The correct answer is C. ΔHθf
We define the standard enthalpy of formation as the enthalpy change when one mole of a substance is formed from its elements under standard conditions. The standard conditions are 1 atm pressure, 273 K temperature and 1 M concentration.
The standard enthalpy of formation is denoted using the symbol ΔHθf.
Hence, ΔHθf is the enthalpy change when 1 mole of a substance is formed from its elements under standard conditions.
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Which formula compares a sample of a gas under two different conditions of pressure and volume, if the temperature is constant?
⚪︎ x/y = k
⚪︎ xy = k
⚪︎ PV = k
⚪︎ V/T = k
⚪︎ P1V1 = P2V2
Answer:
Explanation:
V/t
Based on the information in the table, which two elements are most likely in the same group, and why?
For the reaction C+2H 2 —->CH 4 calculate the percent yield if 98 g of methane is produced when 100. g of carbon reacts with an excess of hydrogen?
The percent yield : 73.5%
Further explanationGiven
Reaction
C+2H₂⇒CH₄
Required
The percent yield
Solution
mol of Carbon(as a limiting reactant) :
[tex]\tt \dfrac{100}{12}=8.3[/tex]
mol CH₄ based on C, and from equation mol ratio C : CH₄, so mol CH₄ = 8.3
Mass of Methane(theoretical yield) :
[tex]\tt mass=mol\times MW\\\\mass=8.3\times 16=133.3~g[/tex]
[tex]\tt \%~yield=\dfrac{actual}{theoretical}\times 100\%\\\\\%yield=\dfrac{98}{133.3}\times 100\%=73.5\%[/tex]
Plz help!
What must change in order to change the amount of power?
Answer:
Mass
Explanation:
which description shows copper at rtp?
a) stationary and closed together
b) stationary and randomly arranged
c)vibrating and in a regular arrangement
d) vibrating and in a random arrangement
Answer:
c)vibrating and in a regular arrangement
Explanation:
Copper is a chemical element represented by the symbol Cu and having atomic number 29. Copper is a transition metal which means its subshells are not completely filled and that is why they are vibrating in the room temperature. But copper is a solid at room temperature with regular arrangement of atoms.
Hence, the correct answer is "c)vibrating and in a regular arrangement".
atoms or helium nickel would represent _____
Answer:
they represent their own atoms
Answer:
Elements
Explanation:
What is the relationship between the circulatory and respiratory systems?
A. They work together to store the waste that blood collects from the body.
B. The circulatory system provides oxygen that the respiratory system uses to fill the lungs
C. The respiratory system provides blood that the circulatory system uses to transport nutrients.
D. They work together to supply oxygen to tissues and rid the body of carbon dioxide
Answer:
The circulatory and respiratory systems work together to circulate blood and oxygen throughout the body. Air moves in and out of the lungs through the trachea, bronchi, and bronchioles. Blood moves in and out of the lungs through the pulmonary arteries and veins that connect to the heart
Explanation:
This should help you out
how many moles are in 100.0 g of gold?
Answer:
196.96655
Explanation:
The answer is 196.96655. I assume you are converting between grams Gold and mole. The molecular formula for Gold is Au. The SI base unit for the amount of substance is the mole.
The quantity present in an atom or molecules of a given substance is called moles it is written as mol and is calculated with the help of molar mass and mass of the given substance.
0.507699 mol is present in the 100 gm of gold.
Moles of gold can be calculated by:Given,
Mass (m) = 100 gmThe atomic weight of Au (M) = 196.967The formula for calculating moles is:
[tex]\rm Moles (n) = \dfrac{Mass}{Molar \;mass}[/tex]
Substituting values in the formula:
[tex]\begin{aligned}\rm n & = \dfrac{100}{196.967}\\\\ & = 0.507699 \;\rm mol\\\\& = 0.5077\;\rm mol\end{aligned}[/tex]
Therefore, 0.5077 mol is present in 100 gm of gold.
Learn more about moles here:
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A student spends 4.5 hours studying for a test. How much time is this equivalent to in seconds
Select one:
a)2,700 seconds
b)16,200 seconds
c)270 seconds
d)6,480 seconds
EZ MODE -_- What could you do in an experiment to get more accurate results? Change two of your variables. Only make observations that involve sight. Only use new materials. Perform repeated trials
Answer:
they change the object hehehehe
Answer:
D. Perform repeated trials.
Explanation:
I did the exam and got it correct :D!
All matter is involved in motion of some kind. True or false
Answer:
true
Explanation: all matter down to the molecular or even atomic level has a constant vibration and movement. The only time that any matter could stop moving would be at absolute zero.
A family consumes 2.5 gallons of milk per week. How many liters of milk do they need to buy for one month? (Assume there are exactly 4 weeks in 1 month) SHOW WORK
Answer:
37.85 liters
Explanation:
they need 10 gallons for a month (2.5*4)
after that, convert gallons to liters (conversion to liters= 3.785)
10*3.7585= 37.85
What is the momentum of a bird with a mass of 2 kg flying at 9 m/s? *
Answer:
18 kg.m/sExplanation:
The momentum of an object can be found by using the formula
momentum = mass × velocity
From the question we have
momentum = 2 × 9
We have the final answer as
18 kg.m/sHope this helps you
Where must you be standing if the Sun appears to be directly overhead at noon?
O A. At the South Pole
O B. At the North Pole
O C. At a point somewhere along the prime meridian
O D. At a point somewhere along the equator
Answer:
D
Explanation:
at a point somewhere along the equator
In the case when the Sun appears to be directly overhead at noon should be along with the equator.
What is the equator?It is considered to be the imaginary line that should be arounded with the middle of the planet or the celestial body. It is halfway that lies between the North Pole and the South Pole, at 0 degrees latitude. In the equator, it divides the planet into a Northern Hemisphere and a Southern Hemisphere
Therefore, based on the above explanation, the option d is correct.
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explain how to find the mass of water. show your calculations as well
Answer:
You can find the mass of water by multiplying the density of water by its volume.
mass = Density x volume
Explanation:
It is very easy to find the mass of water once you know the formula of density. "Density" refers to mass per unit volume.
Density (ρ) = [tex]\frac{mass}{volume}[/tex]
Therefore, mass = ρ x volume
The density of water is 1 kg/L.
For example, if the volume of water is 500 ml, then you can get its mass by multiplying 500 ml by 1 kg/L.
Let's convert 500 ml to Liter first.
500 ml x [tex]\frac{1 L}{1,000 ml}[/tex] = 0.5 L
Now, let's compute.
mass = ρ x volume
mass = 1 kg/L x 0.5L
mass = 0.5 kg
The mass of a 500-ml water is 0.5 kg.
Help me asap it’s for my chem
what is a substrate
Answer:
a substrate is surface or material on or from an organism lives, grows, or obtains its nourishment.
Explanation:
Hey I hope this helps.....
All living organisms are composed of
OA. at least three cells.
ОВ.
one or more cells.
OC. at least 100 cells.
OD. only one cell.
Answer:
OB- one or more cells
Explanation:
hope this helps :)
What is the mass of 2.486 * 10^{24} atoms of neon?
Select one:
a)83.33 g Ne
b)0.2046 g Ne
c)8.333 g Ne
d) 4.130 g Ne
Answer:
The answer is A 83.33 g Ne
Explanation:
Used Avogadros Law
5(a) Consider the following schemes
Petroleum
>petroleum fractions
Higher petroleum fractions 1 , petrol + x
X + Y MI >CH,CICH,CI
nX"V (CH2 - CH2 - CH2-CH2)n
(i) State the type of reaction involved in I to IV
Answer:
is number 1
Explanation:
cause i know
TOPICAL ASSINMENT 2
1. If 25cm' of O.IM H,SO, solution neutralised a solution containing 1.06g anhydrous sodium carbonate in
250cm. of solution, calculate the molarity and the volume of the sodium carbonate solution used. (3mks)
The molarity = 0.04 M
The volume = 6.25 ml
Further explanationGiven
25cm³ of 0.1 M H₂SO₄
1.06g Na₂CO₃ in 250cm³ of solution
Required
the molarity and the volume of Na₂CO₃
Solution
Molarity of Na₂CO₃ :
[tex]\tt \dfrac{1.06/106~mol}{0.25~L}=0.04~M[/tex]
Reaction
H₂SO₄ + Na₂CO₃ ⇒Na₂SO₄ + H₂O + CO₂
mol H₂SO₄ = 25 x 0.1 = 0.25 mlmol= 2.5 x 10⁻⁴ moles of Na₂CO₃
The volume of solution used :
[tex]\tt V=\dfrac{n}{M}=\dfrac{2.5.10^{-4}}{0.04}=6.25.10^{-3}~L=6.25~ml[/tex]
What is different about the atomic structure of the oxygen isotopes?
