Explanation:
A physical change is one that alters the physical properties of matter (particularly the form and state).
A chemical change is one in which new kind of matter is formed. It is always accompanied by energy changes (evolution or absorption of energy in form of heat or light or both).
Now, the salient differences between physical and chemical changes;
Physical changes are easily reversible whereas chemical changes are not easily reversible. Physical changes lead to the production of no new kinds of matter whereas chemical changes leads to the production of new kinds of matter. Physical changes involves no change in mass whereas chemical changes involves change in mass. Physical changes require little energy whereas considerable amount of energy is needed for chemical changes.Answer:
The result of a chemical change is a different composition and is often hard to reverse; in a physical change, the composition remains the same and is often easy to reverse.
Explanation:
The number of shovels and cost per 1000 kg for
Ca(OH)2
Answer:500
Explanation:
Which of the following is a physical change ?
• burning a piece of paper
• lighting a match
• chopping a piece of wood
• a rusting nail
Chopping a piece of wood
Physical changes are changes affecting the form of a chemical substance but not it's chemical composition.
Answer:
rusting nail: Rusting would only be a physical change if iron molecules remained pure iron throughout the process. Yeah your correct a physical change is anything seen or felt like changing the temperature of water a chemical change can also be seen also like if a iron nail rusts the nails iron atoms were chemically changed by oxygen.
lighting a match: Breaking a match in two pieces is an example of a physical change. Lighting a match and letting is burn is an example of a chemical change. Chemical reactions cause chemical changes. In a chemical reaction two or more substances, called the reactants, form different substances called products.
burning a piece of paper: Burning of paper is not a physical change. It is chemical change as ash is formed in the process which is new compound and oxides of carbon are also released during the process. By the definition of chemical change, we come to know that during chemical change a new substance must form. These changes are irreversible in nature.
chopping a piece of wood: The chopping of wood is a physical change because as stated previously, any physical change can include cutting, bending, sharpening, etc. When a piece of wood is being cut, it undergoes one of these processes. The chopping of wood doesn't alter the chemical structure of the actual wood.
So Its chopping piece of wood!
Hope this helps!!HELPPP MEE I NEED HELPP PLEASE
Which person participates mostly in the quaternary level of an economy?
A. A coal miner
3. A car mechanie
C. A college professor
D. A car factory worker
SUBMIT
Answer:
B.Michanine
Explanation:
Answer: The answer is a college professor since people in the fourth level of industry create, share, and store information. They do research, give advice, report on events, and keep records. Furthermore, workers in the quaternary include teachers, librarians, accountants, scientists, and reporters, nor do the traits describe coal miners, car machines, and a car factory worker as these are the secondary level since their work involves manufacturing, make sure to study! You got this have a g’day. Again, the answer is C: A college professor.
Explanation:
consider an iron cube and an aluminun cube. If the two cubes were at the same temperature, how would the average kinetic energy of the particles in iron compare with the average kinetic energy of the particles in aluminun
Answer:
I think there would be no differences
Question 8 (3 points)
Cindy dropped a test tube during a lab in science class, spilling its contents on the
floor. She immediately picked up the broken glass and used paper towels to clean up
the spill before redoing her lab.
How should she have handled the clean up?
Answer: she should‘ve called the teacher over to deal with it because she could have gotten cut and the chemical could’ve been dangerous
Explanation:
You are performing an experiment and produce an unidentified compound. You know it is composed of carbon, hydrogen, and oxygen but you do not know how many of each are present. You determine its relative formula mass is 59 g/mol. What is its molecular formula?
A. C2H3O2
B. C4H3O4
C. CH12O2
D. C3H4O
Answer:
C₂H₃O₂
Explanation:
Given the relative formula mass = 59g/mol
Unknown:
Molecular formula of the compound
Solution:
To identify this compound, let us find the molecular mass of the choices given.
The one that tallies with the number 59 is the solution:
For;
C₂H₃O₂;
Atomic mass of C = 12
Atomic mass of H = 1
Atomic mass of O = 16
Insert the parameters and solve;
Relative molecular formula = 2(12) + 3(1) + 2(16) = 59g/mol
So, the first choice is the compound.
What physical property of the metal rods was being tested during step 4 of the procudure?
4. Measure and record how long it takes heat from the hot plate set on "high" to melt the wax ball.
A.
magnetism
B.
thermal conductivity
C.
electrical conductivity
D.
density
Answer:
B. thermal conductivity
Explanation:
They physical property being tested during the fourth step is the thermal conductivity of the materials.
