Answer:
k = 0.0866 days⁻¹
Explanation:
The isotope decay of the atom follows the equation:
ln [A] = -kt + Ln[A]₀
Where [A] is the amount of the isotope after time t = 8.25mg
Time = 12.8days
k is rate constant
[A]₀ is actual amount of the isotope = 25.0mg
Replacing:
ln 8.25mg = -k*12.8days + ln 25.0mg
2.11 - 3.22 = -k*12.8days
-1.11 = -k12.8days
k = 0.0866 days⁻¹
The diagram represents an atom of sodium combined chemically with one atom of chlorine to form a sodium chloride molecule. Sodium Chloride is an example of
Answer:
It is an example of ionic compound and ionic salt
As you are standing on the beach, the waves appear to be coming towards you. What is actually moving forward and why? A Water is moving towards you replacing the old water because of the winds B Water is moving towards you replacing the old water because of currents C Energy created by currents is moving towards you, and not the water itself. D Energy created by the wind is moving towards you, and not the water itself.
Answer:
B
Explanation:
Because unless you are walking towards it and the ocean is not moving then only you are moving
similarities between mole and MOL
Calculate the volume of 2.408x1024 molecules of water vapor at STP.
89.00 L
90.00L
89.61 L
89.60 L
Answer:
B
Explanation: im not rlly sure you can go with what i said or you dont
Which instrument is used to take an image from outer space that shows the depletion of the ozone layer in Earth’s atmosphere?
Answer:
answer is satellite!
Explanation:
Which of these pairs of elements have the same number of valence electrons?
Why is the average air temperature of Makassar warmer than the average air
temperature of Chirstchurch?
Answer:
becuase of the sun
in different places some places would be cold
All of the following have an OCTET of electrons except
о
S-1
O
N-3
O
Be+2
O
Br-1
Answer:
full octets live in noble gas world so you need to be whatever your charge is away from there in steps on the periodic table so s-1 is the one that falls short as it is 2 moves away from Ar which is its closest Noble gas
Explanation:
How would you make up 75 ml of a 45 mg/ml BSA solution?
Answer: see below
Explanation: for 75 ml, take 45*75 mg of BSA and make up to 75 mL with distilled water.
A chemist prepares a solution of silver(I) perchlorate by measuring out of silver(I) perchlorate into a volumetric flask and filling the flask to the mark with water. Calculate the concentration in of the chemist's silver(I) perchlorate solution. Be sure your answer has the correct number of significant digits.
The question is incomplete, the complete question is;
A chemist prepares a solution of silver (I) perchlorate (AgCIO4) by measuring out 134.g of silver (I) perchlorate into a 50.ml volumetric flask and filling the flask to the mark with water. calculate the concentration in mol/L of the silver (I) perchlorate solution. Round your answer to 2 significant digits.
Answer:
13 mol/L
Explanation:
We must first obtain the number of moles of silver I perchlorate involved
Molar mass of silver I perchlorate = 207.32 g/mol
Number of moles of silver I perchlorate = 134g/207.32 g/mol = 0.646 moles
Recall that;
n =CV
C= concentration
V= volume
n = number of moles
C = n/V
C = 0.646 moles * 1000/50
C = 13 mol/L
Help me plzz it’s for
How many atoms of oxygen are on the reactants side of this balanced equation?
2AgNO3 (aq)+ Cu(s) —Cu(NO3)2 (aq)+ 2Ag(s)
12
2
3
6
6
General Formulas and Concepts:Math
Pre-Algebra
Order of Operations: BPEMDAS
Brackets Parenthesis Exponents Multiplication Division Addition Subtraction Left to RightChemistry
Stoichiometry
Analyzing Reactions RxNExplanation:Step 1: Define
[RxN - Balanced] 2AgNO₃ (aq) + Cu (s) → Cu(NO₃)₂ (aq) + 2Ag (s)
Step 2: Identify
Reactants: 2AgNO₃ (aq) + Cu (s)
# of O atoms: 2(O₃) = 6 O
HELPHELPHELPHELPHELPHELPHELPHELPHELPHELPHELPHELPHELPHELPHELP
Answer:
Explanation:
In all, an estimated 8,000 to 10,000 Iraqi forces were killed, in comparison with only 300 coalition troops. Though the Gulf War was recognized as a decisive victory for the coalition, Kuwait and Iraq suffered enormous damage, and Saddam Hussein was not forced from power.
hope this helps a lot!
Clarifying Questions:
1. Why do solid covalent compounds ( molecules) have low melting points?
2. Why do solid ionic compounds (ions) have high melting points ?
3. How are carbon tetrachloride and sodium chloride different from each other?
Please help ASAP
Problem 1
The text (from the screenshot you posted) mentions that
"The atoms of covalent materials are bound tightly to each other in stable molecules, but those molecules are generally not very strongly attracted to other molecules in the material"
Put another way, we can think of each atom as a person, and each molecule as a family or a collection of persons. This is because any molecule is a collection of atoms. In covalent molecules, the connection between any two families isn't that strong since each person is focused more on their respective family, instead of other people outside the family. This is one way to think of it, but you may have a more effective way to remember.
