Answer:
[tex]A=250g[/tex]
Explanation:
Hello there!
In this case, by considering the radioactive decay as a first-order kinetic model:
[tex]A=Ao*exp(-kt)[/tex]
We can firstly calculate the rate constant given the half life:
[tex]k=\frac{ln(2)}{t_{1/2}} =\frac{ln(2)}{520years}=1.33x10^{-3}years^{-1}[/tex]
Thus, we can plug in the elapsed time and the initial amount Ao to obtain:
[tex]A=1,000g*exp[-1.33x10^{-3}years^{-1} *(3061-2021)years]\\\\A=250g[/tex]
Best regards!
How many electrons are represented by a dash (-) in a lewis dot structure compound?
A. 2
B. 4
C.3
D. 1
Which of the following represents a double-displacement reaction?
a. ABC ➡️AB +C
b. A+B ➡️AB
c. AB + CD➡️AD + CB
d. A + BC ➡️AC + B
How many moles of iron would be needed to react with 3.82 moles of
oxygen
The number of moles of iron (Fe) required to react with 3.82 moles of oxygen is 5.09 moles
Balanced equation
3O₂ + 4Fe —> 2Fe₂O₃
From the balanced equation above,
3 moles of O₂ reacted with 4 moles of Fe
How to determine the moles of FeFrom the balanced equation above,
3 moles of O₂ reacted with 4 moles of Fe
Therefore,
3.82 moles of O₂ will react with = (3.82 × 4) / 3 = 5.09 moles of Fe
Thus, 5.09 moles of Fe is needed for the reaction
Learn more about stoichiometry:
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Why does the United kingdom have a temperate climate instead of a polar climate
Answer:
https://www.bbc.co.uk/bitesize/guides/zpykxsg/revision/3 (i know ppl hate it when you put links but i actually think this may explain it)
Explanation:
Elements o fb the same group have the same chemical properties
Answer:
The chemical elements are arranged in order of increasing atomic number. The horizontal rows are called periods and the vertical columns are called groups. Elements in the same group have similar chemical properties. This is because they have the same number of outer electrons and the same valency.
DNA evidence can be used for what? Creating a representation of a suspect Identifying a species of pollen Matching microbiomes All of the above
Answer:
multiple things.
Explanation:
DNA evidence collected from a crime scene can be linked to a suspect or can eliminate a suspect from suspicion. During a sexual assault, for example, biological evidence such as hair, skin cells, semen, or blood can be left on the victim's body or other parts of the crime scene.
Answer:
I think it is just a
Explanation:
The half-life of radium-226 is 1,600 years. It decays into radon-222. What fraction of the original amount of radium-226 in a sample will still be radium
after 8,000 years?
A.1/8
B.1/4
c.1/32
D.1/16
Answer:
Your answer will be C. 1/32
Answer:
C. 1/32
Explanation:
calculate the concentration of the solution produced when a 3.2g of sodium chloride is
issolved in 8dm of water.
Answer:
The concentration of the 3.2 g of sodium chloride in 8 dm³ of water is 6.845 × 10⁻³ M
Explanation:
The concentration of a solution is given as either the ratio of mass to volume, or the ratio of volume to volume or as molarity
[tex]Concentration, C = \dfrac{Mass}{Volume} = \dfrac{Volume}{Volume} = \dfrac{Number \ of \ moles }{Liters \ of \ solution}[/tex]
The number of moles present in 3.2 g of sodium chloride, 'n', is given as follows;
[tex]n = \dfrac{Mass}{Molar \ mass}[/tex]
The molar mass of sodium chloride, NaCl = 58.44 g/mol
n = 3.2 g/58.44 g/mol = 0.0547570157 moles
8 dm³ = 8 Liters
Therefore, the concentration, C = 0.0547570157 moles/(8 liters) = 6.845 × 10⁻³ M
The concentration of the 3.2 g of sodium chloride in 8 dm³ of water = 6.845 × 10⁻³ Molar solution.
compare and contrast between combustion and rusting
Answer:
combustion is fast and destructive it also involves a lot of movement of the atoms where erosion is a slow process that does not involve a lot of energy
Which statement describes the endothermic reaction represented by this
graph?
Answer:
Option A, describes the endothermic reaction represented by this graph
Explanation:
In this graph the energy released (or the potential energy) at the time of product formation is lower than the potential energy of the reactants. Hence, additional energy input will be required to form the product. Thus, energy is absorbed during the reaction.
Option A is correct
Answer: energy is given off by the reaction
Explanation:
Which type of hybridization is observed when central atom is located at the centre of regular tetrahedron
Answer:
sp3 hybridization
Explanation:
Hybridization means the mixing of atomic orbitals to yield hybrid orbitals with characteristics that are different from that of the isolated atomic orbitals before the combination.
sp3 hybridization occurs when one s orbital is mixed with three p orbitals to yield four sp3 hybrid orbitals which can be used to bond to a central atom.
The central atom is then located at the center of a regular tetrahedron at a bond angle of 109°.
How many grams of HCl are needed to form 34.5 grams of Cl2?
Answer:
Expof HCl are required to produce 7.50 moles of ZnCl2? 6. Copper ... When 9.34 g of zinc react with excess hydrochloric acid how many grams of zinc chloride will.lanation:
When V increases, I _______ . It is a direct relationship
A. increases
B. decreases
C. remains constant
Answer:
B
Explanation:
calculate the number of moles present in 9.50g of CO2
Answer: 44.0095.
Explanation:
The empirical formula for butene is
A.
CH2
B.
C₂H4
C.
Ca HG
D
C4H8
What is the scale that measures the acidity or basicity of a solution?
A. Concentration
B. Compound
C. Neutralization
D. pH
Answer:
PH scale is a universal indicator of strongness of base and acid
What property of water allows the water to cover the astronauts hand?
Answer:
The tendency for water molecules to stick together causes it to causes spheres in space. ... Magnetic-like molecules on water's surface cause the surface to behave like an elastic skin. Each molecule is pulled with equal tension by its neighbors.J
Explanation:
Which statement describes the feeling interactions between frogs and insects? Select all that apply.
A. The frog is a predator
B. The interactions is mutualistic
C. The frog is a parasite
D. The number of insects can influence the number of frogs in the ecosystem.
The moon appears to change _________ over the course of the _______________.
Answer:
shape or size? over the course of the month
What is the poH of a solution that has an [H+] = 7.7 x 10-7 M? *
O 7.9
6.5
O 2.3
Answer:
7.9
Explanation:
pH=-log([H+])
pH=-log(7.7×10⁻⁷M)
pH=6.113509275
Now, poH + pH = 14
Making poH the subject,
poH=14-pH
poH=14-6.113509275
poH=7.886490725
≈7.9
∴poH≈7.9
which is the correct order of ease of carbon dioxide production by heating the group II metal carbonates?
Which is the correct order of ease of carbon dioxide production by heating the group II metal carbonates?
A) [tex]BaCO_{3} > SrCO_{3} > CaCO_{3} > MgCO_{3}[/tex]
B) [tex]MgCO_{3} > CaCO_{3} > SrCO_{3} > BaCO_{3}[/tex]
C) [tex]CaCO_{3} > MgCO_{3} > BaCO_{3} > SrCO_{3}[/tex]
D) [tex]SrCO_{3} > BaCO_{3} > CaCO_{3} > MgCO_{3}[/tex]
Answer:
Explanation:
The correct option is A:
[tex]BaCO_{3} > SrCO_{3} > CaCO_{3} > MgCO_{3}[/tex]
On the periodic table, carbonates required stronger heating as one does down the groupings in order for them to decompose. The implication is that the stability of compounds will increase from [tex]MgCO_{3}[/tex] to [tex]BaCO_{3}[/tex] .
So the carbonates will be stable according to the following order:
[tex]BaCO_{3} > SrCO_{3} > CaCO_{3} > MgCO_{3}[/tex], thus making B the correct answer.
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How many moles of O2 are needed to produce 8.33 moles of H2SO4?
Why do gems have different properties than metals? Claim,evidence and Reasoning
Answer:
Gems are natural material, metals are man-made materials!
Explanation:
Minerals occur naturally in the earth's crust and are defined as inorganic solids that have characteristic chemical composition and crystalline structures. ... A gemstone or gem is a piece of mineral crystal, which, in cut and polished form, is used to make jewelry or other adornments.
The explanation regarding the gems contains the various properties as compared to the metals should be described below:
Gems should be composed of the similar substance while on the other hand the metal compose of two or more elements of metallic. Gems should compose of non-metallic elements. Also, the gem does not compose of free electrons. While on the other hand, metal compose of free electrons that conduct electricity. So it does not conduct electricity such as metals.In this way, it should be explained.
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Give the word and chemical equations (including state symbols) for the reaction of potassium and water
Zinc will displace copper from a solution of copper sulfate, and magnesium will displace zinc from a solution of zinc sulfate
a)Write full, balanced chemical equations for the two reactions using state symbols.
Answer:
Zinc is Zn and Magnesium is Mg
A gas at 1.10 atm and 30.0°C fills a flexible container with an initial volume of 2.00 L. If the temperature is raised to 80.0°C and the pressure increased to 2.40 atm, what is the new volume?
Answer:
P1=1.10atm
V1=2.00L
T1=30.0+273=303
P2=2.40atm
V2=?
T2=80.0+273=353
Explanation:
V2=1.10*2.00*353=776.6
2.40*303=727.2
776.6/727.2=1.0679L
The new volume occupied by the of gas as its temeprature and pressure is raised is 1.07L.
Combined gas lawCombined gas law put together both Boyle's Law, Charles's Law, and Gay-Lussac's Law. It states that the ratio of the product of volume and pressure and the absolute temperature of a gas is equal to a constant.
It is expressed as;
P₁V₁/T₁ = P₂V₂/T₂
Given the data question;
Initila pressure P₁ = 1.10atmFinal pressure p₂ = 2.40atmInital temperature T₁ = 30.0°C = 303.15KFinal temperature T₂ = 80.0°C = 353.15KInitial Volume V₁ = 2.00LFinal Volume V₂ = ?To calculate the new volume that the gas occupy, we subtsitute our given values into the expression above.
P₁V₁/T₁ = P₂V₂/T₂
P₁V₁T₂ = P₂V₂T₁
V₂ = P₁V₁T₂ / P₂T₁
V₂ = ( 1.10atm × 2.00L × 353.15K ) / ( 2.40atm × 303.15K )
V₂ = 776.93LatmK / 727.56atmK
V₂ = 1.07L
Therefore, The new volume occupied by the of gas as its temeprature and pressure is raised is 1.07L.
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Can any one plz solve and send this question who ever solve this right I will make you brainliest this is physic
Answer: Energy = 10000J - 2000J = 8000J
Therefore, the energy is dissipated the skier moves down to the slope is 8000J
Explanation:
What is the mass of 1 mole of Na3,PO4?
Answer:
163.940671 grams
Explanation:
You can view more details on each measurement unit: molecular weight of Na3PO4 or grams This compound is also known as Trisodium Phosphate. The SI base unit for amount of substance is the mole. 1 mole is equal to 1 moles Na3PO4, or 163.940671 grams.
Determine the pH of a 2.8 ×10−4 M solution
of Ca(OH)2.
Answer:
pH = 10.75
Explanation:
To solve this problem, we must find the molarity of [OH⁻]. With the molarity we can find the pOH = -log[OH⁻]
Using the equation:
pH = 14 - pOH
We can find the pH of the solution.
The molarity of Ca(OH)₂ is 2.8x10⁻⁴M, as there are 2 moles of OH⁻ in 1 mole of Ca(OH)₂, the molarity of [OH⁻] is 2*2.8x10⁻⁴M = 5.6x10⁻⁴M
pOH is
pOH = -log 5.6x10⁻⁴M
pOH = 3.25
pH = 14-pOH
pH = 10.75Consider the following reaction: Solid zinc was added to 1.0 M HC1.
After 20.0 s, the temperature of the container increased by 0.5°C and 25.00 mL of
H2 was produced. The rate of this reaction was
Answer:
1.25 mL/s
Explanation:
Your are told that 25.0 mL of H2 was produced 20 seconds. This is equal to rate 25/20 = 1.25 mL/s
When a reaction progresses, the reactant concentration gradually decreases and the product concentration gradually increases. Here the rate of the reaction is 1.25 mL/s.
What is rate of reaction?The rate of a chemical reaction is defined as the rate of decrease of concentration of a reactant or the rate of increase of concentration of a product. The rate of the reaction is usually expressed in units mol L⁻¹s⁻¹. The rate of the reaction are affected by several factors like concentration of the reactants, temperature, etc.
An equation which expresses the experimentally observed rate of a reaction in terms of the molar concentration of the reactants which determine the rate of the reaction is called rate equation.
Here it is seen that 25.0 mL of H2 was produced 20 seconds. So the rate is given as:
Rate = 25/20 = 1.25 mL/s
Thus the rate of the reaction is 1.25 mL/s.
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Ethyl alcohol has a density of 0.80 g/mL. What is the volume of 44g of ethyl alcohol
ANSWER CHOICES
55 mL
35 mL
42 mL
0.80 mL
Answer:
55mL
Explanation:
44g / 0.8g/mL = 55mL