For the following exothermic reaction, predict under which conditions the reaction will be spontaneous.
2Mg(s) + O2(g) → 2MgO(s)
a. The reaction is always spontaneous.
b. The reaction is spontaneous at high temperatures.
c. The reaction is never spontaneous.
d. Insufficient data is provided to answer this question.
e. The reaction is spontaneous at low temperatures.
Answer:
e. The reaction is spontaneous at low temperatures.
Explanation:
The reaction 2Mg(s) + O2(g) → 2MgO(s) is an exothermic reaction. Let us recall that in an exothermic reaction, heat and light are given out and ΔH is negative (less than zero).
In an exothermic reaction increase in temperature shifts the equilibrium position towards the left and more reactants are produced. However, decrease in temperature shifts the equilibrium position towards the right and more products are obtained.
Also, since the reaction is exothermic, then given that; ΔG = ΔH - TΔS, ΔH is negative for an exothermic reaction and ΔG must be negative for a reaction to be spontaneous. Hence, at low temperature, the value of ΔH - TΔS remains negative (less than zero) hence the reaction is spontaneous.
Hence, Being an exothermic reaction, the process is spontaneous at low temperatures.
What is the coldest element
Answer:
Liquid helium
Explanation:
Liquid helium is known to be the coldest element in the world.
It has a ridiculous boiling point of -452 degrees
It is considered the only element on earth that does not freeze to become solid. normally, it is usually in a form of cryogenic fluid or superfluid.
Hence, the coldest element is known as LIQUID HELIUM
von Answe
2076 Set B Q.No. 23 Are all standard solutions, primary
standard solutions or not? Give reason. 1 g of a divalent metal
was dissolved in 25 mL of 2N H2SO4 (f = 1.01). The excess
acid required 15.1mL of 1N NaOH (f = 0.8) for complete
neutralization. Find the atomic weight of the metal
. [1 +4]
Ans: Atomic weight = 52.05 amu
go5 gram of a divalent metal
Answer:
i have no clue
Explanation:
i have no clue
Which environmental factor might positively impact a plant's traits
Answer:
light, temperature, water, humidity, and nutrition.
Which of the following oxidizing agents is necessary to complete the biochemical reaction below?
aldehyde dehydrogenase
CH3COH + ______ → CH3COOH
a. K2Cr2O7
b. NAD+
c. Cu2+
d. NADH
Answer:
b. NAD+
Explanation:
Aldehydes are oxidized to carboxylic acids in the presence of strong oxidizing agents.
In a biochemical system, the same oxidation reaction occurs by the help of the enzyme alcohol dehydrogenase and NAD+ which is a biological oxidizing agent.
NAD+ is an effective biological oxidizing agent that accepts electrons from molecules and change to its reduced form NADH, which is an effective biological reducing agent that donates electrons. Electron transfer processes are the main functions of NAD+.
_______ is the ability of the body to fight infection via antibodies or specialized cells.
O immunity
O antibiotics
O pathogens
O breathing
Answer:
Immunity
Explanation:
A sample of oxalic acid is titrated with a standardized solution of KMNO4. A 25 mL sample of oxalic acid required 12.7 mL of 0.0206 M KMnO4 to achieve a pink colored solution. The balanced equation for this reaction is shown below:
6 H+ (aq) + 2 MnO4 - (aq) + 5 H2C2O4(aq) → 10 CO2(g) +8 H2O(l) + 2Mn2+(aq)
Required:
a. What does the pink color signify in this reaction?
b. What is the ratio of MnO4 - ions to H2C2O4 molecules in this reaction?
c. How many moles of MnO4 - ions reacted with the given amount of oxalic acid solution?
d. How many moles of H2C2O4 were present?
e. What was the molarity of the oxalic acid solution?
f. If the density of the oxalic acid solution was 1.00 g/mL, what was the percentage by mass of oxalic acid in the solution?