In short, the exterior bonds between different covalent molecules isn't that strong, which means it's easier to break those bonds.
======================================================
Problem 2
The text also says
"The atoms (ions) in ionic materials show strong attractions to other ions in their vicinity"
This is due to the positively and negatively charged ions that attract to one another, and this causes a stronger chain so to speak. The stronger the chain, the harder it is to break when you apply temperature to it. Keep in mind that the only difference between a solid and a liquid is that the solid is a rigid structure while a liquid is more loose and free flowing. The ionic materials having a stronger inner bond like this is why ionic materials have higher melting points. You need to apply more temperature than normal to get the solid to melt.
======================================================
Problem 3
Again we turn to the text and it says
"For example, the molecule carbon tetrachloride is a non-polar covalent molecule, CCl4. It's melting point is -23 degrees Celsius. By contrast, the ionic solid NaCl has a melting point of 800 degrees Celsius"
In short, the difference between the two is that carbon tetrachloride has covalent bonds and NaCl (sodium chloride, aka table salt) has ionic bonds. It's much easier to melt the carbon tetrachloride than it is to melt the table salt.
Side note: carbon tetrachloride was historically used in fire extinguishers, but have been phased out due to safety concerns. Exposure to this toxin can lead to central nervous system problems, kidney failure, or liver problems. Due to its very low melting point, carbon tetrachloride is a liquid at STP.
1. Covalent compounds are held together by weak intermolecular forces. It is because of such weaker forces, which fails to make the compound bind tightly. Since lower heat (energy) is capable of breaking these weak intermolecular forces, therefore the melting and boiling points of covalent compounds is low.
2. Ionic compounds are held together by electrostatic forces between the oppositely charged ions . As the ionic lattice contains such a large number of ions, a lot of energy is needed to overcome this ionic bonding so ionic compounds have high melting and boiling points.
3. In terms of chemical bonding, carbon tetrachloride is a covalent chemical compound whereas sodium chloride is an ionic chemical compound. NaCl is solid in nature while CCl₄ is liquid.
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The absolute temperature of a gas is increased four times while maintaining a constant volume. What happens to the
pressure of the gas?
O It decreases by a factor of four.
O It increases by a factor of four.
O It decreases by a factor of eight.
O It increases by a factor of eight.
Save and Exit
yup help plssss.......
Answer:
D
Explanation:
because it's so hot that it's almost to the point of changing to another element
Answer:
To be honest with you I think it is A or D
Explanation:
bc I said so
lobal wind patterns have less to do with air temperature than local winds. A True B False
Answer:
False
Explanation:
Depends mostly on heating of the earths surface being uneven
It is false that global wind patterns have less to do with air temperature than local winds.
What is global wind?Local winds are those that blow over a small area. Local geography, such as proximity to an ocean, has an impact on them.
Monsoons and land and sea breezes are among them. Global winds occur in belts all over the world.
Temperature differences, particularly the difference in heating at the equator and poles, and the Earth's rotation determine the global atmospheric circulation pattern.
By transporting heat and water, winds shape regional climate and influence daily weather.
Global winds are winds that occur in belts that circle the globe. Global winds, like local winds, are caused by uneven heating of the atmosphere.
Because of the Coriolis effect, winds blow diagonally across the surface.
Thus, the given statement is false.
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Help!!
Which set of Earth components is arranged in order from solid to liquid to gas?
hydrosphere, atmosphere, lithosphere
hydrosphere, lithosphere, atmosphere
lithosphere, atmosphere, hydrosphere
lithosphere, hydrosphere, atmosphere
Answer:
Lithosphere, Hydrosphere, atmosphere
The set of Earth components that is arranged in order from solid to liquid to gas is D. lithosphere, hydrosphere, atmosphere
Lithosphere refers to the solid, outer part of the Earth. It is also known as the Rocky part of the Earth. It consists of the top part of the upper mantle and the brittle crust.Hydrosphere simply refers to the water on the Earth, underground and those that are in the air. This can be seen in ocean, seas, rivers, etc.Atmosphere refers to the layers of gases that can be found on Earth.ut contains gases like nitrogen, oxygen, etc.Read related link on:
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Explain the difference between endothermic and exothermic processes. Provide an example of each.
These are reactions that transfer energy to the surroundings (ie the energy exits from the reaction, hence the name exothermic). The energy is usually transferred as heat energy, causing the reaction mixture and its surroundings to become hotter. A thermometer is used to detect the temperature increase.
Examples:
Combustion
Neutralisation between acids and alkali
Endothermic reactionsThese are reactions that take in energy from the surroundings (ie energy enters the reaction, which will help you to remember the name endothermic). The energy is usually transferred as heat energy, causing the reaction mixture and its surroundings to become colder. A thermometer is used to detect the temperature decrease.
Example:
Electrolysis
What is the Noble gas electron configuration of lead (Pb)?
How many protons, electrons and neutrons does carbon have?
Answer:
6 all hope it helps thanks
Experimental value of acceleration due to gravity is found to be
9.842 m/s2. The accepted value of acceleration due to
gravity is 9.81 m/s2. What is the percent error in calculation?
Answer:
0.33%
Explanation:
From the question given above, the following data were obtained:
Experimental value = 9.842 m/s²
Accepted value = 9.81 m/s²
Percentage error =?
The percentage error in the calculation can be obtained as follow:
Percentage error = |Experimental – Accepted| / Accepted value × 100
Percentage error = |9.842 – 9.81| / 9.81 × 100
Percentage error = 0.032 / 9.81 × 100
Percentage error = 0.33%
Therefore, the error in the calculation is 0.33%
Covert 175g of H2O into moles.
Answer:
9.72 moles.
Explanation:
From the question given above, the following data were obtained:
Mass of H₂O = 175 g
Number of mole H₂O =?
Next, we shall determine the molar mass of H₂O. This can be obtained as follow:
Molar mass of H₂O = (2×1) + 16
= 2 + 16
= 18 g/mol
Finally, we shall determine the number of mole H₂O. This can be obtained as follow:
Mass of H₂O = 175 g
Molar mass of H₂O = 18 g/mol
Number of mole of H₂O =?
Mole = mass /Molar mass
Number of mole of H₂O = 175/18
Number of mole of H₂O = 9.72 moles
Most of Earth's major earthquakes are caused by
x
seasonal heating and cooling of Earth's surface
B
x
weathering of rock at Earth's surface
C
x
earth's gravitational attraction to the Moon
D
x
faulting of rock in earth's crust
Answer:
d
When the stress on the edge overcomes the friction, there is an earthquake that releases energy in waves that travel through the earth's crust and cause the shaking that we feel.
which of the following is not a PPE?
a. face mask
b. gloves
c. laboratory gown
d. sandals
Answer:
D.sandals
Explanation:
I think we need to wear shoes......so to protect or cover our feet
summarize what happens to a balls energy when it bounces?
Answer:
When a ball bounces, it initially gains speed or kinetic energy—the energy of motion. When it reaches Earth, it collides head-on with an incredibly massive object that is, from your perspective, at rest. The ball slows down, deforms temporarily and shoots back up.
Explanation:
I hope this helps.
Answer:
When you hold the ball in the air, the ball has gravitational potential energy. Realizing it will turn the potential energy into kinetic energy. When the ball touches the ground, the kinetic energy will turn into elastic potential energy. When it bounces back up, it will turn into kinetic energy. When the ball is in that position where the ball was being held, it will have gravitational potential energy and repeat the cycle.
Explanation:
Terms to know:
Gravitational potential energy is the energy of an object that possesses because of its position in a gravitational field.
Elastic potential energy is energy stored as a result of applying a force to deform an elastic object.
Kinetic energy is the energy that objects posess due to motion.
how does bases taste?
Answer:
bases taste bitter, feel slippery, and conduct electricity when dissolved in water
Explanation:
Answer:
like peas
Explanation:
2. Which property is a property of water? (Choose all that apply
Cohesion
Relatively high boiling point
High surface tension
Adhesion
Answer:
cohesion and adhesion
Answer:
Cohesion, Adhesion, Relatively high boiling point, and high surface tension.
Explanation:
Cohesion and adhesion give water molecules their 'stickiness' for each other and other molecules/surfaces, and high surface tension is why things like feathers can 'float' on the surface of water.
Which one of the following ionic solids would have the largest lattice energy?
CaBr2
CsI
CaCl2
NaCl
NaF
Answer:
CaCl2
Explanation:
The ionic solid CaCl₂ would have the largest lattice energy. Therefore, option (c) is correct.
What is the lattice energy?Lattice energy is the heat of formation when one mole of crystalline ionic solid is generated from its constituent ions in their gaseous state.
For example, the lattice energy of sodium chloride crystal is the energy change of reaction when Na⁺ and Cl⁻ ions react to produce a NaCl crystal, which is equal to -786 kJ/mol.
The relation between lattice energy and lattice enthalpy at constant pressure is given by:
ΔU (lattice) = ΔH (lattice) - PΔV
Lattice energy is directly proportional to the charge on ions and inversely proportional to the interionic distance between ions.
For NaCl and NaF the charge on the ions is +1 and -1 while the size of the ions is small. So they have less lattice energy.
CsI ionic solid have a larger size of ions Cs⁺ and I⁻. So CsI will have less lattice energy. CsBr₂ has +2 charge on calcium but the size of both ios is larger. So, CsBr₂ will have less lattice energy.
CaCl₂ has + 2 charge on calcium as well as the ionic radius is also samll. Therefore, CaCl₂ would have the largest lattice energy.
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1.24 mole of Cl2= ?molecules
1.24 mol Cl2 x 6.022*10^23
= 7.47 Cl2 molecules
Hope that helps!
Answer:
1 mole of c12=6.022×10^23
so
1.24 mole of c12=1.24×10^23
Explanation:
according to the mole concept
no of mole is very important
if u have that given its very easy to do the solving
if not given go for the no of mole in mole concept for first
and always remember the constant (6.022×10^23) and formulae