Answer:
When some LiCl is dissolved in water, the temperature of the water increases. This means that: (A) the strength of the intermolecular forces between the water molecules is stronger than the bond energy within the LiCl lattice.
Explanation:
When Lithium chloride is dissolved in water, there is a steep rise in the temperature of the water. Based on this evidence, the dissolution of lithium chloride is exothermic.
What is an Exothermic reaction?An exothermic reaction may be defined as a type of reaction in which energy is liberated as a product in the form of light or heat. For these types of reactions, the overall standard enthalpy change ΔH⚬ is negative. It is one of the thermodynamic processes other than endothermic.
In the reaction, lithium intensely reacts with water in order to form lithium hydroxide and highly flammable hydrogen which liberated energy and leads to the steep rise in the temperature of the product compounds. This enhancement in the temperature is accurate evidence of an exothermic reaction.
Therefore, on the basis of the evidence that the reaction of lithium chloride in water causes a steep rise in the temperature of the water represents an exothermic reaction.
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How many moles are there in 200 grams of carbon dioxide Please show work
According to the mole concept, there are 4.54 moles present in 200 grams of carbon dioxide.
What is a mole?Mole is defined as the unit of amount of substance . It is the quantity measure of amount of substance of how many elementary particles are present in a given substance.
It is defined as exactly 6.022×10²³ elementary entities. The elementary entity can be a molecule, atom ion depending on the type of substance. Amount of elementary entities in a mole is called as Avogadro's number.
It is widely used in chemistry as a suitable way for expressing amounts of reactants and products.For the practical purposes, mass of one mole of compound in grams is approximately equal to mass of one molecule of compound measured in Daltons. Molar mass has units of gram per mole . In case of molecules, where molar mass in grams present in one mole of atoms is its atomic mass.Number of mole= mass /molar mass which is 200/44=4.54 moles
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Police investigating the scene of a sexual assault recover a large blanket that they believe may contain useful physical evidence. They take it to the laboratory of forensic serologist Scott Alden, asking him to test it for the presence of semen. Noticing faint pink stains on the blanket, Scott asks the investigating detective if he is aware of anything that might recently have been spilled on the blanket. The detective reports that an overturned bowl of grapes and watermelon was found at the scene, as well as a broken glass that had contained wine. After the detective departs, Scott chooses and administers what he considers the best test for analysing the piece of evidence in his possession. Three minutes after completion of the test, the blanket shows a positive reaction. What test did Scott choose, and what was his conclusion? Explain your answer.
Answer:
Acid Phosphatase (AP) Test
Explanation:
Acid phosphate is an enzyme that is found in the body. It is secreted majorly by the prostrate gland into the seminal fluid. The acid phosphatase test is used to test for the presence of semen in items.
Scott chose the acid phosphatase test because it is very useful in testing for semen on large items such as blankets. The reaction time for an acid phosphatase test for semen is less than 30 seconds. Seeing that the test was completed in three minutes, Scott concluded that the positive reaction was as a result of some other fluid.
The detectives reported that an overturned bowl of grapes and watermelon was found at the scene as well as a broken glass that had contained wine. Scott knew that some fruit juices like that of watermelon give a positive reaction to the acid phosphatase test but with more time that of the semen fluid because the reaction is a very slow one.
Scott concluded that there was no presence of semen on the blanket and therefore there was no sexual assault.
A standard 10.00 g mass is weighed on an analytical balance 100 times. The average and standard deviation obtained gives 10.12 ± 0.03 g. A calibration service is called. After the balance is recalibrated, the new measurements show 10.00 ± 0.03 g. Did the recalibration result in improved accuracy or precision?
Answer:
There was an improvement in accuracy. There was no change in precision.
Explanation:
The average mass after recalibration is closer to the mass of the standard, so the recalibration improved the accuracy (the measurement is closer to an accepted 'true' value).
The standard deviation did not change, so the precision (or how disperse the measurements are) was not affected.
given mass of sodium sulphate contains 1.052 moles of oxygen atom then moles of sodium atom present in it would be equal to (ans=0.526)
how to solve this please help me...!
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1. Why does light bend when it changes medium?
Answer:
The bending of light as it passes from one medium to another is called refraction
Explanation:
Did i answer these right??
12) How many moles of CO can be produced from
10.0 mol of CO2
Answer:
5
Explanation:
There are 2 moles of CO in each CO2. 10 ÷ 2 = 5
(ILL GIVE BREAINLIEST!! ) Which process(es) has steps called prophase, metaphase, anaphase, and telophase?
meiosis and mitosis
mitosis and fertilization
fertilization only
meiosis only
Answer:
mitosis and fertilization is a required answer.
Answer:
meiosis and mitosis
Explanation:
the difference is that meiosis goes through it twice.
This is to be removed in brown sugar and to be rolled with a rolling pin?
Answer:
The lumps should be removed in brown sugar and to be rolled with rolling pin.
Explanation:
In preparing brown sugar as ingredients in baking and pastry, it is important to check if the sugar is lumpy. Although it is not the main ingredient in baking, it is important to check because it could affect the texture of the mixtures. Brown sugar is also much nutritious to white sugar that is why it is more commonly use. The brown sugar become lumpy because when brown sugar is exposed to air it gets harder because the molasses that keeps its soft evaporates that makes the sugar stick together. The rolling pin helps the lump to break up.
WORTH 20 POINTS! MY LIFE DEPENDS ON IT HELP
Why do atoms share electrons in covalent bonds?
1. to become ions and attract each other
2. to fill their valence shell
3. to become more polar
4. to increase their atomic numbers
Answer:
2
Explanation:
Covalent bonding occurs when pairs of electrons are shared by atoms. Atoms will covalently bond with other atoms in order to gain more stability, which is gained by forming a full electron shell. By sharing their outer most (valence) electrons, atoms can fill up their outer electron shell and gain stability.
Answer:
To fill their valance shell and become stable!
Explanation:
please help. it’s my last question.
Given
Atomic symbol
Required
Atomic composition
Solution
Atomic number = number of protons = number of electrons
Mass Number (A) is the sum of protons and neutrons
Number of protons and Number of Neutrons in nucleus
Number of electrons in the shell
From the picture:
protons = 3
neutrons = 4
electrons = 3
atomic number = protons = electrons = 3
mass number = protons + neutrons = 3+4 = 7
There diagrams imply that’s
A TISSUEs are always rectangular
B tissues are made up of cells
C Tissues all look the same
D tissues have the same Function
Answer:
b
Explanation:
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Iontophoresis is a noninvasive process that transports drugs through the skin without needles. In the photo, the red electrode is positive and the black electrode is negative. The electric field between the electrodes will drive the negatively charged molecules of an anesthetic through the skin. Should the drug be placed at the red or the black electrode
Answer:
Follows are the explanation to this question:
Explanation:
When the drug is negatively charged, its negative electrolyte is annihilated to just the positive electrode. It is enticed, and it may not have a picture showing the electrode, however, We suppose that electrodes from either side of a skin slice. Its negative electrode will bypass or push thru the skin if in front of the counter terminal this becomes a red-positive electrode.
Calculate the number of moles 2.5 g of calcium hydroxide.
0.044 mol CaOH
General Formulas and Concepts:Math
Pre-Algebra
Order of Operations: BPEMDAS
Brackets Parenthesis Exponents Multiplication Division Addition Subtraction Left to RightChemistry
Atomic Structure
Reading a Periodic TableWriting CompoundsStoichiometry
Using Dimensional AnalysisExplanation:Step 1: Define
2.5 g CaOH
Step 2: Identify Conversions
[PT] Molar Mass of Ca - 40.08 g/mol
[PT] Molar Mass of O - 16.00 g/mol
[PT] Molar Mass of H - 1.01 g/mol
Molar Mass of CaOH - 40.08 + 16.00 + 1.01 = 57.09 g/mol
Step 3: Convert
[DA] Set up: [tex]\displaystyle 2.5 \ g \ CaOH(\frac{1 \ mol \ CaOH}{57.09 \ g \ CaOH})[/tex][DA] Multiply/Divide [Cancel out units]: [tex]\displaystyle 0.043791 \ mol \ CaOH[/tex]Step 4: Check
Follow sig fig rules and round. We are given 2 sig figs.
0.043791 mol CaOH ≈ 0.044 mol CaOH
You are working to earn enough money for a vacation which costs 2100. Your take-home pay is $16.50/hour, but you only work 4-hour shifts each day. How many days will it take for you to earn enough money to pay for your vacation if all the money you earn goes towards your vacation?
Answer:
32 days.
Explanation:
First we determine how much is made in a day.
16.50 x 4 = 66.
Next, we divide 2100 by 66 to reach our amount of days needed.
2100 / 66 = 31.818181... [81 is what repeats over and over.]
We round this up to the nearest whole number. You can't underpay, so you have to round.
The next whole number would be 32, so our answer is 32 days.
5.6 g of Iron reacts with excess fluorine gas.
The mass of iron fluoride produced is 11.3 g
What is the formula of the iron fluoride?
Answer: FeF3 Iron(III) fluoride
Explanation: 5.6 g = 1/10 mole Fe
11.3-5.6g F = 5.7 = 3/10 mole F
Lithium diorganocopper (Gilman) reagents are prepared by treatment of an organolithium compound with copper(I) iodide. Decide what lithium diorganocopper (Gilman) reagent is needed to convert 1-bromopropane into propylcyclohexane. Draw the structure of the organolithium compound that is used to prepare Gilman.
Answer:
See explanation and image attached
Explanation:
The Gilman reagent is a lithium and copper (diorganocopper) reagent with a general formula R2CuLi. R is an alkyl or aryl group.
They are useful in the synthesis of alkanes because they react with organic halides to replace the halide group with an R group.
In this particular instance, we intend to synthesize propylcyclohexane. The structure of the lithium diorganocopper (Gilman) reagent required is shown in the image attached to this answer.
A student is building a model of the layers of the Earth. Which material would best represent the crust?
a:grouping of magnetic balls
b:Styrofoam packing pellets
C:Bag of shredded paper
d:Thin layer of plaster
Answer:
d
Explanation:
The material that represents the crust is option d. Thin layer of plaster.
What is the crust and which material should be considered for it?It is the outermost shell of a planet i.e. terrestrial. The crust of the earth should be split into older, thicker continental crust, etc. Also, it is made of solid rocks and minerals. Due to this, the thin plaster layer represents the material for the crust.
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Can someone explain how it is 1?
Explanation:
You have 112 g of Fe.
The atomic mass of Fe is 56 g/mol
112g Fe/ 56g/mol = 2 mol Fe <---- you have to convert to moles of iron(iii) sulfate
From the balanced equation, you get that 2 moles of Fe react to produce 1 mole of Fe2(SO4)3
So, to convert:
2 mol Fe* (1 mol Fe2(SO4)3 / 2 mol Fe) = 1 mol Fe2(SO4)3
moles of Fe cancel and the answer is 1 mole of iron(iii) sulfate.
What is the result of 2.58×0.12, including correct significant figures? Select the correct answer below: 0.3096 0.31 0.310 0.3
Answer:
The answer would depend on the required significant number.
Explanation:
0.3096 is the complete answer
0.31 is the answer when the hundredths place is asked
When investigating a factor that effects the rate of photosynthesis, you needed to keep the
plant at a temperature of 250C. How did you do this?
Answer:
Photosynthesis defines the process by which plants and some bacteria manufacture glucose. Scientists summarize the process as follows: using sunlight, carbon dioxide + water = glucose + oxygen. The process occurs within special structures called chloroplasts located in the cells of leaves. Optimum photosynthetic rates lead to the removal of greater amounts of carbon dioxide from the local atmosphere, producing greater amounts of glucose. Since glucose levels within plants are difficult to measure, scientists utilize the amount of carbon dioxide assimilation or its release as a means to measure photosynthetic rates. During the night, for example, or when conditions are not prime, plants release carbon dioxide. Maximum photosynthetic rates vary between plant species, but crops such as maize can achieve carbon dioxide assimilation rates as high as 0.075 ounce per cubic foot per hour, or 100 milligrams per decimeter per hour. To achieve optimum growth of some plants, farmers keep them in greenhouses that regulate conditions such as humidity and temperature. There are three temperature regimes over which the rate of photosynthesis changes.
Low Temperature
Enzymes are protein molecules used by living organisms to carry out biochemical reactions. The proteins are folded into a very particular shape, and this allows them to bind efficiently to the molecules of interest. At low temperatures, between 32 and 50 degrees Fahrenheit – 0 and 10 degrees Celsius – the enzymes that carry out photosynthesis do not work efficiently, and this decreases the photosynthetic rate. This leads to a decrease in glucose production and will result in stunted growth. For plants inside a greenhouse, the installation of a greenhouse heater and thermostat prevents this from occurring.
Explanation:
Gaseous butane CH3CH22CH3 will react with gaseous oxygen O2 to produce gaseous carbon dioxide CO2 and gaseous water H2O. Suppose 0.58 g of butane is mixed with 0.874 g of oxygen. Calculate the maximum mass of water that could be produced by the chemical reaction. Round your answer to 3 significant digits.
Answer:
0.378 g of H₂₂O can be produced.
Explanation:
The combustion reaction is:
2CH₃(CH₂)₂CH₃ + 13O₂ → 8CO₂ + 10H₂O
We convert the mass of reactants to moles:
0.58 g . 1mol / 58.1g = 0.00998 moles of butane
0.874 g . 1mol / 32g = 0.0273 moles of O₂
Oxygen is the limiting reactant. Look at stoichiometry.
2 moles of butane need 13 moles of oxygen to react
Then, 0.00998 moles of gas may react to (0.00998 . 13) / 2 = 0.06487 moles of oyxgen. I only have 0.0273 moles, so i do not have enough oxygen to complete the reaction.
Let's find out the product.
13 moles of oyxgen can produce 10 moles of water.
Then 0.0273 moles of O₂ may produce (0.0273 . 10)/13 = 0.021 moles
We convert to mass → 0.021 mol . 18g /1mol = 0.378 g
what happens when hydrogen gas is passed over hot ferric oxide
Answer:
When hydrogen is passed over hot ferric oxide (FeO) hydrogen reacts with oxygen present in the compound and forms water (H2O) and pure Iron
Explanation:
Answer:When hydrogen gas is passed over hot copper oxide, the black coating on the surface turns brown as the reverse reaction takes place and copper is obtained.
Explanation:
Pls help!!!!!! In your own words, explain how chemists properly represent the law of conservation of matter in their chemical
equations.
Answer:
They represent it by ensuring that the number of atoms of each element (matter) in the reactant side is the same as the product side
Explanation:
The law of conservation of matter stated that matter can neither be created nor destroyed. Chemical equations involve combining atoms of elements. The compounds combined by chemists are called REACTANTS while the produced compounds are called PRODUCTS.
In order to conform to the law of conservation of matter, the same quantity of matter present in the reactants must be present in the products. This means that the number of atoms of each element (matter) in the reactant side must be the same as the product side. For example;
C6H12O6 + 6O2 → 6CO2 + 6H2O
In this chemical equation for photosynthesis, number of atoms in the reactant side (6 carbon, 12 hydrogen, 18 oxygen) are the same as that in the product side (6 carbon, 12 hydrogen, 18 oxygen), hence, this obeys the law of conservation of mass.
In a nutshell, chemists chemists properly represent the law of conservation of matter in their chemical equations by making sure that same number of atoms of reactants is present in the products.
Explain the order of dielectric constants for the following pairs of liquids. a) Carbon tetrachloride (2.2), chloroform (4.8) b) Ethanol (24.3) and methanol (32.6) c) Acetone (20.7) and formamide (110.0)
Answer:
See explanation
Explanation:
Let us have it behind our minds that the dielectric constant reveals the degree of polarity of a molecule. This implies that the more polar a molecule is, the greater its dielectric constant.
Chloroform is a polar molecule while carbon tetrachloride is a nonpolar molecule due to its symmetrical nature. Thus Chloroform has a greater degree of polarity and consequently a higher dielectric constant.
Methanol is more polar than ethanol because polarity of the molecule decreases as more CH2s are added to the molecule, that is, polarity of the molecule decreases with increase in the length of the carbon chain. Since methanol is more polar than ethanol, it should have a greater dielectric constant.
Again, the presence of more akyl groups in acetone makes it less polar than formamide. Consequently, formamide has a greater dielectric constant than acetone.
Breathing equipment used by rescue workers needs to capture the CO2 the humans breath out and produce O2 for them to breath in, like a plant during photosynthesis. One compound capable of doing this is potassium superoxide (KO2), which produces the salt by-product potassium carbonate. What is the balanced chemical equation for this reaction? Don't include states of matter.
Answer: [tex]4KO_2+2CO_2\rightarrow 2K_2CO_3+3O_2[/tex]
Explanation:
According to the law of conservation of mass, mass can neither be created nor be destroyed. Thus the mass of products has to be equal to the mass of reactants. The number of atoms of each element has to be same on reactant and product side. Thus chemical equations are balanced.
The balanced chemical equation for reaction of potassium superoxide with carbon dioxide to produce oxygen and potassium carbonate will be:
[tex]4KO_2+2CO_2\rightarrow 2K_2CO_3+3O_2[/tex]
A sample of iron, which has a specific heat capacity of 0.449 Jg^-1℃^-1, is put into a calorimeter (see sketch at right) that contains 100.0 g of water. The iron sample starts off at container 93.3 °C and the temperature of the water starts off at 22.0 °C. When the temperature of the water stops changing it's 25.7 °C. The pressure remains constant at 1 atm.
Required:
Calculate the mass of the iron sample. Be sure your answer is rounded to 2 significant digits.
Answer:
[tex]m_{iron}=32.1g[/tex]
Explanation:
Hello!
In this case, since the interaction between hot iron and cold water allows the heat transfer from iron to water and therefore we can write up the following energetic equation:
[tex]Q_{iron}+Q_{water}=0[/tex]
Whereas the heat terms can be written in terms of mass, specific heat and temperature change:
[tex]m_{iron}C_{iron}(T_f-T_{iron}) + m_{water}C_{water}(T_f-T_{water}) = 0[/tex]
So we solve for the mass of iron as follows:
[tex]m_{iron} = \frac{m_{water}C_{water}(T_f-T_{water})}{C_{iron}(T_f-T_{iron}) }[/tex]
Now, we plug in the given data to obtain:
[tex]m_{iron} = \frac{-100g*0.449\frac{J}{g\°C} (25.7\°C-22.0\°C)}{0.449\frac{J}{g\°C} (25.7\°C-93.3\°C) }[/tex]
[tex]m_{iron}=32.1g[/tex]
Best regards!
The French Le Surete included an ex-criminal, Vidocq, who put together files describing the individual modus operendi, or the _____, of each criminal.
criminal behaviors
fingerprints
home addresses
relatives who were also criminals
Answer:criminal behavior
Explanation:
Edge 2021
Answer:
Criminal Behavior
Explanation:
The acid digestion test left 2.595 g of fiber from a composite specimen weighing 3.697 g. The composite specimen weighs 1.636 g in water. If the specific gravity of the fiber and matrix is 2.5 and 1.2, respectively, find the 1. Theoretical volume fraction of fiber and matrix 2. Theoretical density of composite
Answer:
0.4323 ; 1.5394
Explanation:
Given that :
Specific gravity of Fibre (Sf) = 2.5
Specific gravity of Matrix (Sm) = 1.2
Mass of Fibre, Mf = 2.595g
Weight of composite specimen in water , Wc = 1.636g
Composite weight, Ww = 3.697 g
Weight of Fibre and matrix
Volume fraction of Fibre and matrix :
[(Mf/Sf) ÷ (Mf/Sf + Wc/Sm)] * 100
[(2.595/2.5) ÷ (2.595/2.5 + 1.636/1.2)]
(1.038 ÷ 2.4013333)
= 0.43225986
= 0.4323
2.)
Theoretical density of composite :
Weight of composite / (Mf/Sf + Wc/Sm)
3.697 / (2.595/2.5 + 1.636/1.2)
3.697 / 2.4013333
= 1.5395613
= 1.5394
THE ANSWER IS
Magnesium hydroxide (Mg(OH)2): 58.33
Iron(III) oxide (Fe2O3): 159.70
Answer:
Ok, thanks?
Have a good day
Thanks for the answer ^^...yes i only commented for the points
