Answer:
Half life = 10.765 year
Explanation:
Given data:
Mass of sample = 500 Kg
Mass left after 21.53 years = 125 kg
Half life of substance = ?
Solution:
At tome zero = 500 kg
At 1st half life = 500 kg/2 = 250 kg
At 2nd half life = 250 kg/2 = 125 g
Half life:
Half life = time elapsed / number of half life
Half life = 21.53 year/2
Half life = 10.765 year
Models can represent systems
and processes.this is a true or false question
Answer:
True
Explanation:
Hope this helps! :)
Answer:
This is True.
Explanation:
"All is strange and vague."
"Are we dead?"
"Or is this Ohio"
-Animaniacs
Oh yeah, brainliest if you can answer this question :3
Answer:
This is Ohio.
Explanation:
(no dude im dead i live in kentucky XP)
A structural engineer is using this table to design a wall to protect a city near the ocean. How high should the engineer build the wall? 50 meters 100 meters 150 meters 200 meters
Answer: it is D
Explanation: got it wrong so y’all can get it right
Answer:
D. 200 meters
Hope this helps!
Explanation:
what type of element is usually shiny
Answer:
Metal
Explanation:
Answer:
Explanation:metals
CAN you pleaaaase solve this? please please please
Answer:
115.2ml of water should be added.
Explanation:
We start with 46.2ml of 1.396M sugar solution;
We want to end up with a 0.56M sugar solution;
Finding the number of moles in the sugar solution to begin with:
moles of sugar in solution initially = 46.2 × 1.396 = 64.4952
Vd = volume of desired solution (i.e. 0.56M solution)
w = volume of water added
Vd = (46.2 + w)
Using the mol = vol' × conc'n equation:
64.4952 = Vd × 0.56
Vd = 64.4952/0.56
Vd = 115.17
46.2 + w = 115.17
w = 115.17 - 46.2
w = 68.97ml
PERIODIC TABLE TEST WILL GIVE BRAINLIEST!
Helium is a gas found in the earth.
A.True
B.False
Neon is a gas from the earth. *
A.True
B.False
Elements are pure substances. *
A.True
B.False
Families/Groups on The Periodic Table go in this direction. *
A.vertical
B.horizontal
Rows which are called _______ run horizontal on The Periodic Table. *
A.pecans
B.periods
C.perfect
Click all that apply. Matter is found in ____________. *
A.clothing
B.humans
C.plants
D.cars
The worlds most accurate clock is a _____________. *
A.Timex
B.Rolex
C.Atomic
Humans are made of 99% elements. *
A.True
B.False
A grain of sand is the same size as one atom. *
A.true
B.false
The Periodic Table has _______ elements. *
A.112
B.116
C.96
Answer:
1. True
2. True
3. True
4. Vertical
5. periods
6. All the given options
7. Atomic
8. False
9. False
10. 116
Thank you again :-D
Answer:
1. True
2. True
3. True
4. B. vertical
5. B. periods
6. A, B, C, D
7. C. Atomic
8. B. false
9. A. True
10. A. 112
Explanation:
1. Helium is a natural gas found in the atmosphere and below ground.
2. Neon is also natural gas found in Earth's atmosphere and can be seen on the periodic table.
3. An element is considered a pure substance because it is made up of only one type of atom and cannot be broken down into a simpler form.
4. Families/groups go up and down (vertical), while periods go across (horizontal)
5. As I just mentioned, periods run horizontally on the Periodic table.
6. Matter is everything that takes up space and has mass. Therefore, all of the given answers consist of matter. Why else would they matter? :)
7. The title of the "Most Accurate Clock In The World" goes to the British atomic clock at UK's National Physical Laboratory (NPL).
8. Almost 99% of the mass of the human body is made up of six elements: oxygen, carbon, hydrogen, nitrogen, calcium, and phosphorus. Only about 0.85% is composed of another five elements: potassium, sulfur, sodium, chlorine, and magnesium. Therefore, we consist of more that 99%.
9. A grain of sand is relatively small; about the size of one atom.
10. The periodic table has 112 elements because there were 112 elements before IUPAC reviewed elements 113, 115, 117 and 118, and decided to give them official names and symbols. This was relatively recent. The total number of elements is 118 though.
I would like to apologize in advance if any of these were incorrect.
Consider the following reaction. MgCl2(aq)+2NaOH(aq)⟶Mg(OH)2(s)+2NaCl(aq) A 187.0 mL solution of 0.103 M MgCl2 reacts with a 33.58 mL solution of 0.839 M NaOH to produce Mg(OH)2 and NaCl. Identify the limiting reactant.
Answer:
NaOH is the limiting reactant and MgCl2 is in excess.
Explanation:
let's calculate the mole of each reactant.
number of moles of MgCl2 = [tex]\frac{187}{1000} L* 0.103 mol / L =0.01926 mol\\[/tex]
number of moles of NaOH = [tex]\frac{33.58 }{1000}L * 0.839 mol/L =0.0282 mol[/tex]
as per the reaction , 1 mol of Magnesium choloride reacts with 2 moles of NaOH
hence 0.01926 needs 0.01926x2= 0.03852 moles of NaOH , but there are only 0.0282 moles of NaOH available .
The limiting reactant for the reaction between 187.0 mL solution of 0.103 M MgCl₂ and 33.58 mL solution of 0.839 M NaOH is NaOH
We'll begin by calculating the number of mole of MgCl₂ and NaOH present in the solution.
For MgCl₂:Volume = 187 mL = 187 / 1000 = 0.187 L
Molarity = 0.103 M
Mole of MgCl₂ =?Mole = Molarity x Volume
Mole of MgCl₂ = 0.103 × 0.187
Mole of MgCl₂ = 0.019 mole For NaOH:Volume = 33.58 mL = 33.58 / 1000 = 0.03358 L
Molarity = 0.839 M
Mole of NaOH =?Mole = Molarity x Volume
Mole of NaOH = 0.839 × 0.03358
Mole of NaOH = 0.028 moleFinally, we shall determine the limiting reactant. This can be obtained as follow:
MgCl₂ + 2NaOH —> Mg(OH)₂ + 2NaCl
From the balanced equation above,
2 moles of NaOH required 1 mole of MgCl₂.
Therefore, 0.028 mole of NaOH will require = [tex]\frac{0.0282}{2}\\[/tex] = 0.014 mole of MgCl₂
From the calculations made above, we can see that only 0.014 mole of MgCl₂ out of 0.019 mole reacted completely with 0.028 mole of NaOH.
Therefore, NaOH is the limiting reactant and MgCl₂ is the excess reactant.
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Scientists study and record seismic data and volcanic activity in order to support: Convection in the Lithosphere Theory of Plate Tectonics Sea Floor Spreading Theory of Continental Drift
Answer:
Theory of Plate Tectonics
Explanation:
Scientists especially Geologists study and record seismic data and volcanic activities in order to support the theory of plate tectonics.
The theory of plate tectonics suggests that the earth is broken into slabs called the lithosphere that moves over the fluid asthenosphere below.
The use of seismic data presents scientists with a way of vertically looking deep into the earth. Volcanic activities also presents us with the kind of materials down within the earth. Also, coupled with this data, scientists use GPS sensors to monitor the rate of movement of the earth. When studying plate tectonics, it invariably culminates in the study of sea floor spreading and theory of continental drift.What is the mass (in grams) of a CO_2 gas sample that occupies 5.46 L at STP?
Answer:
10.7g of [tex]CO_{2}[/tex]
Explanation:
Any gas at STP occupies 22.4 L/mol.
As such:
5.46/22.4 = 0.244 mol of [tex]CO_{2}[/tex]
mass = mol * molecular weight = 0.244 * 44 = 10.7g of [tex]CO_{2}[/tex]
The mass of a CO₂ gas sample that occupies 5.46 L at STP is 10.7 grams.
What is STP?STP is defined as to enable comparisons between various sets of data, consistent sets of settings for experimental measurements must be defined. The abbreviation STP stands for standard temperature and pressure. Standard temperature and pressure refers to 273.15 K (0 C) and 1 bar, respectively (exactly 105 pascals ). For scientists to be able to compare different sets of data in a meaningful way, a global standard for temperature and pressure must be established.
At STP, any gas takes up 22.4 L/mol.
Thus, 5.46/22.4 = 0.244 moles of CO2
Mass, which is one mole times the molecular weight of 44 molecules
= 0.244 moles x 44
= 10.7 grams.
Thus, the mass of a CO₂ gas sample that occupies 5.46 L at STP is 10.7 grams.
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Which scientist established the law of octaves?
Antoine Lavoisier
Dmitri Mendeleev
Henry Moseley
John Newlands
Answer:
John Newlands
Explanation:
he established the law of octaves
What is the outer energy level and sublevel used in the electron configuration for potassium?
Select one:
a. 4s
b. 3s
c. 3p
d. 4p
Answer:
a. 4s
Explanation:
The outer energy level and sublevel used in the electron configuration for potassium is the 4s sub-level.
Potassium has 19 electrons.
The electronic configuration of this chemical element is:
1s² 2s² 2p⁶ 3s² 3p⁶ 4s¹
The outermost energy level is the 4s
if one knows the mass and the molar mass of product D in a chemical reaction, one can determine the mass of product D procued by using the?
Answer:
Number of moles
Explanation:
Using the number of moles in chemical reactions, we can determine the quantity of products and even the reactants that are combining to form them.
The number of moles is derived using the expression below is;
Number of moles = [tex]\frac{mass}{molar mass}[/tex]
Once we establish the number of moles of any of the specie given from the mass and molar mass, we can relate it to any other species.
A nuclear equation is balanced when?
A balanced nuclear reaction equation indicates that there is a rearrangement during a nuclear reaction, but of subatomic particles rather than atoms. Nuclear reactions also follow conservation laws, and they are balanced in two ways: The sum of the mass numbers of the reactants equals the sum of the mass numbers of the products.
Please mark brainliest:)
A force of attraction between the opposite of charges of the ions in an lonic compound is called what?
Answer:
Ionic bonds
Explanation:
The force of attraction between the opposite charges of the ions in an ionic compound is called an ionic bond.
An ionic bond results from the electrostatic force of attraction between oppositely charged ions.
This attraction creates an ionic or electrovalent bond.
The bond type is usually between a metal ion and a non-metal ion.
Write the complete and balanced combustion reaction for H2+O2—>
Answer:
2H2 + 02 --> 2H20
Explanation:
H2 + 02 --> H2O
H =2x2 = 4 | H = 2 x 2 = 4
|
O =2 | O = 1 x 2 = 2
dm me if u have questions regarding the solution hihi :)
Calculate the molarity of a solution prepared by diluting 125 mL of 0.400 M K2Cr2O7 with 875 mL of water?
0.057 M is the molarity of a solution prepared by diluting 125 mL of 0.400 M [tex]K_2Cr_2O_7[/tex] with 875 mL of water.
What are moles?A mole is defined as 6.02214076 × [tex]10^{23}[/tex]of some chemical unit, be it atoms, molecules, ions, or others. The mole is a convenient unit to use because of the great number of atoms, molecules, or others in any substance.
Given:
[tex]V_1[/tex] =125 mL
[tex]V_2[/tex] =875 mL
[tex]M_1[/tex] =0.400 M
[tex]M_2[/tex] =?
[tex]M_1 V_1[/tex]=[tex]M_2V_2[/tex]
0.400 M x 125 mL = [tex]M_2[/tex] x 875 mL
0.05714285714 =[tex]M_2[/tex] = 0.057 M
Hence, 0.057 M is the molarity of a solution prepared by diluting 125 mL of 0.400 M [tex]K_2Cr_2O_7[/tex] with 875 mL of water.
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When is a roman numeral most likely needed in the name of an ionic compound?
A. When more than one polyatomic ion appears.
B. When the anion is a polyatomic ion.
C. When more than one cation is used in the formula.
D. When the cation is a transition metal.
Answer:I think it's d but I could be wrong
why is a bannana curved?
Answer:
Explanation:
It's because of the sun! Bananas are curved so they can retrieve sunlight.
give him the brainliest
Impulse is ___ momentum.
A. only a decrease in
B. a change in
c. not related to
D. only an increase in
Answer:
option B is correct
Explanation:
impulse is a change in momentum
in terms of energy, the difference between a short wavelength and a longer wavelength
How might the molecules inside an ice pack be different from the liquid inside of an insulated cup?
Answer:
The molecules inside the ice pack are frozen therefore they are stuck in place. The molecules inside an insulated cup aren't frozen but still stuck inside of their container so that they can not fly out.
Explanation:
The pH of 0.259 M solution of an unknown acid is measured to be 2.353. What is the Ka of the acid?
Answer:
[tex]Ka=7.73x10^{-5}[/tex]
Explanation:
Hello!
In this case, since the pH is measure of the amount of hydrogen ions in solution, first given the pH we can compute the concentration of hydrogen ions via:
[tex]pH=-log([H^+])[/tex]
[tex][H^+]=10^{-pH}=10^{-2.353}=4.436x10^{-3}M[/tex]
Thus, since the ionization of the given acid, leads to the following equilibrium expression as it is a weak one:
[tex]Ka=\frac{[H^+][A^-]}{[HA]}[/tex]
We notice the concentration of hydrogen ions equal the concentration of the acids conjugate base, so we can compute:
[tex]Ka=\frac{4.436x10^{-3}*4.436x10^{-3}}{0.259-4.436x10^{-3}}\\\\Ka=7.73x10^{-5}[/tex]
Best regards!
What is the formula for Mercury (I) Bisulfate?
Answer:
Work shown below!
Explanation:
[tex]Hg^{+1} HSO_{4} =HgHSO_{4}[/tex]
Full in the blanks...
Whoever answer first will get marked brainliest
Answer:
atom, ions, protons neutrons, atomic number
Explanation:
What is the work done in lifting 60 kg of blocks to a height of 20 m
Answer:
1200 JExplanation:
The work done by an object can be found by using the formula
workdone = force × distance
From the question we have
workdone = 60 × 20
We have the final answer as
1200 JHope this helps you
Please don’t answer if you just want points
What is the empirical formula of the substance C6H14010?*
Answer:
[tex]\mathrm {CH_24}[/tex]
Explanation:
To determine the molecular formula, enter the appropriate value for the molecular mass. We get [tex]CH_{2}4[/tex] as our answer to the question.
How many grams of copper (II) nitrate would be produced from 0.80 g of copper metal reacting with excess nitric acid?
Answer:
[tex]m_{Cu(NO_3)_2}=2.36 gCu(NO_3)_2[/tex]
Explanation:
Hello!
In this case, since the chemical reaction between copper and nitric acid is:
[tex]2HNO_3+Cu\rightarrow Cu(NO_3)_2+H_2[/tex]
By starting with 0.80 g of copper metal (molar mass = 63.54 g/mol) and considering the 1:1 mole ratio between copper and copper (II) nitrate (molar mass = 187.56 g/mol) we can compute that mass via stoichiometry as shown below:
[tex]m_{Cu(NO_3)_2}=0.80gCu*\frac{1molCu}{63.54gCu} *\frac{1molCu(NO_3)_2}{1molCu} *\frac{187.56gCu(NO_3)_2}{1molCu(NO_3)_2} \\\\m_{Cu(NO_3)_2}=2.36 gCu(NO_3)_2[/tex]
However, the real reaction between copper and nitric acid releases nitrogen oxide, yet it does not modify the calculations since the 1:1 mole ratio is still there:
[tex]4HNO_3+Cu\rightarrow Cu(NO_3)_2+2H_2O+2NO_2[/tex]
Best regards!
Amount of copper (II) nitrate would be produced is 2.25 gram
Molecular mass:Given that;
Amount of copper metal = 0.80 g
Find:
Amount of copper (II) nitrate would be produced
Computation:
Cu + 4HNO₃ → Cu(NO₃) + 2NO₂ + 2H₂O
Number of moles = Given mass / Molecular mass
Number of moles = 0.80 / 63.5
Number of moles = 0.012 mol
So,
n = Given mass / Molecular mass
0.012 = Given mass / 63.5 + (63.5 + 48)
Given mass = 2.25 gram
Amount of copper (II) nitrate would be produced = 2.25 gram
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What type of reaction is: 4 Fe + 3 O2 → 2 Fe2O3
A. synthesis
B. double replacement
C. decomposition
D. single replacement
Answer:
A. synthesis
Explanation:
The reaction given is a synthesis reaction in which two substances combines to give a product.
In this reaction:
4Fe + 3O₂ → 2Fe₂O₃
The reaction involves the formation of a single product from two or more reactants.
The formation of a compound from union of the constituent elements also falls into this category of reaction.
Which additional product balances the reaction H2SO4 + 2NaOH → Na2SO4 + ? 2H2O 2OH H2O2 H3O
Answer:
a) 2H2O
Explanation:
I took the quiz
Answer:
2H20 or A- the other person was right:) give them brainliest.
Explanation:
I just took the test.
18 protons
22 neutrons
18 electrons
how do i draw this ? please help ASAP.
Explanation:
You need to remember a few things if you want the answer to this question...
A atom has a circle within a circle so consider that it looks like a double circle..Protons and neutrons go in the center of that double circle..Electrons go on the outer sides of the two circles.Because of the given numbers of protons, neutrons, and electrons we know that the element you need to draw is Argon.Therefore you need to draw a atom that is similar to this:
Hope this helps.