Answer:
B. Frequency decreases
An unknown element is a mixture of isotopes ¹²⁰X and ¹²²X. The average atomic mass of X is 120.81 amu. What is the percent abundance of ¹²²X?
Answer:
40.5% is abundance of X-122
Explanation:
we know there are two naturally occurring isotopes of X, X-120 and X-122.
First of all we will set the fraction for both isotopes
X for the isotopes having mass 122
1-x for isotopes having mass 12 0
The average atomic mass of X is 120.81 amu
we will use the following equation,
122x + 120 (1-x) = 120.81
122x + 120 - 120x = 120.81
122x- 120x = 120.81 -120
2x = 0.81
x= 0.81/2
x= 0.405
0.405 × 100 = 40.5%
40.5% is abundance of X-122 because we solve the fraction x.
now we will calculate the abundance of X-120.
(1-x)
1 - 0.405 = 0.595
0.595 × 100 = 59.5 %
59.5 % for X-120.
In the nitrogen cycle, plants use nitrogen compounds to produce *
Answer: Once nitrogen is converted into compounds like ammonium and nitrate, these can be taken up from soils by plants and then the nitrogen can be used to form macromolecules like proteins and nucleic acids (DNA and RNA).
The answer is proteins
As an electron in an atom moves from a higher energy state to a lower energy state, the atom does what?
Answer: absorbs energy
Explanation:
Answer:
releases energy
Explanation:
Scientists describe the motion of an object in relation to which of the following? A)Gravitational pull
B)[Force
C)Another object
D)Its mass
Answer:
A) Gravitational Pull
Explanation:
Objects on Earth are pulled toward the center of Earth. The force of gravity, like all other forces, can cause changes in the speed of objects.
Answer:
c
Explanation:
what would you expect in the melting point data if benzoic acid and acetanilide are mixed in equal amount
Answer:
There will be an increased span of the melting point of acetanilide
Explanation:
if benzoic acid and acetanilide are mixed in equal amounts, there will be an increased span of the melting point of acetanilide than what is known already. This is because the two compounds have mixed together to become a mixture.
Classify each of the following as a Strong acid (sa) or a Weak acid (wa) and indicate how each should be written in aqueous solution. Classify ... In solution this acid should be written as: fill in the blank 1 1. nitric acid fill in the blank 3 2. perchloric acid fill in the blank 5 3. hydrofluoric acid
Answer:
1. nitric acid: sa
2. perchloric acid: sa
3. hydrofluoric acid: wa
Explanation:
A strong acid (sa) is the one that is completely dissociated into ions in water. Conversely, a weak acid (wa) is not completely dissociated in water.
From the options, the strong acids are:
1. nitric acid (HNO₃). It dissociates completely into ions when is dissolved in water, as follows:
HNO₃ → H⁺ + NO₃⁻
2. perchloric acid (HClO₄). It is completely dissociated in water as follows:
HClO₄ → H⁺ + ClO₄⁻
The weak acid is hydrofluoric acid (HF). In water, only a small proportion is dissociated into ions. The proportion of ions formed is given by the equilibrium constant Ka. The dissociation is written by using double arrows:
HF ⇄ H⁺ + F⁻
. A block of wood has a mass of 150 grams and a volume of 550 cm3. What is its density?
Answer:
mass= 150 g
volume= 550 cm3
density= mass/ volume
= 150/550
= 0.27 g/cm3
Number of moles in 9.04 x 1023 molecules of H2O?
Answer:
44x+7y
Explanation:
The number of molecules in one mole of water is 6.02 × 10²³. Therefore, the number of moles of carbon dioxide which contains 9.04 × 10²³ molecules is 1.50.
What is Avogadro number ?The number of atoms that constitutes one mole of a substance is called Avogadro number. It is equal to 6.02 × 10²³. Thus, one mole of every elements contains Avogadro number of atoms.
Similarly, one mole of a compound contains 6.02 × 10²³ number of molecules. Thus, one mole of carbon dioxide contains these much molecules.
Given the number of molecules of water = 9.04 × 10²³
Then, no.of moles = number of molecules/ Avogadro number.
no.of moles =9.04× 10²³ /6.022 × 10²³ = 0.68.
Therefore, the number of moles of H₂O that contains 9.04 × 10²³molecules is 1.50
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Calculate the number of vacancies in gold per cubic centimeter at 1000 K, where the density and atomic weight for gold at are 18.63 g/cm3 and 196.9 g/mol, respectively, at 1000 K. The energy for vacancy formation in gold is 0.98 eV / atom. (Please express scientific notation using E to indicate the exponent - for example, 2.5E3
Answer:
autom is 18.63 g
Explanation:
there
write a skeletal equation for the following reaction: An aqueous solution of barium nitrate and an aqueous solution of sodium sulfate are mixed together. Then balance the completed chemical equation.
Answer:
Ba(NO₃)₂(aq) + Na₂SO₄(aq) ⇒ BaSO₄(s) + 2 NaNO₃(aq)
Explanation:
Let's consider the unbalanced double displacement equation for the reaction of an aqueous solution of barium nitrate and an aqueous solution of sodium sulfate.
Ba(NO₃)₂(aq) + Na₂SO₄(aq) ⇒ BaSO₄(s) + NaNO₃(aq)
To get the balanced equation, we will multiply NaNO₃(aq) by 2.
Ba(NO₃)₂(aq) + Na₂SO₄(aq) ⇒ BaSO₄(s) + 2 NaNO₃(aq)
HELP PLEASE
Which of these is measured in meter per second per second?
•speed
•velocity
•acceleration
•displacement
IM NOT SURE IF MY ANSWERS RIGHT SO IM NOT POSITIVE SORRY
Water only gets evaporated from the ocean. True or false?
Answer:
×
Explanation:
FALSE BECAUSE NOT OCEAN IT IS ALL
What is the source of thermal energy for Earth's mantle?
A Earth's core
B. global warming
C. mantle downwelling
D. radiation from the sun
Answer:
D. Radiation from the sun
Explanation:
The main source of thermal energy for the earth is Sun. The sun is major source which provide heat energy and light energy to the earth. The sun converts almost 4 million tons of energy into electromagnetic radiations which is a source of thermal energy for Earth's Mantle.
On June 21st which location below will experience the longest amount of daylight?
1. Equator
2. North pole
3. Tropic of Capricorn
Answer:
2. North pole
How many moles of Fluorine (F2) are
needed to completely react 8.0
moles of NF3?
Answer:
12 moles of F₂
Explanation:
We'll begin by writing the balanced equation for the reaction. This is illustrated below:
N₂ + 3F₂ —> 2NF₃
From the balanced equation above,
3 moles of F₂ reacted to produce 2 moles of NF₃.
Finally, we shall determine the number of mole of F₂ needed to produce 8 moles of NF₃. This can be obtained as illustrated below:
From the balanced equation above,
3 moles of F₂ reacted to produce 2 moles of NF₃.
Therefore, Xmol of F₂ will react to produce 8 moles of NF₃ i.e
Xmol of F₂ = (3 × 8)/2
Xmol of F₂ = 12 moles
Thus, 12 moles of F₂ is needed for the reaction.
What are in the energy levels that surround the nucleus of an atom?
Please help me answer this question
How many liters of C4H10 are present in 0.25 moles of C4H10 at STP?
Answer:
V = 5.6 L
Explanation:
Given data:
Number of moles of C₄H₁₀ = 0.25 mol
Temperature = standard = 273.15 K
Pressure = standard = 1 atm
Volume of C₄H₁₀ = ?
Solution:
Formula:
PV = nRT
R = general gas constant = 0.0821 atm.L /mol.K
1 atm × V = 0.25 mol × 0.0821 atm.L /mol.K × 273.15 K
V = 5.6 atm.L/ 1 atm
V = 5.6 L
Which of the following is not a good safety practice in the kitchen?
A
keep cleaning agents in a safe place away from food supplies
B
keep household cleaners and other hazardous chemicals in their original container
C
mix household cleaners to get a stronger cleaning product
D
keep the phone number for the poison control hotline next to the phone
Answer:
C. Mix household cleaners to get a stronger cleaning product
Explanation:
dont ever try that
C. Mix household cleaners to get a stronger product.
This is not safe because mixing chemicals may cause a toxic gas to form. This gas is toxic to people and can cause health issues.
I'm really sorry it took so long the school Wifi cut off while i was writing it lol
Which reservoir is found underground in the cracks and spaces in the soil, sand, and rock?
Glaciers
Ground water
Polar ice caps
Rivers
Answer:
Ground water
Explanation:
The ground water reservoir is found underground in cracks and spaces in the soil, sand and rock.
Ground water is a very important portion of the water cycle where water is stored in an aquifer.
Aquifers are porous and permeable formations that stores ground water within them.
In this manner, ground water system is recharged by infiltration of water from the surface. Water percolates and collects inside an aquifer in this manner.
Answer:
Ground Water
Explanation:
Zinc chloride is soluble.
Give the name of a soluble carbonate.
Give the name and formula of the precipitate formed when zinc chloride reacts with the
carbonate in a.
4 a Give the names of two solutions that would react together to form a precipitate of lead
chloride.
b Give the name and formula of the soluble product of this reaction.
Write the word equation for this reaction.
5 Copy and balance the following equations and add state symbols. Then write a word equation for
each.
a NaOH + CuCl2-NaCl + Cu(OH)2
b Ca(NO3)2 + Na2CO3 - CaCO3 + NaNO3
(NH4)2SO4 + Pb(NO3)
2NH4NO3 + PbSO4
с
Is strontium phosphide a ionic or covalent bond
Answer:
Strontium is a soluble earth metal with the nuclear number 38. Phosphate is a polyatomic particle containing phosphorus and oxygen molecules. Strontium loses electrons to turn out to be emphatically charged, and phosphate is an adversely charged particle.
Explanation:
When strontium phosphide comes into contact with water, it transforms into a solid that emits poisonous and combustible fumes. It is a highly reactive substance utilized in the production of chemically reactive devices as well as a laboratory reagent. Strontium phosphide is ionic.
