true or false, a temperature of 0°F is equal to 32°C
Answer:
false
Explanation:
Answer:true
Explanation:
If there are 400 radioactive atoms in a sample, how many will remain after four half-lives have passed?
Enter the exact number as your answer. Do not spell out the number.
Answer:
25 atoms
Explanation:
Given data:
Total number of atoms = 400 atom
Atoms remain after 4 half lives passed = ?
Solution:
At time zero = 400 atom
At first half life = 400 atom/2 = 200 atom
At 2nd half life = 200 atom/2 = 100 atom
At 3rd half life = 100 atom/2 = 50 atom
At 4th half life = 50 atom/2 = 25 atom
Thus, 25 atoms are remained after 4 half lives.
25 atoms of the radioactive atoms will remain after 4 half lives.
Given in the question,
Initial amount of a radioactive element = 400 atomsNumber of half lives = 4Expression for the amount remaining of a radioactive element after 'n' half lives is given by,
[tex]N=N_0(\frac{1}{2})^n[/tex]
Here, [tex]N_0=[/tex] Initial amount
[tex]n=[/tex] Number of half lives
By substituting the vales of [tex]N_0[/tex] and [tex]n[/tex] in the question,
[tex]N=400(\frac{1}{2})^4[/tex]
[tex]=\frac{400}{16}[/tex]
[tex]=25[/tex]
Therefore, 25 atoms of the radioactive atoms will remain after 4 half lives.
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Ca(C2H302)2
Name the following compounds.
Answer:
nut
Explanation:
What does a salt bridge do?
A. It supplies energy to make the redox reaction happen.
B. It supplies the electrolyte solutions with metal ions.
C. It creates a path for metal ions to flow from anode to cathode.
D. It prevents charges from building up in the solutions.
Answer:
D. It prevents charges from building up in the solutions :)
Explanation:
A P E X
may we met again !
i love you,ella
Answer: When I see you again!
Explanation:
lonic bonds tend to form between
a. nonmetals; nonmetals
b. metals; nonmetals
c. metals; metals
d. all of these
You witnessed a student throw away a broken beaker in the regular trash can. Which of the following is the most important reason to alert your instructor?
Answer:
D
Explanation:
What was J.J. Thomson's Model known as?
A. The Pizza Model
B. The Chocolate Chip Model
C. The Mint Chocolate Chip Model
D. The Butterscotch Model
Answer:
B.The Chocolate Chip Model
Explanation:
A hot metal plate at 150°C has been placed in air at room temperature. Which event would most likely take place over
the next few minutes?
O Molecules in both the metal and the surrounding air will start moving at lower speeds.
O Molecules in both the metal and the surrounding air will start moving at higher speeds.
O The air molecules that are surrounding the metal will slow down, and the molecules in the metal will speed up.
O The air molecules that are surrounding the metal will speed up, and the molecules in the metal will slow down.
Answer:
It would be the third answer.
Explanation:
This is because over the next few minutes, the heat would radiate away from the atoms in the metal plate and the atoms around the plate would absorb this radiation.
which of these is an equation that follows the law of conservation of mass
Answer:
D
Explanation:
A mixture contains 21.7 g NaCI, 3.74 g KCI, and 9.76 g Lici. What is the mole fraction of NaCl in this mixture?
Molar mass
NaCl: 58.44g/mol
KCl: 74.55g/mol
LiCl: 42.39g/mol
Answer:Mole Fraction of NaCl=0.5697
Explanation:
No OF Moles of NaCl= Mass / Molar mass
=21.7 g/58.44g/mol
=0.371moles
No OF Moles of KCl= Mass / Molar mass
=3.74g/74.55g/mol
=0.0502moles
No OF Moles of LiCl= Mass / Molar mass
=9.76 g/42.39g/mol
=0.230moles
Mole Fraction of NaCL = Moles of NaCL/ Total number of moles of the mixture
=0.371/( 0.371+ 0.0502+0.230)
0.371/0.6512
=0.5697
Answer:
Mole fraction: 0.570
Explanation:
Mole fraction is defined as the ratio of moles of a compound in a mixture over the total moles of the mixture. To solve this problem, we need to find moles of the 3 salts:
Moles NaCl -Molar mass: 58.44g/mol-:
21.7g NaCl * (1mol / 58.44g) = 0.3713 moles
Moles KCl -Molar mass: 74.55g/mol-:
3.74g KCl * (1mol / 74.55g) = 0.0502 moles
Moles LiCl -Molar mass: 42.394g/mol-:
9.76g LiCl * (1mol / 42.394g) = 0.2302 moles
Mole fraction NaCl:
0.3713mol / (0.3713mol + 0.0502mol + 0.2302mol) =
0.570
Consider the balanced equation. PCl3 + 3H2O Right arrow. H3PO3 + 3HCl What is the percent yield of HCl if 42.0 g of HCl are produced from the reaction of 62.0 g of PCl3? Use Percent yield equals StartFraction actual yield over theoretical yield EndFraction times 100..
Answer:
Percient yield of reaction: 85 %
Explanation:
The reaction is:
PCl₃ + 3H₂O → H₃PO₃ + 3HCl
We only have data from the chloride, so we assume water is in excess. We convert the mass to moles:
62 g . 1mol / 137.32 g = 0.452 mol
If ratio is 1:3, from 0.452 mol we would produce three times as big, that amount. (0.452 . 3) = 1.36 moles of HCl.
We convert the amount to mass.
1.36 mol . 36.45g / 1mol = 49.4 g
This value of produced HCl is the theoretical yield. To determine the percent yield we make:
(Yield produced / Theoretical yield) . 100
(42 g / 49.4g) . 100 = 85%
Answer:
Yes it is 85.0%
Explanation:
The yield ( → ) symbol always points to the
I dont get what the question is?? im so sorry!
Q
a. Ahmed worked on his crops of wheat and maize to produce a better-quality crop (which gives a more yield). In detail, write down how he altered his crop into a better yielding crop.
b. What is the name of the process that Ahmed used to breed his new better-quality wheat and maize.
Answer:
.
Explanation:
NaOH
+
AL-
Na3AlO3 +
H2
How many moles of NaOH are required to produce 405 moles of hydrogen?
Answer:
i have no idea and i dont get it
How many moles are in 1.23 X 1050 atoms of calcium carbonate, CaCO3?
Answer:
Explanation:1 mole is equal to 1 moles CaCO3, or 100.0869 grams.
Balance the following equations:
i. H2SO4 + ….NaHCO3 → Na2SO4 + ….H2O + ……CO2
ii. H2 + I2 → ….HI
iii. …..NaOH + H2SO4 → Na2SO4 + …..H2O
iv. ……FeSO4 → Fe2O3 + SO2 + SO3
v. C3H6O2 + …..O2 → ….CO2 + …..H2O
b) Calculate the molecular masses of the following:
i. H2SO4
ii. CH4
iii. NH3
c) 56g of iron reacts with 71g of chlorine. How many grams of iron react with 35.5g of chlorine?
(I) [tex]H_2SO_4+ 2NaHCO_3--> Na_2SO_4 + 2 H_2O + 2CO_2[/tex]
(II) [tex]H_2+I_2 --> 2HI[/tex]
(III) [tex]2NaOH+H_2SO_4--> Na_2SO_4+ 2H_2O[/tex]
(IV) [tex]2FeSO_4--> Fe_2O_3+SO_2+SO_3[/tex]
(V) [tex]2C_3H_6O_2+7O_2-->6CO_2+6H_2O[/tex]
_____________________________________Molecular Masses of the following:------------------------------------------------------------------------------------------------------------
(I) [tex]H_2SO_4[/tex]
(ANS) [tex]98 \frac{grams}{mol}[/tex]
__________________________________________________________
Solution:
Molecular mass of,
H = 1
S = 32
O = 16
Now,
There are 2 atoms of Hydrogen, 1 atoms of Sulfur and 4 atoms of Oxygen present, thus,
[tex]H_2SO_4 = (1x2)+32+(16x4)[/tex]
[tex]H_2SO_4 = 98 \frac{grams}{mol}[/tex]
_____________________________________(II) [tex]CH_4[/tex]
(ANS) [tex]16 \frac{gram}{mol}[/tex]
_________________________________________________________
Solution:
Molecular Mass,
Carbon = 12
Hydrogen = 1
Now
There are 1 atom of Oxygen and 4 atoms of Hydrogen present, thus,
[tex]CH_4 = 12 + (1x4)[/tex]
[tex]CH_4 = 16\frac{grams}{mol}[/tex]
_____________________________________(III) [tex]NH_3[/tex]
(ANS) [tex]17 \frac{grams}{mol}[/tex]
__________________________________________________________
Solution:
Molecular Mass,
Nitrogen = 14 grams
Hydrogen = 1
Now,
There are 1 atoms of Nitrogen and 3 atoms of Hydrogen present, thus,
[tex]NH_3 = 14 + (1x3)[/tex]
[tex]NH_3 = 17 \frac{grams}{mol}[/tex]
_____________________________________How many Grams of Iron(fe):[tex]Fe + Cl_2 --> FeCl_2[/tex]56 71
x 35.5
_____________________________________[tex]X = \frac{56 x 35.5}{71}[/tex]
Simplify the equation
X = 28 grams
__________________________________________________________
Answer:
28 grams of Iron(fe) will react with chlorine.
