Answer: e. 4.8 h
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) for 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}{0.77hr}=0.9hr^{-1}[/tex]
b) for 160.0 g to decay to 2.07 g
[tex]t=\frac{2.303}{0.9}\log\frac{160.0}{2.07}[/tex]
[tex]t=4.8hr[/tex]
The time required for a 160.0-g sample of 158Eu to decay to 2.07 g is 4.8 hours
From top to bottom within a group of the periodic table, first ionization energy tends to *
A. increase.
B. decrease.
C. remain approximately the same.
D. change in an irregular way.
Answer:
B. decrease.
Explanation:
Because size of atom increases so it is easy to remove electron
C4H10 is an example of a (n) a. Molecular formula b. Structural formula c. Atomic formula d. Geometric formula
Answer:
molecular formula
Explanation:
hope it helps
Which of the following is not a required characteristic for a living organism?
A) reproduction
B) mobility
C) homeostasis
D) adaptation
Answer:
B
Explanation:
living things are not required to move
Is this statement true or false?
Gas Giants all have their own moon
Answer:
True
Explanation:
If you measure the mass of a sample of an unknown gas, and also measure the volume, pressure, and temperature, what identifying quantity can you calculate?
Answer:
The molar mass of the gas
Explanation:
The ideal gas equation of state is:
PV = nRT
If we measure the volume (V), the pressure (P), and the temperature (T), we use the gas constant R (0.082 L.atm/K.mol) to calculate n (moles of gas):
n = PV/RT
Then, we can divide the mass into the number of moles to calculate the molar mass of the gas:
molar mass = mass/n
Use calc to determine whether it is possible to remove 99.99% Cu2 by converting it to Cu(s) in a solution mixture containing 0.12 Cu2 and 0.12 MSn2 suppose it is at room temperature.
Answer:
it is possible to remove 99.99% Cu2 by converting it to Cu(s)
Explanation:
So, from the question/problem above we are given the following ionic or REDOX equations of reactions;
Cu2+ + 2e- <--------------------------------------------------------------> Cu (s) Eo= 0.339 V
Sn2+ + 2e- <---------------------------------------------------------------> Sn (s) Eo= -0.141 V
In order to convert 99.99% Cu2 into Cu(s), the equation of reaction given below is needed:
Cu²⁺ + Sn ----------------------------------------------------------------------------> Cu + Sn²⁺.
Therefore, E°[overall] = 0.339 - [-0.141] = 0.48 V.
Therefore, the change in Gibbs' free energy, ΔG° = - nFE°. Where E° = O.48V, n= 2 and F = 96500 C.
Thus, ΔG° = - 92640.
This is less than zero[0]. Therefore, it is possible to remove 99.99% Cu2 by converting it to Cu(s) because the reaction is a spontaneous reaction.
What is the visual differences between elements compounds and mixtures
Answer: yes I can do that tomorrow
Explanation:
A balloon contains a mixture of 2 gases, X and Y. If the pressure in the balloon is 1.50 atm and there are 3 moles of X and 7 moles of Y present, what is the partial pressure of each gas?
Answer:
Partial Pressure of X = 0.45 atm
Partial Pressure of Y = 1.05 atm
Explanation:
Mixture of gas = Gas X + Gas Y
Total number of moles = 3 + 7 = 10 moles
Total pressure = 1.50 atm
The relationship between partial pressure, total pressure and number of moles is given as;
Partial pressure of gas X / Total pressure = Number of moles of gas X / Total number of moles
Partial Pressure of gas X / 1.50 = 3 / 10
Partial Pressure of gas X = 1.5 * 3 / 10 = 0.45 atm
The total pressure of a mixture is a sum total of the individual pressures, hence;
Pressure of mixture = Partial Pressure of X + Partial pressure of Y
1.5 = 0.45 + Partial pressure of Y
Partial Pressure of Y = 1.5 - 0.45 = 1.05 atm
A 5.0 g sample of metal was heated from 10°C to 40. °C. It absorbed 43.7 J of energy as heat. What is the specific heat of this piece of metal?
Answer:
Balls
Explanation:
Cuz
A 12.0% sucrose solution by mass has a density of 1.05 gem, what mass of sucrose is present in a 32.0-mL sample of this solution?
A) 0.126g
B) 3.66g
C) 4.03g
D) 3.84g
E) 280 g
Answer:
Option C. 4.03 g
Explanation:
Firstly we analyse data.
12 % by mass, is a sort of concentration. It indicates that in 100 g of SOLUTION, we have 12 g of SOLUTE.
