Answer:
A scientist measures the standard enthalpy change for the following reaction to be -139.5 kj :
h2(g) + c2h4(g)c2h6(g)
based on this value and the standard enthalpies of formation for the other substances, the standard enthalpy of formation of c2h4(g) is _____ kj/mol
Explanation:
Hydrogen ΔHof (kJ/mol) ΔGof (kJ/mol) So (J/mol K)
H2 (g)
0
0
130.7
Carbon ΔHof (kJ/mol) ΔGof (kJ/mol) So (J/mol K)
C2H6 (g)
-84.7
-32.8
229.6
Which of the following is NOT an example of pseudoscience?
A. Psychics
B. Healing crystals
C. Vaccines
D. Acupuncture
Answer:
I think its vaccines
PLEASE HELPNIM STUCK
Answer:
I think its C
Explanation: cuz the pictures indicate that is returns to "normal" last.
question 2 of 30
Which of the following is a reduction half-reaction?
OA. Cl₂(1)→ Cl₂(s)
OB. 2Cl + 2e → Cl₂
OC. Cl₂ → 2Cl + 2e
OD. 2C1+ + 2e → Cl₂
SUBMIT
Answer: D
Explanation:
Reduction involves the gaining of electrons.
This eliminates choices A and C.However, charge must be balanced, and this is not the case for choice B, but it is the case for choice D
Which of the following is the correct balanced equation for the reaction in which methane (CH4) burns in atmospheric oxygen (0₂) to make carbon dioxide and water vapor?
Answer: [tex]\text{CH}_{4}+2\text{O}_{2} \longrightarrow \text{CO}_{2}+2\text{H}_{2}\text{O}[/tex]
Explanation:
The unbalanced equation is
[tex]\text{CH}_{4}+\text{O}_{2} \longrightarrow \text{CO}_{2}+\text{H}_{2}\text{O}[/tex]
Balancing this equation, we get:
[tex]\boxed{\text{CH}_{4}+2\text{O}_{2} \longrightarrow \text{CO}_{2}+2\text{H}_{2}\text{O}}[/tex]
What is a quantum of light energy called?
O A. A photon
OB. A frequency
O C. A proton
O D. An electron
Answer:
A) photon
Explanation:
hope it helps and give brainliest if its correct
Answer:
PhotonExplanation:
please mark brainliest pleaseUp late, a tired engineer calculated the molar mass of nitroglycerin (C3H5N3O9) to be 193.7 g/mol, but this incorrect. What is the percent error of this incorrect molar mass
So, the formula mass of nitroglycerin is[tex]3(12.011)+5(1.00794)+3(14.0007)+9(15.9994)=227.0694 \text{ g/mol}}[/tex]
Therefore, the percent error is
[tex]\frac{193.7-227.0694}{227.0694} \times 100=\boxed{-14.70 \% \text{ (to 4 sf)}}[/tex]
HELP FAST!!!!!!!
Which two groups have the same functional group?
O A. Amines and alcohols
B. Aldehydes and esters
C. Ketones and aldehydes
D. Esters and ethers
Answer:
C. Ketones and aldehydes
Explanation:
they are both carbonyl functional group
they both have a carbon-oxygen double bond
testosterone is an example of a ketone
formaldehyde is an example of a aldehyde
opentextbcca
wikipedia
Answer:
Ketones and Aldehydes
Explanation:
i just took tha test
how do we compare the PH of a weak acid and a strong acid of identical concentration and draw a conclusion about the concentration of hydrogen ions?
Answer:
This means that the pH values of strong acids are lower than that of weak acids, which explains why the rate of reaction of strong acids with substances (such as metals, metal carbonates etc) is higher than that of weak acids.
Explanation:
welcome
How many liters of a 0.80 M
solution can be made with 2.0 mol
KNO3?
{?} L
Answer:
Explanation:
Solution
Verified by Toppr
2 molL
−1
Explanation :
Concentration =
Volume of solution
Moles of solute
We assume that potassium nitrate dissolves in the given volume of solvent without gross change in volume.
Concentration =
101.10gmol
−1
404g
How does separating CHEMICALS through DISTILLATION harm the environment ?
Explain in your own words
Explanation:
Distillation is the separation of mixture of two liquids which differ in boiling point. Through Distillation vapour that is formed spread thoroughly in our environment
Ammonia chemically reacts with oxygen gas to produce nitric oxide and water
. What mass of oxygen gas is consumed by the reaction of 9.98 g of ammonia?
Round your answer to 3 significant digits.
9.98 g of NH₃ reacts with 23.4 g of O₂ (up to 3 significant figure).
What is Significant figures ?The digits of a number that are used to express it to the required degree of accuracy, starting from the first non-zero digit.
The given chemical equation ;
4NH₃ + 5O₂ ---> 4NO + 6H₂O
Therefore,
4 moles of NH₃ reacts with 5 moles of O₂.
i.e,
68 g of NH₃ reacts with 160g of O₂.
Therefore,
9.98 g of NH₃ reacts with :
= 160/68 x 9.98
= 23.4 g of O₂ (up to 3 significant figure)
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Fatty acids are a component of:
According to the research, fatty acids, which are long molecules in the form of a hydrocarbon chain, are a component of lipids.
What are lipids?They are hydrophobic and water-insoluble molecules that are formed from the esterification of alcohols with fatty acids.
Lipids are a vital part of the diet of living beings since many vitamins are assimilated in the presence of certain lipids and many fatty acids are essential for animal metabolism.
Therefore, we can conclude that according to the research, fatty acids, which are long molecules in the form of a hydrocarbon chain, are a component of lipids.
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Why did potato chunks a, b, and c gain mass here?
The most likely reason why the potato chunks gained mass is that water entered the potato cells.
How does water enter potato cells?The process of Osmosis allows water to pass through the semi-permeable membrane of potato cells.
This happens when the potato cells have less water than the material around them which then leads to water entering the cells to balance the water concentration.
The potato cells will expand and have more mass as a result.
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Is the relationship between temperature and water density an inverse or direct relationship?
The relationship between temperature and water density is an inverse relationship.
Temperature:-A measure of the typical kinetic energy of the atoms or molecules in a system, the temperature is a physical variable that expresses hot and cold.
Density:-The definition of density is the mass of a substance per unit volume. Density is defined as the ratio of mass to volume, or mass per unit volume.
Relation between temperature and density:-An inverse relationship exists between temperature and density. The density of water drops because of the increased distance between water molecules as temperature rises. Water's density rises when its temperature drops, but only to a certain extent.
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what does ivf stand for and sexual intercom
Answer:IVF
Explanation:
Potassium chlorate decomposes according the following BALANCED equation.
2 KClO3 → 2 KCl + 3O2
How many grams of oxygen gas would be produced if 33.0 g of potassium chlorate react?
Answer:
12.9 g O₂
Explanation:
To find the mass of oxygen gas produced, you need to (1) convert grams KClO₃ to moles KClO₃ (via molar mass from periodic table values), then (2) convert moles KClO₃ to moles O₂ (via mole-to-mole ratio from reaction coefficients), and then (3) convert moles O₂ to grams O₂ (via molar mass). It is important to arrange the conversions/ratios in a way that allows for the cancellation of units (the desired unit should be in the numerator). The final answer should have 3 sig figs to match the given value (33.0 g).
Molar Mass (KClO₃): 39.098 g/mol + 35.45 g/mol + 3(15.998 g/mol)
Molar Mass (KClO₃): 122.542 g/mol
2 KClO₃ ---> 2 KCl + 3 O₂
Molar Mass (O₂): 2(15.998 g/mol)
Molar Mass (O₂): 31.996 g/mol
33.0 g KClO₃ 1 mole 3 moles O₂ 31.996 g
-------------------- x ------------------- x ----------------------- x ------------------ =
122.542 g 2 moles KClO₃ 1 mole
= 12.9 g O₂
the law of definite proportions was first stated by
a. lavoisier
b. galileo
c. proust
d. dalton
Answer:
C.proust
Explanation:
Proust's law of definite proportions.
The law of definite proportions was first put forward by the French chemist Joseph Louis Proust in 1779. The discovery that mass was always conserved in chemical reactions was soon followed by the law of definite proportions, which states that a given chemical compound always contains the same elements in the same proportions by mass.
The law of constant proportions is often referred to as Proust’s law of definite proportions.For example, in a nitrogen dioxide (NO2 ) molecule, the ratio of the number of nitrogen and oxygen atoms is 1:2, but the mass ratio is 14:32 (or 7:16).For example, pure water will always contain hydrogen and oxygen in a fixed mass ratio (a gram of water consists of approximately 0.11 grams of hydrogen and 0.88 grams of oxygen, the ratio is 1:8).━━━━━━━━━━━━━━━━━━━━━
An avalanche comes down the East side of the mountain. If the avalanche lasted for 97 seconds and travels 4.5 miles, what was the velocity of the avalanche?
The velocity of the avalanche is 0.04 miles / sec. If the avalanche lasted for 97 seconds and travels 4.5 miles,
What is Velocity ?Velocity is a vector expression of the displacement that an object or particle undergoes with respect to time .
The standard unit of velocity magnitude (also known as speed ) is the meter per second (m/s). Alternatively, the centimeter per second (cm/s) can be used to express velocity magnitude.
Given ;
Time = 97 secDistance = 4.5 milesFormula used ;
Velocity = Distance / Time
Therefore,
Velocity = 4.5 miles / 97 sec
= 0.04 miles / sec
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The human skeleton is made mostly
of hard blank
tissue.
Which of the following most accurately describes a regulatory molecule that must be transported to its place of action within the body?
hormone
polypeptide
enzyme
Answer:
the answer is hormone
Explanation:
because it is
Rank the gases Ar, N2, CH4, and C₂H6 in order of increasing density at STP.
Rank the gases Ar, N2, CH4, and C2H6 in order of increasing density at STP.
ans : CH4
The density of lead is 11.3 g/mL. What is the mass of 45 mL of the metal?
Answer:
510g
Explanation:
45mL..
1mL
_____ = 510g
11.3g
The energy of a photon from certain wavelength is 1.37 x 10^-20 j, what is the frequency in hz?
Answer:
frequency = 2.07 x 10¹³ Hz
Explanation:
To find the frequency of the photon, you need to use the following equation:
E = hv
In this formula,
-----> E = energy (J)
-----> h = Planck's Constant (6.626 x 10⁻³⁴ J*s)
-----> v = frequency (Hz)
Since you have been given values for two of the variables (in the correct units), you can plug them into the equation and simplify to find the frequency.
E = hv <----- General Equation
E = (6.626 x 10⁻³⁴ J*s)v <---- Plug in Planck's Constant
1.37 x 10⁻²⁰ J = (6.626 x 10⁻³⁴ J*s)v <----- Plug in energy (given)
2.07 x 10¹³ = v <----- Divide both sides by 6.626 x 10⁻³⁴
G identify which substitution product is expected to be favored. explain. the product with retention of configuration is expected to predominate slightly, because the leaving group blocks the nucleophile. the inverted product is expected to predominate slightly, due to sn2 competition. the inverted product is expected to predominate slightly, as a result of ion pairs. the product with retention of configuration is expected to predominate slightly, because the leaving group attracts the nucleophile.
The substitution product that is supposed to be favoured. The product with retention of configuration is expected to predominate slightly because the leaving group blocks the nucleophile.
What is a substitution product?A substitution product is a product that is gotten from a reaction in which a group of reactants is replaced by another group in the reaction.
Therefore, the substitution product is supposed to be favoured. The product with retention of configuration is expected to predominate slightly because the leaving group blocks the nucleophile.
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Help!!! Will give brainliest to those who have the most accurate answer W/explanation!
Answer:
See below
Explanation:
Tap water, bottled water and lake water are all examples of FRESH WATER and likely have the same specific gravity ( or density) .
Ocean water is SALT WATER ....and depending on HOW MUCH salt is in the water, it can be quite a bit denser than fresh water ...which will allow the golf ball ( which is less dense) to float .
A voltaic cell is made using a lead electrode and copper electrode. The electrolytes for each half cell are lead nitrate and copper nitrate. Write the cell notation for this cell and calculate its cell potential (E°cell).
The cell notation is [tex]Pb_{(s)}[/tex] [tex]Pb^{2+} _{(aq)}[/tex] ║[tex]Cu^{+2}_{aq}[/tex] [tex]Cu_{(s)}[/tex] and the cell potential is 0.464
The reaction occurred while losing of hydron is known as oxidation reaction
We can also tell that the reaction occurred while gaining of oxygen atom is known as oxidation reaction.
The reaction occurred while gaining of hydrogen is known as reduction reaction or we can say that the reaction occurred while losing oxygen atom is known as reduction reaction
An electrochemical cell's cell potential is defined as the difference in potential between two half cells. The electrons' capacity to go from one half cell to the other is what causes the potential difference. As a result of the chemical reaction being a redox reaction, electrons can travel across electrodes.
Calculating the Cell potential
E°cell = E°(reduction) - E°(oxidation)
= 0.34 - (-0.0124)
= 0.464
Hence the cell potential is 0.464
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How does gravity depend on the mass of two objects
Gravity increases as the mass of either object increases.
What is gravity?Gravity is the force by which a planet or other body draws objects toward its centre. The force of gravity keeps all of the planets in orbit around the sun.
Since the gravitational force is directly proportional to the mass of both interacting objects, more massive objects will attract each other with a greater gravitational force. So as the mass of either object increases, the force of gravitational attraction between them also increases.
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Convert a speed of 88 m/s to its equivalent in cm/s.
pls help i don’t get it.
Answer:
8800 cm / s
Explanation:
There are 100 cm / m
so: 88 m/s * 100 cm / m = 8800 cm/s
( see how the 'm' cancels out and you are left with cm /s ?)
Which statement best describes how the scientific community analyzes data?
OA. A scientist must always keep his or her data hidden from other
scientists.
B. There is only one possible conclusion to be drawn from a set of
data.
OC. Each scientist must use his or her own, unique data.
OD. Scientists can come to different conclusions based on the same
data.
SUBMIT
Answer: D. Scientists can come to different conclusions based on the same data.
pls help.
Dr. AT is studying the effect playing music has on plant growth. To do this she sets up three greenhouses each growing pea plants. One of the greenhouses plays classical music to the plants all day, the second greenhouse plays pop music, while the third is silent. All other factors, such as water and sunlight are identical between the three greenhouses. After two weeks, Dr. AT measures each pea plant and records her data. What greenhouse is the control group in this experiment?
A. The silent greenhouse.
B. The pop music greenhouse.
C. The classical music greenhouse.
D. The height of the plants.
Answer:
c or d
Explanation:
it says it was playing classic music
In this case, the control group or control variable is the greenhouse where the plants are grown in silence, as this group does not receive any music treatment. Therefore, the correct answer is A.
Variables can be defined as any characteristics, number or a quantity that can be measured . It is also called as a data item . It is called as variable because it can vary and can also have wide variety of values.
There are 3 types of variables 1) manipulated variable where the condition is specified, 2) responding variable which is dependent on the manipulated variable 3)controlled variable which does not change.
In this experiment, the control group is the group that does not receive the experimental treatment and serves as a basis for comparison.
Thus, the correct answer is A , the silent greenhouse.
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