Answer: 149
Explanation:
Using the ideal gas equation; PV = nRT
P= Pressure = 0.910 atm, T= Temperature = ?
V= Volume = 4.0L R = Gas constant = 0.08206 L.atm/mol/K
n = number of moles = 0.297
Making 'T' the subject of the formular, we have;
T = P V/ n R = 0.910 x 4 / 0.297 x 0.08206
= 149
The conversation of cyclopropane to propene in the gas phase is a first order reaction with a rate constant of 6.7x10-⁴s-¹. a) if the initial concentration of cyclopropane was 0.25M , what is the concentration after 8.8min?b) how long (in min) will it take for the concentration of cyclopropane to decrease from 0.25M to 0.15M?
Answer: a) The concentration after 8.8min is 0.17 M
b) Time taken for the concentration of cyclopropane to decrease from 0.25M to 0.15M is 687 seconds.
Explanation:
Expression for rate law for first order kinetics is given by:
[tex]t=\frac{2.303}{k}\log\frac{a}{a-x}[/tex]
where,
k = rate constant
t = age of sample
a = let initial amount of the reactant
a - x = amount left after decay process
a) concentration after 8.8 min:
[tex]8.8\times 60s=\frac{2.303}{6.7\times 10^{-4}s^{-1}}\log\frac{0.25}{a-x}[/tex]
[tex]\log\frac{0.25}{a-x}=0.15[/tex]
[tex]\frac{0.25}{a-x}=1.41[/tex]
[tex](a-x)=0.17M[/tex]
b) for concentration to decrease from 0.25M to 0.15M
[tex]t=\frac{2.303}{6.7\times 10^{-4}s^{-1}}\log\frac{0.25}{0.15}\\\\t=\frac{2.303}{6.7\times 10^{-4}s^{-1}}\times 0.20[/tex]
[tex]t=687s[/tex]
b. How could recycling electronics prevent some of the negative effects of
mining metals? (2 points)
Answer:
It will reduce the quantity of metals extracted for use in the manufacturing of electronics
Explanation:
The manufacturing of electronics is a huge market for the metal extraction industry. Many electronics have metal casing, metal circuit boards etc. This implies that a large quantity of metal is required for the production of electronics. This leads to consistent mining activities in order to supply enough quantity of metal to produce more electronics.
However, if electronics are recycled, less metals are extracted for the electronics industry. This saves energy required for mining operations and minimizes the deleterious environmental impact associated with metal mining from the earth. These deleterious consequences include; erosion, sinkholes, loss of biodiversity, contamination of soil, groundwater, and surface water by the chemicals emitted from mining processes.
Hence, recycling of electronics saves the environment from the degradation caused by consistent mining activities. Reduction of mining activities by recycling ought to be an important goal of the electronics manufacturing industry.
4. If 175 undecayed nuclei remain from a sample of 2800 nuclei, how many half-
lives have passed? (Show your work.) *
Your answer
Answer:
X = 4
Explanation:
Start 2800
End 175
175 = 2800x(0.5)^X
175/2800 = 0.5^X
0.0625 = 0.5^X
log(0.5 x) = log(0.0625)
x · log(0.5) = log(0.0625)
-0.301x = -1.204
x = -1.204/-0.301
x = 4
Balance the following chemical
equation by providing the correct
coefficients.
_FeBr3 +_Na2S -> _Fe2S3 + _NaBr
Answer:
2FeBr3 + 3Na2S ➡️ Fe2S3 + 6NaBr
The type of energy transferred by a wave in a medium is kinetic energy.
Answer:
The statement is true.
Explanation:
The different means by which the energy is transferred is commonly termed to be 'wave'.
Wave refers to the disturbance transmission from a specific point to another. Different sources are involved in this transmission. The vibration of particles helps in the flow of energy from one medium to another. Vibration leads to the formation of kinetic energy flowing from one medium to another.
Which of these is an example of interactions between the atmosphere and hydrosphere? (3 points) formation of snow cracking of rocks due to heat destruction of houses by wind uprooting of trees during tornadoes
Answer:
A. formation of snow
Explanation:
The formation of snow is an example of interactions between the atmosphere and hydrosphere.
As snow formation takes place when water vapor converted into liquid through condensation in the clouds. As water droplets rises high in clouds, cooler air present in atmosphere allow to lower the temperature and water droplets form ice or snow.
Hence, the correct option is A.
Answer:
A:formation of snow
Explanation:
An electron is in a region outside the nucleus. An electron
a) Is larger than a proton and has no charge
b) Has less mass than a proton and has a negative charge
c) Is smaller than a proton and has no charge
d) Has a positive charge
Answer:
b
Explanation:
electrons lie in the orbits of the atom. they are negatively charged and they are very small in size. they have very less mass than proton. ele tron has 1/1840 mass of proton.
Heptane, pentane and octane are accidentally mixed. They all have different boiling points. Pentane boils at 360 ° C, hexane boils at 690 ° C and octane boils at 12 ° C. What method would you use to separate these liquids? Explain how the method works.
Answer:
Fractional distillation
Explanation:
Heat the mixture upto 700°C
The compuond with low boiling point will evaporate first and the compound with higher boiling point will evaporate last.
What are some lessons from
past epidemics that we can
apply to our current coronavirus pandemic?
Answer:
The 1918 influenza pandemic and 2002-2003 SARS outbreak suggests social distancing measures, communication, and international cooperation are the most effective methods to slow down the coronavirus.
Explanation:
How is the human hand different from the ape hand
Answer:
in explanation
Explanation:
Human hands are distinguished from apes by possessing longer thumbs relative to fingers.
Hope this helps!!!
Answer:
The human hand and primate hand both have finger prints and palm prints, or palmar whorls, but the prints differ. Human fingerprints have a higher ride density than primate fingerprints, which means the print ridges, or lines, are closer together. While the human’s prints are denser, primates usually have more lines overall.
Explanation:
I've learned this before
what are two factors about particles that enable them to form solutions (SCIENCE)
Answer:
temperature and whether or not they are polar or non-polar.
How many atoms in 8.9 moles of iron
Answer:
5.3578e+24
Explanation:
1 mole = 6.02 x 10^23
6.02 x 10^23 x 8.9 =
5.3578e+24
review the types of elements that create ionic bonds as
well as the types of elements that create covalent bonds.
• N2 • CCl4 • SiO2
• AlCl3 • CaCl2 • LiBr
Answer:
N2 Covalent
CCl4 Covalent
SiO2 Covalent
AlCl3 Covalent
CaCl2 Ionic
LiBr Covalent
Explanation:
With covalent bonds, there is a sharing of electron pairs between the atoms.
With ionic bonds, there is complete transfer of valence electrons between atoms. Formed by the interaction of a metal with a non-metal.
Where:
Electrons aren't transferred in covalent bonds.
Protons aren't transferred in covalent bonds
Protons aren't shared in covalent bonds
N3-
C4+
Cl-
Si4+ = Metal
O2- = Non-metal
Al3+ = Metal
Li+ = Metal
Ca2+ = Metal
Br 1-, 1+, 5+ = Halogen
N2 = N3- and N3- Covalent
CCl4 = C4+ and Cl- x4 Covalent
SiO2 = Si4+ and O2- x 2 Metal with non metal Covalent
AlCl3 = Al3+ and Cl- x 3 Covalent Though this one is complex as to why because it seems like it should be ionic
CaCl2 = Ca2+ and Cl- x 2 Metal with non-metal Ionic
LiBr = Li+ and Br- Covalent as neither is a non-metal
When 100 g of 20°C water is mixed with 50 g of 50°C water in a closed system, what is the final water
temperature?
A 20°C
B) 30°C
C) 35°C
D50°C
The final temperature of a mixture of 100g of water at 20°C and 50g of water at 50°C is 30°C.
What is the principle of method of mixtures ?
The amount of heat lost by the hotter sample = The amount of heat gained by the cooler water sample
The amount of heat gained by the cooler water sample is: -
Q1₁= m₁c(T – T₁)
The amount of heat lost by the hotter water sample is: -
Q₂ = m₂c(T₂ - T)
Q₁ = Q₂
m₁c(T – T₁) = m₂c(T₂ - T)
T = (m₁T₁ + m₂T₂)/(m₁+ m₂)
Let the final temperature of the mixture of 100g of water at 20°C and 50g of water at 50°C be T.
m₁ = 100g
T₁ = 20°C
m₂ = 50g
T₂ = 50°C
The final temperature of water = (100*20+50*50)/(100+50)
= (2000+2500)/(150)
=4500/150
=30°C
Therefore , the final temperature of a mixture of 100g of water at 20°C and 50g of water at 50°C is 30°C.
To know more about method of mixtures
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I know the correct answer is either a or d. Can anyone explain which one it is and why? CH3C ≡ CCH2CH2Cl is named: a. 1-chloro-3-pentyne b. 5-chloro-2-pentene c. 1-acetylenyl-3-chloropropane d. 5-chloro-2-pentyne
Answer:
D.
Explanation:
CH₃C≡ CCH₂CH₂Cl
Since there are 5 carbons so the suffix used is "pent"
There is a triple bond so its alkyne
So the compound becomes 2-pentyne (2 because the triple bond is with the 2nd carbon)
Then,
The functional group of chlorine is attached with 5th carbon So the compound becomes
5-chloro,2-pentyne
Plz help me with this question
How does a salt bridge improve a battery
The role of the salt bridge is to assure the neutrality of both compartments.
10.Conduction is the method of heat transfer in solids but not liquids and gases. Why?
(1 Point)
Finiter your
Answer:
Conduction only happens when the object is a solid, because conduction happens in objects that are closely, with molecules that are closely packed together, and have a definite shape. Since, in liquids and gases, the shape is not definite nor do they have closely packed molecules., conduction does not take place in them
The table below shows two conclusions about atoms based on experiments by Rutherford and Thompson. Which of these statements best explains why Rutherford and Thompson visualized the atom differently? Atoms of different elements contain different particles. New experimental processes provide new scientific evidence. A single model of an atom cannot be agreed upon by all scientists. Scientists believe in proposing theories which contradict current theories.
Answer:
Scientists with varied experimental processes and interests perceive things differently.
Explanation:
Scientists believe in proposing theories which contradict current theories. So the correct option is D.
What are the atomic models?
Recently, the structure of atoms has been discovered. Before the ideal model of an atom was found, several others were proposed and abandoned.
Atomic Model of J.J. Thomson
In his hypothesis, Thomson compared the definition of an atom to that of a Christmas pudding.He claimed that atoms are made up of a positively charged sphere with embedded electrons.Additionally, he claimed that because the magnitudes of positive and negative charges are equal, an atom as a whole is electrically neutral.
Atomic Model of Rutherford
Rutherford experimented with α-particle scattering on a gold sheet.He noticed that the majority of the negative ions did not deflect when they travelled through the gold foil.Small angles were experienced by certain α-particles, whereas almost 180° was experienced by others.This experiment led Rutherford to the conclusion that an atom's nucleus, a positively charged spherical centre with a radius of 10-10 metres, contains almost all of the atom's mass (having a radius of 10–15 m).
Therefore the correct option is D.
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What happens to mass in an isolated system?
Answer:
In isolated sysrem mass remains constant.
Explanation:
Answer:
Yes is remains constant
Explanation:
Isolated systems can't make energy or matters come in or out, so the mass stays the same.
Think of it as a marble in a balloon once you tie it and shake the marble in the balloon, there is no extra marbles coming in nor is the marble out of the balloon so that mass(weight is the same.
1.
A car tire was inflated to 75 kPa at the repair shop where the
temperature is 15 °C. What is the pressure of the tire on the trip home
if the temperature of the road surface is 32 °C? (Write your answer
nearest whole number)
kPa
Answer:
THE PRESSURE OF THE TIRE ON THE TRIP HOME AT THE ROAD SURFACE TEMPERATURE OF 32°C IS 160 kPa.
Explanation:
Initial Pressure = 75 kPa
Initial temperature = 15 °C
Final temperature = 32 °C
Final pressure = unknown
Using the combined equation of gases;
P1V1/T1 = P2V2/ T2
Since the tire will have the same volume of air in it showing that volume of constant both at the repair shop and on the road surface.
The relationship between pressure and temperature is used with constant volume.
P1/T1 = P2/ T2
75 kPa / 15 °C = P2 / 32 °C
P2 = 75 kPa * 32 °C / 15 °C
P2 = 2400 kPa °C / 15 °C
P2 = 160 kPa.
So therefore, the pressure of the tire on the trip home when the temperature of the road surface is 32°C is 160 kPa.
mixture of 75 cm3of oxygen and 12.5 cm3 of a gaseous hydrocarbon H were exploded in an eudiometer. After cooling to room temperature, 50 cm3 of gas was left and when this was shaken with KOH solution, 12.5 cm3 of oxygen remained. Given that all the volumes were measured at same temperature and pressure, calculate the molar mass of the hydrocarbon H.
Answer:
molar mass of C₃H ₈ = 44 g/mole
Explanation:
Computation of the amount of oxygen that reacts .
⇒ 75 - 12.5
⇒ 62.5 cm³
Computation of proportion of hydrocarbons
2 mole hydrocarbons 3n+1 oxygen
⇒ 3 n + 1 = [62.5 × 2] / 12.5
⇒ 3 n + 1 = 10
⇒ n = 3
So,
Formula of the hydrocarbon is C₃H ₈
Computation of molar mass of C₃H ₈
⇒ [12×3] + [1×8]
⇒ 44 g/mole
why is the renewable energy resource you chose is negative?
