Select the correct answer.
A sample taken from a layer of mica in a canyon has 2.10 grams of potassium-40. A test reveals it to be 2.6 billion years old. How much
potassium-40 was in the sample originally if the half-life of potassium-40 is 1.3 billion years?
O A.
4.20 g
O B.
8.40 g
O C.
12.6 g
• D.
16.8 g
O E.
25.2 g
Answer:
8.36 g
Explanation:
From;
0.693/t1/2 = 2.303/t log (No/N)
t1/2 = half life of potassium-40
t = age of the sample
No= initial amount of the sample
N= amount of the sample at time t
Substituting values;
0.693/1.3 × 10^9 = 2.303/2.6 × 10^9 log (No/2.10)
5.33 × 10^-10 = 8.86 × 10^-10 log (No/2.10)
5.33 × 10^-10/8.86 × 10^-10 = log (No/2.10)
0.6 = log (No/2.10)
Antilog (0.6) = (No/2.10)
No = 2.10 × Antilog (0.6)
No= 8.36 g
Roundup, a herbicide manufactured by Monsanto, has the formula C3H8NO5P. How many moles of molecules are there in a 647.3-g sample of Roundup?
I got the answer 2.305 x 10^24 but for some reason it’s not working. Is it the wrong one?
Answer:
3.830177515 moles
Explanation:
You have :
647.3 g of RoundupMolar mass of Round up which is equal to 169 g.moland the formula: n=m/MTherefore: n=647.3/169
=3.830177515 moles
17. (1.09 x 102) x (2.79 x 10')
18. (5.75 x 104) / (4.71 102)
19.(3.38 x 106) x (7.80 x 104)
20. (7.04 x 10) / (9.45 x 10-)
Answer:
17. 3,101.922
18. 1.2447441822
19. 288,057.12
20. 0.74497354
SOMEONE HELP ASAP I NEED TO FIND AN ANSWER
Answer:
A) Q + XZ = X + QZ is a single displacement reaction.
B) Q + Z = QZ is a synthesis reaction
C) QT = Q + T is a decomposition reaction
D) QT + XZ = QZ + XT is double replacement reaction.
Explanation:
A) Q + XZ = X + QZ
This is a single displacement reaction because it is one in which one element is substituted for another one in a compound. In this case X is substituted for Q.
B) Q + Z = QZ
This is a synthesis reaction because Q and z combine to form a single product QZ.
C) QT = Q + T
This is a decomposition reaction because the compound QT breaks down to form 2 simpler substances Q and T.
D) QT + XZ = QZ + XT
Thus is a double replacement reaction because QT and XZ have exchanged cations to form new compounds QZ and XT
Which reaction occurs at the cathode of a galvanic cell that has an aluminum electrode in an electrolyte with aluminum ions and copper electrode in an electrolyte with copper ions ? The reduction potential for the reduction of Cu^ 2+ = 0.34 The reduction potential for the reduction of AP^ 3+ =-1.68V.
Answer:
[tex]{ \bf{Cu {}^{2 + } + 2e \: → \: Cu }}[/tex]
The reaction that occurs at the cathode of a given galvanic cell is:
Cu²⁺ + 2e⁻ → Cu
What is Galvanic Cell?A galvanic cell can be defined as an electrochemical cell that converts the chemical energy of spontaneous redox reactions into electrical energy. The galvanic cell makes use of chemical reactions to generate electrical energy.
A galvanic cell consists of two half-cells and a salt bridge. Each half-cell further contains an electrode dipped into an electrolyte. When both electrodes are dipped in the same electrolyte, then there is no need for a salt bridge.
At the anode, an oxidation reaction occurs at this electrode. At the cathode, reduction occurs at this electrode. The anode has a negative potential with respect to the solution while the cathode has a positive potential with respect to the solution.
As in the question, the reduction of Cu²⁺ has a positive reduction potential. Therefore, the reduction of the copper will occur at the cathode.
Learn more about Galvanic cell, here:
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Heavy rains fill a reservoir, causing the dam that holds the water to break. As a result, the areas downstream are suddenly flooded. Which question would a scientist seek to answer?
Answer:
"How to prevent the collapse of the dam that contains water from heavy rains?"
Explanation:
Scientists must work to create innovations capable of bringing benefits to human life and combating disadvantageous and harmful situations. The overflow of dams is something very harmful, as the resulting flooding can cause structural, economic and even public health problems. When this overflow is caused by natural elements, such as heavy rains, the work of scientists in solving these issues is even more important and necessary. In order to resolve the dam failure caused by excess rainwater, scientists must work to answer the following question:
"How to prevent the collapse of the dam that contains water from heavy rains?"
What is a reaction rate
Answer:
Explanation:
A reaction rate is the measure of the change in concentration of the disappearance of reactants or the change in concentration of the appearance of products per unit time
What type of reaction is shown below?
H202 + H2O + O2
Single replacement
Combustion
Synthesis
Decomposition
Answer:
Decomposition Reaction
According to the kinetic-molecular theory, the average kinetic energy of gas particles depends on which factor?
Answer:
Temperature.
Explanation:
Kinetic molecular theory of gases states that gas particles exhibit a perfectly elastic collision and are constantly in motion.
According to the kinetic-molecular theory, the average kinetic energy of gas particles depends on temperature.
This ultimately implies that, the average kinetic energy of gas particles is directly proportional to the absolute temperature of an ideal gas. Thus, an increase in the average kinetic energy of gas particles would cause an increase in the absolute temperature of an ideal gas.
Temperature can be defined as a measure of the degree of coldness or hotness of a physical object. It is measured with a thermometer and its units are Celsius (°C), Kelvin (K) and Fahrenheit (°F).
Explain and describe how the photoelectric effect occurs on an atomic level in terms of protons, neutrons, and electrons
ANSWER:
Explaining the experiments on the photoelectric effect. How these experiments led to the idea if light behaving as a particle of energy called a photon.
What type of nuclear decay is shown by the reaction below?
A. Alpha
B. Gamma
C. Beta
O D. Fission
Answer:
C. Beta
Explanation:
What would happen to the entropy in the reaction 203(9) ► 302(9)?
A. It is impossible to tell.
B. It stays the same.
C. It decreases.
D. It increases.
bez number of particles in reaction increases so randomness or entropy increase.
as entropy is the degree of randomness of particles in a system
Which of these statements is true about heat?
Answer:
Explanation:
what are the statments i can't help till i have the posable answers
Our solar system is more than _________ in diameter.
Answer: 287.46 billion km
Explanation: calculated it myself. nah but thats the answer
what are the difference between ionic bond and covalent bond?
Which is stronger?
QUËSTIONS :- what are the difference between ionic bond and covalent bond?
IONIC BONDS :- THEY R BONDS WHICH R FORMED DUE TO THE COMPLETE TRANSFER OF ELECTRONS BETWEEN TWO ATOMS
COVALENT BONDS :- THEY R THE BONDS WHICH R FORMED DUE TO INCOMPLETE TRANSFER OF ELECTRONS BETWEEN TWO ATOMS
IONIC BONDS R MORE STRONGER.
Explanation:
Ionic bond is much stronger than covalent bond because it involves complete transfer of electrons because of which there is formation of cation and anion and there exist huge electrostatic forces of attraction. They also have high melting and boiling point which proves that the ionic bond is very strong.
Differences between ionic bond and covalent bond :
Ionic Bonds. Covalent Bonds
Polarity :High. Low
Shape : No definite shape. Definite shape
Melting Point :High Low
Boiling Point: High Low
Use the average acceleration obtained in Activity 1 to determine how far the ball should drop at 0.3 second, 0.5 second, and 0.7 second. Using the simplified formula y = 1/2 at2 (because y0 = 0 and v0 = 0), calculate y to one decimal place.
Answer:
0.3 sec : -0.4 m
0.5 sec: -1.2 m
0.7 sec: -2.3 m
Explanation:
0.3 sec: 1/2(-9.3 m/s^2)(0.3 s)^2 = -0.4 m
0.5 sec: 1/2(-9.3 m/s^2)(0.5 s)^2 = -1.2 m
0.7 sec: 1/2(-9.3 m/s^2)(0.7 s)^2 = -2.3 m
What is pH?
O A. A measurement indicating how acidic a solution is
B. A concentration of total ions dissolved in solution
C. A level of dissolved gases that are in solution
O D. A component of solutions that makes them acidic
Answer:
Awnser is A
Explanation:
Answer:
Hello There!!
Explanation:
The answer is↬O A. A measurement indicating how acidic a solution is.
hope this helps,have a great day!!
~Pinky~
1-bromo-1-2-diphenylpropane
Answer:
Aldehyde
Explanation:
1-bromo-1-1diphenylpropane
Define the boiling and evaporation using kinetic theory
Answer:
Explanation:
By the kinetic molecular theory (particle model), all matter consists of particles, there are spaces between the particles, the particles are in constant random motion, and there are forces of attraction and repulsion between the particles.
Furthermore, temperature is defined to be a measure of the average kinetic energy of the particles.
Evaporation is a change of phase from liquid to gas explained as follows :
When particles in the liquid phase are heated, they gain kinetic energy and move faster and further apart. Eventually they have enough energy to escape the forces of attraction holding them together in the liquid phase and they move very fast and far from each other and exist in the gaseous phase.
Which statements are correct regarding the Law of Conservation of Matter and Energy?
Matter or energy can create itself.
Matter or energy was created by known principles of physics and chemistry.
Matter or energy can change from one form to the other.
The law agrees with the Biblical account of Creation
(more than one answer)
Answer:
Matter or energy can change from one form to the other
Explanation:
The law of conservation of energy states that energy can neither be created nor destroyed but can only be transformed i.e. changed from one form to another. For example, mechanical energy can be changed to electrical energy.
Likewise, the law of conservation of mass/matter states that matter can not be destroyed or created but can change via physical or chemical means to conserve it. For example, matter can change from liquid state to gaseous state.
From the above two laws, it can be said that "matter or energy can change from one form to the other".
The body's reaction to a change in the environment is called a response.
Please select the best answer from the choices provided
OT
OF
When an Li atom becomes an Li+ ion, the Li atom
Answer:When a lithium atom forms an Li+ ion, the lithium atom (1) gains a proton (2) gains an electron (3) loses a proton (4) loses an electron
is it true that the most reactive metals are quite plentiful in the Earth's crust?
Answer:
yes
Explanation:
as it had got crushed down in the dinosaurs age
Se trata 50 g de aluminio que posee 10% de impurezas con suficiente cantidad de ácido sulfúrico ¿qué peso de sulfato de aluminio se obtiene si el porcentaje de rendimiento fue de 70%? P.A. (uma): Al: 27, S = 32, O = 16
Respuesta:
199.5 g
Explicación:
Paso 1: Escribir la reacción balanceada
2 Al + 3 H₂SO₄ ⇒ Al₂(SO₄)₃ + 3 H₂
Paso 2: Calcular la masa pura de 50 g de Al
Aluminio tiene 10% de impurezas, es decir, 10% de 50 g = 5 g. Luego, tiene 50 g - 5 g = 45 g de Al puro.
Paso 3: Calcular la masa teórica de Al₂(SO₄)₃ obtenida a partir de 45 g de Al
La relación de masas de Al₂(SO₄)₃ a Al es 342:54.
45 g Al × 342 g Al₂(SO₄)₃/54 g Al = 285 g Al₂(SO₄)₃
Paso 4: Calcular la masa real de Al₂(SO₄)₃ obtenida
El rendimiento de la reacción es de 70%.
285 g × 70% = 199.5 g
304 cm x m and 67kg to gram please helpppp!!!!!!!!
Answer:
[tex]304cm = 3.04m \\ 67kg = 67000g[/tex]
Explanation:
[tex]100cm \: = 1m \\ 304cm = x \\ use \: \: cross \: multipication \\ 100x = 304 \\ \frac{100x}{100} = \frac{304}{100} \\ x = 3.04m[/tex]
-------------------------------------------------
[tex]1kg = 1000g \\ 67kg = x \\ \\ use \: cross \: \: multipication \\ 1x = 67 \times 1000 \\ x = 67000g[/tex]
Hope this helps
Have a nice day!
Hi Everyone ✌
hope u all r doin well
Pls Answer
What happens when dilute sulphuric acid is poured on a copper plate ?
Answer:
No observable change.
Explanation:
Copper renders dilute sulphuric acid passive, no reaction.
H2SO4+Cu-->CuSO4+H2
Explanation:
THIS IS THE CORRECT ANSWER
Which of the following pairs lists a substance that can neutralize H2SO4 and the salt that would be produced from the reaction?
O CaOH2 and Ca(SO4)2
OLIOH and Li2SO4
ONH, and NH,SO4
O NH3 and (NH3)2SO4
sh
Answer: b
Explanation:
I took the test
The correct answer is LiOH and Li2SO4.
A strong acid is neutralized by a strong base to yield a normal salt.
A neutralization reaction is a reaction between an acid and a base to yield salt and water only.
An acid can be strong or weak. A base can also be strong or weak. "Strong" or "weak" has to do with the extent of ionization of the acid or base in water. Usually, a strong acid is neutralized by a strong base.
Since H2SO4 is a strong acid, it will require a strong base such as LiOH to neutralize it and the product will be the normal salt Li2SO4.
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The ksp of StS04 is 3.2x10-7 What is the equilibrium concentration of sulfate lon a 1.0-L solution of strontium sulfate to which 0.10 mol of Sr(CH3CO2)2 has been added?
Answer:ehwusvudhwdvwxkwvbxbwxbxiwhxjvwxjvxwjxvjxvwxiwvxiwzgiwxvwjsbwis
HOPE IT HELPS IF YOU LIKE MY ANSWER THEN MARK ME AS BRAINLIEST ;-);-)
A student who is performing an experiment must measure out 0.02-mL of 0.50-M HCl. The most accurate piece of equipment to measure the quantity would be a?
A) 50 mL buret
B) 25 mL graduated cylinder
C) 10 mL cylinder
D) 1 mL pipet
Answer:
Choice D) 1 mL pipet
Explanation:
If you are trying to extract 0.02 mL of HCl, you are going to need a piece of equipment that can measure very small units. Thus, Choice D would be the correct answer.
A gardener decides to use only part of their garden in the spring. What will most likely happen first in the unused part of the garden?
Answer:
Growth of weeds and grasses
Explanation:
The part of the garden, probably left to rest by the Gardner, would start experiencing a legion of invasive plants. Giant weeds and grasses could be seen, and brambles and tree seedlings could also sneak in.
Some Gardeners would recommend the use of herbicides to restore order to an abandoned garden even though certain scientists are of the opinion that chemicals may not offer a sound solution to the problem.
