Answer:
5 half lives
Explanation:
Given that
Thorium - 236 contains the half-life of 10.0 minutes
And there is 250 grams
We need to find out the number of half lives that took place after 50.0 minutes
As in the question
1 half life is 10 minutes
So for 50 minutes, it would be
= 50 minutes × 1 half life ÷ 10 minutes
= 5 half lives
Match the element with its oxidation number (charge).
1. +1 O
2. -1 Ca
3. -3 Si
4. -2 Al
5. +2 N
6. +3 Na
7. +/- 4 F
Answer:
The answer is in the problem
Explanation:
As general rule of number of oxygen is -2:
O → -2
Alkali metals (Li, Na, K) are always +1
Na → +1
Alkali earth methals (Be, Mg, Ca...) are always +2
Ca → +2
The halogen group (F, Cl, Br...) is always -1
F → -1
The oxidation number of Si (+/- 4)
Aluminium is, usually +3
And to complete the octet rule in nitrogen, 3 electrons are required. That means:
N → -3
Which planet is considered to be the most earth like despite the fact it has the hottest surface temperature?
Answer:
Venus
Explanation:
Similar in structure and size to Earth, Venus spins slowly in the opposite direction from most planets. Its thick atmosphere traps heat in a runaway greenhouse effect, making it the hottest planet in our solar system with surface temperatures hot enough to melt lead.
Answer:
Venus
Explanation:
Hope helps
FeCI2 + Na2CO3 = FeCO3 + NaCI Balance this equation please
No links
FeCl2 + Na2CO3 = FeCO3 + 2NaCl
What is Carbonate ion?
Answer:
[tex]{\huge\blue{\fbox{{࿐ᑕᗩᖇᗷOᑎᗩTᗴ IOᑎ࿐}}}}[/tex]
Explanation:✏The fizz in the club soda, the foaming effect in the washing soda are all due to carbonate ions. Carbonate is a salt of carbonic acid possessing the molecular formula CO32–. The main group of elements used as carbonates are alkali and alkaline earth metals.
Formula:✏ [tex]CO3 ^{2 - } [/tex]
ʰᵒᵖᵉ ⁱᵗ ʰᵉˡᵖˢ
i need help with number 3
(THANKS FOR HELPING)
(I WILL BRAINLEST FORGOT HOW TO SPELL IT AND AGAIN THANKS FOR HELPING)
Answer:
Gymnosperm and Angiosperms both are plant groups but Gymnosperm is just very large leaves that come out of the ground and Angiosperms have flowers. Gymnosperm produce seeds in pine cones for example. Some plants in the Gymnosperm group of plants are pines. They produce naked seeds which means that they aren't protected by a ovary (Fruit like an apple) to help them get planted. Angiosperms have seeds that come out of their flowers and are called covered seeds. When the plant is about to die, it's seeds fall out and either float away and grow later of fall where the plant is. Also, insects carry them places too.
Hope this helps.
At a pressure of 1.76 atm and 305 K, a certain gas has a volume of 350.0 mL. What will be the new volume of this gas under STP.
Answer:
hi
Explanation:
I'm just figuring this out
What is the number of moles in 4.81 L of H2S gas at STP?
Answer:
1.19 is the answer
Explanation:
The number of atoms in a 158.4 g sample of CO2 gas at STP is:
1.277 x 1025 atoms
2.167 x 1024 atoms
6.502 x 1024 atoms
6.651 x 1024 atoms
Answer:
6.502 x 10²⁴ atoms.
Explanation:
First we convert 158.4 g of CO₂ into moles, using carbon dioxide's molar mass:
158.4 g ÷ 44 g/mol = 3.6 mol CO₂Then we calculate how many CO₂ molecules are there in 3.6 moles, using Avogadro's number:
3.6 mol CO₂ * 6.023x10²³ molecules/mol = 2.168x10²⁴ CO₂ moleculesAs there are 3 atoms per CO₂ molecule, we triple the number of CO₂ molecules in order to get the answer:
2.168x10²⁴ CO₂ molecules * 3 = 6.504x10²⁴ atomsThe closest answer is the third option, 6.502 x 10²⁴ atoms.
