a. k=0.256/day
b.sample of Au-198 remains after seven days : 1.67 g
Further explanation1. A half-life of 2.7 days⇒t1/2=2.7 days
The half-life can be expressed in a decay constant( λ)
[tex]\tt \displaystyle t_ {1/2} = {\dfrac {\ln (2)} {\lambda}}\\\\\lambda(or~k)=\dfrac{0.693}{2.7}=0.256/day[/tex]
2. We can use formula : (integrated rate law) :
[tex]\tt ln[A]=-kt+ln[Ao]\\\\ln(\dfrac{Ao}{A})=kt[/tex]
Ao=10 g
t=7 days
k=0.256/day
[tex]\tt ln(\dfrac{10}{A})=0.256\times 7\\\\ln(\dfrac{10}{A})=1.792\\\\e^{1.792}=\dfrac{10}{A}\\\\6=\dfrac{10}{A}\rightarrow A=1.67~g[/tex]
The mass of Au-198 that remains after seven days is 1.62 g.
We know that radioactive decay is a first order reaction hence;
k = 0.693/ t12
Where;
k = rate constant
t12 = half life
k = 0.693/ 2.7 days = 0.26 day-1
Using;
N =Noe^-kt
No = amount of radioactive material initially present
N = mass of radioactive substance present at time t
N = 10 e^-(0.26 × 7)
N = 1.62 g
The mass of Au-198 that remains after seven days is 1.62 g.
Learn more about radioactive decay: https://brainly.com/question/14077220
Atoms don’t absorb all wavelengths of light because of…
a. Their valence electrons
b. Their shells
c. Their color
d. They do absorb all wavelengths of light
Answer:
b. Their shells
Explanation:
The electronic shell of atoms represents the energy levels in a particular atom.
To understand the way atoms absorb energy, we must know that the wavelength absorbed is commensurate with the energy of the atom. This available energy allows for specific amount of energy to be absorbed.
Therefore, the electronic shell in an atom determines the absorption wavelength of the atom.
SOMEONE HELP ME PLEASE ILL GIVE BRAINLY
Snapping an instant cold pack is a
Change in temperature
Formation of gas/bubbles
Formation of precipitate
Release of energy (fire/light)
Change in color
Answer:
Answer
Change in temperature
It is an example of an endothermic reaction. It is absorbing heat.
25 points , hi! please look at the attachment for the question, I'm having a hard time because all I have to do is solve through those 2 problems but I'm not sure if I solve the fractions first then multiply that result by 100 or what. I asked my teacher which she helped a little but I don't think she understood where I was lost. If you can help I would really appreciate it. Thank you.
This was the set up question:
4. If 100.0g of nitrogen gas (N2) is reacted with 100.0g of hydrogen gas (H2) to form NH3. What is the limiting and excess reactants?
Hint: Convert grams to moles for each reactant and then convert to moles of NH3. You need your balanced equation from answer 1 to determine the mole relationship between each reactant and the product NH3. Use the periodic table to determine the molar mass of all chemical formulas. Fill in the “?” blanks below to show your work.
and in the screenshot it has everything I'm working with and the conclusions I need to draw from it, I can draw the conclusions just fine on my own but I need help solving.
Answer:
To answer the question, we correctly fill the attached screenshot as follows;
3H₂ + N₂ → 2NH₃The molar mass of H₂ = 2 g/mol[tex]100.0 g \ H_2 \times \dfrac{1 \ mol \ H_2}{2 \ g \ H_2} \times \dfrac{2 \ mol \ NH_3}{3 \ mol \ H_2} = 33.\bar 3 \ mol \ NH_3[/tex]
The molar mass of N₂ = 28 g/mol
[tex]100.0 g \ N_2 \times \dfrac{1 \ mol \ N_2}{28 \ g \ N_2} \times \dfrac{2 \ mol \ NH_3}{1 \ mol \ N_2} \approx 7.143 \ mol \ NH_3[/tex]
A. Therefore, the excess reactant is hydrogen gas H₂ because it makes the most amount of ammonia, NH₃ (33.[tex]\bar 3[/tex] moles of NH₃)
B. The limiting reactant in nitrogen, N₂, because it is the reactant that makes the least amount of the ammonia, NH₃ (approximately 7.143 mol NH₃)
C. The theoretical yield of ammonia, is the maximum amount of ammonium that can be produced from the reaction between the 100 g of hydrogen gas, H₂, and 100 g of nitrogen gas, N₂ which is given by the amount of ammonia produced by the limiting reactant which is approximately 7.143 mole of NH₃
Explanation:
Answer:
Explanation:
Did u ever get answer
Describe the two types of mechanical energy
Answer:
Kinetic energy and potential energy
Explanation:
kinetic energy is when the energy is active and potential energy is when it is about to be active
If the reacants of a chemical raction have 15 Carbon atoms, 72 Lead
atoms, and 88 Nitrogen atoms, what will the products have?
Answer:
In the human body, potential energy is stored in the bonds between atoms and molecules. Chemical energy is the form of potential energy in which energy is stored in chemical bonds. When those bonds are formed, chemical energy is invested, and when they break, chemical energy is released. Notice that chemical energy, like all energy, is neither created nor destroyed; rather, it is converted from one form to another. When you eat an energy bar before heading out the door for a hike, the honey, nuts, and other foods the bar contains are broken down and rearranged by your body into molecules that your muscle cells convert to kinetic energy.
Explanation:
PLEASEEEE Hurry its due in 20 min
Complete and balance each of the following equations for acid-base reactions.
HClO4(aq)+NaOH(aq)→
Express your answer as a chemical equation. Identify all of the phases in your answer.
Answer:
HCl[tex]O_{4}[/tex](aq) + NaOH → NaCl[tex]O_{4}[/tex](aq) + [tex]H_{2} O[/tex](l)
Explanation:
water is a liquid if you can't see
CFCs were found to destroy what important compound in our atmosphere?
A: ozone
B: nitrogen
C: water vapor
D: helium
Answer:
A: ozone
Explanation:
Chlorofluorocarbons (CFCs) and hydrofluorocarbons (HCFCs) destroy ozone in the stratosphere.Answer:
A: ozone
Explanation:
right on EDGE 2021
Can someone pls do this
Explanation:
Sodium sulfate
Na₂SO₄
The sulfate ion is SO₄²⁻
Sodium sulfite
Na₂SO₃
The sulfite ion is SO₃⁻
Sodium sulfide
Na₂S
The sulfide ion is S²⁻
Sodium phosphate
Na₂PO₄
Phosphate ion is PO₄²⁻
Sodium phosphite
Na₃PO₃
The phosphite is PO₃³⁻
Sodium phosphide
Na₃P
The phosphide ion is P³⁻
where was hydrogen discovered
Answer:
maybe greece
Explanation:
by henry cavendish in 1766
In DNA, adenine always pairs with?
Thymine
cytosine
Guanine
What types of atoms will experience radioactivity?
Answer:
Alpha particles, Beta particles, Gamma rays
Alpha Is the least harmful
Beta is second most harmful
Gamma is most dangerous
Explanation:
2.
Which one of the following substances is a compound?
A. Hydrogen
B. Tron
C. Oxygen
D. Sodium fluoride
Explain your answer:
How can radiation, conduction, and convection affect a city? (like Atlanta)
A sample of CO2 weighing 86.34g contains how many molecules?
Answer:
1.181 × 10²⁴ molecules CO₂
General Formulas and Concepts:
Chemistry - Atomic Structure
Reading a Periodic TableUsing Dimensional AnalysisAvogadro's Number - 6.022 × 10²³ atoms, molecules, formula units, etc.Explanation:
Step 1: Define
86.34 g CO₂
Step 2: Identify Conversion
Avogadro's Number
Molar Mass of C - 12.01 g/mol
Molar Mass of O - 16.00 g/mol
Molar Mass of CO₂ - 12.01 + 2(16.00) = 44.01 g/mol
Step 3: Convert
[tex]86.34 \ g \ CO_2(\frac{1 \ mol \ CO_2}{44.01 \ g \ CO_2} )(\frac{6.022 \cdot 10^{23} \ molecules \ CO_2}{1 \ mol \ CO_2} )[/tex] = 1.18141 × 10²⁴ molecules CO₂
Step 4: Check
We are given 4 sig figs. Follow sig fig rules and round.
1.18141 × 10²⁴ molecules CO₂ ≈ 1.181 × 10²⁴ molecules CO₂
1. A mathematical equation that predicts how a physical phenomenon will behave
hypothesis
2. A predicted experimental outcome based on prior knowledge and experience.
quantitative data
3. The variable that is changed on purpose by the scientist.
independent variable
4. The variables that must be kept constant so as not to bias or influence the results
scientific law
5. Data that is descriptive rather than numerical
qualitative data
6. Data that is numerical
control variable
7. A well tested explanation for why a physical phenomenon occurs
scientific theory
Answer:
1. A mathematical equation that predicts how a physical phenomenon will behave - Scientific law
2. A predicted experimental outcome based on prior knowledge and experience - Hypothesis
3. The variable that is changed on purpose by the scientist - Independent variable
4. The variables that must be kept constant so as not to bias or influence the results - Control variable
5. Data that is descriptive rather than numerical -Qualitative data
6. Data that is numerical - Quantitative data
7. A well tested explanation for why a physical phenomenon occurs - Scientific theory
Explanation:
In the method of science in understanding and explaining phenomena in the universe, observations are made, explanations are put forward, experimented and tested, before conclusions are made. Explanations of some common terms in the scientific process is given below:
1. A scientific law is a mathematical equation that predicts how a physical phenomenon will behave.
2. A hypothesis is a predicted experimental outcome based on prior knowledge and experience.
3. A independent variable is the variable that is changed on purpose by the scientist.
4. A control variable is the variable that must be kept constant so as not to bias or influence the results.
5. Qualitative data is data that is descriptive rather than numerical.
6. Quantitative data is data that is numerical
7. A scientific theory is a well tested explanation for why a physical phenomenon occurs.
How do i caculate speed
Answer:
Speed uses the same units as velocity, which is meters divided by seconds (m/s)(It doesn't need to be m/s, but it's the most common unit. It's basically any unit of length divided by any unit of time)
hope this helps and good luck
Answer/Explanation:
Speed is a force and is solved by using acceleration.
You can use the problem to solve for force:
F= MA or Force equals mass times acceleration.
Below is a phase diagram for Carbon Dioxide. Use this diagram to answer the following question.
In this example we will start the Carbon Dioxide out at a temperature of -20oC and 1 atm of pressure. If the pressure was raised to 100 atm of pressure while still staying at -20oC, what phases would the Carbon Dioxide change between?
why do large molecules seem to dissapear in the digestive system
Answer:
They must be dissolving.
Explanation:
Acid molecules must cling to remaining food molecules and slowly dissolve them.
When did the rabbit population reach carrying capacity
Answer: The rabbit population reached carrying capacity during the fourth year of the 10 years we set. Introduction: Population densityis the number of individuals in a population per unit of area. Some limiting factors only affect a population when its density reaches a certain level.
Explanation:
7. Which of the following changes could be associated with either a chemical change OR a
physical change?
a. The change cannot be reversed
b. Bending of metal
c. New substances formed
d. Change in color
Answer:
a: chemical change because the change cannot be reversed.
b: physical change because the action can be reversed.
c: chemical change.
d:chemical change.
any change that cannot be reversed is a chemical change and any change that can be reversed is a physical change.
A solution that has a high concentration of hydrogen ions has what type of pH?
7
14
13
2
Answer:
2
Explanation:
What’s the answer????
Answer:
D=Wavelength A=Amplitude C=Crest F=At rest point
Explanation:
Forgive me if I am wrong!
what are the properties of iconic compounds?
what are the properties of covalent compounds?
which type of compound is sugar?
someone plzz help!
Answer:
in details
Explanation:
what are the properties of iconic compounds?
Ionic compounds exist in the form of ionic groupings in certain forms called (crystalline forms), and we find in these shapes an organized crystal arrangement of ions so that every ion with a specific charge is attracted to a group of ions with the opposite charge, meaning that one ion is bound by several ionic bonds. At the same time, this explains the presence of ionic compounds usually in the solid state (high density). This situation also explains the high melting and boiling points of these compounds.
One of the most important characteristics of ionic compounds is their inability to conduct electrical conductivity in the solid state due to the ions binding and their inability to move while they become conductive of electricity when they are melted or dissolved in water (ions are free to move in the melt and in the aqueous solution).
And among its most important characteristics:
1- It dissolves in water and does not dissolve with benzene, for example (salt) because water is a polar solvent that can separate ions from each other.
2- It has a high melting point due to the force of electrostatic attraction between the positive and negative ions.
3- Its state is solid under normal conditions, due to the force of the electrostatic attraction between the positive and negative ions.
4- Solid ionic compounds do not conduct electricity, but their solutions with water conduct electricity, because when the compound is solid, the ions are connected to each other, but when the compound is a solution, the ions are free to move and conduct the electromagnetic current.
what are the properties of covalent compounds?
In covalent compounds (unlike ionic compounds), we can talk about independent molecules, as covalent compounds are composed of independent molecules linked together by different bonds (van derval, hydrogen) of varying strength. So there are covalent compounds in all three cases according to the strength of these bonds. There are covalent compounds in a gaseous state (weak bonds between molecules), covalent compounds in a liquid state, and also there are covalent compounds in a solid state (strong bonds between molecules). The same is true for melting and boiling points, so covalent compounds Their boiling and melting points vary according to the quality and strength of the bonds between the molecules.
As for the electrical conductivity, in the pure state, the covalent compounds are mostly non-conductive because they are not originally charged or because they are electrically neutral in the presence of charges, but the charged ones may have what is known as the electric torque and will come.
Likewise, in their smelters, the molten solid covalent compound (such as molten sugar) is not conductive of electricity. As for the solution, it may be non-conductive as in the case of a sugar solution or be conductive as is the case in a solution of hydrogen chloride (hydrochloric acid) and the reason for conducting or not in the solution is due to The covalent compound ionization (conversion into separate ions by the action of a solvent) or its de-ionization.
Sugar does not ionize when dissolved in water. Rather, its molecules only separate from each other, while hydrogen chloride does ionize to the hydrogen ion and the chlorine ion.
which type of compound is sugar?
The chemical or molecular formula for sucrose is C 12 H 22 O 11, which means that each sugar molecule contains 12 carbon atoms, 22 hydrogen atoms, and 11 oxygen atoms. A type of sugar called sucrose is also known as sucrose. It is a sucrase made in many different plants.
The properties of the compounds are the following:
a. The properties of the ionic compounds are they are hard, form crystals, have high melting and boiling point, good insulators.
b. The properties of the covalent compound are they are soft, do not form the crystal, have low melting and boiling point, bad insulators.
c. Sugar is a covalent compound.
What is a covalent compound?Covalent compounds are attracted by covalent bonds. They make bonds by sharing one or more pairs of valence electrons.
What is an ionic compound?These compounds are ions or charged particles. They make bonds when an atom or more atoms lose or gain electrons.
Thus, the properties are a. The properties of the ionic compounds are they are hard, form crystals, have high melting and boiling point, good insulators.
b. The properties of the covalent compound are they are soft, do not form the crystal, have low melting and boiling point, bad insulators.
c. Sugar is a covalent compound.
Learn more about covalent compounds
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HUNK
FREE
IN PE
-05
HAE
-B. AFFEE
EMME
"Lanthanide serie
**Actinide series
Where are the non metals located
Answer:
What??? I don't understand.
Explanation:
SOMEONE HELP ME PLEASE ILL GIVE BRAINLY!
Is the following picture an example of a chemical change or a physical change?
A chemical change, because the atoms are rearranging to form new molecules.
A physical change, because the molecules are staying the same.
A chemical change, because the molecules are staying the same.
A physical change, because the atoms are rearranging to form new molecules.
Answer:
It would be a physical change, because the atoms are rerranging to form new molecules!
Explanation:
I'll give brainliest
Answer: Nitrogen
Explanation:
______elements that have a longer half-life are more _______ than those that have a shorter half-life.
Answer:
Radioactive elements
Stable
Explanation:
Radioactive elements that have a longer half-life are more stable than those that a shorter half-life.
Half-life is the time taken for half of a radioactive element to decay by half of its original composition.
Now, if a substance have a long half-life, it is more stable and takes time to break down. For atoms with a short life, they are highly unstable and breaks down readily and easily.
The energy of a gamma ray photon whose frequency is 5.02 x 1020 Hz?
Answer:
The energy of photon is 33.28×10⁻¹⁴ J
Explanation:
Given data:
Frequency of photon = 5.02×10²⁰ Hz
Energy of photon = ?
Solution:
E = h.f
h = planc'ks constant = 6.63×10⁻³⁴ Js
by putting values,
E = 6.63×10⁻³⁴ Js × 5.02×10²⁰ Hz
Hz = s⁻¹
E = 33.28×10⁻¹⁴ J
The energy of photon is 33.28×10⁻¹⁴ J.
Calculate the molecular mass of the following mass of the following chemical compound
C6H12O6
24 G/mol
180 gmol
155 g/mol
19 g/mol
Answer:
132g/mol
Explanation:
Given compound:
C₆H₁₂O₆
Molecular mass of the compound.
This is the sum of the atomic masses of the given elements in the compound;
C = 12
H = 12
O = 6
Molecular mass = 6(12) + 12(1) + 6(16) = 180g/mol
*NEED HELP ASAP!*
Click on photo!
Please help meeee!!!
Answer:
What type of math are you taking.:)
Answer:
CaO
Explanation:
becoz
Ca O
2 2
you must crossing over the eqn
and get CaO