Answer:
Following are the solution to the given points:
Explanation:
Oxalic acid volume [tex]= 25.00 \ mL = 0.0250 \ litres[/tex]
KMnO4 volume [tex]= 12.70 \ ml = 0.0127 \ litres[/tex]
KMnO4 molarity [tex]= 0.0206\ M = 0.0206 \ \frac{mol}{l}[/tex]
In point a:
Its pink presence after full intake of oxalic acid with attachment to KMnO4 is suggested by the end-point of the process due to the small abundance of KMnO4, As just a self predictor, KMnO4 is used.
In point b:
[tex]H_2C_2O_4[/tex] molecules mole ratio to [tex]MnO_4^-[/tex] ions:
The equilibrium for both the oxalic acid and KMnO4 reaction is suggested:
[tex]6H+ (aq) + 2MnO_4- (aq) + 5H_2C_2O_4 (aq) \rightarrow 10CO_2 (g) + 8H_2O (l) + 2Mn_2+ (aq)[/tex]
The reaction of 5 mol of oxalic acid is 2 mol [tex]MnO_4^-[/tex] ions
[tex]H_2C_2O_4[/tex]: molecules mole proportion to [tex]MnO_4^-[/tex] ions:
[tex]5 H_2C_2O_4[/tex]: : [tex]2MnO_4^-[/tex]
In point c:
The Moles of [tex]MnO_4^-[/tex] ions reacted with the [tex]H_2C_2O_4[/tex]:
The molar mass of the solution is the number of solute moles in each volume of water
[tex]Molarity =\frac{moles}{Volume}\\\\Moles \ of\ KMnO_4 = Molarity \times volume[/tex]
Moles with ions reacted to mol with both the amount of : supplied.
In point d:
[tex]H_2C_2O_4[/tex] moles in the sample present:
[tex]H_2C_2O_4[/tex] moles = moles [tex]MnO_4^-[/tex] ions [tex]\times[/tex] mole ratio
[tex]H_2C_2O_4[/tex] moles in the sample = [tex]2.6162 \times 10^{-4}\ mol \times (\frac{5}{2})[/tex]
[tex]H_2C_2O_4[/tex] molecules = [tex]6,5405\times 10^{-4}[/tex] mol are present in the sample
In point e:
Oxalic acid molarity = [tex]\frac{mole}{volume}[/tex]
[tex]=\frac{ 6.54 \times 10^{-4} mol}{0.025\ L} \\\\ = 0.0260 \ M[/tex]
In point f:
Oxalic acid level by mass in the solution:
Oxalic acid mass calculation:
Oxalic acid molar weight = 90.0349 [tex]\frac{g}{mol}[/tex].
Oxalic acid mass per liter = oxalic acid moles per liter [tex]\times[/tex] molar mass
[tex]= 0.0260 \frac{mol}{L} \times 90.0349 \frac{g}{mol}\\\\= 2.3409 \frac{g}{L}\\\\ = 2.3409 \frac{g}{1000 \ mL}\\\\= 0.2409 \frac{g}{100 \ mL}[/tex]
When Oxalic acid solution density[tex]= 1.00 \ \frac{g}{mL}[/tex]
Mass oxalic acid percentage = [tex]0.2409 \%[/tex]
Oxalic acid mass proportion [tex]= 0.24\% \ \frac{W}{v} \ \ Mass[/tex]
Molecular iodine,
I2(g)
dissociates into iodine atoms at 625 K with a first-order rate constant of
0.271s-1
What is the half-life for this reaction?
Answer:
Half-life for this reaction is 2.56s
Explanation:
The general expression in a reaction that follows first-order is:
Ln[A] = -kt + ln[A]₀
Where [A] is concentration of reactant after time t,
k is rate constant = 0.271s⁻¹
[A]₀ is initial concentration of reactant.
Half-life is defined as the time required to decrease the initial concentration of the reactant (I2 in this case) halved.
If [A]₀ = 1
[A] = 1/2
Solving the equation:
Ln[1/2] = -0.271s⁻¹*t + ln[1]
Ln[1/2] = -0.271s⁻¹*t + 0
Ln[1/2] = -0.271s⁻¹t
Ln 2 = 0.271s⁻¹
2.56s = t
Half-life for this reaction is 2.56s
A sample of nitrogen gas is at a pressure of 1.20 atm, a volume of 30.0 liters, and a
temperature of
87.0 OC. How many moles of gas are in the sample? How many grams of gas are in the
sample?
