Hello there!
Question: Which of the following is most likely an indication of a chemical change?
Answer Choices:
A. A loud sound when an MP3 player is turned on.
B. A loud sound when someone claps their hands.
C. A loud sound when a starter's pistol is fired at a race.
D. A loud sound when a large object falls to the ground.
Correct Answer:
C. A loud sound when a starter's pistol is fired at a race.
Reasons:
A would not be correct since an MP3 player is a mechanical object and does not mix any substances that create a reaction.
B would not be correct since clapping hands causes a loud sound due to two forces slamming together and causes a disturbance in the air.
D would not be correct since a large object falling to the ground does not indicate any chemical reactions or changes since its merely the result of a mass hitting another mass.
C would be correct since the gunpowder mixes with other substances inside the pistol's chamber and causes and explosion, and explosions are part of a chemical reaction indicators.
Explain why or why not the change is a chemical change or not.
A. The outside of a piece of cheese has turned green from mold.
B. An antacid tablet dissolves in water and forms carbon dioxide.
C. Ice melts and forms a puddle of water.
D. A piece of clay is broken in half.
Explanation:
A. Not a chemical reaction. Mold is a small organism.
B. Chemical reaction. When antacid tablet reacts with water CO2 is emitted.
C. Not a chemical reaction ice and water are 2 states of H2O. H2O solid and H2O liquid
D. Not a chemical reaction reactants and the result is the same clay.
Earth revolving around the sun, you walking down the street, and molecules moving in space all have
A. Potential energy
B. Kinetic energy
Answer:
B. Kinetic energy
Explanation:
moving is kinetic, potential is inside a body
Select the correct answer.
In which location would a free neutron from a decaying U-235 atom be most likely to cause another atom to split?
OA
in a sample of naturally occurring uranium
B.
in a sample of enriched uranium
O C.
in a sample of rock or soil
D.
in the Sun's core
E.
in a distant star
Answer:
B. in a sample of enriched uranium
Explanation:
Decaying of U-235 atom is a process of nuclear fission. In this process a neutron is bombarded on U-235 and the uranium atom captures the neutron and divide immediately to release neutron. With the release of one neutron another nuclear fission process starts.
The free neutron is then split in a sample of enriched uranium because splitting nucleus releases high energy and enrich uranium increases the percentage of uranium-235 which further undergoes fission. This is why enrich uranium samples are used in atomic reactors.
Hence, the correct option is B.
Why would a laptop, a car, a cellphone, and a watch all contain chemical energy?
Answer:
Maybe its because they need some sort of energy to work, a car is quite straight forawrd but im not sure about a watch :/
1. How does the molecular property of water affect its cohesive properties?
Answer:
Water molecules have strong cohesive forces thanks to their ability to form hydrogen bonds with each other.
Explanation:
Cohesion refers to the attraction of molecules by other molecules of the same type.
The structure of the water molecule is given by two hydrogen atoms and one oxygen atom that are held together by covalent bonds. It is a polar molecule and consequently forms bonds called hydrogen bonds with other molecules.
How many moles are in 6.97g of Chromium?
Answer:
0.134 moles
Explanation:
In order to solve this, we need to find the molar mass of Chromium, which we can see from the periodic table: it is 51.996 g/mol.
Now, we need to set up an equation to convert grams to moles:
[tex]6.97 grams*\frac{1mol}{51.996grams} =0.134mol[/tex]
Thus, the answer is 0.134 moles of Chromium.
Explanation:
Step 1: Find how many moles
Formula → [tex]grams*\frac{1 mol}{51.996grams}[/tex]
[tex]6.97 g *\frac{1 mol}{51.996g}[/tex] ← The g's cancel and there is only moles left on top
[tex]0.13405... mol[/tex]
Answer: Rounded - 0.13405 moles of Chromium
a hurricanes energy comes from
Answer:
Heat and water.
Explanation:
Increased evaporation means more water vapor in the air and more energy ready to be liberated in the hurricane's thunderstorms as water vapor condenses.
Which of the following reactions describes a beta emission?
(PLEASE HELP!!!)