Density is the data that indicates grams of solution in volume of solution.
We need to determine, the volume of solution for the concentration
Density = mass / volume
1.05 g/mL = 100 g / volume
Volume = 100 g / 1.05 g/mL → 95.24 mL
Therefore our 12 g of solute are contained in 95.24 mL
Let's finish this by a rule of three.
95.24 mL contain 12 g of sucrose
Our sample of 32 mL may contain ( 32 . 12) / 95.24 = 4.03 g
Density = Mass
Volume
To find the density of a solid:
Find the mass of the block.
Find the volume of the block using (length x width x height)
Use the equation to find density.
#1 #2 #3 #4 #5 = (2x3x4) #1/#5
Block #
Mass (g)
Length (cm)
Width (cm)
Height (cm)
Volume
(cm3)
Density (g/cm3)
1
75
6
3
4
72
1.04
2
3
4
5
6
7
8
Follow up questions:
Which two blocks were made out of the same material?
How do you know?
Does a larger block always have a higher density?
Answer:
what is it all about???
Please respond guys I’ll give brainliest and 100 points
Compare and contrast the reactions of lithium and cesium when they are added to water. At least 5 sentences
Answer:Both lithium and cesium are classified as alkali metals because they both have just one electron in their outermost shell.
The electronic configuration of both atoms are:
Lithium = 2, 1
Cesium = 2, 8, 18, 18, 8, 1
Explanation:
what is the molarity of a solution made by adding 0.720 mole of NaOH to 2.40 liters of water
Answer:
Molarity = 0.3 M
Explanation:
Given data:
Moles of NaOH = 0.720 mol
Volume of water = 2.40 L
Molarity = ?
Solution:
Molarity is used to describe the concentration of solution. It tells how many moles are dissolve in per litter of solution.
Formula:
Molarity = number of moles of solute / L of solution
Molarity = 0.720 mol / 2.40 L
Molarity = 0.3 mol/L
Molarity = 0.3 M
A candle made of certain wax blend burns at a rate of 44.2 mg/min. What is the value of this burn rate if expressed in grams/hour
Answer:
2.652 g/h.
Explanation:
Burn rate (in mg/min) = 44.2 mg/min
Burn rate (in m/h) =?
We'll begin by converting 44.2 mg/min to g/min. This can be obtained as follow:
1 mg/min = 0.001 g/min
Therefore,
44.2 mg/min = 44.2 mg/min × 0.001 g/min / 1 mg/min
44.2 mg/min = 0.0442 g/min
Finally, we shall convert 0.0442 g/min to g/h. This can be obtained as follow:
1 g/min = 60 g/h
Therefore,
0.0442 g/min = 0.0442 g/min × 60 g/h / 1 g/min
0.0442 g/min = 2.652 g/h
Therefore, 44.2 mg/min is equivalent to 2.652 g/h.
Thus, the burn rate (in m/h) is 2.652 g/h.
If you stretch a rubber band between your fingers and pluck it, the rubber band makes a sound from the vibration. True Or False
Answer:
True
Explanation:
Middle school science help please. ill give brainliest
Answer:
It converts The liquid into a gas at the same temperature.
Explanation:
Answer:
it converts the liquid into gas at the same temperature
Explanation:
when heat is added to a liquid at boiling temperature it converts the liquid into gas at that same boiling temperature
please give brainliest
A solution has a pH of 11.75. Calculate the [H:0*] of the solution
The [H₃0⁺] of the solution : 1.778 x 10⁻¹² M
Further explanationpH is the degree of acidity of a solution that depends on the concentration of H⁺ ions. The greater the value the more acidic the solution and the smaller the pH.
pH = - log [H⁺]
So that the two quantities between pH and [H⁺] are inversely proportional because they are associated with negative values.
A solution whose value is different by n has a difference in the concentration of H⁺ ion of 10ⁿ.
pH of solution = 11.75
the [H₃0⁺] of the solution :
[tex]\tt pH=-log[H_3O^+]\\\\11.75=-log[H_3O^+]\\\\(H_3O^+]=10^{-11.75}=1.778\times 10^{-12}[/tex]
How does the number of valence electrons determine the type and number of bonds an element forms?