Two elements combine to form an ionic compound. Sr is the metal while P is the non-metal in the ionic combination. After transferring its two valence electrons to P to create the phosphide ion, which has a net negative charge of -3, strontium becomes a cation.
Ions are charged particles that form when an atom (or group of atoms) receives or loses an electron, and ionic compounds are composed of these charged particles.
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A student dissolves of styrene in of a solvent with a density of . The student notices that the volume of the solvent does not change when the styrene dissolves in it. Calculate the molarity and molality of the student's solution. Be sure each of your answer entries has the correct number of significant digits.
Answer:
0.576M and 0.655m
Explanation:
...Dissolves 15.0g of styrene (C₈H₈) in 250.mL of a solvent with a density of 0.88g/mL...
Molarity is defined as moles of solute (Styrene in this case) per liter of solution whereas molality is the moles of solute per kg of solvent. Thus, we need to find the moles of styrene, the volume in liters of the solution and the mass in kg of the solvent as follows:
Moles styrene:
Molar mass C₈H₈:
8C = 12.01g/mol*8 = 96.08g/mol
8H = 1.005g/mol* 8 = 8.04g/mol
96.08g/mol + 8.04g/mol = 104.12g/mol
Moles of 15.0g of styrene are:
15.0g * (1mol / 104.12g) = 0.144 moles of styrene
Liters solution:
250mL * (1L / 1000mL) = 0.250L
kg solvent:
250mL * (0.88g/mL) * (1kg / 1000g) = 0.220kg
Molarity is:
0.144 moles / 0.250L =
0.576MMolality is:
0.144 moles / 0.220kg =
0.655mhenry moseley showed how the periodic table could be
Answer: Moseley's experiments in X-ray spectroscopy showed directly from their physics that cobalt and nickel have the different atomic numbers, 27 and 28, and that they are placed in the Periodic Table correctly by Moseley's objective measurements of their atomic numbers.
Explanation:
which of the following is required for a reaction to occur?
a. energy
b. collisions
c. activation energy
d. all of the above
Pentane (CH3CH2CH2CH2CH3) and neopentane (C(CH3)4 both have the C5H12 formula. Which compound has stronger induced dipole, induced dipole forces
Answer:
n-Pentane
Explanation:
All molecules possess dispersion forces. It is possible in non-polar molecules that a temporary distortion in the electron distribution of one molecule can affect the electron distribution in a neighboring molecule. This is known as induced dipole, induced dipole forces.
However, this induced dipole, induced dipole forces depends on the shape of the molecule. Molecules of n-pentane are capable of better interaction via induced dipole, induced dipole forces since the molecules interact over the entire length of the molecule rather than neopentane which is more compact and nearly spherical.
analysis shows the presence of 203 ug of cholesterol. what is the correct set up for conversion of mcg to kg
Answer:
The answer to your question is given below
Explanation:
From the question given above, the following data were obtained:
Mass of cholesterol (in μg) = 203 μg
Mass of cholesterol (in Kg) =?
The following conversion scale can be used to convert micro grams (μg) to kilogram (kg).
1 μg = 1×10¯⁹ Kg
Therefore,
203 μg = 203 μg × 1×10¯⁹ Kg / 1 μg
203 μg = 2.03×10¯⁷ Kg
Thus, 203 μg is equivalent to 2.03×10¯⁷ Kg
How many electrons are there in an atom of carbon?
Answer:
if its a neutral atom there should be 6 electrons because there are 6 protons
Explanation:
Drag the tiles to the correct boxes to complete the pairs.
Match the natural resources to their uses.
water
forests
wetlands
parks
paper
preserving aesthetic value
irrigation
trapping sediments
Answer:
water - irrigation
forests - paper
wetlands - trapping sediments
parks - preserving aesthetic value
Explanation:
One important use of water is for the irrigation of farmlands. Irrigation makes it possible for farming activities to continue all year round.
The papers yield pulp which is used to produce paper. This implies that paper is important product obtained from the forest.
The wetlands trap sediments and retain particulates from both onsite and offsite sources(blue earth county).
A park serves to preserve aesthetic value. This is a primary importance of the parks.
Xavier used a chart to list the roles of two different molecules in protein production.
Which headings best complete the chart?
Y: DNA
Z: tRNA
Y: tRNA
Z: DNA
Y: mRNA
Z: tRNA
Y: tRNA
Z: mRNA
Answer:
Y: tRNA
Z: DNA
Explanation:
This question involves two different nucleic acid molecules that are involved in protein production. Xavier used a chart to highlight the functions these nucleic acids perform during protein synthesis.
- Transfer RNA known as tRNA is a type of RNA molecule found in the ribosomes. It functions to read the mRNA codon and carry corresponding amino acid to the ribosomes for linking with one another. Based on this, "Y" on the chart is a tRNA molecule.
- Deoxyribonucleic acid, also known as DNA, is a molecule found in the NUCLEUS whose function is to store the genetic information in the cell. DNA carries the information needed for the synthesis of protein. Based on this, Z is a DNA molecule.
Answer:
The guy above is right! I got 100 on my test :]