Answer:
1. 1.21mol
2.8.5kg
Explanation:
the number of moles and grams of gas in the sample
Which property is an example of chemical properties?
Answer:
flammability, toxicity, acidity, reactivity , and heat of combustion.
Explanation:
Answer:
Its the banana one
Explanation:
______________________________________________
Answer:
Explanation:k
Answer:
Explanation:
When an atom goes through alpha decay,
a. Only the atomic number changes
b. Only the mass number changes
c. Both the mass and atomic numbers change
d. Neither the mass nor atomic number changes, as only energy is emitted.
3. Which of the following statements is correct?
X Х
1 doubling the pressure of a gas doubles its volume
2. 2.00 L of air at 227°C has twice the pressure of the same 2.00 L of air at -
23°C
3. 2.00 L of air at 100°C has twice the pressure of the same 2.00 L of air at
50°C
4. halving the pressure of a gas halves its volume
Answer:
3. 2.00 L of air at 100°C has twice the pressure of the same 2.00 L of air at 50°C
Explanation:
1) doubling the pressure of a gas doubles its volume
This is incorrect because by increasing the pressure volume is going to be decreased.
2) 2.00 L of air at 227°C has twice the pressure of the same 2.00 L of air at 23°C
This is also incorrect because 2 L air at 227 °C will have the pressure more than twice time as compared to the 2L air at 23°C.
3. 2.00 L of air at 100°C has twice the pressure of the same 2.00 L of air at 50°C
This is correct;
According to Gay-Lussac Law,
The pressure of given amount of a gas is directly proportional to its temperature at constant volume and number of moles.
Mathematical relationship:
P₁/T₁ = P₂/T₂
thus, by increasing the temperature pressure is also goes to increase in the same ratio.
4. halving the pressure of a gas halves its volume
This is incorrect because halving the pressure of gas increasing its volume.
The ______ system produces and stores leukocytes and lymph.
Olymphatic
O reproductive
O nervous
O digestive
Answer:
Lymphatic
Explanation:
[tex]\mathrm{\bold Answer:}[/tex]
[tex]\huge\boxed{\sf The~ lymphatic ~system}[/tex]
[tex]\mathrm{\bold Explanation:}[/tex]
[tex]\underline{\sf The~ primary ~function ~of ~the ~lymphatic ~system ~is ~to ~'transport ~lymph'.}[/tex] [tex]\underline{\sf It~ produces~ and~ releases ~white ~blood ~cells, ~know ~as ~lymphocytes.}[/tex] [tex]\underline{\sf The~ lymphatic ~system ~produces ~and ~stores ~leukocytes ~and ~lymph.}[/tex]
[tex]\bold{\mbox Hope~ this ~helps! :)}[/tex]
11.You and a friend find a rusty wire coat hanger near the
beach. The wire has a much larger diameter than the wire in a new coat
hanger. Your friend says the wider wire disproves the Law of Conservation of
Mass. Explain why he is wrong?
Answer:
because he would've not known properly about it!
water ------- is water--------
Answer:
Water is water.
Explanation:
Water is a colorless and odorless substance found all over Earth. Water is made up of billions of molecules. ... Water on our planet flows as liquid in rivers, streams, and oceans; is solid as ice at the North and South Poles; and is gas (vapor) in the atmosphere. Water is also underground and inside plants and animals
What is the correct answer
Consider the following equilibrium: 2SO^2(g) + O2(9) = 2 SO3^(g)
1. What is equal at equilibrium?
2. What would happen to the forward rate if some 0were removed from this equilibrium?
3. Explain why, in terms of collision theory.
4. Would the reaction still be at equilibrium at this point?
Answer:
At equilibrium, the forward and backward reaction rates are equal.
The forward reaction rate would decrease if [tex]\rm O_2[/tex] is removed from the mixture. The reason is that collisions between [tex]\rm SO_2[/tex] molecules and [tex]\rm O_2\![/tex] molecules would become less frequent.
The reaction would not be at equilibrium for a while after [tex]\rm O_2[/tex] was taken out of the mixture.
Explanation:
EquilibriumNeither the forward reaction nor the backward reaction would stop when this reversible reaction is at an equilibrium. Rather, the rate of these two reactions would become equal.
Whenever the forward reaction adds one mole of [tex]\rm SO_3\, (g)[/tex] to the system, the backward reaction would have broken down the same amount of [tex]\rm SO_3\, (g)\![/tex]. So is the case for [tex]\rm SO_2\, (g)[/tex] and [tex]\rm O_2\, (g)[/tex].
Therefore, the concentration of each species would stay the same. There would be no macroscopic change to the mixture when it is at an an equilibrium.
Collision TheoryIn the collision theory, an elementary reaction between two reactants particles takes place whenever two reactant particles collide with the correct orientation and a sufficient amount of energy.
Assume that [tex]\rm SO_2\, (g)[/tex] and [tex]\rm O_2\, (g)[/tex] molecules are the two particles that collide in the forward reaction. Because the collision has to be sufficiently energetic to yield [tex]\rm SO_3\, (g)[/tex], only a fraction of the reactions will be fruitful.
Assume that [tex]\rm O_2\, (g)[/tex] molecules were taken out while keeping the temperature of the mixture stays unchanged. The likelihood that a collision would be fruitful should stay mostly the same.
Because fewer [tex]\!\rm O_2\, (g)[/tex] molecules would be present in the mixture, there would be fewer collisions (fruitful or not) between [tex]\rm SO_2\, (g)[/tex] and [tex]\rm O_2\, (g)\![/tex] molecules in unit time. Even if the percentage of fruitful collisions stays the same, there would fewer fruitful collisions in unit time. It would thus appear that the forward reaction has become slower.
Equilibrium after ChangeThe backward reaction rate is likely going to stay the same right after [tex]\rm O_2\, (g)[/tex] was taken out of the mixture without changing the temperature or pressure.
The forward and backward reaction rates used to be the same. However, right after the change, the forward reaction would become slower while the backward reaction would proceed at the same rate. Thus, the forward reaction would become slower than the backward reaction in response to the change.
Therefore, this reaction would not be at equilibrium immediately after the change.
As more and more [tex]\rm SO_3\, (g)[/tex] gets converted to [tex]\rm SO_2\, (g)[/tex] and [tex]\rm O_2\, (g)[/tex], the backward reaction would slow down while the forward reaction would pick up speed. The mixture would once again achieve equilibrium when the two reaction rates become equal again.
Classify the changes involved in the following processes as physical or chemical changes:
(a) Photosynthesis
(b) Dissolving sugar in water
(c) Burning of coal
(d) Melting of wax
(e) Beating aluminium to make aluminium foil
(f) Digestion of food
Answer:
a) Photosynthesis - chemical change
b) dissolving sugar in water -physical change
c) burning of coal- chemical change
d) melting of wax- Physcial change
e) beating of aluminum to make Almunium foil-Physical change
f) digestion of food- chemical change
how can we remove the turbidity from water?
Answer:
Settling and decanting is a method to reduce turbidity by letting the water sit for 2-24 hours so that the particulates settle to the bottom of the container. The clear water is then decanted off the top into a second container.
Explanation:
Settling and decanting is a method to reduce turbidity by letting the water sit for 2-24 hours so that the particulates settle to the bottom of the container. The clear water is then decanted off the top into a second container.
Help needed within the next 10 minutes
16.2 g of Water are formed
A scientist added bacteria and a nutrient medium that could support the growth of the bacteria to a sterilized petri dish. No other materials were added. The graph models the growth of the bacteria over time.
Answer:
A scientist added bacteria and a nutrient medium that could support the growth of the bacteria to a sterilized petri dish. No other materials were added. The graph models growth of the bacteria over time. ... The bacteria did not reproduce in the system, and eventually each individual died at the end of its life cycle.
Explanation:
Plz mark brainliest thanks
If you add 0.001 moles of sodium chloride to a liter of water, what will be the pH of the solution?
Answer:
The pH of the resulting solution will be 7.
Explanation:
Sodium chloride is a salt that is formed from the reaction of sodium hydroxide (a strong base) and hydrochloric acid ( a strong acid), as shown below.
[tex]NaOH \ + \ HCl ----> \ NaCl \ + \ H_2O[/tex]
Generally, when strong acids react with strong bases, neutral salts and water are formed. Sodium Chloride (NaCl) is an example of such neutral salts formed.
Since sodium chloride (NaCl) is neutral, its concentration will not alter the pH of the water and the pH of the resulting solution will be 7.
Determine the electron geometry, molecular geometry, and idealized bond angles for each of the following molecules.
a. CF4
b. NF3
c. OF2
d. H2S
Answer:
CF4- electron geometry- tetrahedral
Molecular geometry- tetrahedral
bond angle- 109 degrees
NF3- electron geometry- tetrahedral
Molecular geometry- trigonal planar
bond angle - less than 109 degrees
OF2 - electron geometry- tetrahedral
Molecular geometry- bent
bond angle- less than 109 degrees
H2S- electron geometry- tetrahedral
Molecular geometry- bent
less than 109 degrees
Explanation:
All the compounds mentioned here are based on a tetrahedron according to VSEPR theory. There are four regions of electron density in each molecule.
However, the presence of lone pairs causes a distortion away from the expected tetrahedral geometry predicted by VSEPR theory.
Hence the presence of one or more lone pairs on the valence shell of the central atom causes distortion from the expected geometry.
11. Which is another way of saying the law of conservation of mass?
Matter cannot be created or destroyed.
The mass of the reactants always equals the mass of the products,
the law of conservation of matter
all of the above
Answer:
all of the above
Explanation:
The Law of Conservation of Mass states that matter is neither created nor destroyed. It also states that in a chemical reaction, the total mass of the reactants equals the total mass of the products.
The Law of Conservation of Matter states that matter can change form through physical and chemical changes but matter is conserved. The same amount exists before and after the change. Matter is not created or destroyed.
So the answer will be all of the above.
Hope that helps.
how can you tell when a solid substace dissolves in water and does not react
Answer:
because it starts to fall apart and it eventually just disappears like for example putting a bleach tablet it water it will take day to desolve but it desolves any way though.
The diagram below shows a food web in a woodland.
A food web diagram showing cornstalks with two arrows pointing away from it. One of the arrows points to the letter X and the other arrow points to a grasshopper. There are two arrows pointing away from the grasshopper. One is pointing to a baby sparrow and the other to the letter Y. There is an arrow pointing away from the baby sparrow to a snake and an arrow pointing away from the letter X to the snake.
If a certain organism is a secondary consumer, what best explains its position in the food web? (3 points)
a
X, because organism X feeds on producers
b
Y, because organism Y feeds on producers
c
X, because organism X feeds on a carnivore
d
Y, because organism Y feeds on a herbivore
Explanation:
Options A and B have wrong reasons because to feed on producers means that it is a primary consumer.
Option C is wrong because organism X only feeds on cornstalks.
Organism Y does feed on the grasshopper, which feeds on the cornstalks. It is a secondary consumer.
Hence Option D is correct.
List all the physical properties of the iceberg.
Answer: My answer is in the explanation
Explanation:
Physical and mechanical characteristics of iceberg ice were studied from samples collected near the shores of eastern Newfoundland. Although the physical characteristics show considerable diversity, iceberg ice has some common features and is generally porous, lacks significant concentrations of dissolved materials, contains internal cracks and has an irregular interlocking grain structure.
Li2O + CaF2 --> LiF + CaO
You have 3 moles of Li2O. How many grams of LiF will be produced?
a
8.7 grams
b
156 grams
c
78 grams
d
1.8 x 10^24 grams
Answer:
8.77 grams
Explanation:
Which of the following BEST describes a way in which water moves in the water cycle?
A. Water falls from the sky as rain. It stays where it falls until it evaporates
B. Water falls from the sky as snow. As the snow melts, the water runs up to Earth's mountains.
C. Water falls from the sky as rain. The water then flows downhill
D. Water falls from the sky as hail. The hail is eventually buried in the ground
Answer: Its A or D
wish i had an actual answer sorry..
The correct answer should be A