Answer:
There’s a high need for energy storage and are very expensive. Renewable energy is also not always available because some need sun while others need wind.
Explanation:
How are molecules and ionic compounds
the same?
A substance that is made up of more than one atom is called _____.
Answer:
It is called a compound.
Explanation:
Will a battery with magnesium (Mg) as the anode and aluminum (Al) work to power a flashlight? Why or why not?
Answer:
Yes because magnesium has a more negative reduction potential than aluminum.
Explanation:
The single factor that will determine whether a battery with magnesium as anode and aluminium as cathode will work or not is the respective electrode potentials of the two elements.
Recall that in a battery, oxidation occur at the anode and reduction occurs that the cathode. The reduction potential shows the ease with which a metal is reduced or oxidized. The substance with the most negative reduction potential will function as the anode while the substance with the less negative electrode potential will function as the anode.
The reduction potential of Magnesium is -2.37 V while that of aluminum is -1.66 V. This implies that magnesium must function as the anode and aluminum as the cathode in order to have a spontaneous electrochemical process in the cell.
Rice has a bulk density of 0.9 g/mL, but an individual grain of rice has a
density of 1.1 g/mL. Water has a density of 1.0 g/mL. What would happen to
a cup of rice when poured into a pot of water?
Answer:
Individual grain of rice will sink.
Explanation:
Given:
Rice bulk density = 0.9 g/ml,
Individual grain of rice density = 1.1 g/ml
Water density = 1.0 g/ml
Find:
What happens with a cup of rice when poured into water =?
Explanation:
Each piece of grains of rice will sink into the water because individual grains of rice has a higher density than water.
0.5 g of salt is dissolved in 25 g of water. Calculate the percentage amount of salt in the solution.
Guys, please help me and tell me how you found the answer!
If a gas has a pressure of 1.69 atm at a temperature of 300 K, what will the pressure change to if the container is cooled to 100 K?
Also
If a gas has a pressure of 715 mm Hg at the temperature of 500 K, what will the pressure change to if the container is heated to 900 K?
Answer:
The First one is: 0.563atm
The second one is: 1.692atm
Hope this helps!
Explanation: Look at Photo Attached
The pressure has been reduced with the cooling of the container, and the change in pressure has been 1.06 atm. The pressure has been increased with the heating of the container and the change in pressure has been 572 mm Hg.
Assuming the gas has been following the ideal behavior. According to the ideal gas equation,
PV =nRT
If the same gas has been heated, the n and R will be constant, as well as with the constant volume of initial and final pressure, the relationship to the P and T can be given as:
[tex]\rm \dfrac{Initial\;pressure}{Initial\;temperature}\;=\;\dfrac{Final\;pressure}{Final\;temperature}[/tex]
(a) For the gas with an initial pressure of 1.69 atm, the final pressure will be:
[tex]\rm \dfrac{1.69}{300}\;=\;\dfrac{Final\;Pressure}{100}[/tex]
Final pressure = 0.563 atm.
The change in pressure = Initial pressure - Final pressure
The change in pressure = 1.63 - 0.563 atm
The change in pressure = 1.06 atm.
The pressure has been reduced with the cooling of the container, and the change in pressure has been 1.06 atm.
(b) For the gas at initial pressure 715 mm Hg, the final pressure will be:
[tex]\rm \dfrac{715}{500}\;=\;\dfrac{Final\;Pressure}{900}[/tex]
Final pressure = 1,287 mm Hg.
The change in pressure = Final pressure - Initial pressure
The change in pressure = 1,287 - 715 mm Hg
The change in pressure = 572 mm Hg
The pressure has been increased with the heating of the container and the change in pressure has been 572 mm Hg.
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I AM GIVING BRAINLIEST! PLEASEEEEEEEEEEE HELPPPPP I NEEED HELPPPP PLEASEEEE
Find the molecular formula for a compound with-
4.04 g N, 11.46 g O, molar mass 108.0 g/mol.
? moles N =
? moles O =
N : O =
empirical formula =
molecular mass of empirical formula =
The molar mass ratio of (molecular formula/empirical formula) =
molecular formula =
Answer:
moles of N
4.04 g / 14.01 = 0.288
moles of O
11.46 / 16 = 0.72 moles
divide both of them by the lowest number of moles to get the ratio
0.288 / 0.288= 1
0.72 / 0.288 = 2.48
now multiply both by 2, to make it a whole number =
ratio = 2 : 5
empirical formula = N2O5
the molar mass of the compound = 108.01
molar mass of the empirical formula = 108.02
when you divide this to get the factor the factor is also 1, so you dont really change anything
FORMULA = N2O5
Explanation:
I had it written done from my school notes
I really hope this helps