A mixture of He, Ar, and Xe has a total pressure of 2.40 atm. The partial pressure of He is 0.300 atm, and the partial pressure of Ar is 0.250 atm. What is the partial pressure of Xe?
Express your answer to three significant figures and include the appropriate units.
The partial pressure of Xe in the mixture is 1.850 atm. (partial pressure of Xe = Total pressure - Partial pressure of He - Partial pressure of Ar = 1.850 atm).
To find the partial pressure of Xe, we need to subtract the partial pressures of He and Ar from the total pressure.
Total pressure = partial pressure of He + partial pressure of Ar + partial pressure of Xe
Given:
Total pressure = 2.40 atm
Partial pressure of He = 0.300 atm
Partial pressure of Ar = 0.250 atm
Let's solve for the partial pressure of Xe:
Partial pressure of Xe = Total pressure - Partial pressure of He - Partial pressure of Ar
Partial pressure of Xe = 2.40 atm - 0.300 atm - 0.250 atm
Partial pressure of Xe = 1.850 atm
Therefore, the partial pressure of Xe in the mixture is 1.850 atm.
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How many liters would you need to make a 0.8 M solution with 20 grams of lithium chloride?
Answer:
0.5875L
Explanation:
concentration = mole/ volume
n(LiCl) = 20 / (7 + 35.5) = 0.47 mol
volume = mole / conc.
volume = 0.47 /0.8
= 0.5875 dm³ = 0.5875L
At a certain temperature the rate of this reaction is first order in HI with a rate constant of 0.0632 s
2HI g = H2 g + I2 g
Suppose a vessel contains HI at a concentration of 1.28M. Calculate how long it takes for the concentration of HI to decrease to 17.0% of its initial value.
Answer:
[tex]28.037\ \text{s}[/tex]
Explanation:
[tex][A]_0[/tex] = Initial concentration = 1.28 M
[tex][A][/tex] = Final concentration = [tex]0.17[A]_0[/tex]
k = Rate constant = 0.0632 s
t = Time taken
For first order reaction we have the relation
[tex]kt=\ln\dfrac{[A]_0}{[A]}\\\Rightarrow t=\dfrac{\ln\dfrac{[A]_0}{[A]}}{k}\\\Rightarrow t=\dfrac{\ln\dfrac{[A]_0}{0.17[A]_0}}{0.0632}\\\Rightarrow t=28.037\ \text{s}[/tex]
Time taken to reach the required concentration would be [tex]28.037\ \text{s}[/tex].
How many liters of 3.6 M solution can be made using 110 grams of
lithium bromide (LiBr)?
Answer:
0.2878 liters
Explanation:
It is possible to make 0.2878 liters of 4 M solution of lithium bromide using 100 grams of the compound.
24.3 2 An artifact classified as seeds, found in a site at Newlands Cross, Ireland, is found to have a 14C radioactivity of 0.103 counts per second per gram of carbon. If living carbon-containing objects have an activity of 0.255 counts per second per gram of carbon, estimate the age of the artifact?
The half-life of 14C is 5730 years.
______ years
Answer:
Age ≅ 7500 years
Explanation:
All radioactive decay is 1st order kinetics and described by the expression
A = A₀e^-kt => t = ln(A/A₀) / -k
k = 0.693 / t(half life) = (0.693 / 5730)yrs⁻¹ = 1.21 x 10⁻⁴ yrs⁻¹
t = Age = [ln(0.103/0.255) / - 1.21 x 10⁻⁴] yrs = 7500 years
Consider the following data on some weak acids and weak bases:
acid base
name formula Ka name formula Kb
hydrocyanic acid HCN 4.9 x 10^-10 hydroxylamine HONH2 1.1 x 10^-1
hypochlorous acid HCIA 3.0 x 10^-18 ethylamine C2H5NH2 6.4 x 10^-4
Use this data to rank the following solutions in order of increasing pH. In other words, select a '' next to the solution that will have the lowest pH, a '' next to the solution that will have the next lowest pH, and so on.
a. 0.1 M HONH3Br
b. 0.1 M NaNO3
c. 0.1 M C2H5NH3Cl
d. 0.1 M NaF
Answer:
a < c < b < d
Explanation:
The weak acid with the lowest pKa will be the most acidic. In the other way, the conjugate base which the acid is weakest will be strongest.