Write the formula for diphosphorous pentoxide
Answer:
P4O10
Explanation:
Which sentence from “Broken Chain” contains the most descriptive language? “He asked his mother if he could have braces, like Frankie Molina, her godson, but he asked at the wrong time.” “He went to the back yard, where he unlocked his bike, sat on it with the kickstand down, and pressed on his teeth.” “Sunday morning, Ernie and Alfonso stayed away from each other, though over breakfast they fought over the last tortilla.” “At four he decided to get it over with and started walking to Sandra’s house, trudging slowly, as if he were waist-deep in water.”
Answer:
" At four he decided to get it over with and started walking to Sandra's house, trudging slowly, as if he were waist-deep in water. "
Explanation:
The sentence "At four he decided to get it over with and started walking to Sandra's house, trudging slowly, as if he were waist-deep in water" is the most descriptive language.
What is descriptive language?Descriptive language is a technique that are used in speaking and writing which involves a detailed description of a place or a person.
It's intended to create a vivid and specific picture in the reader's mind to give them a better feel for the story
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how many molecules of nitrogen are in 1.25 mol N2?
Answer:
7.52 x 10²³ molecules N
Explanation:
multiply 1.25 mol of N2 by Avogadro's Number
Compare the properties of solid , liquid , and gas?
In a carbon dioxide molecule, a double covalent bond forms when the carbon atom shares what
pairs of valence electrons with each oxygen atom.
Answer:
2 pair of an electron
Explanation:
carbon having 6 valence electron 2 electron involved in covalent bonding so 4 electron means 2 pairs of an electron will left.
What energy allows for the difference in the spacing of molecules in a liquid versus a gas?
A. Electrical energy
B. Radiant energy
C. Potential energy
D. Kinetic energy
Answer:
kinetic energy
Explanation:
yeah it's correct
A student in chemistry class mixes two clear solutions together. Which of the following is the best evidence that a chemical reaction has occurred?
Question 5 options:
The solutions are soluble when mixed together.
The volume of the liquids increased.
A Yellow precipitate is formed when mixed together.
One liquid is insoluble in the other liquid.
Answer:
a yellow precipitate is formed when mixed together
A student in chemistry class mixes two clear solutions together. Then, a Yellow precipitate is formed when mixed together.
What is the solution ?A particular kind of homogenous combination made up of two or more components is known as a solution. A solute is a material that has been dissolved in a solvent, which is the other substance in the combination.
In a combination called a solution, every component is well combined. Solutions can contain solids, liquids, and gases and are regarded as homogenous mixes. A solute plus a solvent makeup a solution. Any material that dissolves in a solvent is referred to as a solute.
Solid, liquid, and gaseous solutions can be classified as solutions based on the physical states of the solvent and solute. Both the solute and the solvent are in the solid state in solid solutions.
Thus, option C is correct.
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S this true or false most energy we use comes from fossil fuels
Answer:
True. Hope this helps. :)
From acetic acid how to get formic acid ?
Answer:
The Reaction of acetic acid withNaN3 gives out methylamine. rxn of methylamine to HNO2 to give out methanol. oxidation of methanol via Kcr207(H+) to give formic acid.
Which is an example of a compound? * He3 or H2O or C
Answer:
H2O
Explanation:
There is more than one element
Suppose you used 0.5 M NaOH to titrate your vinegar sample instead of 0.1 M. What effect does the concentration of base added have on the reliability of the results of your titration?
Answer: the reliability will be worse
Explanation:
Suppose we used 0.5 M NaOH to titrate our vinegar sample instead of 0.1 M.
Now by using 0.5M instead of 0.1M we are increasing the concentration of NaOH,
We know that the moles used = Volume x concnetration.
so for the same no of moles, if the concentration increases, the volume decreases.
Hence it will consume less NaOH.
now Since the volume decreases, the titration volume of less number will increase the % error.
Therefore the reliability will be worse.
The effect that the concentration of the added base has on the reliability of the results of the titration in question is; The reliability will be worse.
We are told that;
0.5 M NaOH is to be used to titrate a vinegar sample instead of 0.1 M.
Now, 0.5 M means a concentration of 0.5 and since it is higher than 0.1M, it means the concentration of NaOH will increase.
Formula for number of moles used is;
n = V × M
Where;
n is number of moles
V is volume
M is concentration
We can see that number of moles is directly proportional to the volume and concentration.
Thus, if the number of moles remains unchanged, as we have increased the concentration, it means that the volume will decrease.
Thus, lesser volume of NaOH will be used and as a result of this decrease in volume, there will be a greater possibility of error.
In conclusion, we can say that the reliability will be worse.
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what is the metric unit of work
Answer:
newton-meters or (N-m)
Explanation: