Answer:
Step 1: Find the Total Number of Valence Electrons. ...
Step 2: Find the Number of Electrons Needed to Make the Atoms "Happy" ...
Step 3: Determine the Number of Bonds in the Molecule. ...
Step 4: Choose a Central Atom. ...
Step 5: Draw a Skeletal Structure. ...
Step 6: Place Electrons Around Outside Ato
Explanation:
For the combustion of methane, CH4(g) + 2 O2(g) → CO2(g) + 2 H2O(l) △H = -213
kcal/mol
How many kilocalories of energy are released from 5.0 mol of methane?
How many moles of methane are needed to give 100. kcal heat?
Answer:
1.-213(kcal/mol)*5mol=1065kcal
2.100/213 mol
a. The energy released from 5.0 mol of methane is -1065 kcal/mol.
b. The number of moles of methane needed to give 100. kcal heat is 0.4694 moles.
What is combustion?Combustion is a chemical process in which the element reacts with oxygen to produce heat and light. Burning of wood.
The equation of combustion of methane:
CH₄ (g) + 2O₂(g) ------> CO₂ (g) + 2H₂O (l)
a) Enthalpy of the reaction is H = -213 Kcal/mol
This means 213 Kcal heat is released in the burning of one mole of CH4
H reaction = [ H products ] - [ H reactants ]
Hr = [ H(CO₂)g + 2H(H₂O)l ] - [ H(CH₄)g ] = -213 kcal/mol
For 5 moles of methane:
5CH₄(g) + 10O₂(g) -----> 5CO₂(g) + 10H₂O(l)
therefore, new Hr = 5 x -213 = -1065 kcal/mol
H reaction = -1065 kcal/mol
b) 213 kcal is released per mole of Methane
then, to release 100 kcal we need, 100 / (213) = 0.4694 moles
Thus, the energy released is -1065 kcal/mol, and the number of moles is 0.4694 moles.
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Calculate the density of an
object with a mass of 58g and a
volume of 20 mL.
Enter
Answer:
D = 2.9 g/mL
Explanation:
Density = Mass over Volume
D = m/V
Step 1: Define
m = 58 g
V = 20 mL
D = unknown
Step 2: Substitute and Evaluate for Density
D = 58 g/20 mL
D = 2.9 g/mL
II. Pure magnesium metal is often found as ribbons and can easily burn in the presence of oxygen. When 3.86 g of magnesium ribbon burns with 155ml of oxygen at 1.0 atm and 275 K , a bright, white light and a white, powdery product is formed, magnesium oxide. How many grams of excess reactant remain?
Answer:
[tex]Excess=3.53g[/tex]
Explanation:
Hello,
In this case, the undergoing chemical reaction is:
[tex]2Mg(s)+O_2(g) \rightarrow 2MgO(s)[/tex]
Next, we identify the limiting reactant by computing the moles of magnesium oxide yielded by 3.86 g of magnesium and 155 mL of oxygen at the given conditions via their 2:1:2 mole ratios and the ideal gas equation:
[tex]n_{MnO}^{by \ Mg}=3.86gMg*\frac{1molMg}{24.3gMg}*\frac{2molMgO}{2molMg} =0.159molMgO\\\\n_{MnO}^{by \ O_2}=\frac{1atm*0.155L}{0.082\frac{atm*L}{molO_2*K}*275K} *\frac{2mol MgO}{1molO_2} =0.0137molMgO[/tex]
It means that the limiting reactant is the oxygen as it yields the smallest amount of magnesium oxide. Next, we compute the mass of magnesium consumed the oxygen only:
[tex]m_{Mg}^{consumed}=0.0137molMgO*\frac{2molMg}{2molMgO} *\frac{24.3gMg}{1molMg} =0.334gMg[/tex]
Thus, the mass in excess is:
[tex]Excess=3.86g-0.334g\\\\Excess=3.53g[/tex]
Regards!
Chemical properties can be observed without changing the substance
Answer:
chemical properties can only be measured only by changing a substance chemical identity
Explanation:
apex
A type of substance containing atoms of two or more different elements that are chemically bonded together is referred to as a
Answer:
Compound
Explanation:
What is the first step when using a microscope?
A. Place the microscope slide on the stage
B. Plug the microscope in and turn it on
C. Switch to the low power objective lens
D. Secure the slide to the stage clips
Answer:
I think the answer is B :)
Answer:
the first step is B
Explanation: I'm on this lesson
How many electrons does 2Na+1 have
Answer:
So... for the element of SODIUM, you already know that the atomic number tells you the number of electrons. That means there are 11 electrons in a sodium atom. Looking at the picture, you can see there are two electrons in shell one, eight in shell two, and only one in shell three.
Explanation:
brainliest pleaseeee <3
Answer:
so there would be 2 electrons because
Explanation:
sodium has 11 electrons but if you look at the shels it onl has one electron (from the image im looking at) and the other shell only have one so theres 2 electrons
In which phase transition do molecules move directly from a state involving vibration of particles in a fixed position to a state involving random movement of high-speed particles?
evaporation
sublimation
freezing
deposition
would be your answer because it releases other cells out and causes the needy of cells to evaporate and sink.
sublimation is the phase transition do molecules move directly from a state involving vibration of particles in a fixed position to a state involving random movement of high-speed particles.
What is Sublimation?In the process of printing sublimation shirts, an image is first printed on a special sheet of paper before being transferred to a different material, typically polyester or a polyester blend. After that, heat is applied to the ink until it fuses with the fabric.
Sublimation shirt printing is more expensive than other procedures, but it produces shirts that stay longer and don't peel or crack over time.
he primary distinction between sublimation and heat transfer is that during sublimation, just the ink transfers to the substrate. A transfer layer is frequently also transferred to the material during the heat transfer procedure.
Therefore, sublimation is the phase transition do molecules move directly from a state involving vibration of particles in a fixed position to a state involving random movement of high-speed particles.
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A cough syrup contains red dye #40, with a concentration of 4.68 x 10-3 M.a.If you dilute the cough syrup by adding 175 mL of water to a 250. mL sample of the cough syrup, what will be the final concentration?
How do I do this?
Answer:
[tex]M_2=2.75x10^{-3}M[/tex]
Explanation:
Hello.
In this case, since a dilution process is a process by which the concentration of a solution decreases due to the increase of volume by usually adding water, it is important to take into account that the moles remain unchanged:
[tex]n_1=n_2[/tex]
Whereas in terms of molarity (M=n/V) can be written as:
[tex]M_1V_1=M_2V_2[/tex]
In such a way, since the initial concentration is 4.68e-3 M and the volume of such solution is 250. mL, the final volume results from mixing 250 mL of this solution with 175 mL, that is, to a volume of 425 mL. Thus, the concentration turns out:
[tex]M_2=\frac{M_1V_1}{V_2} =\frac{4.68x10^{-3}M*250.mL}{425.mL} \\\\M_2=2.75x10^{-3}M[/tex]
Best regards.
If you dilute the cough syrup by adding 175 mL of water to a 250 mL sample of the cough syrup, the final concentration would be 0.00275 M
Using a simple dilution equation:
number of moles before dilution = number of moles after dilution
Recall that: number of moles = molarity x volume (MV)
Thus:
M1V1 = M2V2
In this case, M1 = 4.68 x 10-3 M, M2 = ? V1 = 250 mL, and V2 = 425 mL
M2 = 4.68 x 10^-3 x 250/425
= 0.00275 M
= 0.00275 M
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the density of a wooden block that has a volume of 5 cm3 & a mass of 30.5 g
Formula: ____________
Mass = ____
Volume = ____
Density = ____
Answer:
The answer is 6.10 g/cm³Explanation:
The density of a substance can be found by using the formula
[tex]density = \frac{mass}{volume} \\[/tex]
From the question
mass = 30.5 g
volume = 5 cm³
We have
[tex]density = \frac{30.5}{5} \\ [/tex]
We have the final answer as
6.10 g/cm³Hope this helps you
Which element has more metallic properties?
Lead or Germanium
lead has more metallic properties
A student heats 25 mL of water from 20°C to 96°C in a glass beaker. The
model represents the motion of the water molecules during heating.
Explain why some of the water molecules shown in the model have
longer arrows than other water molecules during heating.
Answer:
Because the have acquired energy from the heating process, that is why the start moving faster.
Explanation:
Hello.
In this case, since the initial liquid water molecules have a certain energy content, which makes them move with the relatively medium velocity characteristic in liquid-phase substances, once energy starts being added, it is evidenced that the molecules acquire more energy which is able to make them move faster.
In such a way, since the initial water molecules velocity is marked by a medium range arrows, meaning that the molecules are moving not-so-fast, not-so-slow but the heated water molecules are marked by longer arrows, meaning that they move faster, we infer that such velocity increase is due to the addition of heat due to the heating process from 20 °C to 96 °C (just before boiling).
Regards!
Molecular motion is the action of motion of the molecules or the particles in a specific direction. The molecules start moving faster due to the energy given by the heat.
What are the factors affecting molecular motion?The movement of the molecules or the particles in the system is affected by the temperature and the heat given to the system by the external source.
The initial molecules have relative speed and motion in the system and after the addition of the factors the energy of the motion of the particles gets affected.
When the temperature of the water in the beaker is increased then the average kinetic energy of the molecules also increases and hence the motion of the molecules increases.
The medium ranged arrows depict the average speed of the molecule movement in the medium, while the longer arrows suggest the fast-moving molecules of the water.
Therefore, the heat increases energy and in turn the molecular motion.
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why does adding salt to ice make it melt faster
Where is the north pole of the bar magnet, based on the magnetic field lines
shown?
