to Proust's law of definite proportion.
Why is it easy for some elements to lose electrons and harder for others?
Answer:
The further away electrons are from the nucleus the easier it is for atoms to use electrons.
Explanation: