Answer:
Deandre is correct.
Explanation:
When shiny pennies turn dull, due to getting rust. It gets cover with a layer of black or brown color on its surface on the exposure of air.
In this problem,
Deandre says, "I think they turn dull because they're exposed to the air over time." Jamie says, "I think they turn dull because they get dirt on them from being dropped on the ground." Selina says, "I think there is dull metal inside the penny the entire time.
Out of three friends, Deandre is correct. Shiny pennies turn dull because they're exposed to the air over time.
How long does it take for 87.5 % of each isotope to decay?
(The isotopes are below)
Krypton-73= 27 seconds
Krypton-74= 11.5 minutes
Krypton-76= 14.8 hours
Krypton-81= 2.1 x 10^5 years
Answer:
Kr-73 = 23.625 sec
Kr-74 = 10.0625 minutes (603.75 seconds)
Kr-76 = 12.95 hours (777 minutes)
Kr-81 = 1.8375 * 10^6 years
Explanation:
What you do is multiply each of those amounts by 7/8.
27 * 7/8 = 189/8 = 23.625
23/2 * 7/8 = 161/16 = 10.0625
74/5 * 7/8 = 518/40 = 259/20 = 12.95
210000 * 7/8 = 1470000/8 = 183750 = 1.8375 * 10^6
If the sun heated our atmosphere and the molecules began to s;read apart and rise but the atmosphere was to weak to keep them down , what would happen?
Why do flowers have brightly-coloured petals
Answer:
Petals are modified leaves that surround the reproductive parts of flowers. They are often brightly colored or unusually shaped to attract pollinators. Together, all of the petals of a flower are called corolla.
Calculate the H+ ion concentration in a 8.8 x 10-4 M Ca(OH)2
solution.
form the molar concentration of the Ca(OH)2 which is a base we can deduct the pOH
pOH=-lg[OH-]
[OH-]=8.8 x 10-4 M
pOH=4
pH=14-pOH
pH=10
-lg[H+]=10
[H+]=10^-10
The concentration of Hydrogen ion [H⁺] in 8.8×10¯⁴ M Ca(OH)₂ is 5.68×10¯¹² M
The concentration of Hydrogen ion [H⁺] in a solution talks about the acidicity the solution. Thus, we can obtain the concentration of Hydrogen ion [H⁺] in 8.8×10¯⁴ M Ca(OH)₂ solution as illustrated below:
Step 1:Data obtained from the question
Concentration of Ca(OH)₂ = 8.8×10¯⁴ M
Concentration of Hydrogen ion [H⁺] =..?
Step 2:Determination of the concentration of Hydroxide ion [OH¯]
Concentration of Ca(OH)₂ = 8.8×10¯⁴ M
Concentration of Hydroxide ion [OH¯] =?
Ca(OH)₂ (aq)⇄Ca²⁺ (aq) + 2OH¯(aq)
From the balanced equation above,
1 mole Ca(OH)₂ produced 2 moles of OH¯.
Therefore, 8.8×10¯⁴ M Ca(OH)₂ will produce = 8.8×10¯⁴ × 2 = 1.76×10¯³ M
Thus, the Concentration of Hydroxide ion [OH¯] is 1.76×10¯³ M
Step 3:Determination of concentration of Hydrogen ion [H⁺]. Concentration of Hydroxide ion [OH¯] = 1.76×10¯³ M
Concentration of Hydrogen ion [H⁺] =..?[tex]H^{+} * OH^{-} = 1*10^{-14}\\H^{+} * 1.76^{-3} = 1*10^{-14}[/tex]
Divide both side by 1.76×10¯³
[tex]H^{+} = \frac{1*10^{-14} }{1.76*10^{-3}}\\[/tex]
[H⁺] = 5.68×10¯¹² M
Therefore, the concentration of Hydrogen ion [H⁺] in the solution is 5.68×10¯¹² M
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what is the average atomic mass of einsteinium? what are its common isotopes?
Answer:
Boom
Explanation:
The bomb is big and it goes boom and it also creates nuclear fragments everywhere
Which of the following students best describes an element?
Answer:
I dont see anything.
Explanation:
But an element is a substance that is made only out of one atom.
Can someone solve this for me I'm confused.
Answer:
310.53 g of Cu.
Explanation:
The balanced equation for the reaction is given below:
CuSO₄ + Zn —> ZnSO₄ + Cu
Next, we shall determine the mass of CuSO₄ that reacted and the mass Cu produced from the balanced equation. This can be obtained as follow:
Molar mass of CuSO₄ = 63.5 + 32 + (16×4)
= 63.5 + 32 + 64
= 159.5 g/mol
Mass of CuSO₄ from the balanced equation = 1 × 159.5 = 159.5 g
Molar mass of Cu = 63.5 g/mol
Mass of Cu from the balanced equation = 1 × 63.5 = 63.5 g
Summary:
From the balanced equation above,
159.5 g of CuSO₄ reacted to produce 63.5 g of Cu.
Finally, we shall determine the mass of Cu produced by the reaction of 780 g of CuSO₄. This can be obtained as follow:
From the balanced equation above,
159.5 g of CuSO₄ reacted to produce 63.5 g of Cu.
Therefore, 780 g of CuSO₄ will react to produce = (780 × 63.5)/159.5 = 310.53 g of Cu.
Thus, 310.53 g of Cu were obtained from the reaction.
How might a collision between Neptune and Halley's Comet
affect Neptune's orbit?
Answer:
It will mess up the orbit around the sun
Explanation:
The impact of Halley's Comet with Neptune may force the asteroid to descend into Neptune's orbit, which may divert somewhat from its original path.
The collision of two heavenly bodies results in a powerful impact.
This collision might prevent Halley's Comet from continuing on its path and eventually colliding with Neptune.
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Why the graph isn't just a single sloped straight line.
Answer:
the equation could have mulitplication and square roots which may change the function of the line
what volume (in L) of a 3.95 M potassium chloride solution would be needed to make 325 mL of a 2.76 M solution by dilution
Explanation:
Moles of KCl in new solution = 0.325dm³ * (2.76mol/dm³) = 0.897mol.
Hence volume needed = 0.897mol / (3.95mol/dm³) = 0.227dm³ or 0.227L.
Which example describes a chemical change
taking place?
A. water turning into steam
B. sugar dissolving in warm water
C. alcohol evaporating from a food while baking
D. nails rusting while sitting outside
38
Both ionization and dissociation produce ions of the solute in solution.
How do the two processes differ? Write two differences. *
Answer:
Detail is given below
Explanation:
Differences:
Ionization involves the formation of ions while in dissociation substance are break into atoms, ions or molecules.
In ionization atoms and molecules gain positive or negative charge.
While in dissociation positive and negative ions are not essentially formed substance could be break into neutral small particles.
Ionization occur in covalent compounds while dissociation occur in ionic compound.
Ionization example:
Cl + e⁻ → Cl⁻
Dissociation example:
NaCl → Na⁺ + Cl⁻
Here sodium and chloride ions are formed but in sodium chloride these ions were already present.
Another example:
N₂O₄ → 2NO₂
How many grams are in 2.3 x 10^ -4 moles of calcium phosphate?
Answer:
Mass = 713.4 ×10⁻⁴ g
Explanation:
Given data:
Number of moles of calcium phosphate = 2.3×10⁻⁴ mol
Mass of calcium phosphate = ?
Solution:
Formula:
Number of moles = mass/molar mass
Molar mass of calcium phosphate is 310.18 g/mol
by putting values,
2.3×10⁻⁴ mol = mass / 310.18 g/mol
Mass = 2.3×10⁻⁴ mol × 310.18 g/mol
Mass = 713.4 ×10⁻⁴ g
A scoop of potassium oxide was placed in
55g of water which produced 67g of
potassium hydroxide. What mass of
potassium oxide was used?
A scoop of potassium oxide was placed in 55g of water which produced 67g of potassium hydroxide then mass of potassium oxide was used is 12g
Potassium oxide is used widely in the agricultural industry as a fertilizer
Here given data is
Potassium oxide was placed in 55g of water which produced 67g of potassium hydroxide
We have to calculate mass of potassium oxide was used =?
Then the reaction is
K₂O + H₂O → KOH
x + 55g = 67g
x = 67g - 55g
x = 12g
Therefore mass of potassium oxide was used is 12g
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In the ground state, all of the atoms of Period 3 elements have the same
A) atomic number
B) number of oxidation states
C) number of occupied energy shells
D) atomic mass
Answer:
C) number of occupied energy shells
Explanation:
Atomic numbers of different elements must differ, as well as atomic masses. The number of oxidation states differs per atom as well.
DOG SKELETAL SYSTEM BONES SKELETAL TISSUE BONE CELLS SMALLEST TO LARGEST
Answer:
tissue bone cells ,bones skeletal,dog skeletal system
Explanation:
MARKING BRAINLIEST!
Many processes occur in the digestive system. Which process is best classified as a physical change?
A. digestive enzymes breaking down proteins into smaller fragments
B. teeth grinding an almond into smaller pieces in the mouth
C. bacteria converting lactose into simple sugars in the intestines
D. saliva converting the starch molecules in crackers into simpler sugars
Answer:
Teeth gridning
Explanation:
BC YOUR GRINDING IT
1. A group of elements that includes the most active of the nonmetals is the
a. nitrogen group.
c. noble gases.
b. alkaline earths.
d. halogens.
Answer:
D. Halogens
Explanation:
All elements in these groups have 7 valence electrons, meaning their electronegativity is the highest among the elements.
You are required to identify the following substances using their properties Substance A. conducts electricity in both solid and liquid state. Substance
B. conducts electricity in solid state but its electrical conductivity in liquid state is unknown. Also it burns at a vey high temperature to give off carbon dioxide gas.
C. conducts electricity in liquid state but not in solid state Substance
D. does not conduct electricity in any state
You have to identify that; which substance is an ionic compound, which one is covalent compound , which one is a metal and which one is graphite.
Answer:
Explanation:
A. conducts electricity in both solid and liquid state.
Metal
B. conducts electricity in solid state but its electrical conductivity in liquid state is unknown. Also it burns at a vey high temperature to give off carbon dioxide gas.
Graphite
C. conducts electricity in liquid state but not in solid state
Ionic compound
D. does not conduct electricity in any state
Covalent compound
A metal is a substance that conducts both heat and electricity in solid and liquid state. They do this by the presence of free mobile electrons within their atomic space.
Graphite is a non - metal but it has free mobile electrons within its carbon frame work that allows of electrical conduction.
Ionic compounds are conductors only in molten state. In solid state, they do not conduct electricity and are called electrolytes in their liquid or molten form.
Covalent compounds do not ionize in solution and will not have ions which can conduct electric current.
3. What mass of copper could be deposited from a copper(II) Sulphate solution using a current of 5.0 A over 100 seconds? ( F =96,500C,Charge of Cu in CuSO4 = +2)
Mass of copper : 0.165 g
Further explanationGiven
5.0 A over 100 seconds
Required
Mass of copper
Solution
Faraday's law:
The mass of the substance formed at each electrode is proportional to the electric current flowing in the electrolysis
[tex]\tt W=\dfrac{e.i.t}{96500}[/tex]
e = Ar / valence = eqivalent weight
i = current
t = time
W = weight
CuSO₄ ----> Cu²⁺ + SO₄²⁻
Cu ----> Cu²⁺ + 2e
e = Ar/2
= 63,5/2 = 31,75
[tex]\tt W=\dfrac{31.75\times 5\times 100}{96500}=0.165~g[/tex]
23. Select the evidence that Thomson used to conclude his findings.
(a) Electrons become excited with more energy and then release that energy as atomic
spectra.
(b) Performed a series of experiments using pressure, properties of gases, and properties
of compounds.
(c) Battery Passed a cathode ray between positively and negatively charged plates and observed the cathode ray attracting to the positively charged plate.
(d) Bombarded a thin layer of gold foil with alpha particles and detected that some alpha
particles passed through the gold foil while others deflected.i
Answer:
The answer is C
Explanation:
Thomson conducted many tests with cathode rays. Which led to his discovery of the electron.
his table shows the mass and volume of four different objects.
A two-column table with 4 rows. The first column titled objects has entries W, X, Y, Z. The second column titled Measurements has entries Mass: 16 grams Volume: 84 centimeters cubed in the first cell, Mass: 12 grams Volume: 5 centimeters cubed in the second cell, Mass: 4 grams Volume: 6 centimeters cubed in the third cell, Mass: 408 grams Volume: 216 centimeters cubed in the fourth cell.
Which ranks the objects from most to least dense?
X, Y, W, Z
X, Z, Y, W
W, Y, Z, X
Z, Y, X, W
Ranks the objects from most to least dense : X,Z,Y,W
Further explanationGiven
Object W : m=16 g, V=84 cm³
Object X : m=12 g, V= 5 cm³
Object Y : m=4 g, V= 6 cm³
Object Z : m=408 g g, V= 216 cm³
Required
Density
Solution
Density formula:
[tex]\large {\boxed {\bold {\rho ~ = ~ \frac {m} {V}}}}[/tex]
ρ = density
m = mass
v = volume
1. Object W
[tex]\tt \rho=\dfrac{16}{84}=0.19[/tex]
2. Object X
[tex]\tt \rho=\dfrac{12}{5}=2.4[/tex]
3. Object Y
[tex]\tt \rho=\dfrac{4}{6}=0.67[/tex]
4. Object Z
[tex]\tt \rho=\dfrac{408}{216}=1.89[/tex]
From most to least dense : X,Z,Y,W
Dan wants to test the effects of different amounts of antibiotic on bacteria. While setting up his experiment he makes sure to use the same type of antibiotic, the same type of bacteria, and the same type of incubator for each trial. Which phrase below best describes this part of the experiment?
Answer:
C
Explanation:
A. analyzing results
B. collecting data
C. choosing controlled variables
D. making a prediction
The correct answer would be choosing controlled variables.
The controlled variables are factors that are kept constant among the different groups of subjects during the course of an experiment so as to be able to isolate the effects of a single factor - the independent variable.
There are basically 3 types of variables in a scientific experiment;
1. The independent variable
2. The dependent variable
3. The controlled variable
The independent variables are the variables whose effects are to be determined in the course of experiments. The dependent variables are the variables that are actually measured during the course of experiments and whose values vary along with that of the independent variables. The controlled variables are other variables required for the experiment but which must be kept constant among subjects in order to be able to isolate the effects of the independent variable.
The correct option is C.
How many grams of carbon are required to produce 0.460 moles of SiC?
SiO2 + C → SiC + CO
Answer:
Sick Core corona +iep =Qurintine
Questlon 7 of 10
Which object will require the greatest amount of force to change its motion?
O A. A 72 kg object moving 25 m/s
O B. A 55 kg object moving 32 m/s
OC. A 75 kg object moving 22 m/s
O D. A 63 kg object moving 27 m/s
A 72 kg object moving 25 m/s will require the greatest amount of force
Further explanationGiven
mass of object and the velocity
Required
the greatest amount of force
Solution
Newton's 2nd law :
∑F = m. a
F = force, N
m = mass = kg
a = acceleration due to gravity, m / s²
Assuming the object is moving from rest (vo = 0) and the time needed to reach its velocity is the same (delta t = equal), it can be formulated:
[tex]\tt \Sum F=m.\dfrac{v_f-v_i}{\Delta t}\\\\F=m.\dfrac{v_f}{\Delta t}[/tex]
So the force on an object depends on the product of its mass and velocity
Or if we use the impulse and momentum formula
[tex]\tt F.\Delta t=m(v_f-v_i)\\\\F,\approx m.v_f[/tex]
So that we determine which is the greatest from the multiplication of mass and velocity will produce the greatest force as well
A 72 x 25 = 1800
B. 55 x 32 =1760
C. 75 x 22 = 1650
D.63 x 27 = 1701
Option A has the greatest force
The model below shows a part of a human body's muscular system.
Muscles are organs that make movement possible. Which organ system is responsible for controlling muscular movement?
A. Endocrine system
B. Skeletal system
C. Nervous system
D. Digestive system
Answer:
you must go to jones im doing the same test
Explanation:
A compound consists of 50.04% carbon, 5.59% hydrogen, and 44.37% oxygen. What is the empirical formula of this compound?
The empirical formula of the compound is C₃H₄O₂
From the question given above, the following data were obtained:
Carbon = 50.04%
Hydrogen = 5.59%
Oxygen = 44.37%
Empirical formula = ?Divide by their molar mass
C = 50.04 / 12 = 4.17
H = 5.59 / 1 = 5.59
O = 44.37 / 16 = 2.773
Divide by the smallest
C = 4.17 / 2.773 = 1.5
H = 5.59 / 2.773 = 2
O = 2.773 / 2.773 = 1
Multiply by 2 to express in whole number
C = 1.5 × 2 = 3
H = 2 × 2 = 4
O = 1 × 2 = 2
Therefore, the empirical formula of the compound is C₃H₄O₂
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The length of a year is equivalent to the time it takes for one.. (pls help I honestly forgot )
What energy transformation occurs when a person is running
Answer:
Kinetic Energy (Hope This Helps)
Explanation:
(Brainliest)
Answer:
Chemical energy to kinetic energy. (Arguably heat energy (thermal) because of respiration)
What mass of gold (Au) contains the same number of atoms as 2.61 g of aluminum (Al)?
Answer:
19.11g
Explanation:
mole = mass ÷ molar mass
mole = 2.61 ÷ 27
mole = 0.097mol
Number of atoms in 2.61g of Aluminum = 6.022 × 10^23 × 0.097
= 0.584 × 10^23
= 5.84 × 10^22atoms
To get the same number of atoms for Gold (Au), we multiply the atomic mass of Au by 0.097mol
Atomic mass of Au = 197g/mol
mass = mole × molar mass
mass = 0.097 × 197
mass = 19.109g
mass = 19.11g