Answer:On the Right End
Explanation: Trust me I just got it wrong on APEX to answer it for y’all On the right end is the correct answer
Answer:
Right end
Explanation:
Just did the quiz
Which changes MUST happen for elements to become a compound
Answer:
Chemical changes in compounds happen when chemical bonds are created or destroyed. Then the molecular structure changes; new molecules form and a new substance is created. Often heat is used to begin a chemical change, as when baking a cake. Another example of a chemical reaction is the rusting of a metal trash can.
Hope this helps you Do mark as brainliest ✌️An element is constituted of only atoms and no other entities are present in it. Whereas a chemical compound is a substance made up of various identical molecules of the same or different atoms.
The atoms of the same or different species bond together to form a compound.
Chemical bonding is present among them that cannot be simply separated.The compounds can have ionic, covalent and hydrogen bonds present in them.When the new atoms combine the structure changes of the new molecule formed.To learn more about compounds and atoms follow the link:
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The lowest energy state of an atom is its
A. Highest-occupied energy level.
B. Principle quantum number.
C. Electron configuration.
D. Ground state.
Answer:
Principle quantum number.
Explanation:
True or false: An oxidation number is not the same as an actual charge on an ion. True false question. True False
Answer:
True
Explanation:
They are actually the same
The answer is False.
The oxidation number is the number of electrons removed or added to an element or compound. This is also equal to the charge on the ion.
For example, if Sodium atom loses one electron, it becomes oxidized to the + 1 state.
Na → Na⁺ + e⁻.
So, the oxidation number of Sodium is the charge on the Sodium ion which is + 1.
So, the oxidation number is equal to the charge on the ion.
So, the answer is False.
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What is the mass number of Carbon–12, which has 6 protons and 6 neutrons?
Answer:
It has the atomic mass of 12.
The graph shows the average monthly rainfall for a
forested area.
In which month is a high alert for fire danger most
likely?
A. April
B. August
C. May
D. October
Answer:
The Answer would be A. April
Explanation:
Least amount of rainfall out of all the months we have to choose from.
In two to three sentences, explain the trend for atomic size. Why does this trend occur?
Answer:
The number of energy levels increases as you move down a group as the number of electrons increases. Each subsequent energy level is further from the nucleus than the last. Therefore, the atomic radius increases as the group and energy levels increase. 2) As you move across a period, atomic radius decreases.
Explanation:
A sample of an ideal gas has a volume of 2.38 L at 283 K and 1.03 atm. Calculate the pressure when the volume is 1.97 L and the temperature is 307 K.
Gas Has A Volume Of 2.21 L At 287 K And 1.11 Atm. Calculate The Pressure When The Volume Is 1.03 L And The Temperature
Explanation:
g If the pressure of each gas is increased at constant temperature until condensation occurs, which gas will condense at the lowest pressure
The question is incomplete; the complete question is;
If the pressure of each gas is increased at constant temperature until condensation occurs, which gas will condense at the lowest pressure?
A) Octane
B) Ethane
C) Butane
D) All the gases will condense at the same pressure
Answer:
Octane
Explanation:
If we study the table closely we will realize that octane has the greatest molecular mass among all the gases shown.
The greater the molecular mass, the lower the pressure required for the condensation of the gas. Hence, the lowest pressure is required for the condensation of octane at constant temperature.
Electron spin around the nucleus in specific paths called?
Answer:
Electron cloud
Explanation:
Living things help contribute to the water cycle.
A. true
B.false
Which of the following is the metric system based on?
Which of the following representations shows the correct placement of trophic levels?
Secondary Consumers
Primary Consumers
Producers
Ok here is the next one
I’m counting on you
Thanks.
food moves through the mouth by muscle movement
Which carboxylic acid can be combined with an alcohol to form the ester shown below?
Answer:
CH₃CH₂CH₂COOH.
Explanation:
To know which option is correct, let us hydrolysed the given ester. This is illustrated in the attached photo.
Hydrolysis of ester involves breaking the ester bond by a water molecule to produce the corresponding alcohol and carboxylic acid.
From the reaction given in the attached photo, we can see that the carboxylic acid needed to produce the desired ester is butanoic acid, CH₃CH₂CH₂COOH.
I will mark brainliest as soon as there are two answers! Please be quick, I'm timed
A mineral forms in water heated by magma inside Earth.
Which statement best describes this mineral?
The mineral formed through evaporation.
The mineral crystallized from molten material.
The mineral formed when a hot water solution cooled.
The mineral likely has all the same properties as the surrounding rock.
Answer: i would do the mineral formed when a hot water solution cooled because you said that a mineral forms in water heated by magma inside Earth.
Explanation:
The answer would be C
Explanation:
When magma cools down it will change into a rock type so the answer would be C.
Help pls:)?
If the low power objective has 10X printed on it, what would be the total magnification when looking through the microscope?
Answer:
The magnification of the microscope is equal to the magnification of the ocular lens times the magnification of the objective lens. Since the objective lens has 10x printed on them at "low power". The total magnification would be 10 times 10.
Explanation:
i hope this helps C: