This question is incomplete, the complete question is;
g Consider a pure sample of a radioactive isotope with a mass number of (46 + A). If the sample has mass of (25.0 + B) micrograms and the isotope has a half-life of (4.50 + C)x10⁶ years,
determine the decay rate for the sample. Give your answer in decays/second and with 3 significant figures.
A = 1, B = 1, C = 11.
Answer:
the decay rate for the sample is 469,625.898 decay/s
Explanation:
Given the data in the question;
[tex]T_{\frac{1}{2}[/tex] = ( 4.50 + C ) × 10⁶ years
C = 11
[tex]T_{\frac{1}{2}[/tex] = ( 4.50 + 11 ) × 10⁶ years
[tex]T_{\frac{1}{2}[/tex] = 15.50 × 10⁶ years
[tex]T_{\frac{1}{2}[/tex] = 15.50 × 10⁶ × 365 × 24 × 60 × 60
λ = 0.693 / [tex]T_{\frac{1}{2}[/tex]
so
λ = 0.693 / ( 15.50 × 10⁶ × 365 × 24 × 60 × 60 )
also
N = ( 25.0 + B )
B = 1
N = ( 25.0 + 1 )
N = 26 × 10⁻⁶
isotope with a mass number of ( 46.0 + A ) , A=1
= ( 46.0 + 1 ) = 47
N = 26 × 10⁻⁶( 1/47 )( 1 / 1.67 × 10⁻²⁷ ) = 3.31252 × 10²⁰
R = λN
so
R = (0.693 / ( 15.50 × 10⁶ × 365 × 24 × 60 × 60 )) × (3.31252 × 10²⁰)
R = 1.41773 × 10⁻¹⁵ × (3.31252 × 10²⁰)
R = 469,625.898 decay/s
Therefore, the decay rate for the sample is 469,625.898 decay/s
URGENT PLZ HELP
Which of the following statements is true?
a. In an endothermic process heat is transferred from the surroundings to the
system.
b. In an exothermic process heat is transferred from the surroundings to the
system.
C. The surroundings will feel cooler in an exothermic process.
d. The surroundings will feel warmer in an endothermic process.
Answer:
A.
Explanation:
In an endothermic reaction heat is applied.
In an endothermic process, heat is transferred from the surroundings to the system.
What are endothermic and exothermic processes?
An exothermic process is one that gives off heat. This heat is transferred to the surroundings. An endothermic process is one in which heat has to be supplied to the system from the surroundings.
The endothermic process is a term that describes a reaction where the system absorbs the energy from its surrounding in the form of heat. A few examples of the endothermic process are photosynthesis, evaporating liquids, melting ice, etc.
The exothermic reaction is the opposite of an endothermic reaction. It releases energy by light or heat to its surrounding. A few examples are neutralization, burning of a substance, reactions of fuels, etc.
Hence, option A is the correct answer.
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The electric field around a positive charge will:
What chemical test to differentiate propane and propene
Answer:
If you add bromine water, an aqueous solution of bromine, to the test tubes, you can tell which is propene, the alkene. The bromine reacts with and saturates the double bonds in alkenes, and so decolourises.
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what are twin primes between 1 to 100
The following substances dissolve when added to water. Classify the substances according to the strongest solute-solvent interaction that will occur between the given substances and water during dissolution. Drag the appropriate items to their respective bins. Not all bins may contain an item and some bins may contain multiple items.NH3 AlBr3 CH3OH AlCl
Answer:
NH3 ------dipole - dipole forces
CH3OH ------ dipole - dipole forces
AlBr3 ------- ion - dipole forces
AlCl3 ------- ion - dipole forces
Explanation:
Let us recall that water is a polar molecule. This means that water has a positive as well as a negative end. NH3 also has a dipole. The interaction between solute and solvent dipoles leads to the dissolution of NH3 in water. Hence the strongest intermolecular force here is dipole - dipole forces.
Similarly, CH3OH possesses a polar -O-H group which can interact with water via dipole - dipole interaction as its strongest intermolecular force.
As for AlBr3 and AlCl3, the two substances dissociate into ions in solution and these ions interact with the dipole in water via ion - dipole interaction as its strongest intermolecular interaction.
