Answer:
1.6
Explanation:
log 43 = 1.6335
B, 1.6
Explanation: E21
calculate the amount of I - 125 that remains after 178.2 days if we started with 300 grams.
Answer:
38.3 g
Explanation:
The half life of a substance is the time taken for the substance to decay to about half of its amount.
Let us assume that I-125 have a half life of 60 days. It means that every 60 days, the amount of I - 125 would be halved.
The amount of I - 125 (A) that remains after t days is given by:
[tex]A=A_o*\frac{1}{2^n} \\[/tex]
Where Ao is the initial amount and n = t / half life
Given that:
Ao = 300 g, t = 178.2 days.
Therefore n = t / half life = 178.2 days / 60 days = 2.97
[tex]A=A_o*\frac{1}{2^n} \\A=300*\frac{1}{2^{2.97}}\\ A=38.3\ g[/tex]
Explain how you could use Avogadro's Law given the grams of a known compound and volume.
According to Avogadro's law, volume is directly proportional to number of moles which is in relation with the grams of a compound.
What is Avogadro's law?
Avogadro's law is a gas law which states that the total number of atoms or molecules has a direct proportion to the volume occupied by a gas at a constant temperature and pressure.
It is closely related to ideal gas equation as it links temperature, pressure, volume and the amount of substance.It is given as, V∝n,
The straight line graph of volume versus moles is a straight line passing through the origin which implies that zero moles of gas occupy zero volume.The law was proposed by Amedeo Avogadro in year 1811.
The law can be derived from the assumption of kinetic theory of gases considering their ideal behaviour.
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A scuba tank contains air at 2975 psi and 25°C. The tank is left in a car in the
hot sun and the temperature increases to 44°C. What will be the pressure (psi)
in the tank?
Answer:
The new pressure is 3164.58 psi.
Explanation:
We have,
Initial pressure, [tex]P_1= 2975\ psi[/tex]
Initial temperature, [tex]T_1=25^{\circ}=298.15\ K[/tex]
The tank is left in a car in the hot sun and the temperature increases to 44°C, [tex]T_2=44^{\circ} =317.15\ K[/tex]
Let [tex]P_2[/tex] is the final pressure in the tank. Gay Lussac's law,
[tex]P\propto T\\\\\dfrac{P_1}{P_2}=\dfrac{T_1}{T_2}\\\\P_2=\dfrac{P_1T_2}{T_1}[/tex]
Plugging all the values,
[tex]P_2=\dfrac{2975\times 317.15}{298.15}\\\\P_2=3164.58\ psi[/tex]
So, the new pressure is 3164.58 psi.
What is a chemical equation?
A. a substance
B. a shorthand representation of a chemical reaction
C. a shorthand representation of a chemical bond
D. a diatomic molecule
write the balanced standard combustion reaction for the c5h7on3s2
Answer:
4C5H7ON3S2 + 25O2 —> 20CO2 + 14H2O + 6N2 + 4S2
Explanation:
When C5H7ON3S2 under go Combustion, the following are obtained as illustrated below:
C5H7ON3S2 + O2 —> CO2 + H2O + N2 + S2
Now, let us balance the equation. This is illustrated below:
C5H7ON3S2 + O2 —> CO2 + H2O + N2 + S2
There are 3 atoms of N on the left side and 2 atoms on the right side. It can be balance by putting 4 in front of C5H7ON3S2 and 6 in front of N2 as shown below:
4C5H7ON3S2 + O2 —> CO2 + H2O + 6N2 + S2
There are 20 atoms of C on the left side and 1 atom on the right side. It can be balance by putting 20 in front of CO2 as shown below:
4C5H7ON3S2 + O2 —> 20CO2 + H2O + 6N2 + S2
There are 28 atoms on H on the left side and 2 atoms on the right side. It can be balance by putting 14 in front of H2O as shown below:
4C5H7ON3S2 + O2 —> 20CO2 + 14H2O + 6N2 + S2
There are 8 atoms of S on the left side and 2 atoms on the right side. It can be balance by putting 4 in front of S2 as shown below:
4C5H7ON3S2 + O2 —> 20CO2 + 14H2O + 6N2 + 4S2
Now, there are a total of 54 atoms of O on the right side and 6 atoms on the left side
It can be balance by putting 25 in front of O2 as shown below:
4C5H7ON3S2 + 25O2 —> 20CO2 + 14H2O + 6N2 + 4S2
Now, we can see that the equation is balanced.
Match each situation below to a letter on the illustration.
Ball
starts
here
Letter
Situation
Potential energy is the highest
Losing kinetic energy, gaining potential energy
Kinetic energy is highest
Losing potential energy, gaining kinetic energy
Answer:a
Explanation:
In the position A, the potential energy is maximum and the kinetic energy is minimum. At the point B, kinetic energy is highest. At the point C, the losing kinetic energy, gaining potential energy and at D, losing potential energy, gaining kinetic energy.
What is kinetic energy ?Kinetic energy of moving body is the energy generated by virtue of its position. Potential energy is generated by virtue of its position at a height from the surface. When a body starts moving from rest, its potential energy starts convert to kinetic energy.
As the height increases, potential energy increases. When an object moves down, its acceleration due to gravity increases and more energy to fall down make its kinetic energy higher.
Thus, the situations can be matched as follows;
A, the potential energy is maximum and the kinetic energy is minimum. B, kinetic energy is highest.
C, the losing kinetic energy, gaining potential energy and
D, losing potential energy, gaining kinetic energy.
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A salt is made by adding an excess of an insoluble metal oxide to an acid.
How can the excess metal oxide be removed? *
D filtration
B crystallisation
A chromatography
C distillation
Answer:
Filtration
Explanation:
Filtration is used to separate solid substances from liquids or large molecules from small molecules. Since, Acid is a liquid and metal oxide is solid so Filtration can be used to separate these two.
What are the 3 critical components of an electromagnet and what purpose do they each serve?
Answer:
A source of electricity, a wire coil, and an iron core
Explanation:
An electromagnet has three critical components:
1. A source of electricity
This is often a battery.
It generates the electric current that produces the magnetic field.
2. A wire coil
The wire carries the electric current.
Stacking the wire into loops makes a stronger magnetic field.
The more loops in the coil, the stronger the field.
3. An iron core
An iron core greatly increases the strength of the magnetic field within it and at its ends.
What is the energy of an electromagnetic wave with a frequency of 8 x 10^12
Hz?
A. 4.2 x 10-22 J
B. 2.4 x 1021 J
C. 1.59 x 10-12
D. 5.3 x 10-21 J
Answer:
Energy, [tex]E=5.3\times 10^{-21}\ J[/tex]
Explanation:
It is required to find the energy of an electromagnetic wave with a frequency of [tex]8\times 10^{12}\ Hz[/tex]. The energy of a wave in terms of its frequency is given by :
[tex]E=h\nu[/tex]
[tex]\nu[/tex] = frequency of em wave
[tex]E=6.63\times 10^{-34}\times 8\times 10^{12}\\\\E=5.3\times 10^{-21}\ J[/tex]
So, the energy of an electromagnetic wave is [tex]5.3\times 10^{-21}\ J[/tex]
Answer:
D. [tex]5.3 * 10^-21 J[/tex]
Ava’s best friend has an indoor cat. Ava notices that she sneezes every time that she visits her friend. Ava suspects that she is allergic to cats but is unsure. What is the best thing for Ava to do next?
C) Test her suspicion by going to see an allergist to diagnose the allergy.
It's right
What is a chemical reaction?
a. a process of bonding substances together
B. a process that leads to have filled valence shells
following the octet rule
C. a process that releases or consumes energy
D. all of the choices
Answer:
D.
