Answer:
anthropogenic sources like landfills, agricultural activities,coal mining and combustion and some sources are natural ones
calculate the gravitional force in between two object of mass 25kg and 20kg if distance between them is 5m?
Answer:
Explanation:The equation for this is F = -GmM/R^2 where the minus sign says the force is attractive m is 10 kg, M is 20 kg and R is 5 meters. If you crunch the numbers you get an answer of:
How many mm of 0.200 M FeCl3 are needed to react with an excess of K2S to produce 2.75 g of Fe2S3 if the percent yield for the reaction is 65.0%?
Answer:
130 mL
Explanation:
2FeCl3(aq) + 3K2S(aq) -----> Fe2S3(s) + 6KCl(aq)
Percent yield = actual yield/theoretical yield × 100
actual yield = 2.75 g
Theoretical yield = x
65= 2.75/x × 100
x= 2.75 × 100/65
x= 4.2 g
Number of moles of FeCl3 = mass/molar mass = 4.2 g/ 162.2 g/mol = 0.026 moles
Then;
n= CV
n= number of moles
C= concentration
V= volume
V= n/C
V= 0.026 moles/ 0.200 M
V= 0.13 L or 130 mL
1) The percentage of oxygen in dry air is _______
A. 0.1
B. 1.0
C. 21
D. 79
2) The composition of the Earth’s earliest atmosphere was different to that of the present atmosphere. Which of these gases was present in large amounts in the Earth’s earliest atmosphere?
A. Oxygen
B. Carbon dioxide
C. Ammonia
D. Nitrogen
Answer:
1) The percentage of oxygen in dry air is _______
C. 21
2) The composition of the Earth’s earliest atmosphere was different to that of the present atmosphere. Which of these gases was present in large amounts in the Earth’s earliest atmosphere?
B. CARBON DIOXIDE
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Answer: The percentage of oxygen in dry air is . 21
Explanation: Ammonia gases was present in large amounts in the easth7s earliest atmosphere
Hope it will help you
explain with example the need of standard measurement system
Answer:
A standard system of measurement is very important because it helps us from making mistakes at the moment of doing calculations and correctly working...
Answer:
A standard measurement system is important because it allows scientists to compare data and communicate with each other about their results. Metric System – is a measurement system based on the number 10.
If an atom has 32 protons in the nucleus, how many electrons will it have orbiting the nucleus
An atom is neutral as it has the same number of electrons that of protons. So, if an atom has 32 protons i.e. the atomic number of it is 32, then it will have 32 electrons revolving the nucleus.
Complete the following blanks on the basis of law of conservation of mass.
1) Na + O2 -----> 2NaO
8 g + 65 g ---> ______
2) 2H2 + O2 → 2H2O
24 g + ____ → 62 g
8g + 65g = 73g
24g + 38g = 62g
Answer:
1)Na + O2 = > 2NaO
8 g + 65 g = > 73g
2) 2H2 + O2 → 2H2O
24 g + 38g→ 62 g
If aluminum is placed in an aqueous solution of silver nitrate and a single replacement reaction happens, what would be the balanced equation to represent the reaction?
Answer:
The balanced equation would be:
3AgNO3+Al→3Ag+Al(NO3)3
Explanation:
If hydrofluoric acid is a stronger acid than acetic acid, which statement is most likely true?
The conjugate acid of hydrofluoric acid is weaker than that of acetic acid.
The conjugate acid of hydrofluoric acid is stronger than that of acetic acid.
The conjugate base of hydrofluoric acid is weaker than that of acetic acid.
The conjugate base of hydrofluoric acid is stronger than that of acetic acid.
Answer: The statement conjugate base of hydrofluoric acid is weaker than that of acetic acid is most likely true.
Explanation:
A strong acid upon dissociation gives a weak conjugate base. This can also be said as stronger is the acid, weaker will be its conjugate base or vice-versa.
Hydrofluoric acid is a strong base as it dissociates completely when dissolved in water.