The weak base with the lowest pKb will be the most basic. And the conjugate base of the weakest base will be a strongest acid.
Using the values:
Ka HCN = 4.9x10⁻¹⁰
Kb HONH2 = 1.1x10⁻⁸
Ka HClA 3.0x10⁻⁸
Kb C2H5NH2 = 6.4x10⁻⁴
The NaNO3 is the conjugate base of a strong acid as HNO3. That means its solutions are almost neutral
The HONH3Br is the conjugate acid of a weak base. Its solutions will be acidics
C2H5NH3Cl is the conjugate acid of a weak base as ethylamine, its solutions will be acidic.
As ethylamine has a lower pkb than hydroxylamine, the conjugate acid of hydroxylamine will be more acidic.
NaF is the conjugate base of a weak acid as HF. Its solutions will be basics
The order in increasing pH is:
HONH3Br < C2H5NH3Cl < NaNO3 < NaF
a < c < b < dWill give brainliest
In an experiment, the molar mass of the compound was determined to be 228.276 g/mol. What is the molecular formula of the compound?
PLZ HELP "NO LINKS"
A vessel of volume 22.4 dm3 contains 2.0 mol H2(g) and 1.0 mol N2(g) at 273.15 K.
(a) Calculate the mole fractions of each component.
H2:
N2:
(b) Calculate the partial pressures of each component.
H2:
N2:
(c) Calculate the total pressure.
Thanks!
Answer: (a) Mole fraction of [tex]H_{2}[/tex] is 0.66.
Mole fraction of [tex]N_{2}[/tex] is 0.33
(b) The partial pressure of [tex]H_{2}[/tex] is 1.98 atm.
The partial pressure of [tex]N_{2}[/tex] is 0.99 atm.
(c) The total pressure is 3.0 atm
Explanation:
Given: Volume = [tex]22.4 dm^{3}[/tex] (1 [tex]dm^{3}[/tex] = 1 L) = 22.4 L
Moles of [tex]H_{2}[/tex] = 2.0 mol
Moles of [tex]N_{2}[/tex] = 1.0 mol
Total moles = (2.0 + 1.0) mol = 3.0 mol
Temperature = 273.15 K
Now, using ideal gas equation the total pressure is calculated as follows.[tex]PV = nRT\\[/tex]
where,
P = pressure
V = volume
n = number of moles
R = gas constant = 0.0821 L atm/mol K
T = temperature
Substitute the values into above formula as follows.
[tex]PV = nRT\\P \times 22.4 L = 3.0 mol \times 0.0821 L atm/mol K \times 273.15 K\\P = 3.0 atm[/tex]
The mole fractions of each component:The mole fraction of [tex]H_{2}[/tex] is calculated as follows.
[tex]Mole fraction = \frac{moles of H_{2}}{moles of H_{2} + moles of N_{2}}\\= \frac{2.0 mol}{(2.0 + 1.0) mol}\\= 0.66[/tex]
The mole fraction of [tex]N_{2}[/tex] is as follows.
[tex]Mole fraction = \frac{moles of N_{2}}{moles of H_{2} + moles of N_{2}}\\= \frac{1.0 mol}{(2.0 + 1.0) mol}\\= 0.33[/tex]
The partial pressures of each component:Partial pressure of [tex]H_{2}[/tex] are as follows.
[tex]P_{H_{2}} = P_{total} \times mole fraction of H_{2}\\= 3.0 atm \times 0.66\\= 1.98 atm[/tex]
Partial pressure of [tex]N_{2}[/tex] are as follows.
[tex]P_{N_{2}} = P_{total} \times mola fraction of N_{2}\\= 3.0 atm \times 0.33\\= 0.99 atm[/tex]
Soil comes in different colors.
Answer: yes they come in different colors.
Explanation:
Most shades of soil is mostly black,brown,red,gray,and white the color of soil and other properties including texture, structure, and consistency are used to distinguish and identify soil.
The object shown is made of glass. What is it called?
Answer: prism
Explanation: A prism is a polyhedron, with two parallel faces called bases. The other faces are always parallelograms. The prism is named by the shape of its base.
If you had 15 molecules of H2 and an unlimited supply of N2, how many
NH3 molecules can you make?
N2 + 3H2 --> 2NH3
Answer:
10 molecules of NH₃.
Explanation:
N₂ + 3H₂ --> 2NH₃
As the N₂ supply is unlimited, what we need to do to solve this problem is convert molecules of H₂ into molecules of NH₃. To do so we use the stoichiometric coefficients of the balanced reaction:
15 molecules H₂ * [tex]\frac{2moleculesNH_3}{3moleculesH_2}[/tex] = 10 molecules NH₃10 NH₃ molecules could be prepared from 15 molecules of H₂ and unlimited N₂.
Which of the following accurately describes the function of the muscular
system?
O A. To prevent and fight disease
B. To provide support for the body
C. To get rid of wastes and excess water
D. To allow the body to move
Terry, a student, performs a titration. He completes these steps as part of his titration procedure: 1. He cleans and rinses a burette with standardized base. 2. He fills the burette with standardized base solution. 3. He reads and records the initial burette volume. 4. He adds a base from the burette to an acid. 5. He observes a color change in the Erlenmeyer flask. 6. He stops the addition of base from the burette. 7. He reads and records the final burette volume. Which steps will provide information needed to calculate the volume of base needed to reach the equivalence point? A. 1 and 6 B. 3 and 7 C. 3, 4, and 6 D. 1, 2, and 7
Answer:
D
Explanation:
D is the answer because 2 is needed to know
Answer:
B) 3 and 7
Explanation:
i just took the test
The mass of an atom of element x is equivalent to the total mass of 7 hydrogen atoms
Answer: I'm not sure what your question is but i'll answer as best as I can.
Explanation:
Since X is equal to 7 H and we know that H is equal to 1.008, we can just do 7x1.008 = 7.056 g. I hope i helped and please clarify more in the future.
The atomic mass of an element is given by the sum of the mass of protons and neutrons. The element X is lithium as it has a mass of 6.941 u.
What is atomic mass?Atomic mass is the sum of the masses of the isotopes of that element and is given by adding the masses of the number of protons and neutrons of the elemental atom.
The atomic mass of one hydrogen atom is 1.008, so seven hydrogens will be, 7 x 1.008 = 7.056 g. Now, from the periodic table, it can be seen that an atomic mass of 7.056 g is closest to the atomic mass of a lithium atom (6.941 u).
From the mass, it can be said that seven hydrogen atom has an equivalent mass as that of one lithium atom in the periodic table. The lithium atom has atomic number 3 and an atomic mass of 6.941 g/mol.
Therefore, element X is lithium.
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PLEASE HELP ME classify this reaction:
your options are
1. synthesis
2. decomposition
3. combustion
4. single replacement
5. double replacement
explain your answer for brainliest
But Are Punnett square percentages always correct?
Answer:
yes
Explanation:
cuz is a square and if all angles are equal of a square then it is correct
Rank the following solutions from lowest to highest vapor pressure.
Rank from lowest to highest. To rank items as equivalent, overlap them.
10.0 g of potassium acetate KC2H3O2 in 100.0 mL of water
20.0 g of sucrose (C12H22O11) in 100.0 mL of water
20.0 g of glucose (C6H12O6) in 100.0 mL of water
Solution :
When non volatile solute is added to solvent, vapor pressure gets lowered.
Relative lowering in vapor pressure is given :
[tex]$\frac{P^0-P}{P^0}$[/tex] = [tex]$\text{mole fraction}$[/tex] of solute
[tex]$\frac{P^0-P}{P^0}=x_B$[/tex]
[tex]$P^0$[/tex] = vapor pressure of pure solvent
P = vapor pressure of solution
[tex]$x_B$[/tex] = mole fraction of solute
[tex]$x_B=\frac{n_B}{n_A+n_B}$[/tex]
[tex]$n_B $[/tex] = [tex]$\text{number of moles of solute}$[/tex]
[tex]$n_A$[/tex] = [tex]$\text{number of moles of solvent}$[/tex]
Number of moles [tex]$=\frac{\text{weight}}{\text{molecular weight}}$[/tex]
[tex]$\frac{P^0-P}{P^0}=\frac{w_B/M_B}{w_A/M_A+w_B/M_B}$[/tex]
[tex]$\approx \frac{w_B/M_B}{w_A/M_A}$[/tex]
1. For 10 g of [tex]$CH_3COOK$[/tex]
[tex]$CH_3COOK \rightarrow CH_3COO^- + K^+$[/tex]
Ions = 2
It will affect colligative property.
[tex]$\frac{P^0-P}{P^0} = \frac{i \times 10/98}{w_A/M_A}$[/tex]
Relative lowering in vapor pressure will be :
[tex]$=\frac{2 \times 10/98}{w_A/M_A}$[/tex]
[tex]$=\frac{0.20}{w_A/M_A}$[/tex]
2. For 20 g sucrose
Sucrose is non electrolyte, i = 1
[tex]$\frac{P^0-P}{P^0} = \frac{ 20/342}{w_A/M_A}$[/tex]
[tex]$=\frac{0.050}{w_A/M_A}$[/tex]
3. For 20 g of glucose.
Glucose is a non electrolyte, i = 1
[tex]$\frac{P^0-P}{P^0} = \frac{20/180}{w_A/M_A}$[/tex]
[tex]$=\frac{0.11}{w_A/M_A}$[/tex]
[tex]$w_A/M_A$[/tex] is same in all three solutions.
Hence, lowering in vapor pressure is maximum in [tex]$CH_3COOK$[/tex] and minimum is Sucrose.
Vapor pressure from lowest to highest.
10 g of [tex]$CH_3COOK$[/tex] < 20 g of glucose < 20 g of sucrose
The pressure exerted by vapor to the other gas is called vapor pressure.
The formula used to solve the question is as follows:-
[tex]\frac{P^o -P}{P^o}[/tex]
The water vapor depends on the following:-
Water pressureTemperature.After solving the equation, the correct sequence is as follows:-
[tex]CH_3COOK > GLUCOSE > SUCROSE[/tex]
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Cuo
+ H2 → → Cu + + H20
colorless
water
black
powder
reddish
solid
gas
vapor
Explanation:
because there is 2 hydrogen atoms in the reactions side of the equation (you can tell because the H has a 2 in the subscript) you have to have 2 hydrogen atoms in the reactants side to help balance out the equation. and since the copper and oxygen atoms are already balanced there is no coefficient needed.
All solutes will dissolve at some point.
O True
O False
Answer:
False
Explanation:
CH3CH2OH can interact with
other like molecules through ___?
Answer: dispersion forces, dipole-dipole and hydrogen bonds
Explanation:
What is one benefit that nuclear power plants currently provide for our environment?
O A. They provide energy without increasing carbon dioxide emissions.
O B. They provide energy without increasing nuclear waste.
C. They provide energy while increasing natural gas pollution.
O D. They provide energy while increasing biomass by-products.
Explanation:
Nuclear power plants deliver electricity 24 hours a day, 7 days a week, irrespective of weather and seasons. As well as reducing greenhouse gas emissions, nuclear generation helps reduce air pollution
Answer:
D
Explanation:
Just did the test
Λλ(Lamda) Represents what??
Answer:
λ Represents:-
one wavelength of electromagnetic radiationthe decay constant in radioactivityfunction expressions in the lambda calculusa general eigenvalue in linear algebrathe expected number of occurrences in a Poisson distribution in probabilitythe arrival rate in queueing theorythe failure rate in reliability engineeringthe Lagrange multiplier in mathematical optimization, known as the shadow price in economicsthe Lebesgue measure denotes the volume or measure of a Lebesgue measurable setlongitude in geodesylinear densityecliptic longitude in astronomythe Liouville function in number theorythe Carmichael function in number theorythe empty string in formal grammara formal system in mathematical logicthermal conductivitythe Lorentz transformation-TheUnknownScientist