Which of the following reactions shows that the formation of CO2 releases
393.5 kJ/mol?
A. C(s) + O2(g) → CO2(g) + 393.5 kJ
O B. C(s) + 20(g) + 393.5 kJ → CO2(9)
O C. C(s) + O(g) + CO2(g) + 393.5 kJ
D. C(s) + O2(g) + 393.5 kJ → CO2(g)
Answers
Answer:
A. C(s) + O2(g) → CO2(g) + 393.5 kJ
Explanation:
The formation of carbon IV oxide (CO2) is an exothermic process. n exothermic process is a chemical process in which heat is evolved. Speaking in lay man's terminology, heat is one of the 'products' of the reaction. This implies that heat is evolved by the process.
The formation of CO2 is always a combustion reaction where heat is evolved or released by the reaction system. Hence the reaction could be shown as;
C(s) + O2(g) → CO2(g) + 393.5 kJ
This implies that 393.5 kJ of energy is released in the reaction in the form of heat. Hence the answer given in the answer box.
Answer: C(s) + O2(g) → CO2(g) + 393.5 kJ
Related Questions
4. Which of these terms describes the process of acid rain wearing away limestone?
Acryptic erosion
B.chemical weathering
C.cryptobiotic weathering
D.chemical erosion
Answers
Answer:
B. Chemical weathering
Explanation:
Erosion is the process whereby the soil and rocks are washed away by wind, water, ice or gravity.
Weathering is the process of weakening and breaking down of rocks and minerals either by non-living (abiotic) or living (biotic) factors or by both, such as temperature changes, plants and animals, acids, salts and water, etc.
From the above definitions, it can be seen that acid wearing away limestone is a rock weathering process by a non-living agent, an acid.
Option A is wrong because the process is weathering
Option B is correct because an acid is a chemical and the process involved is weathering
Option C is wrong because an acid is non-living
Option D is wrong because the process involved is weathering
the wavelength of a light wave whose frequency 5.0x 10^9 s^-1 is
Answers
Answer:
wavelength = 6 cm .
Explanation:
frequency given = 5 x 10⁹ .
wavelength = velocity of light / frequency
= 3 x 10⁸ / 5 x 10⁹
= .06 m
= 6 cm
The molecular formula for pentyne is
a.c6h6
b.c5h8
c.c5h12
d.c6h14
Answers
Answer:
B
Explanation:
The molecular formula for pentyne is C5H8
Connie was making sodium chloride by adding an acid to an alkali. She followed the progress of the reaction with a pH sensor .What else could she have used to detect when the reaction was complete?
Answers
What Connie could have used to detect when the chemical reaction was complete is an: acid-base indicator.
A chemical reaction is a chemical process that involves the continuous rearrangement (transformation) of either the ionic, atomic or molecular structure of a chemical element through the breakdown and formation of chemical bonds, in order to produce a chemical compound.
When a strong acid such as Hydrogen chloride (HCl) react with a strong alkali such as Sodium hydroxide (NaOH), it gives rise to the formation of Sodium chloride (NaCl) and Water ([tex]H_2O[/tex]);
[tex]HCl + NaOH[/tex] ----> [tex]NaCl + H_2O[/tex]
The progress of the above chemical reaction can be followed by using a pH sensor and the final pH of a strong acid and strong base is seven (7), meaning it is neutral.
However, Connie could make use of an acid-base indicator to detect when the chemical reaction is complete.
An acid-base indicator can be defined as a chemical substance that changes color with respect to the pH (hydrogen ion concentration) of a solution or chemical reaction. Some examples of an acid-base indicator are:
Litmus paper.Methyl red.Red cabbage juice.Bromothymol blue.Methyl orange.Phenolphthalein.In conclusion, an acid-base indicator is typically used for detecting when a chemical reaction between an acid and an alkali is complete.
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Answer:When a strong acid such as Hydrogen chloride (HCl) react with a strong alkali such as Sodium hydroxide (NaOH), it gives rise to the formation of Sodium chloride (NaCl) and Water ();
---->
Explanation:
Please help me with those questions please
Answers
Answer:
I know the answer to 5, i think
Explanation:
No, if both parents were left-handed, they would not have to be left-handedexample of potassium salt
Answers
Answer:
1) Sodium Chloride
2) Potassium Dichromate
3)Calcium Chloride
4)Sodium Bisulfate
Explanation:
Ex:1) Sodium chloride (NaCl) is the most common type of salt in our lives. Known as table salt, it forms a cubic lattice when it's in solid form. It's one of the safest materials you can use in a chemistry class or kitchen.
Ex:2) Potassium dichromate (K2Cr2O7) is an orange-colored salt composed of potassium, chromium and oxygen. Not only is it toxic to humans, it's also an oxidizer that is a fire hazard. Potassium dichromate should never be thrown away. Instead, it should be washed down the drain with a lot of water. Always use rubber gloves when working with this compound. If you spill a potassium dichromate solution on your skin, it gives you a chemical burn. Keep in mind that any compound with chromium in it is a potential carcinogen.
Ex:3)Calcium chloride (CaCl2) resembles table salt in its white color. It is widely used to remove ice from roads. It's more effective than sodium chloride as a deicer, because calcium chloride produces three ions, while calcium chloride produces only two. Calcium chloride can melt ice down to minus 25 F, as much as 10 degrees lower than for sodium chloride. Calcium chloride is so hygroscopic, which is the ability to absorb water, that if you leave it in a room uncovered, it can absorb enough water from the air to dissolve into a solution all on its own.
Ex:4) Sodium bisulfate (NaHSO4) forms from sodium, hydrogen, sulfur and oxygen. It is created from sulphuric acid and retains one of the acid's hydrogen ions, which gives this salt acidic qualities. Known as a dry acid, sodium bisulfate is used in commercial applications, such as reducing the pH level of spas and swimming pools, washing concrete and cleaning metals. In its solid form, sodium bisulfate forms white beads. This salt is poisonous and can damage your skin, so use rubber gloves when handling it. If ingested, call the poison control center immediately and do not induce vomiting.
boron has two naturally occurring isotopes .there are 10 b(20%)and 11b(80%).what is the average atomic mass of boron
Answers
Answer:
Explanation:
Average Atomic mass of any element =[ ∑ Abundance* mass of element] /100
= 10*20 +11*80 /100
= .........
Hope this helps you
Consider the intermediate equations: 3 equations.
C(s) + O2(g) --> CO2(g) Delta H1 = -393.5 kJ
2CO(g) + O2(g) --> 2CO2(g) Delta H2 = -566.0 kJ
2H2O(g) --> 2H2(g) + O2(g) Delta H3 = 483.6 kJ
With the overall reaction:
C(s) + H2O(g) --> CO(g) + H2(g) Delta Hrxn = ?
QUESTION 1:
What must be done to calculate the enthalpy of reaction?
The first must be halved.
The first must be reversed.
The second must be halved.
The second must be reversed.
The third must be halved.
The third must be reversed.
QUESTION 2:
What is the overall enthalpy of reaction?
Delta Hrxn = ____ kJ
Answers
Answer:
C. The second equation must be halved
D. The second equation must be reversed
E. The third equation must be halved.
Delta Hrxn= 131.3 kJ
Explanation:
The correct answer is -582 KJ.
What is the enthalpy of reaction?
Enthalpy is the heat content of a system.The enthalpy change of a reaction is roughly equivalent to the amount of energy lost or gained during the reaction.A reaction is favored if the enthalpy of the system decreases over the reaction.What is the overall enthalpy of the reaction?
Equal to the sum of the standard enthalpies of the intermediate reaction steps is called overall enthalpyLearn more about enthalpy below,
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What systems need to be in place to ensure fairness in healthcare?
Answers
Answer:
The Healthcare system should be a welcome place to the different tiers of people in the society. There should be zero form of discriminations and everyone should be should be treated in the same way. Defaulters should be frowned at and adequate punishments should be meted out. There should be strict accountability of the funds made available to the healthcare centers to prevent diversion and any corrupt practices. These systems need to be in place to ensure fairness in healthcare.
Action and reaction forces are described by newtons what law of motion
Answers
According to Newton, whenever objects A and B interact with each other, they exert forces upon each other. ... These two forces are called action and reaction forces and are the subject of Newton's third law of motion. Formally stated, Newton's third law is: For every action, there is an equal and opposite reaction.
There are total three laws of newtons, first law of newtons, second law of newton and third law of newton. Therefore, action and reaction forces are described by newtons third law of motion.
What is newton's third law?Newton's first law is also called law of inertia. An object at rest remains at rest, and an object in motion remains in motion at constant speed and in a straight line unless acted on by an unbalanced force.
Third law states that for every action there is an equal and opposite reaction. Third law is applicable in many field of physics. The third law is applicable in the running of rockets. The third law is also used by swimmers during swimming in pool.
Therefore, action and reaction forces are described by newtons third law of motion.
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Which if the following matters occupies more space, assuming similar number of molecules? A.(Solid) B.(Liquid) C.(Gas) D. (Solid and gas)
Answers
Why are prefixes not used in naming ionic compounds?
A. Two ions can combine in only one combination.
B. The number of ions is not fixed in a compound.
C. A roman numeral is used instead of a prefix
D. A subscript follows each name instead of a prefix.
Answers
Answer:
A.
Explanation: thats what i got right on the quiz lol
Prefixes are not used in naming ionic compounds because two ions can combine in only one combination.
It is common in organic chemistry and with a few other molecular species, to name the compound using a prefix such as di, tri, tetra etc to indicate the positions of moieties in the molecule. This is important because there could be several possible combinations of atoms in a molecule.
In the case of ionic compounds, the combining ions can only have one possible arrangement.
Hence, the reason why prefixes are not used in naming ionic compounds is because two ions can combine in only one combination.
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What do all pure substances have in common?
Answers
Answer:
All the pure substances are made up of atoms and group of atoms known as molecules. They also have weight, volume and colour white solids also have the shape and hardness or texture. Pure substances also have points at which they boil and solidify.
Answer:
Pure substances are defined as substances that are made of only one type of atom or molecule. The purity of a substance is the measure of the extent to which a given substance is pure.
Explanation:
Why would we want to correct for water vapor?
Answers
Answer:
The vapor pressure due to water in a sample can be corrected for in order to get the true value for the pressure of the gas.
Explanation:
This is how osmium appears in the periodic table.A purple box has O s at the center and 76 above. Below it says osmium and below that 190.23.
Rounded to the nearest whole number, how many neutrons, on average, are in an atom of osmium?
a76
b114
c 190
d266
Answers
Answer:
114
Explanation:
plz make me brainiest
Which elements are diatomic?
Answers
Answer:The elements hydrogen, nitrogen, oxygen, fluorine, chlorine, bromine and iodine are diatomic elements
Definition of diatomic elements:Diatomic elements are special as the atoms that form it do not like to be alone. That is, you will never find a nitrogen or fluorine atom, for example, hanging out solo. Rather, these atoms will always be paired together because they need to pool resources to have enough electrons.
Answer:
H2, O2, N2, F2, Cl2, Br2, I2
Explanation:
These occur naturally has molecules of 2 atoms.
They are all gases except Br2, liquid and iodine which is solid.
Convert to standard notation.
8.127 x
10-4
Answers
If its positive to the right
Answer 0.0008127
Answer:
0.0008127
Explanation:
This is easy
metallic pan is provided with a wooden plastic handle give reason
Answers
The metallic pan iis most likely going to be used on a stove.
The stove is heating something, and the conductive metallic pan will, well, conduct that heat throughout the entire body of the pan. Doing this will spread the heat to the handle, burning your hands.
Both wood and plastic are insulators, and they do not conduct heat or electricity. They will insulate your hands and protect them from the heat.
Does the conductivity increase or decrease?
O It increases at first, then decreases.
O It continuously decreases
O It continuously increases
O lt decreases at first, then increases
Answers
Answer:
It continuously decreases.
Explanation:
the thermal motion makes the electrons to collide and disturb the free flow. Thus, conductivity is decreased.
where are people mostly exposed to chemicals?
Answers
Answer:
people are mostly exposed to chemicals through their nose, mouth, eyes, and ears
Explanation:
they are the easiest way for anything, bad or good, to enter the body because people touch their face alot.
This might not answer what you were looking for but the other answer covered it pretty well so I thought I'd give you another angle to the question!
Hope this helps!!
If 1.50 L of 0.780 mol/L sodium sulfide is mixed with 1.00 L of a 3.31 mol/L lead(II) nitrate solution, what mass of precipitate would you expect to form?
Answers
Answer:
336.1 g of PbS precipitate
Explanation:
The equation of the reaction is given as;
Na2S(aq) + Pb(NO3)2(aq) ----> 2NaNO3(aq) + PbS(s)
Ionically;
Pb^2+(aq) + S^2-(aq) -----> PbS(s)
Number of moles of sodium sulphide= concentration of sodium sulphide × volume of sodium sulphide
Number of moles of sodium sulphide= 0.780 × 1.5 = 1.17 moles
Number of moles of lead II nitrate= concentration of lead II nitrate × volume of lead II nitrate
Number of moles of lead II nitrate= 3.31× 1.00= 3.31 moles
Then we determine the limiting reactant. The limiting reactant yields the least amount of product.
Since 1 moles of sodium sulphide yields 1 mole of lead II sulphide
1.17 moles of sodium sulphide also yields 1.17 moles of lead II sulphide
Hence sodium sulphide is the limiting reactant.
Thus mass of precipitate formed= amount of lead II sulphide × molar mass of sodium sulphide
Molar mass of lead II sulphide= 287.26 g/mol
Mass of lead II sulphide = 1.17 moles × 287.26 g/mol
Mass of lead II sulphide= 336.1 g of PbS precipitate
What is the pH of a 6.4x10^-10 m OH- solutions
Answers
Answer:
pH: 4.80617997398
pOH: 9.19382002602
[H+]: 1.5625E-05
[OH-]: 6.4E-10
ACID
Hope it helps :)
If two identical atoms are bonded together, what kind of molecule is formed?
A. A bent, nonpolar molecule
B. A linear, polar molecule
C. A linear, nonpolar molecule
D. A linear, ionic molecule
Answers
Answer:
C. A linear, nonpolar molecule
Explanation:
Molecules which are alike usually have the same degree of pull which results in them sharing electrons. This sharing of electrons is known as the molecules exhibiting Covalent bonding between them.
The equal pull also results in the cancelling out of electrons and favoring non polar bonds due to the absence of free electrons which would have been able to interact with H2O in a polar binding system.
Answer:
C
Explanation:
APEX
7. What volume of a 0.10 mol/l HCl solution is needed to neutralize 10 ml of a 0.15
mol/l LiOH solution (5 points)
Answers
Answer: The volume of a 0.10 mol/l HCl solution needed to neutralize 10 ml of a 0.15 mol/l LiOH solution is 15 ml
Explanation:
To calculate the volume of acid, we use the equation given by neutralization reaction:
[tex]n_1M_1V_1=n_2M_2V_2[/tex]
where,
[tex]n_1,M_1\text{ and }V_1[/tex] are the n-factor, molarity and volume of acid which is [tex]HCl[/tex]
[tex]n_2,M_2\text{ and }V_2[/tex] are the n-factor, molarity and volume of base which is LiOH.
We are given:
[tex]n_1=1\\M_1=0.10mol/L\\V_1=?mL\\n_2=1\\M_2=0.15mol/L\\V_2=10mL[/tex]
Putting values in above equation, we get:
[tex]1\times 0.10\times V_1=1\times 0.15\times 10\\\\V_1=15mL[/tex]
Thus the volume of a 0.10 mol/l HCl solution needed to neutralize 10 ml of a 0.15 mol/l LiOH solution is 15 ml
Where do you find the molar mass of an element
Answers
Answer:
Mass of a given chemical element or compound divided by the amount of substance.
(g/mol)
If a gas at 35°C and 2.3 atm is heated to 50°C, then what will the new pressure be? (Gay Lussac's Law)
Remember to convert Celsius tempertature into Kelvin. (Take the Celsius values and add 273)
Answers
Answer:
THE NEW PRESSURE OF THE GAS AT 50 °C IS 2.41 atm.
Explanation:
Initial temperature = 35 °C = 35 + 273 K= 308 K
Final temperature = 50 °C =50 + 273 K = 323 K
Initial pressure = 2.3 atm
Final pressure = unknown
Using the combined gas equation to get the relationship between pressure and temperature for a given gas sample, we have;
P1 / T1 = P2 / T2
P2 = P1 T2 / T1
P2 = 2.3 * 323 / 308
P2 = 742.9 /308
P2 = 2.41 atm.
THE NEW PRESSURE IS 2.41 atm at 50 °C
1.)A strong acid solution requires 3.2 grams of sulfuric acid (H2SO4). How many molecules of sulfuric acid are in the solution?
2.) While measuring out the sulfuric acid you accidentally spilled some of it! Before trying to clean it up you put some baking soda (NaHCO3) on to it neutralize it. If you scatter 7.8 g of baking soda on the acid how many moles of baking soda have you used?
Answers
Answer: 1. There are [tex]0.20\times 10^{23}[/tex] molecules of sulfuric acid in the solution.
2. 0.093 moles of baking soda have been used.
Explanation:
According to avogadro's law, 1 mole of every substance occupies 22.4 L at STP and contains avogadro's number [tex]6.023\times 10^{23}[/tex] of particles.
To calculate the moles, we use the equation:
1. [tex]\text{Number of moles of sulpfuric acid}=\frac{\text{Given mass}}{\text {Molar mass}}=\frac{3.2g}{98g/mol}=0.033moles[/tex]
1 mole of [tex]H_2SO_4[/tex] contains = [tex]6.023\times 10^{23}[/tex] molecules of sulfuric acid
Thus mole of [tex]H_2SO_4[/tex] contains = [tex]\frac{6.023\times 10^{23}}{1}\times 0.033=0.20\times 10^{23}[/tex] molecules of sulfuric acid
There are [tex]0.20\times 10^{23}[/tex] molecules of sulfuric acid in the solution.
2. [tex]\text{Number of moles of baking soda}=\frac{\text{Given mass}}{\text {Molar mass}}=\frac{7.8g}{84g/mol}=0.093moles[/tex]
0.093 moles of baking soda have been used.
A 2.575 g piece of gold (specific heat = 0.129 J/g°C) at a temperature of 75°C is placed into cold water at 10°C. If the gold loses 10.0 J of energy, what is its final
temperature in the water? Enter your answer to the
nearest whole number of °C.
Answers
Answer:
The final temperature of the mixture is 44.9°C
Explanation:
Mass of the substance (gold) = 2.575g
Specific heat capacity of gold = 0.129J/g°C
Initial temperature (T1) = 75°C
Final temperature (T2) = ?
Energy lost = 10J
Heat energy(Q) = MC∇T
Q = heat energy (in this case lost)
M = mass of the substance
C = specific heat capacity of the substance
∇T = change in temperature of the substance = (T2 - T1)
Q = MC∇T
Q = MC(T2 - T1)
-10 = 2.575 × 0.129 × (T2 - 75) energy is -ve because it was energy lost.
-10 = 0.3321 × (T2 - 75)
-10 = 0.3321T2 - 24.9075
Collect like terms
0.3321T2 = 24.9075 - 10
0.3321T2 = 14.9075
T2 = 14.9075 / 0.3321
T2 = 44.88
T2 = 44.9°C
The final temperature of the mixture is 44.9°C
Which is one way that topographic maps are different from other maps?
Answers
Answer:
The answer is A. Unlike other maps, topographic maps indicate man-made and natural landforms.
Explanation: Took the test and got 100% Edg. 2020
Answer:
A)Unlike other maps, topographic maps indicate man-made and natural landforms.
Explanation:
What is the molarity of a solution prepared by dissolving 7.0 moles of NaCl solute in 585 ml of solution
?
Answers
Answer:
12 mol/L
Explanation:
Molarity = moles/L solution = 7.0 mol /0.585 L ≈ 12 mol/L
