Answer:
To prevent autolysis (enzymes attack) as well as putrefaction (bacterial attack) of tissues.
A quantity of 1.922 g of methanol (CH3OH) was burned in a constant-volume bomb calorimeter. Consequently, the temperature of the water rose by 4.20 Ce … lsius. If the heat capacity of the bomb plus water was 10.4 kJ/degree Celsius, calculate the molar heat of combustion of methanol
The formula for calculating the amount of energy or heat released is:
ΔH = C ΔT
where ΔH is heat of combustion, C is heat capacity, while ΔT is change in temperature
ΔH = 8.69 kJ / °C * (5.14°C)
ΔH = 44.67 kJ
Then we calculate the moles of CH3OH which has molar mass of 32.04 g/mol:
moles = 1.922 / 32.04 = 0.05999 mol
SO the molar heat of combustion is:
ΔHm = 44.67 kJ / 0.0599875 mol
ΔHm = 744.60 kJ / mol
The valence electrons of a krypton (Kr) atom in the ground state are located in the
A. first energy level (shell).
B. second energy level (shell).
C. third energy level (shell).
D. fourth energy level (shell).
Answer:
D
Explanation:
The valence electrons are the outer electrons and must be located in the outermost shell. In this case, D.
How many valence electrons are there in the molecule CH3OCH2CH3.
Answer:
There are 27 Valence electrons : )
4+1+1+1+6+4+1+1+4+1+1+1 is 27
Explanation:
There are a total of [5×1]+[2×4]+[7]=21[5×1]+[2 × 4 ] + [ 7]=21 valence electrons
Pls help plz answer this question
Answer:
A) Carbon dioxide and Oxygen
Explanation:
Percentage of gases in the Planet's atmosphere:
Carbon dioxide = 4 % Nitrogen = 72 % Oxygen = 24 %Percentage of gases in the Earth's atmosphere:
Carbon dioxide = 0.036 % (traces)Nitrogen = 78 % Oxygen = 21 %___________________
On observing the percentage composition of the atmospheres of the two Planets, we get:
The newly discovered planet has more percentage of Oxygen than The Earth. Percentage of Carbon dioxide is more in the planet than in the EarthNitrogen is less in the planet than in the Earth.___________________
Answer:
What's asked is the name of the gases that are in higher amounts in the atmosphere of the newly discover planet
Therefore,
A) Carbon dioxide and Oxygenwhat percentage of oxygen is attributed fossil fuel combustion
A.43%
B.77%
C.4%
D.17%
Answer:
C. 4%
Explanation:
The answer is 4%
the weak base ionization constant (ka) for h2c2o4 is equal to what?
The acid ionization constant is the quantitative measure of the acidic strength. For oxalic acid, Ka = [H⁺] [HC₂O₄⁻] / [H₂C₂O₄]
What is acid dissociation?Acid dissociation (Ka) is the ratio of the concentration of the conjugate base and hydrogen ion to the concentration of the chemical.
Oxalic acid is a weak acid and gets dissociated as:
H₂C₂O₄ ⇌ H⁺ + HC₂O₄⁻
or
HC₂O₄⁻ ⇌ H⁺ + C₂O₄²⁻
The acid ionization constant for the reactant and the product is given as:
Ka = [H⁺] [A⁻] / [HA]
Ka = [H⁺] [HC₂O₄⁻] / [H₂C₂O₄]
Therefore, the ionization constant for oxalic acid is given as Ka = [H⁺] [HC₂O₄⁻] / [H₂C₂O₄]
Learn more about acid ionization constant here:
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Identify the unit that is used for atomic masses
Answer:
Explanation: Atomic weight is measured in atomic mass units (amu), also called daltons.
napthalene combustion can be used to calibrate the heat capacity of a bomb calorimeter The heat of combustion of naphthalene is -40.1kj/g. When .8210g of naphthalene was burned in a calorimeter containing 1,000g of water, a temperature rise of 4.21C was observed. What is the heat capacity?
