Answer: 8.1 days
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 = x
a - x = amount left after decay process= [tex]\frac{x}{4}[/tex]
a) to find rate constant
Half life is the amount of time taken by a radioactive material to decay to half of its original value.
[tex]t_{\frac{1}{2}}=\frac{0.693}{k}[/tex]
[tex]k=\frac{0.693}{2.7days}=0.257days^{-1}[/tex]
b) for completion of one fourth of reaction
[tex]t=\frac{2.303}{k}\log\frac{x}{\frac{x}{4}}[/tex]
[tex]t=\frac{2.303}{0.257}\log{4}[/tex]
[tex]t=8.1days[/tex]
Thus after 8.1 days , one fourth of original amount will remain.
Which of the following is the correct definition of conduction?
A.
the transmission of heat across empty space
B.
the electromagnetic radiation from the surface of an object which is due to the object's temperature
C.
the transfer of heat by currents within a liquid or gas
D.
the transmission of heat across matter
Answer:
the transmission of heat across matter
Explanation:
Conduction is the transmission of heat across matter. Even though heat flows across matter during conduction, the matter itself does not flow.
Unlike bacteria, an animal cell contains
Answer:
Membrane
Explanation:
Unlike a bacteria , an animal cell contains membrane which bounds organelles.
Calculate the molarity of a nitric acid solution if 38 ml of the solution is neutralized by 16 ml of 0.25 M barium hydroxide solution. The balanced equation for the reaction is
Answer:
l
Explanation:
What is the value for AG at 500 Kif AH = 27 kJ/mol and AS = 0.09 kJ/(mol-K)?
Answer: -18
Explanation:
Facts
What is the value for ΔG at 500 K if ΔH= 27 kJ/mol and ΔS = 0.09 kJ/(mol⋅K)?
Explanation: ΔG= -18 kJ/mol
In order to control pollution, you should reduce the need for _____________ goods and transportation.
Answer:manufacture
Explanation:
The pollution can be controlled with the help of reducing the need for the manufactured good and transportation.
What is pollution?A pollution can be given as the presence of the harmful substances in the environment. The harmful substances known as pollutants deteriorate the quality of the environment and effect the health of living organism as well.
The pollution in air has been contributed with the increased need of the manufactured goods and transportation, and thereby the reduction will be found to reduce the pollution too.
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Will a reaction occur in KCl +Br2= KBr + Cl2
does temperature and pressure affect the solubilty of any solute
Answer:
Yes very much so, especially gases
Explanation:
Solubility of gases decrease with increasing pressure. Be familiar with Henry's Law.
- Hope that helps! Please let me know if you need further explanation.
Answer:
Yes, it does.
Coal contains carbon and other elements. Carbon dioxide forms when coal burns in the presence of oxygen. Which of these is the best evidence that a chemical reaction occurs when coal burns? Select one: A new substance is produced. Coal is made up of more than one element The shape of the coal changes. Oxygen is present.
Answer:
a new substance is produced
Explanation:
i just took my test and got this question right
The best evidence that a chemical reaction occurs when coal burns is a new substance is produced. The correct option is A.
What is coal?Coal is a carbon containing fossil fuel, which is formed when the organic matter is decomposed inside the earth with heat and pressure by the earth crust. It is the most used fossil fuel.
Carbon dioxide is a gas produce when these fossils fuel burned. It is a green house gas and increase the warmth of the earth when produced. It is taken by plants to make their food.
When coal burns, it produces carbon dioxide which is a gas and coal is a solid, so here the chemical reaction is happening which is producing a new substance.
Thus, the correct option is A. A new substance is produced.
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Complete and balance this neutralization reaction: HNO3 + Al(OH)3
Answer:
Al(OH)3 + HNO3 = Al(NO3)3 + H2O - Chemical Equation Balancer.
Explanation:
Grinding a seltzer tablet into powder increases the rate of reaction due to an increase of which factor?
Temperature
Surface area
Reactants
Concentration
Answer:
Surface area
Explanation:
The rate of a chemical reaction is increased when the surface area of a solid reactant is increased. This can be done by cutting the substance into small pieces, or by grinding it into a powder. If the surface area of a reactant is increased, it implies more particles are exposed to the other reactant.
When a seltzer tablet is ground into powder, the idea is to expose more of its surface to the other reactant. Since rate reaction depends on effective collision between reactants, more exposed particles implies a greater degree of collision between reactants and a faster rate of reaction.
Answer:
the answer is the second option got it right so do worry
Explanation:
hope this helps
The teacher made a 0.5M solution. How is this number read/said?
Answer:
It reads as follows: 0.5 moles of solute per liter of solution.
Explanation:
Molarity is the most frequent way of expressing the concentration of solutions in chemistry, and it indicates the number of moles of solute dissolved per liter of solution; is represented by the letter M.
Which word describes the amount of matter an object contains?
O altitude
Odensity
O mass
O pressure
The pressure of a 70.0L sample of gas is 600 mm Hg at 20.0C. If the temperature drops to 15.0C and the volume expands to 90.0L, what will the pressure of the gas be?
Answer:
458.7 mmHg
Explanation:
Step 1:
Data obtained from the question. This includes:
Initial volume (V1) = 70L
Initial pressure (P1) = 600 mmHg
Initial temperature (T1) = 20°C
Final temperature (T2) = 15°C
Final volume (V2) = 90L
Final pressure (P2) =...?
Step 2:
Conversion of celsius temperature to Kelvin temperature.
This is illustrated below:
T(K) = T (°C) + 273
Initial temperature (T1) = 20°C
Initial temperature (T1) = 20°C + 273 = 293K
Final temperature (T2) = 15°C
Final temperature (T2) = 15°C + 273 = 288K
Step 3:
Determination of the new pressure of the gas.
The new pressure of the gas can be obtained by using the general gas equation as shown below:
P1V1/T1 = P2V2/T2
600 x 70/293 = P2 x 90/288
Cross multiply to express in linear form
P2 x 90 x 293 = 600 x 70 x 288
Divide both side by 90 x 293
P2 = (600 x 70 x 288) / (90 x 293)
P2 = 458.7 mmHg
Therefore, the new pressure of the gas is 458.7 mmHg
3z-1
= 162+2.642-2
4
Z=
the answer is z = 47.214
Answer:
z = 47.214
Hope this helped
Which of the following is an example of the endocrine system maintaining homeostasis?
Group of answer choices
Detecting a pain stimulus and sending a signal to the spinal cord to perform an automatic response
Producing an excessive amount of hormones in the blood and not sending a signal to stop production
Releasing insulin to decrease blood sugar and releasing glucagon to increase blood sugar
Using sense organs to get information about the outside world and direct an appropriate body response
Answer:Releasing insulin to decrease blood sugar and releasing glucagon to increase blood sugar
Explanation: homoestasis is the process by which the body keep it's internal environment constant, regardless of change in the external environment. The human body has a normal range in which it's system operates and it uses homoestasis to keep these at constant.
Homeostasis could be positive or negative. It usually involves a sensor which detects the changes in the body and passes the information to the control center, a control center which receive information from the sensor and sends signals to the effectors and the effector which acts on the information sent by the control center to effect normalcy.
In this case, when a person eats food,he gets glucose. Blood sugar most be kept at constant so the endocrine system release the hormone insulin. Insulin helps to convert glucose to glycogen, which is the form it can be stored in the liver
When the blood sugar levels is low, the brain which is the control center causes glucagon to be released . This hormone converts glycogen to glucose
Answer:
Answer:Releasing insulin to decrease blood sugar and releasing glucagon to increase blood sugar
Explanation:
A gas sample is stored in a 2 liter container under 3 atmospheres of pressure at 28 C. If the gas is placed into a 5 liter container at 39 C, what will the pressure be?
Answer:
28c
Explanation:
HELPPP. What is the molarity (molar concentration) of a 500.0mL that contains 5.60g of KOH? Please show your work, with units, and include a therefore statement.
Answer:
.2 M
Explanation:
grams/molar mass=ans./volume(L)=molarity
5.6/56=ans./.500=.2 M
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Could u please balance this equation
Explanation:
I don't know how to explain
Consider the equation for acetic acid plus water HC2H2O2 + H2O --> C2HcO2- + H3O+ a)compare the strengths of the two acids in the equation. Do the same for the two bases. b) Determine which direction -- forward or reverse -- is favored in the reaction.
Considering the two acids and bases involved, the reverse reaction is favored.
Reversible reactionThe term reversible reaction refers to a reaction that can go either forward or backwards depending on the conditions of the reaction.
We must recall that acetic acid is a weak acid hence the equilibrium position would always lie towards the left hand side of the equation. Hence considering the two acids and bases involved, the reverse reaction is favored.
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In Humans, the liquid waste
filtered by the kidneys is stored
in the ......?
A) Stomach
B) Bladder
C) Lungs
D) I'm not sure. I need
more help with this
topic.
In ΔDEF, the measure of ∠F=90°, FE = 16, DF = 63, and ED = 65. What ratio represents the tangent of ∠E?
Answer:
63/16
Explanation:
tanE=
adjacent
opposite
=
16
63
Answer:
63/16
Explanation:
this for delta math?
What is the pH of a solution that has a [ ] = 0.020 M?
Answer:
HCl is a strong acid, it dissociates 100% (I.e. completely): [HCl]F = 0.020 M = [H3O+] So, pH = - log [H3O+] = -log [HCl]F = -log(. 020)=1.70 Voila!
Why is a telephone considered an example of matter?
Answer:
Matter is anything that is made up of atoms. Whether its a computer, a drink, a suitcase, a telephone, whatever.
If it has mass, if it occupies space, and if it has volume, then it is matter.
Also, matter comes in the form of solids, liquids, and gasses.
In this case, the telephone is a solid.
plzzz mark me brainliest if this helped :)
I need 3 more brainliests to become an expert
Answer:
Matter is anything that is made up of atoms.
Explanation:
If it has mass, occupies space, and has volume, then it is matter. Also, matter comes in the form of solids, liquids, and gasses. The telephone is a solid.
What is the formula for frequency?
Answer:
Frequency = Velocity / Wavelength
or
f = v / λ
A 5.72-L football is filled with air at 1.85 atm. At the same temperature, the volume of the football is reduced to 2.13 L. What is the pressure of air in the ball?
Answer:
4.97 atm
Explanation:
P2=V1P1/V2
I know this is correct because P and V at constant T have an inverse relationship.
- Hope that helps! Please let me know if you need further explanation.
5. How is a cell wall different from a cell membrane?
A redox reaction is set up so that both half reactions take place in separate beakers that are connected by a salt bridge and a wire. A path for the transfer of ions is provided by the? (1) anode (2) cathode (3) salt bridge (4) wire
Answer:
Salt bridge
Explanation:
Salt bridge is used in an electrolytic cell to transfer electrons from the anode to the cathode.
Salt bridge are used because they do not interfere with the constituents of the cell I.e the anode (+very electrode) and cathode(-ve electrode).
Examples of salt bridges are AgNO₃, KCl etc.
Salt bridge can be described as a tool used to link the oxidation half cell and reduction half cell in an electrolytic set-up or galvanic cell.
What is an oxidizing agent ?
Answer:
A substance that tends to bring about oxidation by being reduced and gaining electrons
Explanation:
Answer:
An oxidizing agent is a substance that takes negatively charged electrons "away" from a substance or object; usually taking these electrons for itself it can also transport the electrons from an object and "give" them to another substance or object. The object that has been oxidized will then have a positive charge after losing the negative electrons and the substance receiving the electrons will become negative.
Explanation:
Examples include halogens, potassium nitrate, and nitric acid.
You are given the reaction Cu + HNO3 Cu(NO3)2 + NO + H2O complete the final balanced equation based on half-reactions
The balanced equation based on half-reactions is 2Cu + 8HNO3 + 6H+ -> 2Cu(NO3)2 + 2NO + 4H2O.
How to determine the balanced equation based on half-reactionsTo complete the balanced equation for the given reaction Cu + HNO3 -> Cu(NO3)2 + NO + H2O using half-reactions, we need to break down the overall reaction into separate oxidation and reduction half-reactions.
1. Oxidation Half-Reaction:
Cu -> Cu2+ + 2e-
In this step, copper (Cu) is oxidized, losing two electrons to form copper(II) ions (Cu2+).
2. Reduction Half-Reaction:
HNO3 + 3H+ + 2e- -> NO + 2H2O
In this step, nitric acid (HNO3) is reduced, gaining two electrons to form nitric oxide (NO) and water (H2O).
Now, to balance the half-reactions, we need to make sure that the number of electrons gained in the reduction half-reaction is equal to the number of electrons lost in the oxidation half-reaction. In this case, we can achieve this by multiplying the oxidation half-reaction by two.
Balanced Half-Reactions:
Oxidation: 2Cu -> 2Cu2+ + 4e-
Reduction: HNO3 + 3H+ + 2e- -> NO + 2H2O
Finally, we can combine the balanced half-reactions to obtain the balanced equation for the overall reaction:
2Cu + 8HNO3 + 6H+ -> 2Cu(NO3)2 + 2NO + 4H2O
Therefore, the balanced equation based on half-reactions is 2Cu + 8HNO3 + 6H+ -> 2Cu(NO3)2 + 2NO + 4H2O.
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Why does the addition of a solute lower the freezing point of a solution?
A The solute is colder than the solvent.
B The solute disrupts crystal formation by the solvent.
C The solute tends to sink to the bottom of the solution.
D The solute has bigger molecules than the solvent.
Answer:
B
Explanation:
