Answer: The decay constant for C14 is [tex]0.000121years^{-1}[/tex]
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
for completion of half life:
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}{5730years}=0.000121years^{-1}[/tex]
The decay constant for C14 is [tex]0.000121years^{-1}[/tex]
please solve if the pressure of 200cm cube of a gas is half at constant temperature.what will be the new volume
Answer:
400 cm³
Explanation:
Let p₁ Pa be the original pressure of the gas
p₂ Pa be the new pressure of the gas
V₁ m³ be the original volume of the gas
V₂ m³ be the new volume of the gas
According to Boyle's Law,
p₁V₁ = p₂V₂
p₁ × 0.0002 = 1/2 p₁ × V₂
0.0002 = 1/2 × V₂
V₂ = 0.0004
∴ The new volume of the gas = 0.0004 m³ = 400 cm³
The new volume will be 400 cm³
What is Boyle's Law?
Boyle’s law is a gas law which states that the pressure exerted by a gas (of a given mass, kept at a constant temperature) is inversely proportional to the volume occupied by it.
PV = constant
Boyle's Law can be used to compare changing conditions for a gas. In other words, the pressure and volume of a gas are inversely proportional to each other as long as the temperature and the quantity of gas are kept constant.
Given,
initial volume = 200cm³
Let us assume the initial pressure is p, then the final pressure will be 0.5p.
Using Boyle's law,
P₁V₁ = P₂V₂
p × 200 = 0.5p × V₂
V₂ = (p × 200) ÷ ( 0.5p)
V₂ = 400 cm³
Therefore, the new volume will be 400 cm³
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Why wouldn’t a tennis player with two sneakers “bond” to any other tennis players? Why wouldn’t a helium atom with two electrons “bond” to any other atoms?
Answer:
Explained below.
Explanation:
A tennis player with two sneakers wouldn't bond to any other tennis player because he is already stable and complete with the 2 and doesn't need another players assistance to make him stand well.
However, helium atom with two electrons wouldn't bond to any other atoms because it is stable. This stability arises from the fact that it has two protons and 2 electrons, of which the 2 electrons completely fill its valence shell/outer most shell to make it neutral.
#15 need help don’t understand
Please help me!!! this is due now
1. What are the rows of the periodic table called and what do they tell us?
Answer:
The elements are arranged in seven horizontal rows, called periods or series, and 18 vertical columns, called groups.
Each row represents one period; the period number of an element indicates how many of its energy levels house electrons. Sodium, for instance, sits in the third period, which means a sodium atom typically has electrons in the first three energy levels.
Explanation:
1. If 3.2 L of nitrogen monoxide and 4.3 g of oxygen gas are combined, what volume of nitrogen dioxide will be formed? 2NO + 0, -> 2NO,
Answer:
[tex]3.2 \div 22.4 = \frac{1}{7} mol \: no[/tex]
[tex]4.3 \div 32 = 0.134mol \: o2[/tex]
Explanation:
NO is limit reactant so:
1÷7×46=6.57 grams of NO2 will form
All but one statement below tell why scientists work in groups
A.problems are complex
B.research progress takes a lot of time and money
C.some scientists are lazy and steal the ideas of others
D.research progress occurs in small steps, so many people are needed
There are two major isotopes of Lithium. The first has a mass of 6.015 amu and
represents 7.59%. The other is mass 7.0160 amu, which accounts for 92.41%. What is the
average atomic mass of naturally occurring Lithium?
Answer:
6.9399amu
Explanation:
Isotopes are elements with same atomic number but different atomic masses.
To determine the average atomic mass one must multiply the absolute atomic mass (amu) of each isotope times its absolute atomic mass. This will give the weight average contribution of each isotope. The sum of the weight average contributions gives the final weight average atomic mass of the element. The wt. avg. atomic mass is the value posted on the periodic table.
It is recommended that a table be sketched in the following form ...
Isotope | % fractional amt. X Isotopic mass(amu) => Wt. Avg**.
Li-6 7.59% => 0.0759 x 6.015amu => 0.4565
Li-7 92.41% => 0.9241 x 7.016amu => 6.4835
*amu => atomic mass units ∑ Li-6 + Li-7 = 6.9399amu
**Wt.Avg. => weight average contribution of isotope = fractional amt x Isotopic mass(amu)
*** Final Wt. Avg. = ∑Wt.Avg. Contributions (value posted of periodic table)
Methylpropene is used to make synthetic rubber and
contains 0.556g carbon, 0.0933g hydrogen. What is the empirical formula?
Answer:
CH₂
Explanation:
First we convert the given masses of elements into moles, using their respective molar masses:
C ⇒ 0.556 g ÷ 12 g/mol = 0.0463 mol CH ⇒ 0.0933 g ÷ 1 g/mol = 0.0933 mol HNow we divide those results by the lowest value between the two of them:
C ⇒ 0.0463 / 0.0463 = 1H ⇒ 0.0933 / 0.0463 = 2Meaning the empirical formula is CH₂.
What is the Empirical formula of sucrose (C12H22O11) ?
Sucrose is C12H22O11 and here we can not express it as the simplest ration of integers. So its empirical formula is same as that of its molecular formula I.e-C12H22O11.2017年10月31日
_ C4H8O+ _O₂ _ CO2+ H₂O
balancing equations
select the statement that best describes the adaptions of animals and plants
where is the selections?
320.0 g of NaCl would contain how many formula units? (Molar mass of
NaCl is 58.44 g/mol) *
Answer:
Formula unit = 32.9746×10²³
Explanation:
Given:
Mass of NaCl = 320 g
Molar mass of NaCl = 58.44 g/mol
Find:
Formula unit
Computation:
Formula unit = [Mass of NaCl / Molar mass of NaCl]Avogadro's number
Formula unit = [320 /58.44]6.022×10²³
Formula unit = 32.9746×10²³
Calculate the volume of a balloon that can hold 113.4 g of nitrogen dioxide, NO2 gas at STP-
Answer:
55.18 L
Explanation:
First we convert 113.4 g of NO₂ into moles, using its molar mass:
113.4 g ÷ 46 g/mol = 2.465 molThen we use the PV=nRT formula, where:
P = 1atm & T = 273K (This means STP)n = 2.465 molR = 0.082 atm·L·mol⁻¹·K⁻¹V = ?Input the data:
1 atm * V = 2.465 mol * 0.082atm·L·mol⁻¹·K⁻¹ * 273 KAnd solve for V:
V = 55.18 LWhen a hydrocarbon molecule and an oxygen molecule react chemically, energy breaks molecular bonds of the reactants and forms the new molecular bonds of the products. How is energy involved in bonds forming and breaking during the reaction?
Choose one.
A. Energy is released as bonds form and is released as bonds break.
B. Energy is released as bonds form and is absorbed as bonds break.
C. Energy is absorbed as bonds form and is released as bonds break.
D. Energy is absorbed as bonds form and is absorbed as bonds break.
Answer:
C. Energy is absorbed as bonds form and is released as bonds break.
Explanation:
In chemistry, when a bond is broken energy is released, while and bond formation is a process that requires energy -meaning energy is absorbed-.
It is for this reason that reactions of the type A + B → C are endothermical, while reactions of the type C → A + B are exothermical.
Empirical evidence
A
should never be replicable and repeated.
B
helps scientists understand the natural world.
C
will always make a hypothesis true.
D
comes from made up stories about the world.
Answer:
Empirical evidence - B - helps scientists understand the natural world.
Explanation:
Definition from the web," Empirical evidence is information acquired by observation or experimentation. Scientists record and analyze this data. The process is a central part of the scientific method. "
The scientific method-The scientific method begins with scientists forming questions, or hypotheses, and then acquiring the knowledge through observations and experiments to either support or disprove a specific theory. "Empirical" means "based on observation or experience," according to the Merriam-Webster Dictionary. Empirical research is the process of finding empirical evidence. Empirical data is the information that comes from the research.
Before any pieces of empirical data are collected, scientists carefully design their research methods to ensure the accuracy, quality and integrity of the data. If there are flaws in the way that empirical data is collected, the research will not be considered valid.
The scientific method often involves lab experiments that are repeated over and over, and these experiments result in quantitative data in the form of numbers and statistics. However, that is not the only process used for gathering information to support or refute a theory.
This helps scientists by -Identifying empirical evidence in another researcher's experiments can sometimes be difficult. According to the Pennsylvania State University Libraries, there are some things one can look for when determining if evidence is empirical:
Can the experiment be recreated and tested?Does the experiment have a statement about the methodology, tools and controls used?Is there a definition of the group or phenomena being studied?If 13.5 L of nitrogen gas reacts with 17.8 L of hydrogen gas at STP, according to the following reaction, what mass of ammonia would be produced? N2 + 3 H2 --> 2 NH3 Report your answer with proper significant figures, only a number answer is required, no units needed for this form.
Answer: N5 + H4 and then do 13.5 * 17.8 then solve so 240.3 divided by 9
Your answer is 26.7 Pretty sure
Explanation: (study)
Answer:
Work is all on the paper
The value of the equilibrium constant for a reaction
a. changes with temperature.
b. changes with time.
c. is the same under all conditions.
d. changes with concentration.
Answer:
a. changes with temperature.
Explanation:
Hello there!
In this case, according to the thermodynamic definition of the equilibrium constant in terms of the Gibbs free energy of reaction and the temperature of the system:
[tex]lnK=-\frac{\Delta G}{RT}[/tex]
It is possible to figure out that the equilibrium constant varies as temperature does, not only on the aforementioned definition, but also in the Gibbs free energy as it is also temperature-dependent. Therefore, the appropriate answer is a. changes with temperature.
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For each of the following, determine whether the observation is primarily a physical change or a chemical change.Explain.
a. On a hot day, drops of water collect on the outside of a glass holding iced tea.
b. Clear, colorless lemon juice is added to a glass of iced tea.The tea color changes from brown to yellow-brown.
c. Water is added to a glass of iced tea.The tea color lightens.
Answer:
A)Physical change
B)physical change
C)physical change
Explanation:
A) there is no new substances formed from the process, so it's still physical change
B)there is no new substances formed from the process, so it's still physical change since tea is still the substance that is formed. The color changes is still physical
C) addition of water to the tea is still the same, tea was formed. no new substances formed,
When a substance pass through a physical change, it has its composition still remains the same, it's molecules can be rearranged. There is no formation of new substance as far
physical change is concerned.
When a substance pass through a
chemical change, it has its molecular composition changed . In a chemical change there is formation of new substances.
How many L are required to make 3.5 M hydrochloric acid using 1.1 moles?
0.31 L
General Formulas and Concepts:Math
Pre-Algebra
Order of Operations: BPEMDAS Brackets Parenthesis Exponents Multiplication Division Addition Subtraction Left to RightEquality Properties
Multiplication Property of Equality Division Property of Equality Addition Property of Equality Subtraction Property of EqualityChemistry
Atomic Structure
MolesAqueous Solutions
Molarity = moles of solute / liters of solutionEquilibrium - Acid/Base
Strong AcidsWeak AcidsWriting AcidsExplanation:Step 1: Define
[Given] 3.5 M HCl
[Given] 1.1 moles
[Solve] Liters solution
Step 2: Solve
Substitute in variables [Molarity]: [tex]\displaystyle 3.5 \ M = \frac{1.1 \ moles}{x \ L}[/tex][Solution] Cross-Multiply [Equality Property]: [tex]\displaystyle x \ L = \frac{1.1 \ mol}{3.5 \ M}[/tex][Solution] Divide: [tex]\displaystyle x = 0.314286 \ L[/tex]Step 3: Check
Follow sig fig rules and round. We are given 2 sig figs.
0.314286 L ≈ 0.31 L
What volume, in milliliters, of a 0.140 M solution of KCl contains 2.65 g of the compound?
Express the volume to three significant figures and include the appropriate units.
Answer:
Calculate moles KCl: 2.55 g / 74.55 g/mol = 0.0342 moles KCl
Volume KCl = 0.0342 mol X (1 L/0.150 mol) = 0.228 L X 1000 mL/L = 228 mL
Explanation:
Volume=288mL
Given:
Molarity=0.140 M
Mass=2.65 g
To find:
Volume=?
Molar mass of KCl = 74.55 g/mol
Firstly, we need to calculate the number of moles of KCl:
[tex]\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}} \\\\\text{Number of moles}=\frac{2.65g}{74.55g/mol} \\\\\text{Number of moles}=0.0355 moles[/tex]
In order to calculate the volume,
[tex]\text{ Volume of KCl} = 0.0342 mol * (1 L/0.150 mol) \\\\\text{ Volume of KCl} = 0.228 L * 1000 mL/L \\\\\text{ Volume of KCl} = 228 mL[/tex]
The volume in mL will be 228mL.
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why cancer is not a pathogen?
Answer:
Because their cells duplicate inside of you not normally!
Explanation:
Hope this helps! Plz mark as brainliest! :)
* Urgent Bet no one knows this *
Answer: The name of the super continent that existed millions of years ago.
Explanation:
Our continents as they exist today were once joined together into a super continent known as Pangea. Over the millennia, the land masses broke off and drifted away creating the location of the continents we know today.
(つ ^‿^ )つ Hey there!
Answer → Is the second answer, The name of the super continent that existed millions of years ago.
✨Hope this helps!✨
How many moles are in 163.5 liters of oxygen gas?
One mole of oxygen gas, which has the formula O2, has a mass of 32 g and contains 6.02 X 1023 molecules of oxygen but 12.04 X 1023 (2 X 6.02 X 1023) atoms, because each molecule of oxygen contains two oxygen atoms.
#12 don’t understand need help significantly
C. 8.80 mol H₂
General Formulas and Concepts:Math
Pre-Algebra
Order of Operations: BPEMDAS
Brackets Parenthesis Exponents Multiplication Division Addition Subtraction Left to RightChemistry
Atomic Structure
Reading a Periodic TableMolesStoichiometry
Using Dimensional AnalysisAnalyzing Reactions RxNExplanation:Step 1: Define
[RxN - Balanced] N₂ (g) + 3H₂ (g) → 2NH₃ (g)
[Given] 100 g 2NH₃
[Solve] moles H₂
Step 2: Identify Conversions
[RxN] 2 mol NH₃ (g) → 3 mol H₂ (g)
[PT] Molar Mass of N - 14.01 g/mol
[PT] Molar Mass of H - 1.01 g/mol
Molar Mass of NH₃ - 14.01 + 3(1.01) = 17.04 g/mol
Step 3: Stoich
[DA] Set up conversion: [tex]\displaystyle 100 \ g \ NH_3(\frac{1 \ mol \ NH_3}{17.04 \ g \ NH_3})(\frac{3 \ mol \ H_2}{2 \ mol \ NH_3})[/tex][DA] Multiply/Divide [Cancel out units]: [tex]\displaystyle 8.80282 \ mol \ H_2[/tex]What creates an electric current in
a battery?
Answer: The answers are kinda blury but use this info to help u out or read over the passage
Explanation:A battery is a device that stores chemical energy and converts it to electrical energy. The chemical reactions in a battery involve the flow of electrons from one material (electrode) to another, through an external circuit. The flow of electrons provides an electric current that can be used to do work.
Answer: metal bending
Explanation: is the metal
What is the pH of 2.88*10^-5 M LiOH?
Answer: 9.46
Explanation: in LiOH solution concentration of OH- ions is 2.88·10^-5 M
And pOH = -log( 2.88·10^-5 M) = 4.54. Because PH + pOH = 14.00
Then pH = 14-4.54
Diethylamine and HCl react to produce ________.
Answer:
diethylammonium chloride
Explanation:
In the given question, diethylamine and HCl react to produce diethylammonium chloride.
A reaction is a chemical process that includes the change of one or more substances into one or more different substances.
The reaction between dimethylamine and HCl produces dimethylammonium chloride. The chemical equation for the reaction is represented as:
[tex]\rm (CH_3)_2NH + HCl \rightarrow (CH_3)_2NH_2+ Cl^-[/tex]
In this reaction, dimethylamine acts as a base and accepts a proton [tex]\rm (H^+)[/tex] from HCl to form the salt, dimethylammonium chloride.
Therefore, diethylammonium chloride is formed when diethylamine and HCl reacts.
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Where are the most reactive nonmetals located on the periodic table?