The half-life of the radioactive isotope polonium-218 is 3.05 minutes.
How long will it take for the activity of a sample of polonium-218 to decrease from 2.81E4 Ci to 3.52E3 Ci?
Answer: It will take 9.13 minutes for the sample.
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 = initial amount of the reactant = [tex]2.81\times 10^4[/tex]
a - x = amount left after decay process = [tex]3.52\times 10^3[/tex]
a) 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}{3.05min}=0.227min^{-1}[/tex]
b) for activity to decrease from 2.81E4 Ci to 3.52E3 Ci:
[tex]t=\frac{2.303}{0.227}\log\frac{2.81\times 10^4}{3.52\times 10^3}[/tex]
[tex]t=9.13min[/tex]
Thus it will take 9.13 minutes for the sample.
[tex]t_{99.9}=40min[/tex]
The time after which 99.9% reactions gets completed is 40 minutes
What is Trinitrogen hexaflouride formula
Answer:
N3F6
Explanation:
Tri- means three so three nitrogens and hexa- means six so six flourines.
Nitrogen and fluorine forms covalent compounds. The formula of one of their compound trinitrogen hexaflouride is N₃F₆.
What is covalent compounds?Covalent compounds are formed by the sharing of electrons between two atoms. Atoms which are electron deficient forms covalent compounds. The number of shared electron is based on the valency of each bonded atom.
Nitrogen is 7th element in periodic table and it have five valence electrons. Thus it needs 3 more electrons to attain stability. Fluorine is 9th element with 7 electrons in its valence shell and it needs one more electron to gain stability.
In the compound trinitrogen hexafluoride, there are three nitrogens and six fluorine. Each nitrogen shares one electron with fluorine and each fluorine in turn shares its one electron. Thus the formula of the compound is N₃F₆.
To find more about nitrogen compounds, refer the link below:
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The infrared spectrum of the starting material (2-methylcyclohexanone) will have a peak present at ____________, which will be absent in the product (2-methylcyclohexanol).
Answer:
1710 cm^-1
Explanation:
The Infrared spectrum of the starting material will have a peak present at 1710 cm^-1. this is because
2-methylcyclohexanone has a ketone group (C=O) which will be reduced to an alcohol group (O-H), in the product i.e. (2-methylcyclohexanol). therefore the peak for the stretching vibration of the ketone carbonyl (C=O) is present only in the starting material only .and The peak for the stretching is at 1710 cm^-1
Why is an electron ejected when green light hits the metal?
Explanation:
If a large photon strikes the surface, that has enough strength to take out an electrode, which will then travel to the positive side since it is negative. Current is flowing at this stage. Since the reduced photons will be unable to distinguish between atoms, no power can pass.
how do I solve this?
Answer:
Explanation:
When you divide exponentials, you subtract the powers. For the numbers infront, just use a basic calculator for.
7.95/6.02 = 1.32
10^22/10^23 = 10^-1
1.32 x 10^-1 is your answer
help w this please and thank you.
Answer: see below
Explanation: filling the blanks in this order
point source
Pollution
Wastewater
waste
Nonpoint source
Contaminants
fertiliser
suburban yards
Identify which trends in the diagrams below describe
atomic radius, ionization energy, electron affinity,
and electronegativity
Explanation:
the atmoc radius across the period
Atom radius as you move form left to right the atomic in the period table atomic radius decrease do to decrease the number of shell and it causes the Electron closed to nucleus. and also cause to decrease the inozation engey, electronegative andelectro affinity....... in the group the atomic radius increase as you move down the group do to increase number of shell because the Electron are far-away to the nuclear and it causes the small amount of energy to ionization so that the ionization engey , electronaffity and electronegative are increase“Sound plays an important role in our lives”. Give two points in support of this statement.
Answer:
First job out of college was in an industrial manufacturing setting. Was told by plant engineer to walk around, get used to normal sounds. He stressed anything "abnormal" is a noise more so than a sound. Report abnormalilies to supervisor immediately!! So essentially sounds are giving us warnings something is abnormal.Sounds also provide feedback. Say you are performing an experiment, requires boiling water to sanitize. Start the burner under a vessel, go on about other preparations. Sound of water boiling will trigger setting a timer for how long to let it boil.Get off work, pleasant music, nature sounds can help us decompress from a stressful day on the job.Hope some of these give you impetus to think of other bullet points, sounds good to me. !!
Explanation:
what element is stored in the shells and skeltyons of living organisims?
Answer:
carbon
Explanation:
Many organisms use carbon to make calcium carbonate, a building material of shells and skeletons. Other chemical processes create calcium carbonate in the water. The using up of carbon by biological and chemical processes allows more carbon dioxide to enter the water from the atmosphere.
Which change will cause more CO2 to form in a closed container?
Answer:
Option C Removing Na₂CO₃
Option E Heating the container.
