Answer:
–87.3 KJ.
Explanation:
The equation for the reaction is given below:
H₂(g) + ½O₂(g) —> H₂O(l) ∆H = -285.8 kJ
Next, we shall determine the mass of H₂O produced from the balanced equation. This can be obtained as follow:
Molar mass of H₂O = 18 g/mol
Mass of H₂O from the balanced equation = 1 × 18 = 18 g
SUMMARY:
From the balanced equation above,
When 18 g of H₂O was produced, ∆H was –285.8 KJ.
Finally, we shall determine ∆H when 5.5 g of H₂O is produced. This can be obtained as illustrated below:
From the balanced equation above,
When 18 g of H₂O was produced, ∆H was –285.8 KJ.
Therefore, 5.5 g of H₂O will produce ∆H of = (5.5 × –285.8) / 18 = –87.3 KJ
Thus, the ∆H when 5.5 g of H₂O was produced is –87.3 KJ.
Household ammonia has a pH of 12; household bleach has a pH of 13. Which of the following statements about these substances is true? Group of answer choices The ammonia has 10 times as many OH- ions as the bleach. The ammonia has 10 times as many H+ ions as the bleach. A solution that could buffer the bleach and ammonia would remove excess OH- ions. Both of these substances are strong acids.
Answer:
The ammonia has 10 times as many H+ ions as the bleach.
Explanation:
pH is defined as -log[H+]
[H+] of ammonia is = 10^-12 = 1x10-12M
Bleach = 1x10-13M
pOH = 14-pH = 2 for ammonia and 1 for bleach
[OH-] = 10^-pOH = 0.01M for ammonia and 0.1M for bleach
Thus:
The ammonia has 10 times as many OH- ions as the bleach. FALSE.
The ammonia has 10 times as many H+ ions as the bleach. TRUE.
A solution that could buffer the bleach and ammonia would remove excess OH- ions. FALSE. A buffer maintains OH- ion concentration
Both of these substances are strong acids. FALSE. Strong acids have pHs < 7
What is the basic idea for how to find surface area of any solid?
Answer:
Find the area of each face that you see and then multiply each area by two to account for the face on the opposite side.
Identify which of the following statements about the isotopes of an element is correct.
A. They have the same electron configuration.
B. They have the same mass number.
C. They have the same numbers of protons and neutrons in the nucleus.
D. They have more protons than neutrons.
Answer:
A
Explanation:
because B is wrong as it doesn't have the same mass number. C is wrong as it has different number of neutrons. D is wrong as it has more neutrons than protons.
The only two elements in alkenes and alkynes are A. Carbon and Nitrogen B. Carbon and Hydrogen C. Oxygen and Nitrogen D. Oxygen and Hydrogen
Answer:
B. Carbon and Hydrogen
Explanation:
An alkyne can be regarded as unsaturated hydrocarbon which have at least one carbon—carbon triple bond. They are acyclic aliphatic hydrocarbons, they can be (branched or unbranched) , They have general chemical formula of [ CₙH₂ₙ−2]. One of the compound belonging to this family is Propyne( C3H4) Hence, they contain Hydrogen and Carbon.
Alkenes can be regarded as class of hydrocarbons which posses only carbon and hydrogen, they are unsaturated compounds having least one carbon-to-carbon double bond.
alkenes can also be regarded as "olefins". one of the members of this family is Ethene (C2H4). general formula of alkenes can be written as [C nH 2n],
n=number of carbon atoms present in the molecule
Which of the following statements about the procedure for distillation is false?
A) You should attach metal clips to the water tubes when you attach them to the condenser.
B) You are to continue heating the round-bottom flask until all liquid has been distilled.
C) When setting up the distillation apparatus, you should use 3 metal clamps.
D) As you conduct the distillation experiment, you are to store your fractions, securely sealed with caps and placed standing upright, in a beaker until you are ready to obtain GC data.
Answer: B) You are to continue heating the round-bottom flask until all liquid has been distilled.
Explanation:
Fractional distillation refers to a method that's useful for the separation of mixtures of solvents whereby there is less than 40°C in the boiling point difference.
With regards to the options given, the incorrect statement about the procedure for distillation is that you are to continue heating the round-bottom flask until all liquid has been distilled. This isn't correct.
Which is a thermosetting plastic?
Polythene
PVC
Melamine
Nylon
A warm air moist air mass moves over a cold air mass is most likely to lead to which type of server weather
Some factories that burn coal produce smoke with harmful chemicals,
such as sulfur. Scrubbers are devices that are attached to the
smokestacks to reduce the amount of sulfur put into the atmosphere. To
evaluate the effectiveness of these devices, what data would need to be
collected?
The amount of sulfur emitted by a smokestack before and after the scrubber is attached.
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Name a popular polyester
Answer:
Terylene
Explanation:
Answer: she or his is right the Terylene is a popular polyester which is used in dress materials. PET (Poly Ethylene Terephthalate) is another example of polyester.M
Explanation:
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Using the periodic table, choose the more reactive nonmetal.
Te or O
the answer is Te because O is oxygen.
Answer:
O
Explanation:
this is because it is oxygen
Methane is the chief constituent of petroleum fuel
A:yes
B:no
Chemical bonding may involve any of the following except the
1. change in mass in a chemical reaction
2. unequal sharing of a pair of electrons between two nonmetals
3. electrostatic attraction between two ions
4. transfer of an electron from one atom to another
Answer:
Number 1 is wrong it doesn't change the mass
Chemical bonding may involve any of the following except the " change in mass in a chemical reaction".
What is chemical reaction?A chemical reaction is referred to as a process which it involves the chemical change of one set of chemical compounds into yet another set of chemical substances.
What is chemical bonding?A molecule and compound's atoms, ions, and groups of atoms are held together by an attractive force, referred as chemical bond.
Chemical bonding may involve any of the following except the " change in mass in a chemical reaction".
Therefore, the correct answer will be option 1.
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What is the function of the rough
ER?
A. build proteins
B. modify and repackage proteins
C. contains enzymes
A. build proteins
Explanation:
The endoplasmic reticulum can either be smooth or rough, and in general its function is to produce proteins for the rest of the cell to function. The rough endoplasmic reticulum has on it ribosomes, which are small, round organelles whose function it is to make those proteins
In the formation of a covalent bond, electrons are …..
A- Gained
B- Transfered
D- Lost
E- Shared
Answer:
E-shared
A covalent bond consists of the mutual sharing of one or more pairs of electrons between two atoms.
Silicon dioxide reacts with carbon to form silicon carbide and carbon monoxide as shown in the unbalanced reaction below. Determine the percent yield of silicon carbide if 79.1 grams of carbon reacts with an excess of silicon dioxide and 67.4 g of silicon carbide is actually recovered.
SiO2 + C → SiC + CO
What are some properties that can be used to determine a chemical reaction has occurred?
Answer:
Some signs of a chemical change are a change in color and the formation of bubbles. The five conditions of chemical change: color change, formation of a precipitate, formation of a gas, odor change, temperature change.
Answer:
Change in Color
Heat is released (bubbles in solution)
Sometimes even a change in texture
A new smell
Formation of a precipitate
The below table compares the number of electrons in two neutral atoms.
atom:
Ne 10
Na 11
Compare the electron configuration and atomic radius of these two atoms and use that to explain the difference in their reactivity.
Write a report on the implications of entropy to a Christian 500 words
Secondary succession can only occur as a transition from primary succession.
Answer:
false
Explanation:
edge 2022
How many atoms are in 490 moles of barium?
Answer:
2.95 * 10^23 atoms
Explanation:
The number of atoms in a mole is always equal to Avogadro's constant, which is 6.02214076×10²³ mol⁻¹.
To find the number of atoms in 0.490 moles of barium, multiply it with Avogadro's constant:
0.490 mol * 6.02214076×10²³ mol⁻¹ ≈ 2.9508 * 10^23
Convert to SigFigs (if necessary):
2.95 * 10^23
What is the product of
Mg(NO3)2 + Na2CO3?
Answer:
MgCO3 + 2 NaNO3
Explanation:
Formulating an Investigative Question In this experiment, you will use a track and a toy car to explore the concept of movement. You will measure the time it takes the car to travel certain distances, and then complete some calculations. In the space below, write a scientific question that you will answer by doing this experiment.
Answer:
A scientific question to be asked is; What is the average speed of the toy car?
Explanation:
A scientific question is a question which is well defined, the values in the question can be measured, and the inputs and outputs related to the question are controllable
The parameters measured in the experiment are;
The time elapsed during the movement of the car, Δt
The distance the car moves, d
From the obtained measurements, the value can be calculated is the average speed of the toy car as follows;
[tex]The \ average \ speed \ of \ the \ toy \ car, \ v_{avg} = \dfrac{d}{\Delta t}[/tex]
Therefore, a scientific question to be asked that will be answered by doing the experiment is; What is the average speed of the toy car?
Answer:
Sample Response: How can we change the speed of a toy car on a racetrack to describe the car’s motion?
What did you include in your question? Check all that apply.
a focus on describing the toy car’s motion
a suggestion for a way to change the car’s motion
room for observations and an opportunity to look at motion objective
Explanation:
which of the acyclic hydrocarbon series is represented by CnH2n
Answer:
alkenes
Explanation:
The general formula for alkenes is CnH2n
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What is the structure of an amino acid? A. Amino group, phosphate group, pentose sugar, nitrogen base B.Amino group, R group, carboxylic acid group C. Amino group, disulfide group. R group D. Phosphate group, pentose sugar, nitrogen base
Amino acids are the monomers that make up proteins. Each amino acid has the same fundamental structure , which consists of a central carbon atom, also known as the alpha (α) carbon, bonded to an amino group (NH2), a carboxyl group (COOH), and to a hydrogen atom.
Amino group, R group, and the carboxylic acid group. Hence, option B is correct.
What are Amino acids?Amino acids are the monomers that makeup proteins.
Each amino acid has the same fundamental structure, which consists of a central carbon atom, also known as the alpha (α) carbon, bonded to an amino group (NH2), a carboxyl group (COOH), and to a hydrogen atom.
Hence, option B is correct.
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A hydrocarbon was found to contain 82.8% by mass of carbon. It has
an Mr of 58. Find the empirical and molecular formulas of this
compound.
Answer: C4H10
Explanation: [tex]\left \{ {{12x+y=58} \atop {\frac{12x}{58} =82,8%}} \right. \\[/tex]%
==> x=4, y=10 C4H10
What is ozone hole?
What causes an ozone hole?
Answer:
Ozon prevents us from UV rays of the sun. Ozone hole means that UV rays are entering the Earth. This results in cancer.
Explanation:
Chlorofluorocarbons are causing this
Answer:
The term ‘ozone hole’ refers to the depletion of the protective ozone layer in the upper atmosphere (stratosphere) over Earth's polar regions. People, plants, and animals living under the ozone hole are harmed by the solar radiation now reaching the Earth's surface—where it causes health problems, from eye damage to skin cancer.
Ozone depletion occurs when chlorofluorocarbons (CFCs) and halons—gases formerly found in aerosol spray cans and refrigerants—are released into the atmosphere.
The solution of sugar at 60.0 degrees celcuis is 290.0 g/ 100 g water. If you add 100.0 g of sugar to 25 g of water at 60.0 degrees celcuis will the sugar dissolve?
Answer:
you will produce a saturated solution, At 0 degrees Celsius, sugar is claimed to dissolve 180 grams in 100 grams of water. This means that if you dissolve that much sugar in 100 g of water, you'll get a saturated solution.
Explanation:
The correct answer for the given question about Saturated solution is only 72.5 gram will get dissolved and rest which is 27.5 gram will remain undissolved.
How to apply concept of Saturated solution to solve this question?In question it is given that at 60° C 290 gram of sugar in 100 gram of water produce saturated solution.
So at 60° C 290/100 gram of sugar in 1 gram of water will produce saturated solution.
Hence we can say that at 60° C (290/100)×25 gram of sugar in 25 gram of water will produce saturated solution.
means at 60° C 72.5 gram of sugar in 25 gram of water will produce saturated solution.
Now, adding 100 gram of sugar in 25 gram of water.
Since you can only hope to dissolve 72.5 gram at 60°,
Hence the resulting solution will contain undissolved sugar.
So only 72.5 gram will get dissolved and rest which is 27.5 gram will remain undissolved.
Thus, We can conclude that Only 72.5 grams of sugar will dissolve, leaving the remaining sugar of 27.5 grams undissolved.
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Can somebody help please to balance those I couldn’t balance it
Answer:
1.
(NH4)2Cr2O7——>Cr2O7+N2+4H2O
2.
6CO2+6H2O——>C6H12O6+6O2
Are neutralization reactions always exothermic ?
Explanation:
Neutralisation reactions are not always exothermic. ... When an acid is neutralised by an alkali the reaction is exothermic.SInce strong acids and strong bases are completely dissociated in solution, no formal bonds are being broken. The formation of two very strong covalent bonds between hydrogen and the hydroxide ion is responsible for the neutralization reaction's exothermic character.
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