For example, [tex]HF \rightleftharpoons H^{+} + F^{-}[/tex]
The conjugate base is [tex]F^{-}[/tex] which is a weak base.
Acetic acid is a weak acid as it dissociates partially when dissolved in water. So, the conjugate base of acetic acid is a strong base.
[tex]CH_{3}COOH \rightarrow CH_{3}COO^{-} + H^{+}[/tex]
Thus, we can conclude that the statement conjugate base of hydrofluoric acid is weaker than that of acetic acid is most likely true.
Select from below all elements that follow the DUET rule (not the octet rule). (you can select multiple)
a) Li
b) Mg
c) O
d)He
e) H
f) Ne
True or false The atomic number of an element is always more than the mass number of that element.
Cuál o cuáles de las siguientes características son correctas para la mayoría de los compuestos del carbono?
I) Los compuestos del carbono son solubles en disolventes no polares como el hexano, benceno, éter, etc.
II) Los compuestos del carbono generalmente presentan puntos de fusión y de ebullición bajos
III) La gran mayoría de los compuestos del carbono son combustibles, sean estos, gaseosos, líquidos o sólidos
IV) El enlace covalente es característico de los compuestos del carbono
Todas son correctas
II
I y IV
I, III y IV
Answer:
Todas son correctas
Explanation:
I) Los compuestos del carbono son solubles en disolventes no polares como el hexano, benceno, éter, etc. VERDADERO. La mayoría de los compuestos de carbono son apolares, y basados en la regla: Similar disuelve similar, podemos presumir que la mayoría de compuestos de carbono se disuelven en solventes no polares.
II) Los compuestos del carbono generalmente presentan puntos de fusión y de ebullición bajos. VERDADERO. Al ser sustancias apolares, sus fuerzas electrostáticas son bajas. De la misma manera, como su masa atómica es pequeña, las fuerzas de Van der Waals son despreciables haciendo que sus puntos de fusión y ebullición sean bajos respecto a sustancias de estrucutra similar.
III) La gran mayoría de los compuestos del carbono son combustibles, sean estos, gaseosos, líquidos o sólidos. VERDADERO. Los gases (Como el gas natural) son combustibles usados para cocina. Los líquidos (Como la gasolina) son combustibles y bastante inflamables. Los sólidos (Como la madera) se usan como combustibles para hacer asados o son el combustible en incendios forestales.
IV) El enlace covalente es característico de los compuestos del carbono. VERDADERO. La polaridad del carbono es neutral haciendo que la mayoría de los enlaces que forma sean covalentes.
Todas son correctas
If you refuse a legal chemical test issued by a law enforcement officer, the Division of Motor Vehicles is required to:
Answer: Revoke the driver's license for at least 12 months
Explanation:
Chemical tests are used in order to measure the amount of drugs or alcohol that is in the body of a person when the person was arrested. To do this, samples of the urine or blood of the person can be taken and the result will be used to know if the person was driving under the influence of alcohol or not.
If the person refuse a legal chemical test issued by a law enforcement officer, the Division of Motor Vehicles is required to revoke the the driver's license of the person for at least 12 months.
How many oxygen (O) atoms would a carbon (C) atom need to bond with to form a stable compound?
A.3
B.4
C.1
D.2
Which of the following elements is the largest in size?
A) O
B) He
C) K
ODH
Answer:
C) K
Explanation:
K has an electron configuration of 2.8.8.1
HELP PLSSS WOOT WOOT
Calculate the average atomic mass for element X
Answer:
51.6058
Explanation:
The percentage of abundance is changed to decimal by dividing 100
Metals like potassium and sodium are kept in paroffin oil. Why?
Answer:
because they are high reactive to the air thats why we keep them in paroffin oil
The bottle slides down the hill and is moving at a velocity of 14 meters/second the instant it hits the ground. The vertical height from where Jeff dropped the bottle is meters. Ignore friction, and use , PE = m × g × h, and g = 9.8 m/s2.
Answer:
10 m
Explanation:
From the question given above, the following data were obtained:
Velocity (v) = 14 m/s
Acceleration due to gravity (g) = 9.8 m/s²
Height (h) =?
Next, we shall determine the energy. This can be obtained as follow:
Velocity (v) = 14 m/s
Kinetic Energy (KE) =?
KE = ½mv²
KE = ½ × m × 14²
KE = ½ × m × 196
KE = m × 98
Finally, we shall determine the height. This can be obtained as follow:
Kinetic energy (KE) = m × 98
Acceleration due to gravity (g) = 9.8 m/s²
Height (h) =?
Since the object is falling from a particular height,
Potential energy (PE) = kinetic energy (KE)
PE = mgh
KE = m × 98
m × 9.8 × h = m × 98
Divide both side by m × 9.8
h = m × 98 / m × 9.8
h = 10 m
Thus, the bottle was dropped from a height of 10 m
ASAP PLEASE ITS FOR MY FINAL!!!!
How would you go about calculating the molarity of the following solution: 19.5 grams of Be(OH)2 is dissolved in enough water to make a 1.5 L solution.
Answer:
0.302M
Explanation:
Molarity, which is the molar concentration of a solution can be calculated as follows:
Molarity = number of moles (n) ÷ volume (V)
According to this question, 19.5 grams of Be(OH)2 is dissolved in enough water to make a 1.5 L solution.
Using mole = mass/molar mass to calculate the number of moles in 19.5g of Be(OH)2
Molar mass of Be(OH)2 = 9 + (16 + 1)2
= 9 + (17)2
= 9 + 34
= 43g/mol
mole = 19.5/43
mole = 0.453moles
Molarity = n/V
Molarity = 0.453/1.5
Molarity = 0.302M
Explain specifically how an electron gives off light in an atom.
Answer:
Then, at some point, these higher energy electrons give up their "extra" energy in the form of a photon of light, and fall back down to their original energy level.
Explanation:
When properly stimulated, electrons in these materials move from a lower level of energy up to a higher level of energy and occupy a different orbital.
The formal charge and P-O bond order in PO43- respectively are 0.6, -0.75 -0.75, 1.25 1.0, -0.75 1.25, -3 98.
Answer:
-0.75 , 1.25
Explanation:
Number of electrons present in valence shell,
P-O = 5 + 8 = 13
Number of electrons involved in bond formation,
13 - 3 = 10
Number of bonds in PO3 - 4ion = 102
Average P-O bond = 1.25
Average formal charge on Oxygen atom is -0.75
One way of purifying gaseous H2 is to pass it under high pressure through the holes of a metal's crystal structure. Palladium, which adopts a cubic closest packed structure, absorbs more H2 than any other element and is one of the metals currently used for this purpose. Although the metal-hydrogen interaction is unclear, it is estimated that the density of absorbed H2 approaches that of liquid hydrogen (70.8 g/L). What volume (in L) of gaseous H2, measured at STP, can be packed into the spaces of 1 dm3 of palladium metal
Answer:
[tex]V=795.26L[/tex]
Explanation:
From the question we are told that:
Volume [tex]V=1dm^3=>1L[/tex]
Density [tex]\rho=70.8g/L[/tex]
Generally the equation for Density is mathematically given by
[tex]\rho =\frac{Mass}{Volume}[/tex]
Therefore
[tex]M=\rho*V[/tex]
[tex]M=70.8*1[/tex]
[tex]M=70.8g[/tex]
Since at STP
[tex]T=273K[/tex]
[tex]P=1atm[/tex]
[tex]Mass =70.8g[/tex]
Therefore
[tex]Moles\ of\ Hydrogen=\frac{Mass}{2g}[/tex]
[tex]Moles\ of\ Hydrogen=\frac{70.8}{2g}[/tex]
[tex]Moles\ of\ Hydrogen=35.4moles[/tex]
Generally the equation for Ideal gas is mathematically given by
[tex]PV=nRT[/tex]
Therefore
[tex]V=\frac{nRT}{P}[/tex]
[tex]V=\frac{35.4*0.0826*273}{1}[/tex]
[tex]V=795.3L[/tex]
what are the six chemicals in production of liquid soaps
1. Sodium triphosphate ·
2. Sodium hydroxide ·
3. potassium hydroxide
4. Sodium Lauryl Sulfate · 5.Hydroxyethylcellulose ·
6. Sodium carbonate
equator runs east and west all the way around the world,halfway between the south poles called the ______________and north poles called________________.