Explanation:
The equation for the reaction is given below:
2NaHCO₃ (s) <=> Na₂CO₃ (s) + CO₂ (g) + H₂O (g)
Enthalpy change (ΔH) = 136 KJ
To obtain more CO₂ do the following:
1. Add more NaHCO₃
From chemical equilibrium, adding more NaHCO₃ means the reactant has increase. Thus, it (the reactant) will react to form more product (CO₂)
2. Removing any of the products. Removing any of the products implies that more reactants are in the reaction vessel than the product. Thus, the reactants will react to produce more products (CO₂)
3. Heating the container. Heating the container will lead to an increase in the temperature of the reaction. Since the enthalpy change (ΔH) is positive it means the reaction is endothermic. Thus, heating the container i.e increasing the temperature will favours the forward reaction i.e more products will be obtained.
NOTE: Pressure has no effect in the reaction system since there is no gaseous reactants.
Considering the options given above, C and E gives the correct answer to the question.
how can natural selection can cause organisms to change over generations.
Answer:
Natural selection changes how well a species can survive in an environment.
Explanation:
I'm not the best at biology, but natural selection a term we use that's describes nature's way of choosing the strongest to survive. The species with the strongest adaptations will survive while the others will die off. For example, if a school of fish was forced to live in a colder habitat than usual, over many years some fish will adapt to that environment and be able to withstand it. But, some fish won't get those adaptations and be killed off. But, future generations will be born with that ability to withstand the cold environment and it would become normal. So, natural selection changes the way a species lives. Hope this helps
How many moles are there in 3.01 x 1024 atoms of argon?
Answer:
Try this for answer 3082.24
19E molar/molal Test
Single, double, or triple covalent bonds in a carbon atom are formed from A) inner shell electrons B) valence electrons. C) both inner shell and valence electrons.
Answer:
B) valence electrons.
Explanation:
Valence electrons can be defined as the number of electrons present in the outermost shell of an atom. Valence electrons are used to determine whether an atom or group of elements found in a periodic table can bond with others. Thus, this property is typically used to determine the chemical properties of elements.
For example, oxygen has a total number of eight (8) electrons while neon has total number of ten (10) electrons. Therefore, an atom of oxygen is able to gain (receive) two (2) more electrons in order to have the same electron arrangements as the noble gas i.e an atom of neon with an atomic number of 10.
Basically, each free electrons (valence electrons) produces a covalent bond.
Hence, single, double, or triple covalent bonds in a carbon atom are formed from valence electrons.
Single, double, or triple covalent bonds in a carbon atom are formed from Valency electrons.
The valency electron are the electrons found in the outermost shell of an
atom.
The valency electron of an atom determines the kind of bonding that exist in
an element .
Neutral Carbon atoms has 6 electrons . The number of valency electrons
(electrons in the outermost shell) in Carbon is 4 valency electrons.
So, carbon can form covalent bond by sharing electrons with other atom of
an element. The bonding maybe single, double or triple bonds .
This bonding are formed by the electrons in the outermost shell(valency electrons)
learn more: https://brainly.com/question/2725863?referrer=searchResults
Match each chemical reaction with the correct identifying type.
2 NaHCO3 (S )→ Na2CO3 (s) + H2O (g) + CO2 (g)
2 C8H18 (l) + 9 O2 (g) → 16 CO2 (g) + 18 H2O (g)
3 H2 (g) + N2 (g) → 2 NH3 (g)
Cu (s) + Ag2SO4 (aq) → 2 Ag (s) + CuSO4 (aq)
Pb(NO3)2 (aq) + 2 KI (aq) → PbI2 (s) + 2 KNO3 (aq)
Double Replacement Single Replacement Synthesis/Composition Decomposition Combustion
1. Electricity is a form of energy created by the free or controlled
movement of charged particles such as electrons.
True
False
Answer:
true
Explanation:
Advantages and disadvantages of Reversible Fuel Cell..
Answer:
Hydrogen fuel cells do not produce any CO2 emissions during operation, even if their production is not necessarily carbon-free. This gives them an advantage over combustion engine vehicles, which can emit small amounts of poisonous carbon monoxide and require well-ventilated rooms for indoor use.
How many moles are in 175 L of Ar?
OA) 7.81 mol
O B) 3920 mol
OC) 4.38 mol
OD 6991 mol
What is the name of the functional group -CH2CH3?
A) propyl
B) methyl
C) ether
D) ethyl
What type of mutation occurred?
Original: ATT CAC
Mutated: ATT TCA C
substitution (point)
insertion (addition)
deletion
Answer:
insertion (addition)
Explanation:
A T was added, making the sequence shift.
What the mass in grams of 6.25 mol of copper(II) nitrate
Answer:
Mass of 6.25 moles of copper(II) nitrate = 1025 grams
Explanation:
Let us calculate the molar mass of Copper (II) nitrate
Molecular formula = Ca(NO₃)₂
Atomic mass of Ca = 40 g/mol
Atomic mass of N =14 g/mol
Atomic mass of O = 16 g/mol
molar mass of Ca(NO₃)₂ = 40 + (14 X2) +( 6X16) = 164 g/mol
moles=\frac{mass}{molarmass}moles=
molarmass
mass
therefore
mass = moles X molar mass
mass = 6.25 X 164 = 1025 grams
Find the mass, in grams, of 4.10x1023 molecules of F2.
Answer:
25.88 g of F₂.
Explanation:
From the question given above, the following data were obtained:
Number of molecules of F₂ = 4.10×10²³ molecules
Mass of F₂ =?
From Avogadro's hypothesis,
1 mole of F₂ = 6.02×10²³ molecules
Next, we shall determine the mass of 1 mole of F₂. This can be obtained as follow:
1 mole of F₂ = 2 × 19 = 38 g
Thus,
38 g of F₂ = 6.02×10²³ molecules
Finally, we shall determine the mass of 4.10×10²³ molecules of F₂. This can be obtained as follow:
6.02×10²³ molecules = 38 g of F₂
Therefore,
4.10×10²³ molecules = 4.10×10²³ × 38 / 6.02×10²³
4.10×10²³ molecules = 25.88 g
Thus, 25.88 g of F₂ contains 4.10×10²³ molecules.
An object is travelling at a speed of 6500. cm per second. Convert the value to the following units (2.54 cm = 1 inch)
a. Kilometers per minute
b. Feet per hour
Answer:
3.900 km/min
7.677 × 10⁵ ft/h
Explanation:
Step 1: Given data
Speed of the object (s): 6500. cm/s
Step 2: Convert "s" to km/min
We will use the following conversion factors.
1 km = 10⁵ cm1 min = 60 s6500. cm/s × (1 km/10⁵ cm) × (60 s/1 min) = 3.900 km/min
Step 3: Convert "s" to ft/h
We will use the following conversion factors.
1 km = 3280.84 ft1 h = 60 min3.900 km/min × (3280.84 ft/1 km) × (60 min/1 h) = 7.677 × 10⁵ ft/h
Which part of a plant creates pollen?
AME
A
pistil
B
stamen
с
petal
D
stem
Answer:
carpel
Explanation:
the pollen producing part of a flower, usually with a slender filament supporting the anther.
A) 24 g
B) 36 g
C) 48 g
D) 60 g
Answer: b 36 g
Explanation:
What is the molecular formula of the product formed from the oxidation of 2-methyl-2,3-pentandiol with Jones reagent (CrO3, H , H2O)
Answer:
C6H12O2
Explanation:
The Jones reagent is a reagent in organic chemistry used to convert primary alcohols to carboxylic acids and secondary alcohols to ketones. Recall that tertiary alcohols can not be oxidized.
The compound 2-methyl-2,3-pentandiol contains one secondary and one tertiary alcohol. The secondary alcohol is oxidized to a ketone while the tertiary alcohol is not oxidized.
Hence the product of the oxidation using Jones reagent is 2-Hydroxy-2-methyl-3-pentanone with the molecular formula C6H12O2.
Hi! I need some solar system facts!
Answer: I can help with that!
Explanation: 1.The tremendous growth in the U.S. solar industry is helping to pave the way to a cleaner, more sustainable energy future. Over the past few years, the cost of a solar energy system has dropped significantly -- helping to give more American families and business access to affordable, clean energy.
Through a portfolio of R&D efforts, the Energy Department remains committed to leveraging America’s abundant solar energy resources -- driving research, manufacturing and market solutions to support widespread expansion of the nation’s solar market.
2.The amount of sunlight that strikes the earth's surface in an hour and a half is enough to handle the entire world's energy consumption for a full year. Solar technologies convert sunlight into electrical energy either through photovoltaic (PV) panels or through mirrors that concentrate solar radiation. This energy can be used to generate electricity or be stored in batteries or thermal storage.
Below, you can find resources and information on the basics of solar radiation, photovoltaic and concentrating solar-thermal power technologies, electrical grid systems integration, and the non-hardware aspects (soft costs) of solar energy. You can also learn more about how to go solar and the solar energy industry. In addition, you can dive deeper into solar energy and learn about how the U.S. Department of Energy Solar Energy Technologies Office is driving innovative research and development in these areas.
3.Solar radiation is light – also known as electromagnetic radiation – that is emitted by the sun. While every location on Earth receives some sunlight over a year, the amount of solar radiation that reaches any one spot on the Earth’s surface varies. Solar technologies capture this radiation and turn it into useful forms of energy.
For this PreLab assignment we will assume all of the acid is the monoprotic acid acetylsalicylic acid (C9H8O4). [Note: for your analysis in the PostLab you will subtract the moles of salicylic acid from the total acid content to determine the amount of acetylsalicylic acid]. How many moles of acetylsalicylic acid are in the 0.2001 g sample of your aspirin
Answer:
0.0011 moles
Explanation:
Recall that;
Number of moles = mass of substance/ molar mass of the substance
Mass of asprin = 0.2001 g
Molar mass of asprin = 180.158 g/mol
Number of moles = 0.2001 g/180.158 g/mol
Number of moles = 0.0011 moles
What is the subscript of Carbon in Isovaleric acid C5H10O2
Differences in air temperature and pressure cause movements of air also known as ?