Thermal conductivity is the ability of a body to transmit heat energy from one place to another.
Since we are measuring how long it takes for heat from the hot plate to reach the wax ball, this is a typical experiment for measuring thermal conductivity. Most metals are good conductors and heat energy moves fast in them.Non-metals are poor conductors with low thermal conductivity.Which of the following is most likely NOT a chemical reaction?
(A)
A white powder and a clear liquid mix and the beaker holding the mixture gets cool to the touch
(B)
A white solid and a clear liquid mix and produce a bright orange, bubbling substance
(C)
A pan containing a clear liquid is place on a hot stove and begins to bubble after a few minutes.
(D)
A blue liquid and a green solid mix and produce a purple paste
Answer:
B is the correct answer because bubbling is a sign of chemical reaction and production of a new substance
An air-filled balloon shrank when moved from a warm room to a refrigerator. Which statement BEST explains why the balloon shrank?
A. The mass of the air decreased as the balloon cooled.
B. Internal pressure of the balloon decreased due to lower kinetic energy.
C. The volume of air decreased as the number of particles decreased.
D. External pressure on the balloon increased due to lower temperature.
Answer:
B. Internal pressure of the balloon decreased due to lower kinetic energy.
Explanation:
The balloon shrank when moved from the warm room to the cold refrigerator because the internal pressures of the balloon decreased due to lower kinetic energy.
As the balloon approaches the refrigerator, the particles begins to lose their heat energy. The kinetic energy of the particles in a body is directly proportional to the amount of heat. Since we move from a warm to a cold place, the kinetic energy drops too.Once upon a time, I was traveling from Kaunas Lithuania to Klaipeda to see Egle, the queen of serpents. Being the queen of serpents, she has certain magical powers. In exchange for some sand, salt, and iron, she will grant my wish. I put all three things in my bottle together and traveled. During my travels, the salt, sand, and iron got mixed up. No big deal right? Wrong. Egle wants each thing separated before she will grant my wish.... Am I just out of luck completely?
Please write your response and explain your reasoning.
Answer:
No
Explanation:
Fortunately, in this scenario, you are not out of luck. Each of these components has a unique trait that would allow you to easily separate them. For starters, you can separate all of the Iron with a strong magnet since iron has a magnetic field while sand and salt do not. Next, you can separate the salt and sand by adding water since salt will dissolve in the water leaving only the sand which is not soluble. Once the sand is removed you would simply need to distill the water/salt mixture which would separate the salt from the water. Now you have all three components separated and can get your wish.
NEEEDDDD HELP ASAP PLZ PLZ PLZ PLZ PLZ HELP ME
Answer:
[tex]ns^2[/tex]
Explanation:
With some manipulation, the Rydberg equation can be rewritten in the form
E=constant×(1nf2−1ni2)
which allows you to calculate the energy of the emitted light. Express this constant in terms of the constants h, c, and RH using relationships between wavelength and energy as well as the Rydberg equation from the introduction.
Express the constant in terms of h and c, and RH.
Please help me with this question?
Answer:
attached below is the detailed solution
answer : value of constant = 2.18 * 10^-18 J
Explanation:
Express the constant in terms of h and c and RH
attached below is the detailed solution
Constant = [tex]h_{C} R_{H}[/tex]
= ( 6.626 * 10^-34 ) * ( 3 * 10^8 ) * ( 1.097 * 10^7 )
= 2.18 * 10^-18 J
The Planck equation and the light speed allow us to find the results for the transformation of the Rydberg equation are:
[tex]E = A ( \frac{1}{n_1^2}\frac{x}{y} - \frac{1}{n_2^2} )\\A= R_H \ h \ c \\A = 2.18 \ 10^{-18} j[/tex]
The Rydberg equation is an empirical expression that explains the wavelength of the emissions.
[tex]\frac{1}{\lambda } = R_H ( \frac{1}{n_1^2} - \frac{1}{n_2^2} )[/tex]
Where λ is the wavelength of the emitted radiation, is the Rydberg constant, n₁ and n₂ are integers with n₁ <n₂
It is asked to write the Rydberg equation for the energy.
Let's use the Planck relation.
E = h f
The light speed is related to the wavelength and frequency of radiation.
c = λ f
Where E is the energy, h the Planck constant, c the speed of light, λ the wavelength and f the frequency.
Let's substitute.
E = [tex]\frac{hc}{\lambda}[/tex]
[tex]\frac{1}{\lambda} = \frac{E}{hc}[/tex]
Let's substitute in the Rydberg equation.
[tex]\frac{E}{hc} = R_H ( \frac{1}{n_1^2} - \frac{1}{n_2^2}) \\E = R_H \ h \ c \ ( \frac{1}{n_1^2} - \frac{1}{n_2^2} )[/tex]
We can write is an constant of the form.
A = [tex]R_H h c[/tex]
The value of the constant is :
A = 1,097 10⁷ 6,626 10⁻³⁴ 3 10⁸
A = 2.18 10⁻¹⁸ J
In conclusion, using the Planck equation and the light speed we can find the results for the transformation of the Rydberg equation are
[tex]E = A ( \frac{1}{n_1^2} - \frac{1}{n_2^2} )\\ A = R_H h c\\[/tex]
A = 2.18 10⁻¹⁸ J
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Classify the following chemical reaction
3 C + 4H2→ C3 H8
Answer:
Synthesis Reaction
General Formulas and Concepts:
Synthesis Reactions: A + B → AB
Decomposition Reactions: AB → A + B
Single-Replacement Reactions: A + BC → AB + C
Double-Replacement Reactions: AB + CD → AD + BC
Explanation:
Step 1: RxN
3C (s) + 4H₂ (g) → C₃H₈ (s)
We see here that we are combining 2 elements to form a compound.A would be C, B would be H₂, and C₃H₈ would be ABTherefore, we have a Synthesis ReactionLight 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]
Pls help me here, thanks in advance
Answer:
What's the problem???
A neutral atom has 37 electrons. How many protons does the
atom have?
Answer:
37
Explanation:
because when an element is neutral it contains thesame amount of protons and electrons.
The number of protons in the given neutral atom is 37.
Explanation:
Atom is made up of three subatomic particles: protons, electrons, and neutrons.Protons are positively charged, electrons are negatively charged and neutron has no charge.Atom is electrically neutral as it contains an equal number of electrons and protons.The atomic number of an atom is equal to the number of protons in an atom.The mass of the atom is equal to the sum of the number of protons and the number of neutrons.Given:
A neutral atom with 37 electrons
To find:
The number of protons.
Solution:
Number of electrons = 37
The given atom is neutral, which means that an equal number of protons and electrons are present.
Number of protons = 37
The number of protons in the given neutral atom is 37.
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Choose the coefficient for blank 1 (in front of Rb)
___ Rb + ___ P --> ___ Rb3P
options:
3
1
4
2
Answer:
3
Explanation:
Step 1: RxN
Rb + P → Rb₃P
Step 2: Balance RxN
We will need 3 Rb's on both sides.
3Rb + P → Rb₃P
I NEED THESE ANSWERED!!! PLEASEEE!!!!!
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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.
What is the percent composition of sulfur in H2SO4?
2.1%
B)
65.2%
C)
98.1%
D)
32.7%
Answer:
D (32.7%)
Explanation:
Answer:D (32.7%)
Explanation:
what is the original name for gold
Answer:
It's Anglo Saxon.
Explanation:
From the Latin aurum, which stands for Aurora, the dawn goddess, comes the symbol Au. Early humans were aware of and highly valued gold. Gold is a beautiful and valuable metal that has been used for at least 5500 years. The original name for gold is Anglo-Saxon.
The element number 79 for gold is Au. Gold's Latin name, Aurum, or shining morning, and its earlier Greek origins predate the Anglo-Saxon term for it. It is one of the more abundant elements with a higher atomic number and exhibits very little reactivity towards the majority of atmospheric conditions, such as water and air.
Although gold is typically inert, it can react with a substance called aqua-regia. A substance called aqua regia is used to dissolve gold. Nitric and hydrochloric acids are combined to make them. The oxidizing agent will be nitric acid, which will result in the creation of gold ions.
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Solve for Keq , given the following concentrations at equilibrium. Based on the calculated Keq, are products or reactants larger?
CO2 = 3.0 M O2 = 1.5 M CO = 2.0 M
Answer:
it blows up very lighty
Explanation:
40 POINTS!! Choose all the answers that apply.
Light _____.
travels in longitudinal waves
does not require a medium to travel through
slows down when traveling through more dense substances
speeds up when traveling through less dense substances
can be absorbed and transformed into heat
is refracted when it changes direction and speed
Answer:
The correct answers are:
does not require a medium to travel through
can be absorbed and transformed into heat
is refracted when it changes direction and speed
Hope this helps, have a great day and stay safe! :) :D :3
Answer:
B,E, and F
Explanation:
does not require a medium to travel through
can be absorbed and transformed into heat
is refracted when it changes direction and speed
TRUST : )
Differences in states of matter are determined by
particle type
particle arrangement
particle color
distance between particles
Answer:
particle distance
solids are tightly packed
liquids are a little farther apart
and gases are very far
True or False: The isotope with the greatest
abundance contributes to the atomic mass
reported on the periodic table more than
the isotope of lower abundance.
Answer:
True
Explanation:
Greater abundance means there is more of those isotopes, so they contribute to the average number more. The average number is the atomic mass.
Which types of reactions would result in the formation of precipitate?
Answer:
Double Displacement Reaction
Explanation:
A double displacement reaction is a type of chemical reaction in which the reactant ions exchange places to form new products. Usually, a double displacement reaction results in precipitate formation.
1. Calculate the amount of energy absorbed when 10 g water at 86 C turns completely to steam vapor at 100C
2. Calculate the amount of energy released when 10 g water at 72 C freezes completely at 0C
Answer:
The amount of energy absorbed when 10 g water at 86 C turns completely to steam vapor at 100 C is 584.76 J
The amount of energy released when 10 g water at 72 C freezes completely at 0 C is 3,012.48 J
Explanation:
Sensible heat is the amount of heat that a body can receive without affecting its molecular structure. If the molecular structure does not change, the state (solid, liquid, gas) does not change. Since the molecular structure does not change, a change in temperature is observed.
In other words, the heat that produces a change in the temperature of a substance without any changes in its physical state (phase change) is called sensible heat.
The equation that allows calculating this type of heat exchange is:
Q = c * m * ΔT
where Q is the heat exchanged by a body of mass m, constituted by a substance of specific heat c and where ΔT is the change in temperature.
1. In this case, you know:
c= 4.184 [tex]\frac{J}{C*g}[/tex]m= 10 grΔT=Tfinal - Tinitial= 100 C- 86 C=14 CReplacing:
Q= 4.184 [tex]\frac{J}{C*g}[/tex] *10 g*14 C
Solving:
Q= 584.76 J
The amount of energy absorbed when 10 g water at 86 C turns completely to steam vapor at 100 C is 584.76 J
2. In this case, you know:
c= 4.184 [tex]\frac{J}{C*g}[/tex]m= 10 grΔT=Tfinal - Tinitial= 0 C- 72 C= -72 CReplacing:
Q= 4.184 [tex]\frac{J}{C*g}[/tex] *10 g*(-72) C
Solving:
Q= -3,012.48 J
The amount of energy released when 10 g water at 72 C freezes completely at 0 C is 3,012.48 J
Which of the following pictures correctly shows the structure of hydronium ion?
Answer: The first picture
Explanation:
The structure of hydronium ion is correctly represented in the first structure where there are three hydrogen atoms and one oxygen atom.
What is an ion?An ion is defined as an atom or a molecule which has a net electrical charge. There are 2 types of ions :1) cation 2) anion . The cation is the positively charged ion and anion is the negatively charged ion . As they are oppositely charged they attract each other resulting in the formation of ionic bond.
Ions consisting of single atom are mono-atomic ions while which consists of two or more ions are called as poly-atomic ions . They are created by chemical interactions . They are very reactive in their gaseous state and rapidly react with oppositely charged ions resulting in neutral molecules.
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Which element am I? Give my symbol ONLY! What a robber says as he's running away!
Answer:
ummmmmmmmmmmmmmmm..mmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmm
Explanation:
ummmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmm.................... candyunicorns1999 has left the chat
Answer:
Bi
Explanation:
An intravenous solution contains 2.5 mEq/L of magnesium ions. How many moles of magnesium are in 750 mL of this solution?
Answer:
.9375 x 10⁻³ moles .
Explanation:
2.5 mEq / L of Magnesium ion
2.5 x 10⁻³ Eq / L
= 2.5 x 10⁻³ / 2 mole / L [ 1 mole = 2 Eq ]
= 1.25 x 10⁻³ mole / L
1 L contains 1.25 x 10⁻³ mole
750 mL = .75 x 1.25 x 10⁻³ mole
= .9375 x 10⁻³ mole .
So 750 mL contains .9375 x 10⁻³ moles .