Explanation:
this is because in a chemical reaction all 3 of those work.
Answer:
A chemical reaction is defined as per encyclopedia Britannia as a "a process in which one or more substances, are converted to one or more different substances, the products."
So A is correct, B is correct, C is correct.
So that means we choose D as they're all correct.
15. What is the name of Fl-?
A)Fluorous ion
B)Fluorine
C)Fluoride ion
D)Fluorine ion
Answer:
C: Flouride Ion
3. Hydrochloric acid is used to clean metals.
The acid reacts with the oxide layer on the surface of the metal, forming a salt and water.
Which word describes the metal oxide?
A alloy
B base
C element
D indicator
Answer:
Base
Explanation:
Acid + Base ⇒ Salt + Water (Neutralization Reaction)
So the substances forming salt and water must be acid and base.
Since HCl is acid so the Metal Oxide would be the base.
which solute will result in a molecular solution?
a. HCN
b. Ba(OH)2
c. CH3COOH
d. CH3CH2OH
Answer:
d. CH3CH2OH
Explanation:
Molecular solution are solutions when a molecular compound is dissolved in them.
CH3CH2OH represents Ethanol or alcohol carrying "OH" group and is a molecule. CH3CH2OH or Ethanol forms a molecular solution in water.
The equation for Ethanol dissolving in water as follows:
CH3CH2OH(l) => CH3CH2OH(aq)
CH3CH2OH srays together as molecules. During dissolving, ethanol molecule fit into spaces between water molecules and completely mix with water.
While HCN, CH3COOH and Ba(OH)2 form ionic solution.
Hence, the correct option is d. CH3CH2OH.
Classify the elements as diatomic or monatomic. If necessary, refer to the periodic table to help you identify the diatomic elements.
carbon
helium
hydrogen
iodine
oxygen
sodium
Answer:
carbon- monatomic
helium- monatomic
hydrogen- diatomic
iodine- diatomic
oxygen- diatomic
sodium- monatomic
Explanation:
the diatomic elements can be remembered with this sentence:
Have No Fear Of Ice Clear Brownies
have- hydrogen
no- nitrogen
fear- fluorine
of- oxygen
ice- iodine
clear- chlorine
brownies- bromine
The diatomic molecules are hydrogen ,iodine ,oxygen while the monoatomic molecules are carbon, helium and sodium.
What are elements?It is defined as a substance which cannot be broken down further into any other substance. Each element is made up of its own type of atom. Due to this reason all elements are different from one another.
Elements can be classified as metals and non-metals. Metals are shiny and conduct electricity and are all solids at room temperature except mercury. Non-metals do not conduct electricity and are mostly gases at room temperature except carbon and sulfur.
The number of protons in the nucleus is the defining property of an element and is related to the atomic number.All atoms with same atomic number are atoms of same element.
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What is the oxidation number of Si
Answer:
0
Explanation:
PLEASE HELP ME OUTTTT
How many grams of Fe3O4 are required to react completely with 54.29 grams of H2?
Fe3O4 + H2 → Fe + H2O
Answer:
Balance the equation
Fe3O4 + 4H2---> 3Fe +4H2O
Molar mass H2=(2*1)=2g/mol
Mass of H2=54.29grams
mole of H2= 54.29/2=27.15mol
4 mol of H2 = 1 mol Fe3O4
27.15mol of H2= 6.79mol of Fe3O4
Moles of Fe3O4 =6.79mol
Molar mass of Fe3O4= (56×3)+(16×4)
=168+64=232g/mol
Grams of Fe3O4 required to react with 54.29 grams of H2 is 232g/mol× 6.79mol
=1575.28g
Explain the energy changes that occur when the following reaction happens:
H2 + Cl2 → 2HCl
A. Energy is absorbed when the HCl bonds form.
B. Energy is needed to break the bonds of H-H in H2 and Cl-Cl in Cl2
C. Energy is released when the bonds of H-H in H2 and Cl-Cl in Cl2 break.
D. Energy is released when the H-Cl bonds form.
E. No energy changes occur when this reaction happens.
Answer:
B
Explanation:
H2 + Cl2 → 2HCl
Hmm redox reaction.
Energy is needed to break the bonds of H-H in H2 and Cl-Cl in Cl2
fill in the blank
_______ is a gaseous state of matter that contains appreciable numbers of electrically charged particles.
Diamond is harder than graphite. This is a _______ observation.
Chemistry is defined as the study of _______.
Answer:
1. plasma; 2. qualitative; 3. matter;
Explanation:
PLASMA is a gaseous state of matter that contains appreciable numbers of electrically charged particles.
Diamond is harder than graphite. This is a QUALITATIVE observation.
Chemistry is defined as the study of MATTER.
Plasma is a gaseous state of matter that contains appreciable numbers of electrically charged particles.Diamond is harder than graphite. This is a qualitative observation.Chemistry is defined as the study of matter.
What is matter?Matter in chemistry, is defined as any kind of substance that has mass and occupies space that means it has volume .Matter is composed up of atoms which may or not be of same type.
Atoms are further made up of sub atomic particles which are the protons ,neutrons and the electrons .The matter can exist in various states such as solids, liquids and gases depending on the conditions of temperature and pressure.
The states of matter are inter convertible into each other by changing the parameters of temperature and pressure.Matter is always conserved according to law of conservation of matter.
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Question 1 of 23
The diagram below shows two mugs of coffee mug A and mug B). Both mugs have the same temperature, but mug A contains 30 ml, while mug B contains 5
thermal energy in both mugs?
B
30°C
30°C
.ll Lisa ko
30 ml
5 ml
O Mug A has more thermal energy than mug B
O Mug A has less thermal energy than mug B
O Mug A and B have the same thermal energy
Previous Question
Flag for re
Answer:
mug A has more thermal energy
Explanation:
What causes the sun's core and the earth's core to have extremely high temperatures?
Select one:
a. The sun undergoes fusion and the earth undergoes fission. b. Both have nuclear fusion occurring in their cores.
c. Both have nuclear fission occurring in their cores.
d. The sun undergoes fission and the earth undergoes fusion.
Consider the unbalanced equation for the oxidation of butene. C4H8 + 6O2 CO2 + H2O For each molecule of C4H8 that reacts, how many molecules of carbon dioxide and water are produced?
two carbon dioxide molecules and two water molecules
four carbon dioxide molecules and four water molecules
two carbon dioxide molecules and four water molecules
four carbon dioxide molecules and two water molecules
Answer: Four carbon dioxide molecules and four water molecules
Explanation:
Answer:
D: four carbon dioxide molecules and two water molecules
Explanation:
There are four carbon dioxide molecules (CO₂) on the right side of chemical reaction, because there are four carbon atoms on the left side of balanced chemical reaction.
There are four water molecules (H₂O) on the right side of chemical reaction, because there are eight hydrogen atoms on the left side of balanced chemical reaction.
The use of nuclear energy can have both positive and negative consequences. Which of the following is a positive consequence of using nuclear energy? a. Nuclear energy uses nonrenewable resources. b. Nuclear energy produces little air pollution. c. Uranium ore used for nuclear power plants must be mined and processed. d. Nuclear energy has no environmental impact. Please select the best answer from the choices provided A B C D
Answer
its B
Explanation:
B.
Nuclear energy produces little air pollution.
how many moles of H2O will be produced from 6 moles of 02
Answer: 12 moles H20
Explanation:
The tools of choice for stoichiometry problems will always be the mole ratios that exist between the chemical species that take part in the reaction.
2H2 [g] + O2 [g]------> 2H 2O (1]]
In a laboratory, Carlos places one plate with grape jelly and another plate with cooked brown rice inside an ant farm. The next day, he finds that both plates are filled with ants. Carlos wonders if there are certain household foods that are more effective than others at attracting ants. How could Carlos use the scientific inquiry process to determine which foods are most effective at attracting ants? Check all that apply.