Answer:
Each isotope of oxygen contains 8 protons, but differs in the number of neutrons. An isotope number is a shorthand representation of its mass. Because protons and neutrons are roughly equal in mass, an isotope's number is equal to the sum of its protons and neutrons.
Explanation:
Isotopes are atoms of the same element that have different numbers of neutrons but the same number of protons and electrons. The difference in the number of neutrons between the various isotopes of an element means that the various isotopes have different masses.
An atom has 38 protons and 42 neutrons it is ?
Answer:
The answer is, Strontium
Answer:
Name Molybdenum
Atomic Mass 95.94 atomic mass units
Number of Protons 42
Number of Neutrons 54
Number of Electrons 42
Explanation:
Replication, Transcription, and Translation Chart
Please answer
DNA Replication:
1。Template Strand: Start with this nucleotide chain.
TACCCTTGAATAAAAAATCTCTGTTTGGTCGGTATTGTTGAAATC
2。Complementary DNA Strand: Write directly below template strand.
Transcription:
3。mRNA Strand: Write the complementary mRNA strand from the DNA template strand (#1).
Translation:
4。Anticodon: Write the anticodon sequence to match the mRNA strand (#3).
5。Protein Synthesis: Write the mRNA sequence that is complementary to the anticodons. Meaning the opposite code of the anticodons (#4).
6。Amino Acid Sequence: Create the amino acid sequence from protein synthesis using 3 letter abbreviation for amino acids (#5).
I can help with 1, 2, 3, and 4... 5 and 6, I don't understand.
Template sequence : TACCCTTGAATAAAAAATCTCTGTTTGGTCGGTATTGTTGAAATC
Complement sequence : ATGGGAACTTATTTTTTAGTGTCAAACCAGCCATAACAACTTTAG
mRNA sequence : AUGGGAACUUAUUUUUUAGAGACAAACCAGCCAUAACAACUUUAG
Anticodon sequence : AUG-GGA-ACU-UAU-UUU-UUA-GAG-ACA-AAC-CAG-CCA-UAA-CAA-CUU-UAG
(not 6) Protein synthesis : START-Gly-Thr-Tyr-Phe-Leu-Glu-Thr-Asn-Gin-Pro-Stop
What happens when the number of electrons and protons inside of an atom are Not equel?
Hello, It's me Moriah Elizabeth!
Answer:
When the number of electrons does not equal the number of protons, the atom is ionized.
What types of radiation cause the parent isotope to change into a different element?
Answer:
Beta decay is most common in elements with a high neutron to proton ratio. Gamma decay follows the form: In gamma emission, neither the atomic number or the mass number is changed. A high energy gamma ray is given off when the parent isotope falls into a lower energy state.
Explanation:
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Why do scientists often use bacteria to produce medicines?
Answer:
Bbbbb eg2020
Explanation:
Bbbbb
What does bananas batteries and people have in common
please help me I will give brainesty if your right
Answer:
Sunlight
Explanation:
My science teacher has told us that plants need the sun to photosynthesis. And even though their is a lot of sun, they need to compete for it still.
There is an equal number of protons and __________ in a neutral atom.
A. electrons
B. neutrons
C. protons
D. elements.
the answer is electrons