Answer:
The answer is 1.50 molesExplanation:
To find the number of moles in a substance given it's number of entities we use the formula
[tex]n = \frac{N}{L} \\ [/tex]
where n is the number of moles
N is the number of entities
L is the Avogadro's constant which is
6.02 × 10²³ entities
From the question we have
[tex]n = \frac{9.01 \times {10}^{23} }{6.02 \times {10}^{23} } = \frac{9.01}{6.02} \\ = 1.496677740...[/tex]
We have the final answer as
1.50 molesHope this helps you
Answer: 1.50 moles
Explanation:
Radioactive isotope X has a half-life of 500,000 years. This isotope may be found in some types of volcanic rocks. A particular sample of volcanic rock taken from a layer that covered up some of the earliest known human-like footprints contains 0.125 mg of isotope X. The volcanic rock sample originally contained 8.00 mg of isotope X. How long ago were these footprints made. I need the equation. Thanks. please I am stuck on this question. PLEASE
Answer: The footprints were made [tex]2.99\times 10^6years[/tex] years long ago.
Explanation:
Radioactive decay follows first order kinetics.
Half-life of isotope X= 500,000 years
[tex]\lambda =\frac{0.693}{t_{\frac{1}{2}}}=\frac{0.693}{500000}=0.00000139year^{-1}[/tex]
The equation for first order kinetics is :
[tex]N=N_o\times e^{-\lambda t}[/tex]
N = amount left after time t = 0.125 mg
[tex]N_0[/tex] = initial amount = 8.00 mg
[tex]\lambda[/tex] = rate constant
t= time
Putting the values we get:
[tex]0.125=8.00\times e^{- 0.00000139years^{-1}\times t}[/tex]
[tex]0.0156=e^{- 0.00000139years^{-1}\times t}[/tex]
[tex]t=2.99\times 10^6years[/tex]
The footprints were made [tex]2.99\times 10^6years[/tex] years long ago.
Two or more atoms that have been chemically combined are
called a
Answer:
compound
Explanation:
HELPP
A monatomic ion always have one unit of charge. (+1 or -1) on the species
true or false
Answer:
No, this is invalid. The term mono in front of monoatomic simply refers to the number of atoms that are present in a compound or simply by itself it has no relationship with respect to the overall charge of the compound.
Explanation:
For instance Ca is considered as a monoatomic ion but it has a charge of +2.
1. Define λmax and explain why it is desirable to do the experimental procedure at λmax? 2. Around what absorbance would you expect the λmax to be with each color solution? (Blue, green, red, yellow) 3. A pipet is used to make the solution dilutions in lab. Suppose in making the dilution, additional distilled water is accidentally added. Will the concentration of the solution be higher or lower that disered? Explain.
Answer:If you help me with the triple beam balance gizmo then i can do this for you
Explanation:please i need help
The periodic table is a(n) _________________________________ system for the elements.
Answer:
Sabihin mo
Explanation:
salamat shoppe
NH3 is a _______________
Answer:
compound
Explanation:
Answer:
your answer would be compound
WILL GIVE 5 STAR RATING AND BRAINLIEST IF YOU ANSWER FIRST AND CORRECTLY
What are the total number of elements in C₄H₉OH ?
The main goal of science is to
Answer:
The goal of science is to learn how nature works by observing the natural and physical world, and to understand this world through research and experimentation.
Explanation:
What do we call the (+) ion in an ionic bond? *
O Cation
O Anion
O Metalloid
O Covalent
Answer:
cation
Explanation:
a cation is an ion with a postitive charge. This (cat)ion (+) = cats are good , anion (onion) are not good (-)
PLEASE HELP 30 POINTS
Because the rock is irregularly shaped, you used the displacement method to measure its volume.
You used (______) to indirectly find the (_____) of the objects.
Options for the 1st fill in the blank:
- a balance
- calculations
- a graduated cylinder
Options for the 2nd fill in the blank:
- density
- mass
- area
Answer:
balance for the 1st and mass for the 2nd
A neutral atom of an element has three energy levels and two valence electrons. Which element in the periodic table does this describe?
Answer:
I think it is Lithium...
Explanation:
the advantage of asexual reproduction is.
a. There are no genetic mutations
b. reproduction doesn't require a mate
c. increase genetic variation
Answer:
1.) Genetic Variation, 2.) reproduction doesn't require a mate.
Explanation:
These are the only two that actually make sense in the blanks, So trust me or trust the other two answers.Your choice.
during chemical reaction do atoms change into a new substance
true or false
Answer:
t
Explanation:
because for atoms to change they have to have some kind of chemical action to get new life
The expression of the speed of light can be written as: (C =
Answer:
The expression of speed of light can be written as "c".
Explanation:
The speed of light is denoted by c. It is originated from the Latin word celeritas which means "speed". Its value is 3×10⁸ m/s.
It is related to the frequency and wavelength as follow,
Speed of light = wavelength × frequency
c = λ × f
λ = c/f
This formula shows that both frequency ad wavelength are inversely related to each other.
Frequency is taken in Hz.
It is the number of oscillations, wave of light make in one second.
Wavelength is designated as "λ" and it is the measured in meter. It is the distance between the two crust of two trough.
which of the following molecules has only two non binding pairs (long pairs) of electrons in its lewis structure?
a)O2
b)CH4
c)NH3
d)H2s
Explanation:
NH₃ has only two non-binding pairs (lone pairs) of e⁻ in it's Lewis structure.
••
H—N—H
|
H
Therefore,
C is correct. ✔
What is the activation energy of a reaction?
Answer:
The activation energy for the forward reaction is the amount of free energy that must be added to go from the energy level of the reactants to the energy level of the transition state. ... Once a reactant molecule absorbs enough energy to reach the transition state, it can proceed through the remainder of the reaction.
Explanation:
Answer: Activation energy is how much energy it takes for a reaction to occur.
Explanation:
pls help me with this question
Answer:
I think its a and c
Explanation:
im smrt
after the nutrients are extracted, where does the food go, waiting to be expelled?
Answer:
Nutrients advance through the alimentary canal to the stomach and small intestine, and waste materials continue from the small intestine to the colon (large intestine) and anus.
Explanation:
This is a property of matter that can be identified without changing the identity of the substance
PLEASE ANSWER QUICKLY!
Answer:
hkile uo gihme rapre
Explanation:
anwser this ASAP please
Answer:
Its D :)
Or not i haven't done this in a while-
What is the role of gravity in the solar system?
Answer:
Explanation:
Gravity is what holds the planets in orbit around the sun and what keeps the moon in orbit around Earth. ... Gravity creates stars and planets by pulling together the material from which they are made. Gravity not only pulls on mass but also on light.
Jimmy's science textbook reflects blue light. What color is the book?
Repeat this calculation using Slater's rules to estimate the screening constant, S, and calculate Zeff for these two ions. Express your answers using two decimal places. Enter your answers numerically separated by a comma. 50 A 6 A 0 21 ? S. Zeff C, Zeff K+ =
Answer:
Cl^- = 5.75
K^+ = 7.75
Explanation:
Now let us calculate the effective nuclear charge four K^+ and Cl^- from Slater's rule.
Given that Cl^- and K^+ has electronic configuration of; [Ne] 3s2 3p6 (they are isoelectronic species)
We compute S as follows;
For n - 2 level, S= 1
For n - 1 level, S= 0.85
For ns,np level S= 0.35
Note: S= screening or shielding constant
1s2, S=2 ×1 = 2
2s2 2p6, S= 8×0.85 = 6.8
3s2 3p6, S= 7 × 0.35 = 2.45
The electron under study is not considered hence seven out of eight electrons in the shell are considered
Hence
S= 2 + 6.8 + 2.45 = 11.25
Since Cl^- has 17 electrons;
Zeff(Cl^-) = 17 - 11.25 = 5.75
For K^+
Zeff = 19 - 11.25 = 7.75
as distance from nucleus increases , energy of shells decreases, correct the wrong statement
as distance from nucleus increases , energy of shells also increases
PLS HELP!! ASAP!! 10 POINTS!!
From Dalton's atomic theory, a few parts were disproven over the course of years of experiments. Which part was modified by the discovery of subatomic particles?
That matter is made of atoms.
If the same elements are in a two different compounds, their ratio will always be the smallest whole number ratio for that compound.
That atoms cannot be divided.
That all atoms of an element are exactly the same
The indivisibility of an atom was proved wrong: an atom can be further subdivided into protons, neutrons and electrons. ... According to Dalton, the atoms of same element are similar in all respects. However, atoms of some elements vary in their masses and densities. These atoms of different masses are called isotopes.
what would you expect to see if a piece of copper metal is placed in a solution that contains nickel(II) ions?
A. copper atoms become copper(II) ions
b. nickel ions become solid nickel
c. no reaction happens
d. a precipitate forms that contains copper and nickel ions
Answer:
c. no reaction happens
Explanation:
Let me take your mind back to the idea of electrode potentials of metals. Remember that the more negative the electrode potential of a metal, the more reducing the metal is. Metals with more negative electrode potentials displace metals with less negative electrode potentials from their aqueous solutions.
The electrode potential of nickel is -0.25 V while that of copper is +0.34 V. Hence, copper is lower than nickel in the activity series and can not displace it from aqueous solution.
This implies that, if a piece of copper metal is placed in a solution that contains nickel(II) ions, no reaction happens .
Two chemicals A and B are combined to form a chemical C. The rate, or velocity, of the reaction is proportional to the product of the instantaneous amounts of A and B not converted to chemical C. Initially, there are 100 grams of A and 50 grams of B, and for each gram of B, 2 grams of A is used. It is observed that 10 grams of C is formed in 7 minutes. How much is formed in 28 minutes? (Round your answer to one decimal place.) grams What is the limiting amount of C after a long time? grams How much of chemicals A and B remains after a long time? A grams B grams At what time is chemical C half-formed? t = min
Answer:
Follows are the solution:
Explanation:
A + B = C
Its response decreases over time as well as consumption of a reactants.
r = -kAB
during response A convert into 2x while B convert into x to form 3x of C
let's y = C
y = 3x
Still not converted sum of reaction
for A: 100 - 2x
for B: 50 - x
Shift of x over time
[tex]\frac{dx}{dt} = \frac{-k(100 - 2x)}{(50 - x)}[/tex]
Integration of x as regards t
[tex]\frac{1}{[(100 - 2x)(50 - x)]} dx = -k dt\\\\\frac{1}{2[(50 - x)(50 - x)]} dx = -k dt\\\\\ integral\ \frac{1}{2[(50 - x)^2]} dx =\ integral [-k ] \ dt\\\\\frac{-1}{[100-2x]} = -kt + D \\\\[/tex]
D is the constant of integration
initial conditions: t = 0, x = 0
[tex]\frac{-1}{[100-2x]} = -kt + D \\\\\frac{ -1}{[100]} = 0 + D\\\\D= \frac{-1}{100}\\\\[/tex]
hence we get:
[tex]\frac{-1}{[100-2x]}= -kt -\frac{1}{100}\\\\or \\\\ \frac{1}{(100-2x)} = kt + \frac{1}{100}[/tex]
after t = 7 minutes , [tex]C = 10 \ g = 3x[/tex]
[tex]3x = 10\\\\x = \frac{10}{3}[/tex]
Insert the above value x into [tex]\frac{1}{(100-2x)}[/tex] equation [tex]= kt + \frac{1}{100}[/tex] to get k.
[tex]\to \frac{1}{(100-2\times \frac{10}{3})} = k \times (7) + \frac{1}{100} \\\\ \to \frac{1}{(100- 2 \times 3.33)} = \frac{700k + 1}{100} \\\\ \to \frac{1}{(100-6.66)} = \frac{700k + 1}{100}\\\\ \to \frac{1}{93.34} = \frac{700k + 1}{100} \\\\[/tex]
[tex]\to 100 = 93.34(700k + 1) \\\\ \to 100 = 65,338k + 700 \\\\ \to 65,338k = -600 \\\\ \to k = \frac{-600}{ 65,338} \\\\ \to k= - 0.0091[/tex]
therefore plugging in the equation the above value of k
[tex]\to \frac{1}{(100-2x)} = kt +\frac{1}{100} \\\\\to \frac{1}{(100-2x)} = -0.0091t + \frac{1}{100}\\\\\to \frac{1}{(100-2x)} = \frac{1 -0.91t}{100}\\\\\to \frac{1}{2(50-x)} = \frac{1 -0.91t}{100}\\\\\to \frac{1}{(50-x)} = \frac{1 -0.91t}{50}\\\\\to 50= (1-0.91t)(50-x)\\\\\to 50 = 50-45.5t-x-0.91tx\\\\\to x+0.91xt= -45.5t\\\\\to x(1+0.91t)= -45.5t\\\\\to x=\frac{-45.5t}{1+0.91t}[/tex]
Let y = C
, calculate C:
y = 3x
[tex]y =3 \times \frac{-45.5t}{1+0.91t}[/tex]
amount of C formed in 28 mins
[tex]x = \frac{-45.5t}{1+0.91t} ,[/tex] plug t = 28
[tex]\to x = \frac{-1274}{1+25.48} \\\\\to x = \frac{-1274}{26.48} \\\\\to x= -48.26[/tex]
therefore amount of C formed in 28 minutes is = 3x = 144.78 grams
C: [tex]y =3 \times \frac{-45.5t}{1+0.91t}[/tex]
y= 136.5 =137
I will give you brainliest
Answer:
Plumbing System
Explanation:
Answer:
C plumbing system
Explanation:
Infrastructure is the basic structures needed for the operation of society
It's how many atoms are in two water molecules (H2O)?
Answer:
The chemical formula for water is H2O which means that every molecule of water has 2 atoms of hydrogen (H) and one atom of oxygen (O). Here comes the key part. From the Periodic Table of Elements, one sees that one mole of hydrogen atoms weighs 1 gram while one mole of oxygen atoms weighs 16 grams.
Explanation:
:)
The number of atoms present in two water molecules is 6 atoms. 4 hydrogen atoms and 2 oxygen atoms.
What are atoms?Atoms are the basic unit of a substance. An atom is made of a nucleus, protons, neutrons and electrons. Different atoms combines to form a molecule and molecules combines to form compounds.
Water has the formulas H₂O, thus one molecule of water contains 2 hydrogen and one oxygen. Therefore, two molecules of water that is (H₂O)₂ have 4 hydrogen and 2 oxygens thus, a total of 6 atoms.
Hence, the number of atoms present in two molecules of water is 6.
To learn more about no. of atoms, refer the link below:
https://brainly.com/question/9049646
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Crystallisation is a separation technique used to separate____ solids from a liquid solvent.
Answer:
separate soluble solids from liquid
Explanation:
A in Chemistry
Crystallization is a separation technique used to separate solute solids from a liquid solvent.
What is Crystallization?Crystallization is the process of disuniting or separating two substances or molecules that are mixed, and are of different forms of matter. Such as solid and liquid. The process separates mixtures by three processes. These processes are freezing, precipitation, and deposition.
It is the main process of separating solid from liquid. In this process, the solute came above the liquid in crystal form and this is called precipitation.
Freezing separates the substance that has a different freezing point. By deposition, the substance that is solid and called solute is deposited below the liquid in the container.
Thus, crystallization separates the solute solids from a liquid solvent.
To learn more about Crystallization, refer to the link:
https://brainly.com/question/17053072
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