A bomb calorimeter with a heat capacity of 3.63 kJ/°C experiences a temperature rise of 4.21 °C when .8210 g of naphthalene is burned.
The combustion of naphthalene is used to calibrate the heat capacity of a bomb calorimeter.
What is a bomb calorimeter?It is a device used to measure the change in the internal energy of a reaction.
To determine the heat capacity of the calorimeter (C), we need to follow a series of steps.
Step 1: Calculate the heat released by the combustion.The heat of combustion of naphthalene is -40.1kJ/g and .8210g were burned.
Qcomb = -40.1kJ/g × .8210g = -32.9 kJ
Step 2: Determine the heat absorbed by the bomb calorimeter.According to the law of conservation of energy, the sum of the heat released by the combustion and the heat absorbed by the bomb calorimeter is zero.
Qcomb + Qbomb = 0
Qbomb = -Qcomb = 32.9 kJ
Step 3: Calculate the heat capacity of the bomb calorimeter.32.9 kJ were absorbed, part by the calorimeter itself and part by the 1,000 g (m) of water, whose specific heat capacity (c) is 4.18 J/g°C.
A temperature rise (ΔT) of 4.21 °C is observed. We can determine the heat capacity of the bomb calorimeter (C) using the following expression.
Qbomb = Qcal + Qwater
32.9 kJ = C × ΔT + c × m × ΔT
32.9 kJ = C × 4.21 °C + (4.18 × 10⁻³ kJ/g.°C) × 1,000 g × 4.21 °C
C = 3.63 kJ/°C
A bomb calorimeter with a heat capacity of 3.63 kJ/°C experiences a temperature rise of 4.21 °C when .8210 g of naphthalene is burned.
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How is a mixture different from a compound?
Answer:
A compound is something like atoms coming together as a team, and a mixture is 2 or more substances mixing together.
Explanation:
Use the heat equation to find out how many joules of energy are needed
to raise the temperature of 67 grams of water form 20°C - 45°C. What is the
answer in kilojoules?
(specific heat of water is 4.2 J/gºC.)
Answer:
About 7.0 × 10³ J or 7.0 kJ
Explanation:
We want to determine the amount of energy needed to raise the temperature of 67 grams of water from 20°C to 45°C.
We can use the heat equation:
[tex]\displaystyle q = mC\Delta T[/tex]
Where C is the specific heat of water.
Substitute and evaluate:
[tex]\displaystyle \begin{aligned} q & = (67\text{ g})\left(\frac{4.2\text{ J}}{\text{g-$^\circ$C}}\right)\left(45^\circ \text{ C}- 20.^\circ\text{ C}\right) \\ \\ & = (67\text{ g})\left(\frac{4.2\text{ J}}{\text{g-$^\circ$C}}\right)(25^\circ \text{ C}) \\ \\ & = 7.0\times 10^3 \text{ J}\end{aligned}[/tex]
Recall that there are 1000 J in a kJ. Hence:
[tex]\displaystyle \begin{aligned} q & = 7.0\times 10^3 \text{ J} \cdot \frac{1\text{ kJ}}{1000\text{ J}} \\ \\ & = 7.0 \text{ kJ}\end{aligned}[/tex]
In conclusion, it will take about 7.0 × 10³ J or 7.0 kJ of energy to raise the temperature of 67 grams of water from 20 °C to 45 °C.
A sample of N2O gas has a density of 2.95 g/L at 298 K. What must be the pressure of the gas?
[tex]\huge{\underline{\underline{\boxed{\sf{\purple{ǫᴜᴇsᴛɪᴏɴ}}}}}}[/tex]
A sample of N2O gas has a density of 2.95 g/L at 298 K. What must be the pressure of the gas?[tex]\huge\fcolorbox{aqua}{lime}{Answer}[/tex]
P = 1203 mm Hg[tex]\huge{\underline{\underline{\boxed{\sf{\purple{Explanation}}}}}}[/tex]
#Given: -p = 2.85 g/LT = 298 K# Solution :-According to ideal gas equation -
➡PV = nRT
➡PV = (W/M)RT
➡PM = (W/V)RT
➡PM = PRT
➡P = pRT/M
➡P = 2.85 × 0.082 x 298 / 44
➡P = 1.583 atm
➡P = 1.583 × 760
➡P = 1203 mm Hg
Therefore, pressure of the gas. must be1203 mm of Hg.Hope this helps you:)
Fe3+ and S2- write the formula for the compound that would be formed
if one gram of sulphur dioxide contains x molecules what will be the number of molecules in 1g of methane
The ratio of molecules in sulphur dioxide and methane will be the same as the ratio of their moles. So, first of all we should find out the number of moles of sulphur dioxide in 1 gram of sulphur dioxide in 1 gram of sulphur dioxide, and the number of moles of methane in 1 gram of methane. This can be done as follows :
(i) The molecular formula of sulphur dioxide is [tex]SO_{2}[/tex]
So, [tex]1[/tex] mole of [tex]SO_{2}[/tex] = [tex]Mass[/tex] [tex]of[/tex] [tex]2'O'[/tex]
[tex]=32+2*16[/tex]
[tex]= 64[/tex] grams
Now, [tex]64g[/tex] of sulphur dioxide [tex]= 1[/tex] mole
So, [tex]1g[/tex] of sulphur dioxide = [tex]\frac{1}{64}[/tex] mole
Thus, we have [tex]\frac{1}{64}[/tex] mole of sulphur dioxide and it contains molecules in it. Now, since equal moles of all the substance contain equal number of molecules, therefore, [tex]\frac{1}{64}[/tex] mole of methane will also contain x molecules of methane.
(ii) Molecular formula of methan is [tex]CH_{4}[/tex]
So, 1 mole of [tex]CH_{4}[/tex] = Mass of C + Mass of 4 H
[tex]=12+4*12[/tex]
Now, 16g of methane = 1 mole
So, 1 g of mathane = [tex]\frac{1}{16}[/tex] mole
We know that:
[tex]\frac{1}{64}[/tex] mole of methane contains = x molecules
So, [tex]\frac{1}{16}[/tex] mole of contains will contain =[tex]\frac{x*64}{16}[/tex] molecules
=[tex]4x[/tex] molecules
Alguien saber esto? Literal no se este material
Answer:
2. 389.15K , 3. 229.15K
Explanation:
K-273.15 = °C
1. How does the figure below illustrate Hund's rule?
Answer:
it indicates that the lower orbitals are filled first and they have the maximum number of electrons compared to the higher orbitals
find the molar mass of 8.54 x 10²⁴ g A₂O₃
Very Very sorry
What is the correct form of the equilibrium constant for the reaction of hydrogen and oxygen to form water? The equation is:
2H 2( g) + O 2( g) ⇌ H 2O( g)
Kc = ([H2O]/[O2] [H2])
Kc = ([H2O]/[O2] [H2]2)
Kc = ([H2O]/[O2] [H22])
Kc = ([H2O]2/[O2] [H22])
Kc = ([H2O]/[O2] [2H2])
Help i dont get it
Answer:
2. Products; FeCl2 and H2S
Reactants; FeS and HCl
3. a) 36g of water
b) 64g of oxygen
No matter what container it is in, a liquid usually:
A.has the same volume
B.has a different volume
C.has the same shape
D.has a different color
Answer:
A
Explanation:
A liquid will will have the same color, it will not have the same shape and its volume will always be constant because you are not creating mass.
Hope this helps!
The diagram below shows the reaction between iron oxide and carbon that produces iron and carbon dioxide. The reaction takes place in a closed system. What is true about the carbon atoms in the reaction? A. The mass of carbon atoms in the reactants is the same as the mass of carbon atoms in the products. B. The total mass of the carbon atoms is the same as the total mass of the iron atoms. C. The mass of the carbon atoms increases between the reactants and the products of the reaction. D. The total mass of the carbon atoms is the same as the total mass of the oxygen atoms.
Answer:
A
Explanation:
The trick here is to know what the conservation of mass means.
It means that no matter what happens and how much change there is, the mass of the carbons on the reactants = the mass of the carbons on the products.
That's exactly what A says.
What is the pH when 30.0 ml of 0.005 M HF is mixed with 15.0 ml of 0.01 M NaOH?
Answer:
7.36
Explanation:
my teacher said that was the right answer
*WILL GIVE BRAINLIEST* Which of the following best approximates the percentages of sand, clay, and silt in a sandy loam? Use the soil texture table below to answer.
A. Sand 40
Clay 30
Silt 30
B. Sand 60
Clay 10
Silt 30
C. Sand 20
Clay 60
Silt 20
D. Sand 25
Clay 15
Silt 60
Nitrogen H2 has :
a)Double bonds
b)Bounded by 6 electrons
c) The bond is ionic
d) Can forms der Waals bonds
e) B& d
Answer:
the bond is ionic
Explanation:
Sound travels from a phone speaker to the ear of the person listening to the call. Sound waves are modeled by the image below. 1) What do the dots in the image represent? 2) How do sound waves travel through air to a person’s ear?
Answer:
Remember the black and red dots represented in the below animation are not molecules. They are just markers enabling us to visualize the local displacement of air particles and so, the rise and fall of pressure within the wave medium.
The air is made up of many tiny particles. When sound is created, the air particles vibrate and collide with each other, causing the vibrations to pass between air particles. The vibrating particles pass the sound through to a person's ear and vibrate the ear drum. Light travels much faster than sound through air.
Explanation:
Check the box under each molecule in the table below that is an isomer of this molecule:
The branched alkanes in boxes two and three all have molecular formula C6H14 and are isomers of the compound shown.
Isomers are compounds that has the same molecular formula but different structural formulas. Hence, isomers of compounds can be represented by the same molecular formula since they contain the same number of each atom.
The molecule shown has molecular formula C6H14. The branched alkanes in boxes two and three all have molecular formula C6H14 and are isomers of the compound shown.
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Will the following replacement reaction occur? MgCl2 + I2 → ?
Yes, it will because chlorine is less reactive than iodine.
No, it will not because iodine is less reactive than chlorine.
No, it will not because iodine and chlorine will not bond.
Yes, it will because the iodine will replace the magnesium.
The replacement reaction will not occur because iodine is less reactive than chlorine.
REPLACEMENT REACTION:A replacement reaction is a type of reaction in which one element is replaced by another in a compound.
The principle behind one element replacing the other is based on the reactivity of an element. A more reactive element will displace a less reactive one.
According to this question, the following displacement reaction is given: MgCl2 + I2 → ?
This reaction will not occur because chlorine is more reactive/electronegative than iodine, hence, iodine cannot displace it.
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At what stage of development are fish the most vulnerable?
Answer:
child stage.
Explanation:
they are more vubnlerabke at that stage
In which case would recalibrating a thermometer be an important next step in an experiment dealing with boiling points?
A) The results of several trials are all very close to each other, but they are noticeably different from the accepted value for the boiling point.
B) A small number of trials are conducted, with results quite different from each other, and with an average that is noticeably different from the accepted value.
C) A single trial is conducted, and the result is very close to the accepted value of the boiling point.
D) The results of several trials vary by a large amount, but the average is close to the accepted value for the boiling point.
I believe the answer would be D
the name of this fatty acid is caprylic acid :
CH3(CH2)6COOH ??
Explanation:
Are you asking if that is the formula for caprylic acid? The answer is yes. CH₃(CH₂)₆COOH is the correct formula.
Caprylic acid, also known as C8 or octanoic acid, is a medium chain triglyceride (MCT) primarily found in coconut oil. It's the shortest of all the MCTs, making it the easiest for the body to break down into fuel. Once it is consumed, C8 is instantly digested and converted into ketones.
Why is the same type of nail used in all test tubes? in every experiment done to show how rusting works and in what conditions.
in test tube 1 iron nail gets both air and moisture which is required for rusting. ... in the test tube 3 iron nail is not rusted because of the calcium chloride which is moisture absorber. hence nail would not get moisture for the rusting.