Answer:
(a) 140 years
(b) 3.125 pounds
Explanation:
QuestIons
(a) How long is five half-life
(b) How much radioactive strontium is left after five half-life
Given that:
Half-life is about 28 years; &
There are 100 pounds of this radioactive waste
Five half-life will be;
= 28 × 5
= 140 years
The amount of radioactive remaining after five half-life is:
[tex]= 100 \times( \dfrac{1}{2}) ^5[/tex]
= 100 × 0.03125
= 3.125 pounds
You have 3.00 L of a 3.74 M solution of NaCl(aq) called solution A. You also have 2.00 L of a 2.00 M solution of AgNO3(aq) called solution B. You mix these solutions together to make solution C. Calculate the concentration (in M) of Cl ions in solution C.
Answer:
[tex]M=2.24M[/tex]
Explanation:
Hello!
In this case, since the molarity and volume of the solutions are given, we are able to compute the moles of chloride ions as they are present in NaCl only:
[tex]n_{Cl^-}=3.00L*3.74\frac{molNaCl}{L}*\frac{1molCl^-}{1molNaCl} =11.22molCl^-[/tex]
Next, since the mixing of solution A and B lead to a volume of 5.00 L, the concentration of chloride ions turns out:
[tex]M=\frac{11.22mol}{5.00L}=2.24M[/tex]
Best regards!
When circumstances are right, most materials undergo a process called thermal expansion. Which statement best describes the cause and effect of thermal expansion? Group of answer choices Matter is heated, and its particles spread out more. Matter is heated, and its particles move closer together. Matter is cooled, and its particles move closer together. Matter is cooled, and its particles spread out more.
Answer: Matter is heated, and its particles spread out more
Explanation:
Thermal expansion occurs when there's an expansion of an object or material or when an object becomes bigger because of a rise in its temperature. This brings about the faster movement of the heated molecules and the atoms spreading out.
Therefore, the cause and effect of thermal expansion will be that when matter is heated, and its particles spread out more.
Why does oxygen have a smaller atom size than nitrogen?
Answer:
The eight protons in oxygen atom's nucleus will exert more force than nitrogen's seven electrons. Also, oxygen has same number of shells as nitrogen. Thus electrons in oxygen atom will be closer to nucleus than in the case of nitrogen. When electrons are closer it means atomic radius is smaller.
Hope this helps! :)
here's the answers.................
If the specific heat of water is 4.18 3/g*^ C much heat is required to increase the temperature of 12 g of water from 23 degrees * C to 39 degrees * C ^ 2
Answer:
Q = 802.6 J
Explanation:
Given data:
Specific heat capacity of water = 4.18 J/g.°C
Mass of water = 12 g
Initial temperature = 23°C
Final temperature = 39°C
Heat required = ?
Solution:
Formula:
Q = m.c. ΔT
Q = amount of heat absorbed or released
m = mass of given substance
c = specific heat capacity of substance
ΔT = change in temperature
ΔT = 39°C - 23°C
ΔT = 16 °C
Q = 12 g× 4.18 J/g.°C × 16 °C
Q = 802.6 J
A 10 gram sample of iron reacts with oxygen to form 18.2 grams of ferric oxide. How many grams of oxygen reacted?
Answer:
[tex]\boxed {\boxed {\sf 8.2 \ grams}}[/tex]
Explanation:
According to the Law of Conservation of Mass, the mass of the products must equal the mass of the reactants.
mass products = mass reactantsIn this problem, the reaction is:
[tex]iron + oxygen = ferric \ oxygen[/tex]
The reactants are iron and oxygen. We know the mass of the iron sample is 10 grams. The product is ferric oxide. The mass of the ferric oxide sample is 18.2 grams.[tex]10 \ g + oxygen=18.2 \ g[/tex]
We want to find how many grams of oxygen reacted. We have to get the oxygen by itself. 10 is being added to oxygen. The inverse of addition is subtraction. Subtract 10 from both sides of the equation.
[tex]10 \ g - 10 \ g+ oxygen = 18.2 \ g - 10 \ g[/tex]
[tex]oxygen= 18.2 \ g - 10 \ g[/tex]
[tex]oxygen= 8.2 \ g \\[/tex]
8.2 grams of oxygen reacted with 10 grams of iron to form 18.2 grams of ferric oxide.
What can you conclude from the figure shown?
(a) The Hund's rule has been violated
(b) The Aufbau principle has been violated
(c) The Pauli's Exclusion principle has been violated
(D) This is a valid orbital diagram
Answer:
A. Hund's rule has been violated
Explanation:
There must be one electron with the same spin in each orbital of the same energy before you can put two in the same orbital. In the photo, the 2s sublevel is completely filled before the 1s sublevel (if anything the 1s should have an up spin and down spin, with the 2s having one up spin).
From the figure , it can be concluded that Hund's rule is violated as 1s sub shell is not completely filled before moving to the 2s sub shell.
What is Hund's rule ?Hund's rule of maximum multiplicity is an atomic rule which is based on the observation of atomic spectra and is used for prediction of ground state of an atom or molecule which have one or more open electronic shells.
It states that, for a given electronic configuration lowest energy term is the one which has greatest value of multiplicities of spin. It implies to the fact that if two orbitals are present which are of equal energy, electrons will occupy them singly before pairing of electrons take place.
The rule finds tremendous use in atomic chemistry,spectroscopy and quantum chemistry.
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How many minutes will it take to plate out 4.50 g of Cu from a solution of Cu(NO3)2 (aq) onto the cathode of an electrolytic cell when 8.00 A of current are used?
a. 28.5 min.b. 3.06 × 10^−9 min.c. 14.2 min.d. 1.82 × 10^3 min.
Answer:
a. 28.5 min
Explanation:
The computation of the number of minutes would it take to plate out is as follows:
Cu+2 +2e [tex]\rightarrow[/tex]Cu
The two moles of electrons could be generated for the copper i.e. deposited
Now
moles of copper is
= 4.5 ÷ 63.5
= 0.071
The 63.5 represents the atomic copper weight
Now mole of electrons deposited is
= 0.071 × 2
= 0.142
Now
quantitiy of electricity needed
= moles of electrons deposited × 96500
= 0.142 × 96500
= 13703 coulums
As per electricity quantity needed
= current × time(seconds)
= 13703 = 8 × t
t = 13703 ÷ 8
= 1713 seconds
= 1713 ÷ 60 minutes
=28.5 min
hence, the correct option is a.
The tungsten- nuclide radioactively decays by alpha emission. Write a balanced nuclear chemical equation that describes this process.
Answer:
The solution to this question can be defined as follows:
Explanation:
The complete question is defined in the attached file.
[tex]W^{180}_{74} \to He^{4}_{2} + Hf^{176}_{72}[/tex]
Here:
[tex]W= Tungsten-180\\\\Hf =Hafnium\\\\He = \alpha \ particle\\\\[/tex]
Do you think it is important for archaeological sites to be protected from development once they are discovered? What are the pros and cons of each side of this issue? Once discovered, should artifacts be left as they are, or removed and displayed for others to learn about? What are the pros and cons of each option? How can cultural or societal influences affect the progression of scientific discovery? Do those influences normally have a positive or negative effect on science's ability to advance?
Answer: lessons and benefits can seem removed from everyday life. ... If they determine a site is significant, it is ... CRM exists because legislators and their con- ... romance of excavation and discovery of the past for ... Archaeology permits intensive study of a single culture over time, removing the myth
What is solubility?
ignore me please I have to write this because brainly wants me to.
Answer:
the ability to be dissolved, especially in water.
Explanation:
What is the degree of oxidation of a simple substance
Answer: The oxidation state of a free element (uncombined element) is zero. For a simple (monoatomic) ion, the oxidation state is equal to the net charge on the ion. For example, Cl– has an oxidation state of -1. When present in most compounds, hydrogen has an oxidation state of +1 and oxygen an oxidation state of −2.
hope this helps........ Stay safe and have a Merry Christmas!!!!!!!!! :D Explanation:
What is the atomic radius
Answer:
The atomic radius of a chemical element is a measure of the size of its atoms, usually the mean or typical distance from the center of the nucleus to the boundary of the surrounding shells of electrons.
Which of the following best describes foliated metamorphic rocks?
A
There are easily recognizable fossils.
B
The rock has ribbon-like layers of bands.
C
They have crystals like igneous rocks.
D
Different sized sediments can be seen.
Answer:
It's C because Metamorphic rocks were once igneous rocks. And, because Gneiss which is a Metamorphic rock has crystals inside of it.
Different rock types appear during rock formation. The best description of foliated metamorphic rocks is that;
B . The rock has ribbon-like layers of bands.Due to the pressure and heat that is exerted on some rock types, there is an alignment or foliation of rocks. The appearance can be described as ribbon-like.
The examples of rocks that fall under this classification are slate, phyllite, gneiss, and schist.
The non-foliated rocks do not show any alignment in their minerals. Examples are; quartzite, marble, and novaculite.
Summarily, option B best describes a foliated metamorphic rock.
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What does scientist use to deign their experiments
Answer:
a chart
Explanation:
a chart a chart is the answer
What is the total number of moles of oxygen atoms present in one mole of Mg(CIO3)2?
1. 5
2. 2
3. 3
4. 6
Answer:
Of oxygen would be 6 moles (4).
Explanation:
Since it is in a bracket you have to multiply 3 and tge 2 to get 6 oxygens.
PLEASE HELP MY TEACHER IS GOING TO SEE ME AFTER CLASS
Answer:
The Nucelous helps prevent bad cells in
Explanation:
what change in the system will increase the boiling point
Answer:
ExplanationIt is moving from 4s to 8s at a constant speed of 4 cm:
Answer:
Boiling points increase as the number of carbons is increased.
Explanation:
The addition of solutes or other substances usually changes the boiling point. Additionally, changing the pressure on a liquid changes its boiling point. Sugar, salt or other non-volatile solutes in water will usually make the boiling point higher.
The relative strength of the four intermolecular forces is: Ionic > Hydrogen bonding > dipole dipole > Van der Waals dispersion forces. The influence of each of these attractive forces will depend on the functional groups present. Boiling points increase as the number of carbons is increased.
can copper be scratched by a fingernail or blade knife. why?
Answer:
it could by blade knife
Explanation:
fingernail has hardness 2.5; copper penny, about 3.5; a knife blade, 5.5
You have 250.0 mL of 4.00 M sugar solution. You added 216.1 mL of water to this solution. Determine the concentration of the sugar solution after the addition of water.
Answer:
[tex]M_2=2.15M[/tex]
Explanation:
Hello!
In this case, since the dilution processes are characterized by the addition of extra solvent, in this case water, to an initial solution in order to decrease the concentration of the solute, in this case sugar; as water is added, the moles of sugar remain unchanged, so the following equation can be written:
[tex]n_1=n_2\\\\M_1V_1=M_2V_2[/tex]
Whereas 1 accounts for the initial 250.0 mL of 4.00 M sugar and 2 for the concentration at the new volume which is:
[tex]V_2=250.0mL+216.1mL=466.1mL[/tex]
Thus, the final concentration is:
[tex]M_2=\frac{M_1V_1}{V_2} =\frac{250.0mL*4.00M}{466.1mL} \\\\M_2=2.15M[/tex]
Best regards!
What is the name for the group of unreactive elements on the periodic table?
Noble Gases, at least that's what I was told. Hope that helps.
How many molecules of carbon tetrachloride are equal to 0.25moles
What is the density of a piece of wood that has a mass of 25.0 grams and a volume of 5.0 cm 3 ?
Answer:
5.0g/cm^3
Explanation:
Since we have the mass of the wood (25.0g) and the volume of the wood (5.0cm^3), can use the formula for density to answer this question.
Density=mass/density
Density=25.0g/5.0cm^3
Density=5.0g/cm^3
Therefore, the density of the piece of wood is 5.0g/cm^3.
I hope this helps!
need help with this.............................................
Answer:
fossil layers
Explanation:
Compare and contrast the mass of the object to the size of the object.
Which reason best explains why metals are malleable?
A. because they have delocalized electrons
B. because they have localized electrons
C. because they have ionic bonds
D. because they have rigid bonds
The correct answer is A on edg 2020
What are four the main causes of erosion? wind, water, ice, gravity O biological, chemical, mechanical, subterranean O freezing, hydration, oxidation, salt crystallization O seismic movement, vocalism, mountain building, ocean waves
Answer:
Water, wind, ice, and gravity
Explanation:
I took the quiz ;)
Write the balanced chemical equation between H2SO4 and KOH in aqueous solution. This is called a neutralization reaction and will produce whater and potassium sulfate. Phases are optional.
0.650 L of 0.430 M H2SO4 is mixed with 0.600 L of 0.240 M KOH. What concentration of sulfuric acid remains after neutralization?
Answer:
0.166M
Explanation:
In a neutralization, the acid, H₂SO₄, reacts with a base, KOH, to produce a salt, K₂SO₄ and water. The reaction is:
H₂SO₄ + 2KOH → K₂SO₄ + 2H₂O
To solve this problem, we need to determine moles of H2SO4 and moles of KOH that reacts to find the moles of sulfuric acid that remains after the reaction:
Moles H2SO4:
0.650L * (0.430mol /L) = 0.2795moles H2SO4
Moles KOH:
0.600L * (0.240mol / L) = 0.144 moles KOH
Moles of sulfuric acid that reacts with 0.144 moles of KOH are:
0.144 moles KOH * (1mol H2SO4 / 2 mol KOH) = 0.072 moles of H2SO4 react.
And remain:
0.2795moles H2SO4 - 0.072moles H2SO4 = 0.2075 moles of H2SO4 reamains.
In 0.650L + 0.600L = 1.25L:
Molar concentration of sulfuric acid:
0.2075 moles of H2SO4 / 1.25L =
0.166MHow many total atoms are present in C6H12O6?
Answer:24 atoms
Explanation:
Answer: 24 atoms
Answer and Explanation:
There are 24 atoms in one molecule of C6 H12 06. This chemical compound has 6 atoms of carbon, 12 atoms of hydrogen, and 6 atoms of oxygen.
Hope this helps.... Stay safe and have a Merry Christmas!!!!!!! :D
Use Figure 5-5 to determine the types of radiation described in problem 5
Answer:6.12 x 10¹⁴ s⁻¹
Objects get their colors from reflecting only certain wavelengths when hit with white light. Light reflected from a green leaf is found to have a wavelength of 4.90 x 10⁻⁷ m. What is the frequency of the light?
Explanation:
Answer: 6.12 x 10¹⁴ s⁻¹
Explanation:
4. How many moles of water are produced when 3.25 moles of CO2 are formed?
Answer:
6.50 mol
Explanation:
The question is incomplete but I looked it up on the web.
How many moles of water are produced when 3.25 moles of CO₂ are formed during the combustion of methyl alcohol (CH₃OH)?
Step 1: Write the balanced equation
2 CH₃OH + 3 O₂ → 2 CO₂ + 4 H₂O
Step 2: Establish the appropriate molar ratio
According to the balanced equation, the molar ratio of CO₂ to H₂O is 2:4.
Step 3: Calculate the moles of water formed with 3.25 moles of carbon dioxide
We will use the established molar ratio.
3.25 mol CO₂ × (4 mol H₂O/ 2 mol CO₂) = 6.50 mol H₂O