Answer:
The third option is correct
Explanation:
What is the molarity of a 0.51 L solution with 5.61 moles of lithium chloride?
plz help asap
Answer:
The molarity is 11 [tex]\frac{moles}{liter}[/tex]
Explanation:
Molarity is a measure of the concentration of a solute in a solution that indicates the amount of moles of solute that appear dissolved in each liter of the mixture.
The molarity of a solution is calculated by dividing the moles of the solute by the liters (volume) of the solution:
[tex]Molarity=\frac{number of moles of solute}{solution volume}[/tex]
Molarity is expressed in units ([tex]\frac{moles}{liter}[/tex]).
In this case:
number of moles of solute= 5.61 molessolution volume= 0.51 litersReplacing:
[tex]Molarity=\frac{5.61 moles}{0.51 liters}[/tex]
Solving:
Molarity= 11 [tex]\frac{moles}{liter}[/tex]
The molarity is 11 [tex]\frac{moles}{liter}[/tex]
Which represents a double replacement reaction and would occur?
NH4NO3(aq) + AgCIO3(aq) → AgNO3(aq) + NH4CIO3(aq)
Na2CO3(aq) + CaCl2(aq) → 2NaCl(aq) + CaCO3(s)
NaF(aq) + KCl(aq) → NaCl(aq) + KCl(aq)
NaCl(aq) → Na+(aq) + Cl-(aq)
Answer:
The correct answer is B . Na2CO3(aq) + CaCl2(aq) → 2NaCl(aq) + CaCO3(s)
Explanation:
hope it works out !!
A double replacement reaction is Na2CO3(aq) + CaCl2(aq) → 2NaCl(aq) + CaCO3(s). Therefore, option B is correct.
What is double replacement reaction ?When pieces of two ionic compounds are exchanged, two new compounds are created. These reactions are known as double replacement reactions, double displacement reactions, exchange reactions, or metathesis reactions.
We need to understand the types of ionic compounds that create precipitates in order to determine whether double-replacement reactions will take place. In order to do this, we employ solubility principles, which are broad generalizations that foretell which ionic compounds will dissolve (be soluble) and which will not (are not soluble or insoluble).
A double displacement reaction is a particular type of reaction in which two reactants swap ions to produce two new molecules. Water-soluble ionic compounds interact with one another in a number of double displacement processes.
Thus, option B is correct.
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If 12.5 grams of strontium hydroxide is reacted with 150 mL of 3.5 M carbonic acid, identify the limiting reactant.
Answer:
Sr(OH)2
Explanation:
We'll begin by calculating the number of mole of carbonic acid in 150mL of 3.5 M carbonic acid solution. This is illustrated below:
Molarity = 3.5M
Volume = 150mL = 150/1000 = 0.15L
Mole of carbonic acid, H2CO3 =..?
Mole = Molarity x Volume
Mole of carbonic acid, H2CO3 = 3.5 x 0.15 = 0.525 mole.
Next, we shall convert 0.525 mole of carbonic acid, H2CO3 to grams.
Mole of H2CO3 = 0.525 mole
Molar mass of H2CO3 = (2x1) + 12 + (16x3) = 62g/mol.
Mass of H2CO3 =..?
Mass = mole x molar mass
Mass of H2CO3 = 0.525 x 62 = 32.55g
Next, we shall write the balanced equation for the reaction. This is given below:
Sr(OH)2 + H2CO3 → SrCO3 + 2H2O
Next, we shall determine the mass of Sr(OH)2 and H2CO3 that reacted from the balanced equation. This is illustrated below:
Molar mass of Sr(OH)2 = 88 + 2(16 + 1) = 88 + 2(17) = 122g/mol
Mass of Sr(OH)2 from the balanced equation = 1 x 122 = 122g
Molar mass of H2CO3 = (2x1) + 12 + (16x3) = 62g/mol.
Mass of H2CO3 from the balanced equation = 1 x 62 = 62g.
From the balanced equation above, 122g of Sr(OH)2 reacted with 62g of H2CO3.
Finally, we shall determine the limiting reactant as follow:
From the balanced equation above, 122g of Sr(OH)2 reacted with 62g of H2CO3.
Therefore, 12.5g of Sr(OH)2 will react with = (12.5 x 62)/122 = 6.35g.
We can see evidently from the calculations made above that it will take 6.35g out 32.55g of H2CO3 to react with 12.5g of Sr(OH)2. Therefore, Sr(OH)2 is the limiting reactant and H2CO3 is the excess reactant
Answer:
Strontium hydroxide.
Explanation:
Hello,
In this case, the undergoing chemical reaction is:
[tex]Sr(OH)_2+H_2CO_3\rightarrow SrCO_3+2H_2O[/tex]
Thus, the first step is to compute the moles of both strontium hydroxide (molar mass = 121.63 g/mol) and carbonic acid given the mass and volume and concentration respectively:
[tex]n_{Sr(OH)_2}=12.5gSr(OH)_2*\frac{1molSr(OH)_2}{121.63gSr(OH)_2} =0.103molSr(OH)_2\\\\n_{H_2CO_3}=3.5mol/L*0.150L=0.525molH_2CO_3[/tex]
Therefore, as they are in a 1:1 molar ratio in the chemical reaction, the same moles of both strontium hydroxide and carbonic acid must react, nevertheless, there are more moles of carbonic acid, for that reason, the limiting reactant is strontium hydroxide.
Best regards.
The diagram is an example of which of the following?
aldehyde
alkane
alkene
alkyne
The answer is B: Alkane
The diagram is an example of an alkane which contains n-carbon and 2n+2 hydrogen.
What is alkane?Alkanes are saturated hydrocarbons. This means that their carbon atoms are joined to each other by single bonds.
Alkanes are organic compounds that consist of single-bonded carbon and hydrogen atoms. The formula for alkanes is [tex]C_nH_2_n_+_2[/tex].
Methane ([tex]CH_4[/tex]), ethane ([tex]C_2H_6[/tex]), propane ([tex]C_3H_8[/tex]) and butane ([tex]C_4H_1_0[/tex]) are the first four alkanes.
Hence, the diagram is an example of alkane.
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Consider the nuclear equation below. Superscript 15 subscript 8 upper O right arrow superscript 15 subscript 7 upper N plus superscript 0 subscript plus 1 e. Which correctly identifies the type of reaction? alpha decay beta plus decay beta minus decay gamma decay
Answer:
beta plus
Explanation:
edg
Answer:
beta plus
Explanation:
edge
Describe the motion of molecules in an ice cube
and in a radiator in winter.
Molecules in an ice cube move more slowly than molecules
radiator
COMPLETE
Describe the motion of molecules in these two
substances when the ice cube is placed on the
radiator.
AUCU
Answer:
Molecules in an ice cube have lower kinetic energy than molecules in a radiator. Molecules in an ice cube move more slowly than molecules in a radiator. They collide with less force than molecules in a radiator.Molecules in an ice cube have lower kinetic energy than molecules in a radiator.
Molecules in an ice cube move more slowly than molecules in a radiator. They collide with less force than molecules in a radiator.
When in direct contact, the fast-moving molecules in the radiator collide with the slow-moving molecules in the ice cube.
Kinetic energy is transferred from the molecules in the radiator to the molecules in the ice cube, causing a slowdown of the radiator molecules and an acceleration of the ice molecules.
Explanation:
Suggest two reasons why the maximum allowed percentage of carbon monoxide
has been decreased for newer cars
The maximum percentage of carbon monoxide (CO) has been reduced for newer cars as this i) will help mitigate global warming and ii) improve human health.
What is Carbon monoxide?Carbon monoxide is a harmful diatomic gas constituting carbon and oxygenCarbon monoxide has no distinct colour or smellTo identify why the limit of carbon monoxide has to be reduced, we have to understand its effects on our environment and health.
What are the impacts of carbon monoxide on the environment?Since carbon monoxide is produced from incomplete burning of fuel, especially in cars, a lot of this gas is made by vehiclesThis leads to air pollution where the amount of carbon monoxide increases to dangerous levels in our atmosphereAs carbon monoxide is a greenhouse gas, it contributes to global warming. What are the effects of carbon monoxide on human health?If a person breathes in carbon monoxide, these molecules bind to haemoglobin better than oxygenEventually, more carbon monoxide than oxygen will be transported in their body This carbon monoxide poisoning is extremely fatal and may lead to death if not treated in timeTherefore, to i) reduce global warming and ii) improve human health, the upper limit of carbon monoxide percentage has been reduced for new vehicles.
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The process of fermentation involves chemical reactions that convert solid glucose (C6H12O6) into aqueous ethanol and carbon dioxide gas. Write the balanced chemical equation
Answer:
C6H12O6 —> 2C2H5OH + 2CO2
Explanation:
The equation for the reaction is given below:
C6H12O6 —> C2H5OH + CO2
We can balance the equation above as follow:
There are 12 atoms of H on the left side and 6 atoms of the right side. It can be balance by putting 2 in front of C2H5OH as shown below:
C6H12O6 —> 2C2H5OH + CO2
There are 6 atoms of C on the left side and 5 atoms on the right side. It can be balance by putting 2 in front of CO2 as shown below:
C6H12O6 —> 2C2H5OH + 2CO2
Now the equation is balanced.
For this assignment, you will ask questions about the factors that have caused a rise in global temperatures over the past century. Then, you will conduct research to answer your questions. You will also graph provided information, analyze the graphs, and make conclusions based on the graphs. Finally, you will write a paper describing the conclusions of your research and graphs.
Answer:
Air pollution is the main cause of rise in temperature over the past century.
Explanation:
Due to increase in the industrialization in different countries of the world and also burning of more fossil fuels in the engines of vehicles and jets are the main reason of increasing global temperature. Both industries and vehicles produce high amount of carbondioxide which is a greenhouse gas that blocks the passage of reflected radiation from the earth surface and traps this radiation which increases the temperature of the earth.
My project is in the file attached, lots of thanks to Maxineishere for helping me with the essay. You may need adobe reader for this as the files are PDF files, I hope you are satisfied! :)
DATE ANSWERED: 5/8/2021
How are a mole and a dozen similar?
Each represents a certain mass of material.
Each names a given number of objects.
Each identifies a specific volume.
Each measures a given number of amus.
Answer:
Each names a given number of objects (c)
Explanation:
Edge
Each names a given number of objects is the similarity present in mole and dozen.
What is mole and dozen?The mole refers to the number of particles or ions present in an atom in the quantity of 6.02 1023 particles while on the other hand, the dozen refer to the number of 12 items.
So we can conclude that each names a given number of objects is the similarity present in mole and dozen.
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How many moles of lithium chloride will be formed by the reaction of chlorine with 0.046 mol of lithium bromide in the following reaction?
2LiBr(aq) + Cl2(g) → 2LiCl(aq) + Br2(l) ans: 0.046 mol LiCl
Answer:
The answer is 0.046 mol.
Explanation:
By looking at the balanced equation, you can form a ratio of lithium chloride and lithium bromide using the coefficient value :
ratio of lithium bromide (2LiBr)
= 2
ratio of lithium chloride (2LiCl)
= 2
So the ratio is 2 : 2 then simplify into 1 : 1 . Which means that 1 mol of lithium bromide is equal to 1 mole of lithium chloride.
In this case, 0.046 mol of lithium bromide will form 0.046 mol of lithium chloride.
The number of moles should be 0.046 mol.
Calculation of a number of moles:Here we can create a ratio of lithium chloride and lithium bromide by applying the coefficient value :
the ratio of lithium bromide (2LiBr) = 2
And, the ratio of lithium chloride (2LiCl) = 2
Here 2:2 means 1:1
So, the number of moles should be the same i.e. 0.046 mol.
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What is the term used to describe the number of protons plus the number of neutrons in an atom?
Answer:
The atomic number is the number of protons in an element, while the mass number is the number of protons plus the number of neutrons.
Explanation:
Why the southern hemisphere experiences summer when the northern hemisphere experiences winter.
Answer:
Northern hemisphere and southern hemisphere are two poles of the earth that are responsible for a different environment.
Explanation:
Theses both hemispheres have different climate at its poles. This happened because of pf the tilt of the earth. on the axis. When the northern pole gets tilt towards the sun it gets to summer.
The northern poles get sarcastically hotter season. So that when the northern pole is hotter the southern pole gets cooler at that time. All has happened because the earth gets tilted towards its poles or axis.
An aqueous solution of sodium thiosulfate releases heat when it crystallizes. What would happen when sodium thiosulfate crystals dissolve in water?
Answer:
An excellent experiment is to heat sodium thiosulfate in a water bath. The solid crystals will dissolve into the water in the hydrated crystals forming a supersaturated solution. ... Placing a small crystal in the supersaturated solution will cause the liquid to turn solid.
how many moles is 22.4 liters of oxygen gas at standard temperature and pressure represent
Answer:
So 1 mole
Explanation:
PV = nRT
P = Pressure atm
V = Volume L
n = Moles
R = 0.08206 L·atm·mol−1·K−1.
T = Temperature K
standard temperature = 273K
standard pressure = 1 atm
22.4 liters of oxygen
Ok so we have
V = 22.4
P = 1 atm
PV = nRT
n = PV/RT
n = 22.4/(0.08206 x 273)
n = 22.4/22.40
n = 1 mole
1. Atomic number is the number of_____in an atom .
A)neutrons
B)protons
C)electrons
Answer:
B. Protons
Explanation:
The atomic number or proton number of a chemical element is the number of protons found in the nucleus of every atom of that element.
Answer:
protons
Explanation:
why is the bone have so much structure??
please help brainlest and 20 points
Answer:
Because if it didn't have structure then your body would fall apart
Explanation:
If you didn't have a spine you couldn't stand up straight
Which of the following statements describes all the variables in an experiment?
A.
All variables are measured to provide data for the experimental results.
.
B.
All variables are kept the same from one part of the experiment to another.
OC.
All variables affect the results of the experiment.
O
D.
All variables are changed from one part of the experiment to another.
Answer:
Answer is C
Explanation:
All the variables can affect the results in an experiment
QUICK I NEED THE ANSWER!! Compare the symmetry of an echinoderm to the symmetry of worms
A. Both echinoderms and worms have bilateral symmetry
B.Echinoderms have bilateral symmetry and worms have radial symmetry
C.Echinoderms have radial symmetry and worms have bilateral symmetry
D.Both echinoderms and worms have radial symmetry
Answer:
C.Echinoderms have radial symmetry and worms have bilateral symmetry
Explanation:
Echinoderms evolved from animals with bilateral symmetry. The larvae of all echinoderms are bilaterally symmetrical but lost during metamorphosis developing into radial symmetry adult. Examples of echinoderms are starfish, sea urchins, sand dollars.
Worms are invertebrate animals having bilateral symmetry. They have a definite anterior (head) end and a posterior (tail) end. Worms have brains that help them detect objects, food, mates, and predators quickly.
What is mechanical weathering? How do water, ice, wind, and organisms cause mechanical weathering? How can organisms and wind cause it?Type out an explanation of why that answer is correct
Answer:b
Explanation:c
Explain how the presence of copper atoms can produce an alloy stronger than pure gold
Answer:
Alloying metal lattice is intruded with strong metal atoms to provide it strength and enhance its durability
Explanation:
Mixture of two substances with an objective of improving the properties of any one of the elements is called an alloy. In the case of gold, Gold is alloyed with copper to enhance its flexibility, toughness and hardness. It can also be alloyed with range of metals including silver, copper, platinum, palladium, and zinc.
Pure gold is extremely soft for practical use. Copper also enhance the malleability and ductility of gold metal.
Speed is calculated by taking
divided by time.
Save and Exit
Next
Submit
Mark this and return
Answer:
Look speed is calculated by using formula
Speed(s)=distance travellelled (d) / total time taken (t)
s=d/t
It's unit is m/s