Answer:
50%
Explanation:
Let assume that there are:
"a" moles of CH4 & "b" moles of C2H2
Then by applying the ideal gas equation:
PV = nRT
[tex]16.8 \times 10^3 \times V = (a+b)RT[/tex]
Make (a+b) the subject of the formula:
[tex](a+b) = \dfrac{16800 \ V }{RT} mol[/tex] --- (1)
Since 1 mole of CH₄ yields 1 mol of CO₂ & 1 mol of C₂H₂ yields 2 moles of CO₂
Then;
the total moles of CO₂ = (a +2b)
Now:
[tex]25.3 \times 10^3 \times V = (a+ 2b)RT[/tex]
[tex](a + 2b) = \dfrac{25200 \ V}{RT \ mol}[/tex] ---- (2)
∴
By solving the above equations
[tex]a = \dfrac{8400 \ V}{RT} \\ \\ b = \dfrac{8400 \ V}{RT}[/tex]
Hence, the estimate of the percentage of methane in the original mixture is:
[tex]= 100 \times \dfrac{a}{(a+b)}[/tex]
[tex]= 100 \times \dfrac{8400\dfrac{ \ V}{RT} }{8400\dfrac{ \ V}{RT} + 8400\dfrac{ \ V}{RT}}[/tex]
= 50%
What would the final freezing point of water be if 3 mol of
sugar were added to 1 kg of water (Kx = 1.86°C/(mol/kg)
for water and i = 1 for sugar)?
A. -1.86°C
B. -5.58°C
C. -0.62°C
Ο Ο
D. +5.58°C
SUBMIT
Answer:
B. -5.58°C.
Explanation:
Hello!
In this case, since the freezing point depression is computed as follows:
[tex]\Delta T_f=-i*m*Kf[/tex]
Whereas i=1 as the van't Hoff's factor of sugar (nonionizing solute), m=3mol/1kg=3mol/kg as the molality and Kf=1.86 °C/(mol/kg) as the freezing point depression constant for water. In such a way, we plug in to obtain:
[tex]\Delta T_f=-1*3\frac{mol}{kg} *1.86\frac{\°C}{mol/kg} \\\\\Delta T_f=-5.58\°C[/tex]
Now, since the freezing point of pure water is 0°C, we infer that freezing point of such solution is:
B. -5.58°C.
Best regards!
The combustion of propane (C3H8) creates water and CO2. Looking at the
reaction below, which of the following would be the mole ratio between propane
and carbon dioxide? *
C3H8 +502->4H2O + 3C02
A)3 mole CO2 / 5 mole C3H8
B)3 mole C3H8/4 mole CO2
C)3 mole CO2 / 1 mole C3H8
D)3 mole C3H8 / 1 mole CO2
Answer:
C)3 mole CO2 / 1 mole C3H8
Explanation:
Why was Niels Bohr’s atomic model superior to all the earlier models?
A.
It proved that the atom was indivisible and therefore the smallest unit of matter.
B.
It showed how the electron could orbit the nucleus without falling into it.
C.
It was the first to show that the atom had no net charge.
D.
It used wave behavior to explain the positions of electrons around the nucleus.
Answer:
B
Explanation:
The Niels Bohr's atomic model superior to all the earlier models is because it showed how the electron could orbit the nucleus without falling into it
What do you notice about the movement of the molecules of the two samples?
Explanation:
For sample A, I put the temperature to 93.2 C and sample B to 6.8 C. Once I dragged them together, I noticed that the numbers were going down the second I put them together! Sample A was getting colder and Sample B was getting warmer. As I let both the samples do their thing, I realized they weren't changing temperatures anymore. Both samples stopped at 50.0 C and have never changed temperatures since then.
When iron is combined with copper (1) nitrate, it produces iron (II) nitrate and
copper. Which of the following could NOT be a mole ratio in this chemical
reaction?
A)1 mole Fe / 2 mole Cu
B)1 mole Fe(NO3)2 / 2 mole Cu
C)2 mole Cu(NO3)2 / 2 mole Fe
D)1 mole Fe(NO3)2 / 1 mole Fe
Answer:
C)2 mole Cu(NO3)2 / 2 mole Fe
Explanation:
I'm pretty sure.
When iron is combined with copper (1) nitrate, it produces iron (II) nitrate and copper. The following could NOT be a mole ratio in this chemical reaction is:
D) 1 mole Fe(NO₃)₂ / 1 mole Fe
To determine which of the given mole ratios could NOT be part of the chemical reaction between iron and copper(1) nitrate, we need to write the balanced chemical equation for the reaction and then compare it to the given ratios.
The balanced chemical equation for the reaction is:
Fe + Cu(NO₃)₂ → Fe(NO₃)₂ + Cu
A) 1 mole Fe / 2 mole Cu
This mole ratio is consistent with the balanced chemical equation, where 1 mole of Fe reacts with 2 moles of Cu(NO₃)₂ to produce 1 mole of Fe(NO₃)₂ and 1 mole of Cu. So, this ratio could be part of the chemical reaction.
B) 1 mole Fe(NO₃)₂ / 2 mole Cu
This mole ratio is also consistent with the balanced chemical equation, where 1 mole of Fe(NO₃)₂ is produced by reacting 2 moles of Cu(NO₃)₂. So, this ratio could be part of the chemical reaction.
C) 2 mole Cu(NO₃)₂ / 2 mole Fe
This mole ratio is consistent with the balanced chemical equation, where 2 moles of Cu(NO₃)₂ react to produce 2 moles of Fe(NO₃)₂. So, this ratio could be part of the chemical reaction.
D) 1 mole Fe(NO₃)₂ / 1 mole Fe
This mole ratio implies that 1 mole of Fe(NO₃)₂ is produced by reacting with 1 mole of Fe, which is not consistent with the balanced chemical equation. The equation shows that 1 mole of Fe reacts with 1 mole of Cu(NO₃)₂ to produce 1 mole of Fe(NO₃)₂ and 1 mole of Cu. Therefore, this ratio could NOT be part of the chemical reaction.
So, the correct answer is:
D) 1 mole Fe(NO₃)₂ / 1 mole Fe
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What does a control group show in an experimental investigation?
Answer:
the effects that the scientists are causing by manipulating varuables
2
What is the difference between weight and mass?
A Weight depends on density and mass depends on gravity.
B Weight depends on gravity and mass depends on volume.
C
Mass depends on gravity and weight is constant.
D Welght depends on gravity and mass is constant.
Answer:
Weight is the measure of the force of gravity on an object. The mass of an object will never change, but the weight of an item can change based on its location. For example, you may weigh 100 pounds on Earth, but in outer space you would be weightless.
Explanation:
I can't see the options but I hope this helps!
Answer:
the answer is B.
I hope this helps!
Explanation:
PLSASE HURRY I REALLY NEED IT
Consider this graph showing temperature over time. What would happen in the situation? The temperature decreases from 25° to 15°C, the material ____ heat and its kinetic energy ____ as the material, freezes to become a solid.
Answer:
One of the major effects of heat transfer is temperature change: heating increases the temperature while cooling decreases it. We assume that there is no phase change and that no work is done on or by the system. Experiments show that the transferred heat depends on three factors—the change in temperature, the mass of the system, and the substance and phase of the substance.
bill nye chemical reactions:
the picture looks cut off but can someone please help!
Answer:
. A(n) _______________________________ is matter that is composed of 2 or more different kinds of atoms.
2. A chemical reaction in which energy is released/given off is _____________________________________.
3. A(n) _________________________________ is a process in which substances are changed into other
substances.
4. Matter that is composed of only 1 kind of atom is a(n) ______________________________.
5. ___________________ is the ability to do work and/or transfer heat.
6. A chemical reaction in which energy is absorbed/taken in is _______________________________.
Knew/New
Write down 3 things you already knew about chemical reactions that were confirmed through watching the
video:
1.
2.
3.
Write down 3 new things that you learned from watching the video:
1.
2.
3.
Episode Guide
1. Chemicals can react to form new _________________________________.
2. Chemical reactions happen when ____________________ hook together.
3. Energy is given off during a chemical reaction because ____________________ are combining with other
__________________________.
4. During the "Try this" experiment, we see the students using vinegar and salt to clean old copper pennies.
The copper gets stripped away and the pennies look new again. Explain why you think this happens.
__________________________________________________________________________________________
Answer Key
compound
exothermic
chemical reaction
element
Energy
endothermic
Answers will vary.
Answers will vary.
chemicals
electrons
electrons
electrons
Copper atoms in the penny react with oxygen atoms from the air & together they form copper oxide which
makes the pennies look dull and dirty. The copper oxide dissolves in a weak acid (the vinegar & salt).
5. When vinegar and baking soda react together, the new substance that is produced is ___________________.
6. _______________ & ______________ are both dangerous by themselves, but when they react together they
form table salt.
7. Pyrotechnician is a name given to people who work to create _________________________.
8. In another experiment, we see kids blow up a balloon by mixing together vinegar and baking soda. When
the kids touch the blown up balloon, it is ____________ to the touch. This means that the reaction is
endothermic or exothermic
9. When someone gets hurt playing sports, often times a cold pack is used for the injury. The cold pack takes
up more energy than it gives off and it gets very ___________ to the touch. This means that the reaction taking
place is endothermic or exothermic
10. How do you know baking a cake is a chemical reaction? ________________________________________
11. There are ___________ naturally occurring elements.
12. If elements are in the same group on the periodic table, what does that tell you? ______________________
__________________________________________________________________________________________
True or False
1. When something burns, heat & light are given off. T or F
2. Your stomach growling is an example of a chemical reaction. T or F
3. Water is 1 part hydrogen and 2 parts oxygen. T or F
4. When baking a cake, a chemical reaction takes place. T or F
5. Everything is made of chemicals. T or F
6. Alfred Nobel invented dynamite. T or F
7. You should always wear safety goggles when working with chemicals. T or F
8. Sodium chloride is better known as sugar. T or F
9. A substance can feel a little warm if the reaction is endothermic. T or F
10. When developing film, red light doesn't affect the picture. T or F
11. A cold pack gets cold because the reaction takes more energy than it gives off. T or F
12. If chemicals behave similarly, they are grouped together on the periodic table. T or F
13. Chemical reactions happen when protons link atoms together. T or F
14. When vinegar and baking soda react, oxygen is produced. T or F
15. Fireworks are not an example of chemical reactions. T or F
carbon dioxide
Sodium chlorine
fireworks
warm
cold
The ingredients (flour, milk, eggs, etc.) are changed
Explanation:
write the neutralization equations that take place in the stomach with the bases present in the antacid product
Answer:
See explanation.
Explanation:
Hello!
In this case, since the antacid is usually composed by the following bases:
- Calcium, magnesium and aluminum hydroxides.
- Hydrogen sodium carbonate.
- Sodium carbonate.
In such a way, the feasible reactions that undergo when they react with the stomach acid are shown on the attached picture. As you can see, they all have in common the formation of chlorides and water, which are the neutralization products that calm down the acidity as they are neutral.
Best regards!
Measurements show that unknown compound X has the following composition: element mass % chromium 68.4% oxygen 31.5% Write the empirical chemical formula of X.
Answer: The empirical formula of X is [tex]Cr_2O_3[/tex]
Explanation:
If percentage are given then we are taking total mass is 100 grams.
So, the mass of each element is equal to the percentage given.
Mass of Cr = 68.4 g
Mass of O = 31.5 g
Step 1 : convert given masses into moles.
Moles of Cr =[tex]\frac{\text{ given mass of Cr}}{\text{ molar mass of Cr}}= \frac{68.4g}{52g/mole}=1.31moles[/tex]
Moles of O =[tex]\frac{\text{ given mass of O}}{\text{ molar mass of O}}= \frac{31.5g}{16g/mole}=1.97moles[/tex]
Step 2 : For the mole ratio, divide each value of moles by the smallest number of moles calculated.
For Cr = [tex]\frac{1.31}{1.31}=1[/tex]
For O = [tex]\frac{1.97}{1.31}=1.5[/tex]
The simple whole number ratio of Cr : O= 2: 3
Hence the empirical formula is [tex]Cr_2O_3[/tex]
What are 3 characteristics of all invertebrates
Answer:
None have backbones
No cell walls
Multicellular
Includes radial or bilateral body symmetry.
Explanation:
Covalent bonding occurs between atoms when 1. The potential energy of the shared elec- trons is lower in the bond than it would be if the electrons were not shared between two nuclei 2. The potential energy of the shared elec- trons is independent of the covalent bond, but the potential energy of the newly formed molecule is greater than the individual atoms 3. Covalent bonding occurs when the octet rule is satisfied regardless of the potential en- ergy of the shared electrons 4. The potential energy of the shared elec- trons is higher in the bond than it would be if the electrons were not shared between two nuclei
Answer:The potential energy of the shared elec- trons is lower in the bond than it would be if the electrons were not shared between two nuclei
Explanation:
The entire essence of chemical combination is the attainment of a lower potential energy.
When two atoms are isolated at a large distance from each other, the potential energy is high.
However as the nuclei of the two atoms approach each other, the potential energy decreases until a minimum is attained. The distance between the nuclei at this point is the bond distance.
Hence, the potential energy of the shared electrons is lower in the bond than it would be if the electrons were not shared between two nuclei.
30 POINTS HELP Which idea was supported by Aristarchus, Copernicus, and Galileo?
The planets have epicycles.
The planets revolve around the Sun.
The stars rotate around the Sun.
The center of the solar system is Earth.
Answer:
SO SORRY it took so long but the answer is B :)
Explanation:
Trust me and good luck :)
The theory that the planets move around the sun was endorsed by Aristarchus, Copernicus, as well as Galileo. The solar system revolves around the sun.
What is Aristarchus?Aristarchus of Samos was just a Greek astronomer that suggested the very first heliocentric model of the cosmos, wherein the sun, rather than the earth, was even at its center. Despite the fact that his hypothesis was acknowledged by other philosophers of the time, it was dismissed as unrealistic, and the geocentric model remained in use for the next 1,700 years.
What is Copernicus?Copernicus was also the first to assert that the Earth as well as the other planets orbit the sun. It was really a significant shift in thinking.
What is sun?Sun can be considered as a star in solar system.
The theory that the planets move around the sun was endorsed by Aristarchus, Copernicus, as well as Galileo. The solar system revolves around the sun.
Therefore, the correct answer will be option (b).
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How many moles are 3.21×10^28 molecules of N2?
Answer:5 to the 7th power
Explanation:
Divided 7 and y then add 4
Mole measure the number of elementary entities of a given substance that are present in a given sample. Therefore, 5.33×10²⁴moles are in 3.21×10²⁸ molecules of Nitrogen.
What is mole?The SI unit of amount of substance in chemistry is mole. The mole is used to measure the quantity of amount of substance. It measure the number of elementary entities of a given substance that are present in a given sample.
Given number of molecules of nitrogen=3.21×10²⁸ atoms
we know one mole of any element contains 6.022×10²³ atoms which is also called Avogadro number
mole of nitrogen=given number of atoms ÷ 6.022×10²³(Avogadro number)
Substituting the values
moles of nitrogen=3.21×10²⁸ ÷ 6.022×10²³
mole of nitrogen= 5.33×10²⁴moles
Therefore, 5.33×10²⁴moles are in 3.21×10²⁸ molecules of Nitrogen.
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in a pond food chain that includes tadpoles, algae, turtles, dragonflies, and frogs, which one is the primary consumer
Answer:
turtles
Explanation:
Turtles eat frogs and no animal in the pond can consume a turtle
Would you expect oxygen (O) to react more like sulfur (S) or nitrogen (N)? Support your prediction with evidence .
Answer:
Sulfur
Explanation:
Oxygen like sulfur would chemical react and combine with other compounds in the same way. This is because they are both located in the same group on the periodic table.
Elements in the same group have the same chemical properties and they will react the same way.
The general formula of the elements in this group are ns² np⁴.
All the elements in this group have 4 electrons in their np⁴ shell and they belong to the p-block.
Which of the following describes light? (SELECT ALL THAT APPLY.)
A. Light passes through all objects.
B. Light is reflected off the surface of mirrors.
C. Light travels in a straight line.
D. Light waves behave in predictable ways.
Answer:
The light reflects twice before it finally exits the system. Draw a normal at the point of incidence to the first mirror; measure the angle of incidence (45 degrees); then draw a reflected ray at 45 degrees from the normal. Repeat the process for the second mirror.
Explanation:
Hope that helps!
Describe the process of freezing ice cream in terms of heat flow.
Answer:
Freezing the mix is one of the most important operations in making ice cream, for upon it depend the quality, palatability, and yield of the finished product. Typically, freezing of ice cream is accomplished in two steps: (1) dynamic freezing, where the mix is frozen quickly while being agitated to incorporate air and to limit the size of ice crystals formed; and (2) static freezing, where the partially frozen product is hardened without agitation in a special low-temperature environment designed to remove heat rapidly. Although these steps primarily encompass freezing, or the formation of ice crystals, there are several other important processes that take place during this time that significantly impact the quality of ice cream. Both the dispersion of air bubbles and rearrangement of fat globules occur during the freezing steps.
Explanation:
How many electrons would Fluorine have to gain or lose to become stable?
Answer:
is most likely to gain one electron to form an ion with a 1- charge.
Investigate: Press Reset. Start with 2.000 moles of sulfur, then press Start. How many atoms do you think this amount represents
Answer:
1.204428 * 10^24 atoms
Explanation:
Number of moles = 2 mol
Number of atoms = ?
The relationship between moles and atoms is given by the avogadro's umber. This is the number of units in one mole of a substance. The units can be atoms, ions etc In this case it is atoms. The number is equal to 6.02214076 * 10^23
This means;
1 mol = 6.02214076 * 10^23
2 mol = x
Upon solving for x,
x = 2 * 6.02214076 * 10^23
x = 12.04428 * 10^23
x = 1.204428 * 10^24 atoms
Circle the element with the LOWER IONIZATION ENERGY.
11. B or C
12. Ga or B
13. K or Ca
14.P or S
15. Co or Cr
Answer:
Answers with detail given below.
Explanation:
Ionization trend along period:
As we move from left to right across the periodic table the number of valance electrons in an atom increase. The atomic size tend to decrease in same period of periodic table because the electrons are added with in the same shell. When the electron are added, at the same time protons are also added in the nucleus. The positive charge is going to increase and this charge is greater in effect than the charge of electrons. This effect lead to the greater nuclear attraction. As a result of this greater nuclear attraction atomic radius decreases and ionization energy increases.
Ionization trend along group:
As we move down the group atomic radii increased with increase of atomic number. The addition of electron in next level cause the atomic radii to increased. The hold of nucleus on valance shell become weaker because of shielding of electrons thus size of atom increased.
As the size of atom increases the ionization energy from top to bottom also decreases.
Elements with lower ionization energy:
11) B
12) Ga
13) K
14) P
15) Cr
What is the temperature if 2L of 3moles HCl react with 2atm?
Answer:
[tex]T=16K=-256.8\°C[/tex]
Explanation:
Hello!
In this case, according to the gas laws, we would be able to assume HCl can be modeled as an ideal gas for this calculation purpose; in such a way, we use the following equation to compute the temperature:
[tex]PV=nRT\\\\T=\frac{PV}{nR}[/tex]
In such a way, we plug in moles, volume and pressure to obtain:
[tex]T=\frac{2atm*2L}{3mol*0.08206\frac{atm*L}{mol*K}}\\\\T=16K=-256.8\°C[/tex]
Best regards!
A certain ore is 37.3 % nickel by mass. How many kilograms of this ore would you need to dig up to have 65.0 g of nickel
Answer:
0.174kg of Ore are required
Explanation:
The ore of 37.3% in nickel by mass means that in 100g of ore there are 37.3g of nickel. As we need to obtain 65g of nickel we can convert this mass to mass of ore using the conversion factor (100g Ore / 37.3g Nickel) as follows:
65g of nickel * (100g Ore / 37.3g Nickel) = 174g of Ore are needed to have 65.0g of nickel. In kilograms:
174g Ore * (1kg / 1000g) =
0.174kg of Ore are requiredWhat is the molar mass of magnesium sulfate, MgSO4?
Answer:
120.37 g/mol is the molar mass of magnesium sulfate
What element contains 8 valence electrons and tends not to react with other elements?
Answer:
C. Oxygen
Explanation:
Oxygen has 8 electrons and doesn't react with fluorine noble gases
write an equation illustrating the condensation of p-diaminobenzene with the acid chloride of oxalic acid (cocl)2
Answer:
Explanation:
p-diaminobenzene is popularly known as p-phenylenediamine. It undergoes a condensation reaction with metal halides. As a white solid (p-diaminobenzene), it can be darkened by air oxidation. The reaction showing the condensation of p-phenylenediamine with (CoCl)₂ can be seen in the image attached below.
How many protons, neutrons, and electrons does k^1+ have
Answer:
protons 19
nuetorns 20
electrons 19
metling point 63.65 C
Explanation:
How many milliliters of 60% carbonic acid must be mixed with how many milliliters of 15% carbonic acid to make 650 milliliters of a 38% carbonic acid solution
Answer:
348.9 mL of the 60% solution and 251.1 mL of the 15% solution.
Explanation:
First, we calculate how many mililiters of pure carbonic acid are there in 650 mL of a 38% solution:
650 mL * 38/100 = 247 mLThen we can express the sum of both initial solutions as:
1) x * 60/100 + y * 15/100 = 247for the volume of carbonic acid; and
2) x + y = 600 mLFor the volume of the solutions.
We now have a system of two equations and two unknowns (x is the volume of the 60% solution and y is the volume of the 15% solution).
We express x in terms of y in equation 2):
x = 600 - yAnd replace x in equation 1):
(600 - y) * 60/100 + y * 15/100 = 247360 - 0.6y + 0.15y = 247-0.45y = -113y = 251. 1 mLFinally we calculate x using equation 2):
x + 251.1 = 600x = 348.9 mLMatch the word with the definition. Write the correct letter in the space
provided. Reminder
that your answers should be blue.
A. Proton
B. Periodic Table
C. Atom
D. Chemical Symbol
E. Group
F. Atomic Number
G. Atomic Mass
H. Period
1. Electron
J. Neutron
K. Nucleus
1. Average mass of all the isotopes of that element
2. Series of elements arranged in rows on the periodic table
3 Smallest particle that still can be considered an element
4. Subatomic particle with no charge
5. An abbreviation of an element's name, usually one or two letters
6. Subatomic particles with a positive charge
7.
A small region in the center of an atom
8.
Arrangement of elements showing repeating pattern of their
properties
9. Series of elements arranged in columns on the periodic table
10.
Subatomic particles with a negative charge
11.
Number of protons in the nucleus of an atom
Answer:
this may be wrong and if it is im sorry
A=6
B=8
C=3
D=5
E=9
F=11
G=1
H=2
I=10
J=4
K=7
