Answer:
Explanation:
CH4 + 2O2 ==> CO2 + 2H2O
mols CH4 = grams/molar mass
Using the coefficients in the balanced equation, convert mols CH4 to mols CO2.
Now convert mols CO2 to grams. g = mols x molar mass.
When 3.93 grams of lactic acid, CHoOs(s), are burned in a bomb
calorimeter that has a total heat capacity of 10.80 kJ-K-1, the
temperature of the calorimeter increases by 5.43 K. Assume AHrxn
=
AErxn. Given that AH°f of H¿O(I) = -285.8 kJ-mol-1 and AH°f of CO:(g)
= -393.5 kJ• mol-1, calculate the AH°f of lactic acid.
The heat released in the combustion of lactic acid is absorbed by the
calorimeter and in the decomposition of the lactic acid.
ΔH°f of lactic acid is approximately -716.2 kJ
Reasons:
Known parameters are;
Mass of the lactic acid = 3.93 grams
Heat capacity of the bomb calorimeter = 10.80 kJ·K⁻¹
Change in temperature of the calorimeter, ΔT = 5.34 K
ΔHrxn = ΔErxn
ΔH°f of H₂O(l) = -285.8 kJ·mol⁻¹
ΔH°f of CO₂(g) = -393.5 kJ·mol⁻¹
The chemical equation for the reaction is presented as follows;
C₃H₆O₃ + 2O₂ → 3CO₂ + 3H₂OThe heat of the reaction = 10.80 kJ·K⁻¹ × 5.34 K = 57.672 kJ
Molar mass of C₃H₆O₃ = 90.07 g/mol
Number of moles of C₃H₆O₃ = [tex]\dfrac{3.93 \, g}{90.07 \, g/mol}[/tex] = 0.043633 moles
Number of moles of CO₂ produced = 3 × 0.043633 moles = 0.130899 moles
Heat produced = 0.130899 mole × -285.8 kJ·mol⁻¹ = -37.4109342 kJ
Moles of H₂O produced = 0.130899 moles
Heat produced = 0.130899 mole × -393.5 ≈ -51.51 kJ
Therefore, we have;
Heat absorbed by the lactic acid = ΔH°f of H₂O + ΔH°f of CO₂ + Heat absorbed by the calorimeter
Which gives;
Heat absorbed by lactic acid = -37.4109342 kJ - 51.51 kJ + 57.672 kJ ≈ -31.249 kJ
The heat absorbed by the lactic acid ≈ -31.249 kJ
[tex]\Delta H^{\circ}f \ of \ C_3H_6O_3 = \dfrac{-31.249}{0.043633} \approx -716.2[/tex]
ΔH°f of C₃H₆O₃ ≈ -716.2 kJ
Heat of formation of lactic acid ≈ -716.2 kJ.
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When doing medical research with human subjects, which four limitations are unavoidable?
Answer:
Answer
The limitations are-
1. Privacy of the individuals involved in the research process.
2. Physical and psychological risks should be minimized
3. The subjects should be chosen equitably
4. Only reasonable exposure to risks is admissible.
Explanation
The privacy of the individuals involved in the research must be taken into consideration. This will ensure safety of patient data and information. The risk of physical and physiological well being of the person must be taken into consideration in such a research. In addition to that, the subject must be made to understand every procedure and the risks involved before testing. Moreover, only minimal exposure to risks is allowed and must have been previously tested in animals to avoid deaths.
Muối sunfua với hidro sunfua có giống nhau về tính chất vật lý không ạ. Ứng dụng và điều chế muối sufua như thế nào ạ
the answer is is is is is is is is is is is is is is
HELPPPPPP
Calculate the frequency of light with a wavelength 559nm
Answer:
Refer to the attachment
The water in a fishery became polluted when toxic waste was dumped into its pond, causing the fish population to substantially decline. The percents of fish that survived are recorded in the table.
Day 1 2 3 4 5
% Survival 79 55 38 31 19
a) What is the order of the reaction live fish ------> dead fish?
b) What is the rate constant?
c) If the fish continue to die at this rate, how many fish will be alive after 10 days?
In the pond, the percentage of fish left after ten days is 4%.
Given that;
N(t) = Noe^-kt
Where;
N(t) = percentage of fish at time t
No = Initial percentage of fish
k = rate constant
t = time taken
Given that we had 100% fish population at the beginning, we can see that this reaction is first order.
The rate constant is obtained from;
When t = 5
19 = 100e^-5k
19/100 =e^-5k
0.19 = e^-5k
ln 0.19 = -5k
k = ln (0.19)/-5
k = 0.33
In ten days;
N(10) = 100e^-0.33(10)
N(10) = 4%
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Can you give a definition of what Sodium Hydroxide
Answer:
Sodium hydroxide, also known as lye and caustic soda, is an inorganic compound with the formula NaOH. It is a white solid ionic compound consisting of sodium cations Na⁺ and hydroxide anions OH⁻
Explanation:
Also can you mark me as brainliest.
EXPLAIN BRIEFLY WHY CHEMISTRY IS CONSIDERED AS MAJOR BRANCH OF SCIENCE
Answer:
Chemistry is sometimes called “the central science,” because it bridges physics with other natural sciences, such as geology and biology. Chemistry is the study of matter and its properties.
Explanation:
~found it~
Pls help I don’t understand: Which of these is a balanced chemical reaction?
A) CO + O2–>CO2
B) CO + 2O2–> 2CO2
C) 2CO + O2—> 2CO2
D) 2CO + 2O*small 2 not 202*—> 2CO2
Answer:
C) 2CO + O₂ → 2CO₂
Explanation:
The equation C is correct.
2CO + O₂ → 2CO₂
This equation have four oxygen atom and two carbon atoms on both side of equation. So it is correctly balanced.
All others are incorrect:
A) CO + O₂ → CO₂
this is incorrect because there are three oxygen atoms on left while two atoms on right.
B) CO + 2O₂ → 2CO₂
this is incorrect because there are five oxygen atoms on left while four atoms on right.
D) 2CO + 2O₂ → 2CO₂
this is incorrect because there are six oxygen atoms on left while four atoms on right.
What mineral is composed of sodium chloride (NaCl)?
Answer:
Salt
Explanation:
The mineral form halite , or rock salt is sometimes called common salt
Which statement describes the bonds in nitrate (NO3-)?
A) Nitrogen and oxygen have an electronegativity difference of 0.5, so the bond is polar covalent, with oxygen pulling the electrons toward it.
B) Nitrogen and oxygen have an electronegativity difference of 0.5, so the bond is nonpolar covalent.
C) Nitrogen and oxygen have an electronegativity difference of 0.5, so the bond is ionic.
D) Nitrogen and oxygen have an electronegativity difference of 0.5, so the bond is polar covalent, with nitrogen pulling the electrons toward it.
The bond in NO3- ion is polar covalent and oxygen pulls the electrons.
A polar covalent bond is formed when there is a significant difference in electronegativity between covalently bonded atoms.
Such bonds are said to be polar covalent with the electron density tilted towards one of the bonding atoms.
In NO3-, Nitrogen and oxygen have an electronegativity difference of 0.5, so the bond is polar covalent, with oxygen pulling the electrons toward it.
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The answer is A, Nitrogen and oxygen have an electronegativity of 0.5, so the bond is polar covalent, with oxygen pulling the electrons toward it.
Electronegativity is defined as, a value that describes the relative strength with which an atom of an element attracts electrons to itself in a chemical bond. Moreover, electronegativity can be used to define a bond.
A electronegativity of 0.5-1.7 is determined to be a polar covalent bond, thus the bonds in nitrate is polar covalent.
We know that electronegativity increases on the periodic table across a period, but decreases down a group. Thus, oxygen has a greater electronegativity than nitrogen.
state why vulcanologist make predications about when a volcano will erupt
Answer:
They want to know how long it has been since it last erupted.
Explanation:
Scientists study a volcano's history to try to predict when it will next erupt. They also want to know the time span between its previous eruptions
Protons and neutrons have opposite, but equal magnitude, charges. An atom contains the same number of protons and electrons Neutrons and electrons are found in the nucleus of an atom. Protons have about the same mass as electrons. Electrons make up most of the mass of an atom. which one is true about subatomic particles
Answer:
the true statement is an atom contains the same number of electron and protonExplanation:
let us see the behaviour of the sub atomic particles
nutrons and protons found in the nucleus of an atoman atom have the same number of electron and proton but they have different chargenutron is chargeless particlemost mass of the atom concentrated in the nucleus of an atomelectrons have almost 0 mass from an atommass of proton and mass of nutron are equvalent or almost equalthere are many properties of subatomic particles i have listed some of them above .
I think it is help ful for youhelppppppppppppppppppppppppp
True
All matter is made up of atoms.
im guessing it probably true
Plz help me plz will give Brainly
Explanation:
a brittle, High melting solid : option B (MgCl2).
1) H2S
2) H2O
3) I2
weakest to strongest.
hope this helps you.
1. ATOMIC RADIUS: For each of the following sets of atoms, rank the atoms from smallest to largest atomic radius.
a. Li, C, F
b. Li, Na, K
c. Ge, P, O
d. C, N, AI
Answer:
The answer is letter C
Select the statements that correctly describe an asteroid. Check all that apply
Largest of the space rocks found orbiting the Sun.
Smallest of the space rocks found orbiting the Sun.
most are found between Mars and Jupiter
most are found between Jupiter and Saturn
Answer:
Explanation:
Most of this ancient space rubble can be found orbiting the Sun between Mars and Jupiter within the main asteroid belt. Asteroids range in size from Vesta – the largest at about 329 miles (530 kilometers) in diameter – to bodies that are less than 33 feet (10 meters) across.
What determines an object’s ability to float?
what element has a high content of brilliant yellows color
Answer: , sulfur and gold are most obviously yellow.
Explanation: Phosphorus, arsenic and antimony have allotropes which are yellow or whitish-yellow; fluorine and chlorine are pale yellowish gases.
What is a small description of a molecule
Answer:
molecule, a group of two or more atoms that form the smallest identifiable unit into which a pure substance can be divided and still retain the composition and chemical properties of that substance.
What is the mass % of acetone in a 1.85 M solution of acetone (MM = 58.08 g/mol) in water? The density of the solution is 0.971 g/mL.
A 1.85 M acetone solution (MM = 58.08 g/mol) with a density of 0.971 g/mL has a mass percent of acetone of 11.0%.
What is the mass percent?It refers to the mass of solute in 100 grams of solution.
Let's suppose we have 1 L of the solution.
Step 1: Calculate the mass of solute (acetone).We have a 1.85 M solution of acetone (MM = 58.08 g/mol). We will calculate the mass of acetone using the following expression for molarity.
M = mass acetone / MM acetone × liters solution
mass acetone = M × MM acetone × liters solution
mass acetone = 1.85 mol/L × 58.08 g/mol × 1 L = 107 g
Step 2: Calculate the mass of the solution.We have 1 L (1000 mL) of the solution with a density of 0.971 g/mL.
1000 mL × 0.971 g/mL = 971 g
Step 3: Calculate the mass percent of acetone.%acetone = (107 g/971 g) × 100% = 11.0 %
A 1.85 M acetone solution (MM = 58.08 g/mol) with a density of 0.971 g/mL has a mass percent of acetone of 11.0%.
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helpppppppppppppppppppppppppppp
Answer:
condensationExplanation:
Condensation is a process in which the evaporated liquid substance such as water vapor gets turned back to its liquid form water.
So, condensation is the process in which water vapor changes to liquid .what is the total amount of energy absorbed by the substance as it completely changes from a solid at 40 degrees to a gas at 200 degrees
Answer:
I don't know the answer sorry man
Calculate the number of days after the explosion for a sample of iodine-131 to go from 100%
iodine-131 to less than 1% iodine-131. Complete chart.
It will take 56 days to go from 100% iodine-131 to less than 1% iodine-131.
From the table, we can see that the half life of iodine-131 is 8 days. We can see that it takes 8 days to have 50% of iodine-131
After 16 days, we will have 25 % of iodine-131
After 24 days, we will have 12.5 % of iodine-131
After 32 days, we will have 6.25% of iodine-131
After 40 days, we will have 3.125% of iodine-131
After 48 days, we will have 1.5625% of iodine-131
After 56 days, we will have 0.78125% of iodine-131
After 56 days, the percentage of iodine-131 drops to less than 1%.
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PLS HELP WORTH 25 POINTS WILL MARK BRAINLIEST IF CORRECT
Examine the false statement. When pressure is added to a reaction at chemical equilibrium, the reaction responds by increasing the amount of pressure it exerts on its surroundings. Select the rewording that makes the statement true.
A. When pressure is added to a reaction at chemical equilibrium, the reaction responds by increasing the rate of reaction, which will decrease the number of particles and offset the pressure.
B. When pressure is removed from a reaction at chemical equilibrium, the reaction responds by decreasing the amount of pressure it exerts on its surroundings.
C. When pressure is removed from a reaction at chemical equilibrium, the reaction responds by increasing the rate of reaction, which will decrease the number of particles and increase the pressure.
D. When pressure is removed from a reaction at chemical equilibrium, the reaction responds by decreasing the amount of pressure it releases to its surroundings.
E. When pressure is added to a reaction at chemical equilibrium, the reaction responds by decreasing the amount of pressure it absorbs from its surroundings.
IT'S NOT C OR E
Answer:
A i think. Good luck!!!!
Is halogen radioactive
Answer: yes
Explanation:
30 POINTS TO HONEST ANSWER WILL REPORT IF U JUST ANSWER FOR POINTS-
Which of the following correctly balances the equation below? 263 106 Sg 259 104 Rf
A. Y
B. 4 2 He
C. 0 -1 e
D. 0 1 H
Answer:
The answer is 4 2 He. I know this because alpha decay occurs when an unstable nucleus emits an alpha particle which is identical to a helium-4 nucleus.
What energy keeps the water cycle going?
Answer:
the the that keeps the water cycle going is heat
how many moles of of Al are needes to form 2.43 mol of Al2Br6?
A. 7.29 mol
B. 1.22 mol
C. 2.43 mol
D. 1.62 mol
E. 4.86 mol
Answer:
c
Explanation:
c .
answer
your
this
questions
Colligative properties are dependent only on the number of particles in a solution, and not their identity. (select all that apply) Select one or more: a. Acidity b. Depression of freezing point c. Lowering of vapor pressure d. Osmotic pressure e. Elevation of boiling point f. Mortality g. Value h. Molarity
These colligative properties include reduced vapor pressure, increased boiling point, decreased freezing point, and increased osmotic pressure.
What do you mean by osmotic pressure?When a semipermeable membrane separates a solution from pure water, osmotic pressure is defined as the pressure that must be applied to the solution side to stop fluid movement.These colligative properties include reduced vapor pressure, increased boiling point, decreased freezing point, and increased osmotic pressure. As described in this module, this small set of properties is critical to many natural phenomena and technological applications.The pressure required to prevent water from diffusing through a membrane via osmosis is known as osmotic pressure. The concentration of the solute determines it. Water diffuses from the lower concentration area to the higher concentration area.Osmotic pressure is a 'colligative' property, like freezing point depression, which means that it depends on the number of particles in solution but not on their chemical identity.To learn more about : Osmotic pressure
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Please answer question (e)
Answer:
here is no question (e).............