Answer:
Dipole -dipole forces :Ammonia [tex]NH_3[/tex]
Aluminium Chloride [tex]AlCl[/tex]
Methanol [tex]CH_3OH[/tex]
Ion dipole forces :Aluminium bromide [tex]AlBr_3[/tex]
Explanation:
Because water is not in ionic form it can only forms dipole forces which are strongest. Methanol, Ammonia and AlCl are also dipoles not ions . Thus dipole dipole forces exist.
On the other hand, aluminium bromide are ionic and it can forms ion dipole bonds with water.
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Provide a balanced molecular equation, total ionic, and net ionic equation for sodium phosphate and zinc acetate.
Answer: Balanced molecular equation :
[tex]2Na_3PO_4(aq)+3(CH_3COO)_2Zn(aq)\rightarrow 6CH_3COONa(aq)+Zn_3(PO_4)_2(s)[/tex]
Total ionic equation:
[tex]6Na^+(aq)+3PO_4^{2-}(aq)+6CH_3COO^-(aq)+3Zn^{2+}(aq)\rightarrow 6CH_3COO^-(aq)+6Na^+(aq)+Zn_3(PO_4)_2(s)[/tex]
The net ionic equation:
[tex]2PO_4^{3-}(aq)+3Zn^{2+}(aq)\rightarrow Zn_3(PO_4)_2(s)[/tex]
Explanation:
Complete ionic equation : In complete ionic equation, all the substances that are strong electrolyte are present in an aqueous state as ions.
Net ionic equation : In the net ionic equations, we are not include the spectator ions in the equations.
Spectator ions : The ions present on reactant and product side which do not participate in a reactions. The same ions present on both the sides.
When sodium phosphate and zinc acetate then it gives zinc phosphate and sodium acetate as product.
The balanced molecular equation will be,
[tex]2Na_3PO_4(aq)+3(CH_3COO)_2Zn(aq)\rightarrow 6CH_3COONa(aq)+Zn_3(PO_4)_2(s)[/tex]
The total ionic equation in separated aqueous solution will be,
[tex]6Na^+(aq)+2PO_4^{3-}(aq)+6CH_3COO^-(aq)+3Zn^{2+}(aq)\rightarrow 6CH_3COO^-(aq)+6Na^+(aq)+Zn_3(PO_4)_2(s)[/tex]
In this equation, and are the spectator ions.
By removing the spectator ions from the balanced ionic equation, we get the net ionic equation.
The net ionic equation will be,
[tex]2PO_4^{3-}(aq)+3Zn^{2+}(aq)\rightarrow Zn_3(PO_4)_2(s)[/tex]
What is the formula for sodium selenide?
What must happen in order for water to change state?
A. It must maintain its thermal energy level.
B. It must absorb or release energy.
C. It must be insulated.
D. It must convert thermal energy to solar energy.
Answer:
B
Explanation:
if it releases energy it becomes a solid(Solid)
if it absorbs energy it becomes a gas(Water Vapor)
How many moles are in 454 grams of dinitrogen trioxide (N2O3) ?
Answer:
5.97 mol
Explanation:
To find the number of moles when given the mass of a substance, we divide the mass of the sample by its molar mass.
so, we get,
nN203 = 454 g / 76.01 g /mol
= 5.97 mol
Ethanol is a common laboratory solvent and has a density of 0.789 g/mL. What is the mass, in grams, of 133 mL of ethanol?
[tex]V = \text{133 mL}[/tex]
[tex]\rho = \text{0.789 g/mL}[/tex]
Required:[tex]m[/tex]
Solution:[tex]\rho = \frac{m}{V}[/tex]
[tex]m = \rho V[/tex]
[tex]m = (\text{0.789 g/mL})(\text{133 mL})[/tex]
[tex]\boxed{m = \text{105 g}}[/tex]
Ethanol is a common laboratory solvent and has a density of 0.789 g/mL. 105g is the mass, in grams, of 133 mL of ethanol.
What is mass?In physics, mass is a quantitative measurement of inertia, a basic characteristic of all matter. It essentially refers to a body of matter's resistance to changing its speed or location in response to the force that is applied. The change caused by a force applied is smaller the more mass a body has.
The kilogram, which would be specified as equivalent to 6.62× 10³⁴ joule second in terms of Planck's constant, is the unit of mass inside the International Units System (SI).
density = mass / volume
mass =density× volume
= 0.78× 1.33
=105g
Therefore, 105g is the mass.
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how is acid different from base
How many molecules are there in a candle wax
Answer:
6
Explanation:
17. The equation below represents a chemical reaction that occurs in living cells.
CoH1206 + 602 -- 6002 + 6H20 + energy
How many atoms are represented in the reactants of this equation?
Answer:
36 atoms
Explanation:
C₆H₁₂O₆ + 6O₂ → 6CO₂ + 6H₂O + energyThe reactants are in the left side of the equation. First we determine how many atoms are there in the C₆H₁₂O₆ molecule:
6 C atoms + 12 H atoms + 6 O atoms = 24 atoms in totalThere are two atoms in a O₂ molecule, and there are 6 O₂ molecules in the equation:
2 * (6 O atoms) = 12 atoms in totalThe total number of atoms in the reactants is
24 + 12 = 36 atomshow many liters of 0.150 m hcl would be required to react completely with 8.00 grams of magnesium hydroxide
Answer:
how many liters of 0.150 m hcl would be required to react completely with 8.00 grams of magnesium hydroxide
Explanation:
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1. The octane present in gasoline burns according to the following equation:
2 C8H18 + 25 O2 → 16 CO2 + 18 H2O
(a) How many moles of O2 are needed to react fully with 27.5 moles of octane?
Answer:
[tex]n_{O_2}=343.75molO_2[/tex]
Explanation:
Hello there!
In this case, according to the combustion of octane:
[tex]2C_8H_1_8+25O_2\rightarrow 16CO_2+18H_2O[/tex]
We can see there is a 2:25 mole ratio of octane to oxygen; therefore, we can calculate the moles of oxygen via the following stoichiometric factor:
[tex]n_{O_2}=27.5molC_8H_1_8*\frac{25molO_2}{2molC_8H_1_8} \\\\n_{O_2}=343.75molO_2[/tex]
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Investigation Question: How do organisms get their genes?
THIS ANSWER SHOULD BE 3 OR MORE SENTENCES.
Answer:
from the chromosome..l dont know
LEVEL 3
Write the correct order
of letters to the finish line.
A E B E C
Example:
ABCGH
G
H
N
eza
Not correct
A 5.0 g sample of a pesticide was decomposed with metallic sodium in alcohol, and the liberated chloride ion was precipitated with AgCl. Express the results of this analysis in terms of percent DDT (C14H9Cl5, molar mass, 354.72 g/mol)) based on the recovery of 0.1606 g of AgCl
Answer:
1.59%
Explanation:
First, we convert 0.1606 g of AgCl into moles, using its molar mass:
0.1606 g ÷ 143.32 g/mol = 1.12x10⁻³ mol AgClThen we convert the calculated moles of Cl (equal to AgCl moles) into moles of DDT:
1.12x10⁻³ mol Cl * [tex]\frac{1molDDT}{5molCl}[/tex] = 2.24x10⁻⁴ mol DDTNow we convert 2.24x10⁻⁴ moles of DDT into grams, using its molar mass:
2.24x10⁻⁴ mol DDT * 354.48 g/mol = 0.0794 gFinally we calculate the percentage of DDT in the sample:
0.0794 g / 5.0 * 100% = 1.59%The _______________________________________ of a plant cell are where photosynthesis takes place.
Answer:
chloroplast
Explanation:
Answer:
chloroplasts
Explanation:
Basic Stoichiometry
Part 1: Mole ←→ Mass Conversions
Choose 2: Convert the following number of moles of chemical into its mass in grams.
1. 0.436 moles of (NH4)Cl = ______g
2. 0.50 moles of Ca(NO3)2 = ______g
Choose 2: Convert the following masses into their corresponding number of moles.
3. 23.5 g of NaCl = ______moles
4. 79.9 g of KMnO4 =______moles
5) The combustion of a sample of butane, C4H10 (lighter fluid), produced 2.46 grams of water.
Answer:
1. 23.3 g
2. 82 g
3. 0.402 mol
4. 0.506 mol
Explanation:
We can convert moles (n) to mass (m) using the following expressions that include the molar mass (M).
n = m/M
m = n × M
1. The molar mass of NH₄Cl is 53.49 g/mol.
m = 0.436 mol × 53.49 g/mol = 23.3 g
2. The molar mass of Ca(NO₃)₂ is 164.09 g/mol.
m = 0.50 mol × 164.09 g/mol = 82 g
3. The molar mass of NaCl is 58.44 g/mol.
n = 23.5 g/(58.44 g/mol) = 0.402 mol
4. The molar mass of KMnO₄ is 158.03 g/mol.
n = 79.9 g/(158.03 g/mol) = 0.506 mol
1.1
Which of these is NOT an intermolecular force?
A
Covalent bonding
B
Hydrogen bonding
с
London / dispersion forces
Dipole - dipole forces
1.2
London forces are found between ...
A two polar molecules.
B two non-polar molecules.
C a polar molecule and a non-polar molecule.
Da polar molecule and an ionic substance.
(2
1.3 Which of the following compounds have a shape that can be described as
trigonal bipyramidal?
A
CH4
B
PCL5
с
SF6
D
BF3
(2)
1.4
Which of the following have the same molecular geometry?
CO2, H20, BeCl2 and N20
A
CO2, BeCl2 and N2O
B
H20 and N20 only
C
H20, BeCl2 and CO2
CO2 and N20 only
(2)
Answer:
1.1) Covalent bonding
Explanation:
All of the above are intermolecular forces except covalent, which is intramolecular.
Convert 6.62 X 10^23 atoms to moles
Answer:
1.099
Explanation:
Hope this helps
Answer:
1.09944660051578e-23
Explanation:
If a sample of oxygen gas has a pressure of 810 torr at 298 K, what will be its pressure if its temperature is raised to 330K?
Answer:
The pressure is = 897 torr
Explanation:
We use Gay Lussac's Law.
N2 + 3H2 → 2NH3
How many moles of hydrogen, H2, are needed to react with 3.5 moles of nitrogen, N2?
Answer:
10.5 got it!!!!
A dilute solution of hydrofluoric acid has a volume of 3.0 L and a molarity of 3.0
M. If the original solution had a volume of 2.0L, what was the initial molarity?
Answer:
4.5M
Explanation:
The solution was diluted from 2.0L to 3.0L, the dilution factor was:
3.0L / 2.0L = 1.5.
That means the solution was diluted 1.5 times.
As the final molarity of the diluted solution is 3.0M, the initial molarity of the solution was:
3.0M * 1.5 =
4.5M is the molarity of the original solutionhow can landforms be weathered?
Answer:
they can become smaller or start fall apart or aroud
Explanation:
how many grams are in 6.8L of Oxygen gas (O2) at STP
Answer:
9.7 g
Explanation:
From the question,
Note: The molar volume of all gas at stp is 22.4 dm³ or 22.4 L
1 mol of oxygen gas (O₂) at stp = 22.4 dm³
X mole of oxygen gas (O₂) at stp = 6.8 L
X = (1 mol×6.8 L)/22.4 L
X = 0.3036 mol.
But,
Number of mole (n) = mass (m)/molar mass (m')
n = m/m'
m = n×m'.................. Equation 2
Where n = 0.3036 mol, m' = 32 g/mol
Substitute into equation 2
m = 0.3036×32
m = 9.7 g
Sandy is conducting an investigation to find out which
food his dog likes best. Which is the dependent variable
in his investigation?
color of the
dog's dish
BROWN
amount of
food eaten
the type of
food given
PINK
LIGHT GREEN
Answer: Whats the question?
An ideal gas in a sealed container has an initial volume of 2.80 L. At constant pressure, it is cooled to 18.00 °C, where its
final volume is 1.75 L. What was the initial temperature?
Ti =
'c
Answer:
[tex]T_1=-91.18\°C[/tex]
Explanation:
Hello there!
In this case, given the T-V variation, we understand it is possible to apply the Charles' law as shown below:
[tex]\frac{T_1}{V_1}= \frac{T_2}{V_2}[/tex]
Thus, since we are interested in the initial temperature, we can solve for T1, plug in the volumes and use T2 in kelvins:
[tex]T_1= \frac{T_2V_1}{V_2}\\\\T_1= \frac{(18.00+273.15)K(1.75L)}{(2.80L)}\\\\T_1=182K-273.15\\\\T_1=-91.18\°C[/tex]
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plz, help me I'm so confused!
(this is also science)
Answer:
Well, there is no photo...
Explanation: