A substance that cannot be converted into another substance is known as an element. Each type of atom that makes up an element is unique. The correct option is A.
A substance whose atoms all contain the same number of protons is said to constitute an element; alternatively, all the atoms of a certain element must contain the same number of protons. Chemical reactions cannot degrade elements since they are the simplest chemical forms.
A compound is created when two or more components join chemically in a predetermined mass ratio.
Thus the correct option is A.
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When 14.8 g KOH is dissolved in 85.6 g of water in a coffee-cup calorimeter, the temperature rises from 19.3 °C to 32.76 °C. What is the enthalpy change per gram of potassium hydroxide dissolved in the water?
Answer:
This question is incomplete, the complete question is; assuming that the solution has a specific heat of 4.18 J/g°C
The answer is 381.67 J/g
Explanation:
Enthalpy change denoted by ΔH can be calculated using the formula;
ΔH = m × c × ΔT
Where; m= mass of reactants
c= specific heat
ΔT = change in temperature
ΔT = T2 - T1
ΔT = 32.76 - 19.3
ΔT = 13.46 °C
mass of reactants= 85.6 + 14.8 = 100.4g, c = 4.18J/g°C
Hence; ΔH = m × c × ΔT
ΔH = 100.4 × 4.18 × 13.46
ΔH = 5648.78J
Enthalpy change per gram of potassium hydroxide dissolved in the water is;
ΔH = 5648.78/14.8
ΔH = 381.67 J/g
The enthalpy change per gram of potassium hydroxide dissolved in the water is 382 J/g
How to determine the heat Mass (M) = 14.8 + 85.6 = 100.4 gInitial temperature (T₁) = 19.3 °C Final temperature (T₂) = 32.76 °CChange in temperature (ΔT) = 32.76 – 19.3 = 13.46 °C Specific heat capacity (C) = 4.184 J/gºC Heat (Q) =?
Q = MCΔT
Q = 100.4 × 4.184 × 13.46
Q = 5654.19 J
How to determine the enthalpy change ΔHHeat (Q) = 5654.19 JMass of KOH (m) = 14.8 gEnthalpy change (ΔH) =?ΔH = Q / g
ΔH = 5654.19 / 14.8
ΔH = 382 J/g
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The particles of a gas inside a balloon are experiencing an increase in their average kinetic energy and the number of collisions with the wall of the balloon. What is the most likely outcome? higher gas pressure inside the balloon higher air pressure outside the balloon a decrease in gas temperature inside the balloon a large increase in air temperature outside the balloon
The higher Gas pressure inside the balloon. Hence, option A is correct.
How is kinetic energy related to temperature?In a molecule, the kinetic energy existing is "directly proportional" to the temperature of the molecule. If one of the values increases, then the other value also increases and vice-versa.
The higher Gas pressure inside the balloon. As the number of collisions with the wall of the balloon increases, the pressure inside increases.
Hence, option A is correct.
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11. A sample contains 25% water and weighs 201 grams. Determine the grams of water in the
sample.
Answer:
[tex]m_{water}=50.25g[/tex]
Explanation:
Hello,
In this case, considering that the by-mass percent of water is:
[tex]\% m/m=\frac{m_{water}}{m_{sample}}*100\%[/tex]
Given such percent and the mass of the sample, we can find the mass of water in grams in the sample by solving for it as shown below:
[tex]m_{water}=\frac{\%m/m*m_{sample}}{100\%}\\ \\m_{water}=\frac{25\%*201g}{100\%}\\ \\m_{water}=50.25g[/tex]
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Identify the characteristics of a good recrystallization solvent. Select one or more: Dissolves a chemical sample well at high temperatures. Is not an organic liquid with a low boiling point. Does not dissolve a chemical sample well at low temperatures. Does not dissolve a chemical sample well at high temperatures. Dissolves a chemical sample well at low temperatures. g
Answer:
Dissolves a chemical sample well at high temperatures.
Does not dissolve a chemical sample well at low temperatures.
Explanation:
Recrystallization involves the dissolution of the solute in a solvent at high temperature. As the solution cools, it becomes saturated and the solute crystallizes out of the solution.
A good recrystallization solvent must only dissolve the solute at high temperature and must not dissolve it at low temperature. Hence, these are the two conditions required for any good recrystallization solvent.