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Answer:
hanigin ng mga pule natin
A typical scuba tank has a volume of 11 liters and can support a diver for one hour. An adult breathes about 3 liters of air with each breath.
How can an 11-liter tank give a diver enough oxygen for one hour?
Answer:
The correct answer is - at high pressure a huge amount of gases can be stored in less volume.
Explanation:
We already know that pressure is inversely proportional to the volume of gas which means if we increase the pressure the volume of gas becomes less.
P = 1/V
So in the scuba divers tank, the oxygen is filled at very high pressure so the high amount of the oxygen can be filled in less volume and which will last for longer than a normal pressure tank can last.
Which redox reaction would most likely occur if silver and zinc metal were added to a solution that contained silver and zinc ions?
Answer:
D. Zn²⁺ + 2Ag → Zn + 2Ag⁺
Explanation:
On the reduction potential chart, we have that silver ion Ag⁺ is a stronger oxidizing agent than, zinc, Zn, which is a reducing reducing agent the compared to silver
Therefore, the redox reaction that will occur is that the zinc, Zn, will be oxidized to Zn²⁺ ion, while the silver, Ag²⁺ ion will be reduced to silver deposits Ag, therefore, the zinc will displace the silver in the solution containing silver and zinc ions because zinc is higher than silver in the reactivity series
The reduction potential Zn → Zn²⁺ + 2e⁻ = +0.76
The reduction potential for Ag⁺ + e⁻ → Ag = +0.8
Therefore, given that redox reactions are reversible, we get the following likely redux reaction;
Zn(s) + 2Ag⁺(aq) ⇄ 2Ag(s) + Zn²⁺(aq)
Therefore, from the given options;
Zn²⁺(aq) + 2Ag(s) → Zn(s) + 2Ag⁺(aq) is the reaction most likely to occur.
Can Someone Help Me Plz :)
Answer:
ΔH = -746.6kJ
Explanation:
Using Hess's law we can find the ΔH of a reaction from the sum of similar reactions. From the reactions:
1. 2CO(g) + O2(g) → 2CO2 ΔH = -566.0kJ
2. N2(g) + O2(g) → 2NO(g) ΔH = 180.6kJ
The negative reaction of 2:
-2. 2NO(g) → N2(g) + O2(g) ΔH = -180.6kJ
The sum of 1 - 2:
2CO(g) + O2(g) + 2NO(g) → 2CO2 N2(g) + O2(g) ΔH = -566.0kJ + (-180.6kJ) =
ΔH = -746.6kJ
Subtracting the molecules that don't change:
2CO(g) + 2NO(g) → 2CO2 + N2(g) ΔH = -746.6kJ
At standard conditions, 1000 grams of carbon dioxide is how many liters?
Answer: 4.93
Explanation:
Why Should a magnesium ribbon be cleaned before burning ?
A magnesium ribbon is cleaned to remove the protective layer of basic magnesium carbonate from its surface, so that it may readily combine with the oxygen in air (on heating).
Answer:
Magnesium gets covered with a layer of magnesium oxide when kept in air for a long time. This layer hinders the burning of magnesium. Hence, it is to be cleaned before burning.
The southernmost point of india is _____
(a) indra point
( b) Gulf
( c) Amaravati
(d) jarawas
Answer:
(a) indra pointExplanation:
Indira point is the southern most point of India and is situated on great nicobar island in the nicobar island.
Answer:
Your Ans Is
(A) Indra point.