Answer:
The Answers are: A. C. D.
Answer:
by making quantitative observations about the number of ants found on each plate of food
by comparing a plate of cooked brown rice to another household food such as peanut butter
by designing an experiment to test different foods and the number of ants each food attracts
Explanation:
It was right on edge
What is it called when Earth’s magnetic poles change places?
a.
a strike-slip fault
c.
sea-floor spreading
b.
magnetic reversal
d.
continental drift
Answer:
Its b. Magnetic reversal
Explanation:
Answer:
B
Explanation:
i just did it
HURRY UP ANSWER MY QUESTION
Why does a balloon filled with gas become smaller when placed in a colder environment?
A.atoms / molecules speed up in the cold and thus push out on the balloon more
B.atoms / molecules slow down at lower temperatures and thus push out on the balloon less frequently and with less energy
C.atoms / molecules slow down in the cold and thus push out on the balloon more
D.atoms / molecules speed up in the cold and thus push out on the balloon less
Previous
Answer:
B
Explanation:
If you remeber a balloon in hot air, it pops. This is because the molecules are moving too fast and need more space to move, thus popping the balloon. If you put a balloon in cold air, then it shrinks, the molecules not moving fast enough and don't need as much space.
Write the name of each numbered part of the eye.
If they are traveling at the same speed, which will have the most kinetic energy?
A. A 5-kilogram ball
B. A 25-kilogram ball
C. A 10-kilogram ball
D. A 1-kilogram ball
Answer: B. (A 25 kg ball)
Explanation:
Since [tex]KE = \frac{1}{2} mv^{2} \\[/tex], and velocity is the same for all four balls, the ball with the greatest mass will have the greatest kinetic energy (since mass and KE are directly related). Below shows these calculations:
A. m = 5
[tex]KE = \frac{1}{2} mv^{2} \\[/tex]
[tex]KE = \frac{1}{2} (5)v^{2} \\[/tex]
[tex]KE = 2.5v^{2} \\[/tex]
B. m = 25
[tex]KE = \frac{1}{2} mv^{2} \\[/tex]
[tex]KE = \frac{1}{2} (25)v^{2} \\[/tex]
[tex]KE = 12.5v^{2} \\[/tex]
C. m = 10
[tex]KE = \frac{1}{2} mv^{2} \\[/tex]
[tex]KE = \frac{1}{2} (10)v^{2} \\[/tex]
[tex]KE = 5v^{2} \\[/tex]
D. m = 1
[tex]KE = \frac{1}{2} mv^{2} \\[/tex]
[tex]KE = \frac{1}{2} (1)v^{2} \\[/tex]
[tex]KE = 0.5v^{2} \\[/tex]
How many moles of zinch oxide can be produced from 275 of zinc?
Answer:
[tex]\large \boxed{\text{4.21 mol}}[/tex]
Explanation:
We must do the conversions :
mass of Zn ⟶ moles of Zn ⟶ moles of ZnO
We will need a chemical equation with masses and molar masses, so, let's gather all the information in one place.
Mᵣ: 65.38
Zn + … ⟶ ZnO + …
m/g: 275
(a) Moles of Zn
[tex]\text{Moles of Zn} = \text{275 g Zn}\times \dfrac{\text{1 mol Zn}}{\text{65.38 g Zn}} = \text{4.206 mol Zn}[/tex]
(b) Moles of ZnO
The molar ratio is 1 mol ZnO:1 mol Zn
[tex]\text{Moles of ZnO} =\text{4.206 mol Zn} \times \dfrac{\text{1 mol ZnO}}{\text{1 mol Zn}} = \text{4.21 mol ZnO}\\\\\text{The reaction produces $\large \boxed{\textbf{4.21 mol}}$ of ZnO}[/tex]