What is temperature
Answer:
Temperature is a physical quantity that expresses hot and cold. It is the manifestation of thermal energy, present in all matter, which is the source of the occurrence of heat, a flow of energy, when a body is in contact with another that is colder. Temperature is measured with a thermometer.
Answer:
The degree or intensity of heat present in a substance or object
Find the reagent to sythesize 1- phenyl-1-propanol
Starting Material: Ethyl−MgBr and Benzaldehyde
Solvent:
EtOH
Answer:
aqueous acid is used as a reagent.
Explanation:
Addition of Grignard reagent in aldehyde and followed by the acidification give rise to the primary or secondary alcohol. when the formaldehyde is used than the primary alcohol is formed otherwise secondary alcohol is formed.
in this reaction we also use the aqueous acid for the acidification as a reagent. We add aqueous acid when ethanol is present. This is because ethanol is get converted in the presence of aqueous acid into the chloroethane.
A bird flies 3.7 meters in 46 seconds, what is its speed?
v=
d=
t=
Answer:
speed = 3.7/46 = 0.080m/s
d= 3.7m
t= 46s
Explanation:
What determines the reactivity of an akali metal?
Answer:
The number of valence electrons determines an element's reactivity, or how likely the element is to react with other elements.
Explanation:
Which four practices are examples of how humans use science?
A. Making decisions that help humans survive
OB. Developing technologies that help humans thrive
C. Developing explanations based on facts
D. Imagining entertaining stories that explain observations
O E. Gathering facts that explain natural events
Answer:
A. Making decisions that help humans survive
B. Developing technologies that help humans thrive
C. Developing explanations based on facts
E. Gathering facts that explain natural events
Explanation:
The above are examples of the practices of how humans use science.
Science has been of tremendous help to humans in making decisions that make humans survive and develop technologies that help humans thrive. It has helped to gather and develop explanations that are based on facts. It has helped to explain natural events.
How are most meteoroids formed? A. As the Sun burns, it throws off small, solid particles at a regular rate which are launched into the Solar System. B. They are created in the explosions that occur when stars die and eventually reach the Solar System. C. They are small pieces that are left over from the formation of the Solar System. D. They are small pieces of debris that are the result of collisions of asteroids, comets, moons, and even planets within the Solar System. Will give brainlist
Answer:
It is no. D
Explanation:
Many meteoroids are formed from the collision of asteroids, which orbit the sun between the paths of Mars and Jupiter in a region called the asteroid belt.
An unopened 350 mL can of diet Dr. Pepper will float in a lake. However, it’s also true that an unopened 350 mL can f regular Dr. Pepper will sink in the same lake! Based on these two facts, which type of soda is the least dense? Explain your answer.
Answer:
Diet Dr. Pepper
Explanation:
The density of an object and the liquid involved determines if that particular object will float or sink in the particular liquid. An object will FLOAT if its density is lower than that of the liquid substance while it will SINK if its density is higher than that of the liquid substance.
In this case, water (lake) is the liquid substance. According to the question, an unopened 350 mL can of DIET Dr. Pepper will float in a lake because it is less dense than the water while an unopened 350 mL can of REGULAR Dr. Pepper will sink because it is more dense than water.
Hence, the DIET type of soda is the least dense
Explain why CaCl2 is likely to have properties similar to those of CaBr2
Answer:
Because both compounds (CaCl2 and CaBr2) contain elements (bromine and chlorine) from the same group (group 7)
Explanation:
Elements are organized into groups on the periodic table based on the number of valence electrons contained in their outermost shell. These elements in the same group i.e. same number of valence electrons, will behave in a similar manner chemically.
CaCl2 and CaBr2 are two compounds that contains elements (Chlorine and Bromine) from the same group, which is group 7. Elements in group 7 are called HALOGENS and have 7 valence electrons in their outermost shell.
Bromine (Br) and Chorine (Cl) are responsible for the similarity in the properties of CaCl2 and CaBr2 because the Chlorine and Bromine contained in them will cause them to react similarly and behave similarly in the presence of other compounds.
Which statement explains why carbon-14 dating cannot be used to date ancient rocks?
Carbon-14 decays at a varying rate.
Carbon-14 decays relatively quickly.
Carbon-14 can be used only to date the remains of organisms.
Carbon-14 has a half-life that is much longer than potassium.
Answer:
its, b
Explanation:
took the test on e2020
Carbon-14 dating cannot be used to date ancient rocks because:
B. Carbon-14 decays relatively quickly.
Carbon-14 dating:It is a method for tracking down the time of natural materials, like wood, in light of their substance of radioactive carbon. Also, it is a technique for estimating the time of natural matter by investigating its carbon content.
The decay takes place around 55,000 years i.e half the amount of the radioisotope present at any given time.
Thus, option B is correct.
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Alkynes are reduced to trans alkenes by a process called dissolving metal reduction. The reaction uses sodium or lithium metal as the reducing agent and liquid ammonia as the solvent. The method is specific in the formation of trans alkenes from alkynes. The method involves two successive transfers of single electrons from the alkali metal to the triple bond, with abstraction of protons from the ammonia solvent.Draw curved arrows to show the movement of electrons in this step of the mechanism.Arrow-pushing Instructions
Answer:
Explanation:
The movement of the electrons is illustrated in the picture attached to this answer. It is a four-step reaction mechanism.
First STEP: The first step involves the transfer of an electron from sodium to form a radical anion.
Second STEP: This radical anion then removes a proton/hydrogen from ammonia in a bid to neutralize itself (hence the hydrogen becomes bonded to the anion).
Third STEP: The sodium (from NaNH₂ formed) transfers an electron again to produce a vinyl carbanion.
Fourth STEP: The carbanion then removes a proton/hydrogen from ammonia (like in the second step) to form a neutral trans-alkene.
NOTE: The circled numbers denote each step while the mechanism on the left represents the use of any alkyl group (R and R') while the mechanism on the right assumes both alkyl groups are methyl. Hence, 2-butyne started the reaction and the final product was trans-2-butene.
What is the mass of 87.94 mL of ethanol, which has a density of 0.79 g/mL?
Answer:
The answer is
69.47 gExplanation:
The mass of a substance when given the density and volume can be found by using the formula
mass = Density × volumeFrom the question
volume of ethanol = 87.94 mL
density = 0.79 g/mL
The mass of ethanol is
mass = 87.94 × 0.79
mass = 69.4726
We have the final answer as
69.47 gHope this helps you
How many moles are in 34.0 g of dinitrogen oxide?
Answer:
0.773 mole
Explanation:
From the question given above, the following were obtained:
Mass of dinitrogen oxide (N₂O) = 34 g
Mole of N₂O =.?
Next, we shall determine the molar mass of N₂O. This can be obtained as follow:
Molar mass of N₂O = (14 × 2) + 16
= 28 + 16 = 44 g/mol
Finally, we shall determine the number of mole in 34.0 g of dinitrogen oxide (N₂O) as follow:
Mass of dinitrogen oxide (N₂O) = 34 g
Molar mass of N₂O = 44 g/mol
Mole of N₂O =.?
Mole = mass /Molar mass
Mole of N₂O = 34/44
Mole of N₂O = 0.773 mole
Therefore, 0.773 mole is present in 34 g of dinitrogen oxide
What does a cell nucleus do?
Select one:
a. control everything the cell does
b. surround the cell
c. hold important chemicals the cell needs
d. protect the cell.
Answer:
a. control everything the cell does
Explanation:
the nucleus is like the brain of the cell
Convert 0.0017hL into mL
Answer:
170ml
Explanation:
multiply the volume value by 100000
Give the charge on the transition metal of each of the following compounds:
A. Au2SO4
B. Fe2(CrO4)3
C. Zn(OH)2
Enter your answer as +1, +2, etc.
Au
type your answer...
Fe
type your answer...
Zn
type your answer...
In Au₂SO₄, the charge on each gold atom is +3.
The charge on the transition metal gold (Au) in Au₂SO₄ can be determined by considering the overall charge of the compound and the charges of the other ions present. In this case, the sulfate ion carries a charge of -2.
Charge on Au: +3
In Fe₂(CrO₄)₃, the transition metal iron (Fe) is present. The compound contains two iron atoms. To determine the charge on each iron atom, the charges of the other ions in the compound. The chromate ion carries a charge of -2, and the compound as a whole is neutral.
Charge on Fe: +3
The transition metal zinc (Zn) is present in Zn(OH)₂. To determine the charge of the zinc ion, to consider the charges of the other ions. The hydroxide ion (OH-) carries a charge of -1. Since there are two hydroxide ions, their combined charge is -2.
Charge on Zn: +2
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What is the hardness (HB) of each of the alloys?
(a) 0.25 wt%C with spheroid:te,
(b) 0.25 wt%C with coarse pearlite,
(c) 0.60 wt%C with fine pearlite, and
(d) 0.60 wt%C with coarse pearlite.
Answer:
A) 62.5 HB
B) 75 HB
C) 95 HB
D) 90 HB
Explanation:
From the attached animated figure, we can trace the values of hardness (HB) for each of the alloys.
The scale we are using in the attachment to read our values for HB is the HRB scale that shows the Rockwell hardness on the right hand side.
A) For 0.25 wt%C with spheroidite, Tracing the line out on the green curve and reading the scale on the right, the hardness is approximately 62.5 HB
B) For 0.25 wt%C with coarse pearlite, Tracing the line out on the blue curve and reading the scale on the right hand side, the hardness is approximately 75 HB
C) For 0.60 wt%C with fine pearlite, Tracing the line out on the red curve and reading the scale on the right hand side, the hardness is approximately 95 HB
D) For 0.60 wt%C with coarse pearlite. Tracing the line out on the blue curve and reading the scale on the right hand side, the hardness is approximately 90 HB
a race car at the Daytona 500 zips around the track .its travel the first 80 kilometers in 0.4 hours. the next 114 kilometers take 0.6 . the following 80 kilometers take 0.4 hours to calculate the race car average speed.
A race car at the Daytona 500 zips around the track its travel the first 80 km in 0.4 hours, the next 114km take 0.6, the following 80 km take 0.4, so the average speed is 195.71 km/hr.
How do we calculate the average speed?Average speed of any body will be calculated by dividing the total time to cover the ditance from the total distance covered.
Total distance to cover = 80km + 114km + 80km = 274km
Total time to cover distance = 0.4hr + 0.6hr + 0.4hr = 1.4hr
Average speed of car = 274/1.4 = 195.71 km/hr
So, the average speed of car is 195.71km/hr
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What does 3.5 degree of unsaturation tell you?
Answer:
It means the chemical entity is a radical
Explanation:
When we talk of unsaturation, we are referring to the number of pi-bonds in a chemical entity. The alkane, alkene and alkyne organic family are used to as common examples to explain the term unsaturation.
While alkynes have 3 bonds, it must be understood that they have 2 pi bonds only and as such their degree of saturation is two.
In the case of an alkene, there is only one single pi bond and as such the degree of unsaturation is 1.
Now in this case, we have a fractional 0.5 degree of unsaturation alongside the 3 to make a total of 3.5. So what’s the issue here?
The fractional part shows that the chemical entity we are dealing with here is a radical. While the integer 3 shows that there are 3 pi-bonds, the half pi bond remaining tells us that there is a missing electron on one of the atoms involved in the chemical bonding and as such, the 1/2 extra degree of unsaturation tends to tell us this.
Kindly recall that a radical is a chemical entity within which we have at the least an unpaired electron.
What is the difference between pure and applied chemistry?
Answer:
Explanation:
The major difference between pure and applied chemistry is the purpose and intent of the study.
Pure chemistry deals with the study of matter, matter transformations, and interactions between the different materials of the world, for only the sake of gaining empirical knowledge about the various substances that exist in the world. It does not really seek to apply this knowledge to do anything industrial.
Applied chemistry is the study of chemistry with the aim of utilizing this knowledge to solve the various problems that man faces. This approach of study is not for knowledge sake alone, rather it is for industrial application
The major difference between pure and applied chemistry is the purpose and intent of the study.
Pure chemistry deals with the study of matter, matter transformations, and interactions between the different materials of the world, for only the sake of gaining empirical knowledge about the various substances that exist in the world. It does not really seek to apply this knowledge to do anything industrial.
Applied chemistry is the study of chemistry with the aim of utilizing this knowledge to solve the various problems that man faces. This approach of study is not for knowledge sake alone, rather it is for industrial application.
Thus,the major difference between pure and applied chemistry is the purpose and intent of the study.
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write a brief short note on translation and transcription?
Answer:
Transcription is when you make a copy of the RNA from DNA. This is how the mRNA can leave the nucleus which exists to the cytoplasm and into ribosomes where protein synthesis occurs. Translation is what happens after transcription and this is where protein synthesis occusrs in the ribosomes/endoplasmic reticulum.
Explanation:
The best thermometer to use where temperatures drop below -39°C (-38.2°F) is:_______.
Answer:
The best thermometer to use for this temperature is the alcohol-in-a -glass thermometer.
Explanation:
The alcohol thermometer is a type of thermometer which uses ethanol as its thermometric liquid. This has some advantages at low temperatures because ethanol freezes at about −114.9 °C that is (−174.82 °F).
Due to its low freezing point, it can still function effectively as a thermometric liquid, expanding and contracting properly based on the applied heat, when dealing with temperature measurements that are at about -38.2°F.
When Z-4,5-dimethyloct-4-ene is treated with hydrogen chloride, HCl, the result is:________.
A. 4 stereoisomers
B. None of these
c. a pair of diastereomers
D. a racemic mixture OS a meso compound
Answer:
The correct option is c
Explanation:
The chemical equation for the reaction of Z-4,5-dimethyloct-4-ene and HCl is shown on the first uploaded image
Now looking at the product we see that there are two who has four different groups attached to them this carbon are known as chiral carbons hence the product formed is a pair of diastereomers
What are the best practices for safely handling waste in the lab? Select one or more: Check labels or instructions before any disposal. Always wear appropriate Personal Protective Equipment. Place any paper towels from the clean-up in the trash. Remove gloves for better manipulation of the waste containers
Answer:
Consult labels or instructions before disposing of it. Always wear the proper personal protective equipment. Put all cleaning paper towels in the trash
Explanation:
Gloves should never be removed when disposing of waste, since these can contain infected fluids or even cultivated microorganisms that are pathogens for our lives and can enter through a lesion of the continuity solution of the epithelium in our hands.
In other words, if there is a wound, and it is contaminated with waste by not wearing gloves, the risk of contracting diseases is much greater.
I need help on this!!!!!
1. How many ATOMS of carbon are present in 7.48 grams of carbon monoxide ?
Answer:
The answer is 1.61 × 10²³ atoms
Explanation:
To determine number of atoms, we will use the formula below
Number of atoms = number of moles (n) × avogadro's constant (6.02 x 10²³)
n was not provided, hence we will solve for n
n = mass/ molar mass
molar mass of carbon monoxide, CO (where C is 12 and O is 16) is 12 + 16 = 28
mass was provided in the question as 7.48
n = 7.48/28
n = 0.267
Hence,
number of atoms = 0.267 × 6.02 x 10²³
= 1.61 × 10²³ atoms
Discuss and Implement the Price Adjustment Strategies in the current market. Apply each strategy with 3 examples along with the picture. This question is related to Marketing.
Answer:
There are many different price adjustment strategies which can be implemented in the current market.
Explanation:
Psychological pricing:
Psychological pricing is a strategy in which the price of a product is displayed with mostly one cent difference so the whole number shown is less by $1 and this difference can get higher if the price of the product is more.
Example 1: The price for a toy in a toy shop is $4.99, if rounded this will be $5 but the whole number visible is $4.
Example 2: The price of a laptop is $193, this again is nearly $200 but the price is reduced by $7 in order to influence their customers into buying the product.
Example 3: The price of a car is $35,995, this again is about $36,000 but the buyer may be influenced by this technique and result in purchasing the product with such price.
Geographical Pricing:
Geographical pricing is a strategy where different prices are charged in different outlets, this strategy is made keeping in mind the purchasing power of the locality, if the local people can pay higher price for a product then the price is high there but same product may have a lower price in an area where people can not pay high price.
Example 1: Price of a T-shirt is $15 in a posh area while the price of the same T-shirt is $5 in an area with poor locality.
Example 2: Price of a hair brush is $10 in a poor area while the same brush is available in a posh area at a rate of $35.
Example 3: Price for a food item is $6 in a restaurant in posh area while the same burger is available for $3 in a restaurant in a poor area.