_____________________________________Best Regards,'Borz'What is the formula to the covalent molecule Hexaboron Diphosphide?
Answer:Naming Covalent compounds
A B
hexaboron silicide B6Si
chlorine dioxide ClO2
hydrogen iodide HI
iodine pentafluoride IF5
Explanation:
What goes in cellular respiration and what comes out of cellular respiration?
Oxygen and glucose are both reactants in the process of cellular respiration. The main product of cellular respiration is ATP; waste products include carbon dioxide and water.
PLEASE HELP ASAP!!
What is the purpose of a unit conversion?
O
A. To change an amount in one unit to its equivalent amount in
another unit
B. To express a scientific expression in a general form all scientists
can understand
C. To express the amount of something in terms of its number of
smallest units
D. To keep track of the units associated with a number throughout an
equation
Answer:
A
Explanation:
A conversion factor is used to change the units of a measured quantity without changing its value.
Unit conversion is very important because the rest of the world other than three contries uses the metric system. So, converting unitsis important in science because it uses the metric system. The metric system are measurements like cm, m, l, mL, etc.
Which of the following is the correct electron dot structure for a hydroxide ion?
Answer:
A
Explanation:
A hydroxide ion is given as:
OH⁻
The electron dot notation shows only the chemical symbol of the element surrounded by dots to represent the valence electrons. The chemical symbol denotes the nucleus and all electrons except the valence electrons.
The dots are arranged on the four sides in pairs.
Oxygen is made up of 6 valence electrons, and since the ion has a net negative charge, the hydrogen and oxygen achieved their stable configuration this way.
what properties of gold and platinum make these metals desirable for jewelry?
Answer: They are non-reactive and don't conform with other elements to form compounds. Because they are non-reactive, they don't corrode easily.
Explanation:
The properties of gold and platinum which make these metals desirable for jewelry is due to their electronic configuration due to which they are non-reactive and do not corrode easily.
What is electronic configuration?Electronic configuration is defined as the distribution of electrons which are present in an atom or molecule in atomic or molecular orbitals.It describes how each electron moves independently in an orbital.
Knowledge of electronic configuration is necessary for understanding the structure of periodic table.It helps in understanding the chemical properties of elements.
Elements undergo chemical reactions in order to achieve stability. Main group elements obey the octet rule in their electronic configuration while the transition elements follow the 18 electron rule. Noble elements have valence shell complete in ground state and hence are said to be stable.
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Is nuclear energy poised to be part of America’s future?
Answer:
Nuclear energy powers our businesses, homes and military. America’s 95 operating nuclear reactors generate approximately 20% of our nation’s electricity and provide over half of our carbon-free energy. They also create good-paying jobs at power plants and uranium mines. Wyoming produced 87% of America’s domestic uranium supply in 2018.
Today, nuclear energy faces serious hurdles. Regulatory costs and subsidies for renewable energy technologies are forcing America’s nuclear power plants to close at an alarming rate.
Russia and China are subsidizing their government-owned nuclear companies to assert their energy influence around the world. China is searching the globe for uranium reserves and investing heavily in the countries where it’s found. They want to secure more nuclear fuel for themselves and increase their control of the global supply.
Meanwhile, American nuclear power plants have come to rely on cheap Russian imports of uranium to meet their nuclear fuel needs. Right now, roughly 40% of the uranium coming into the United States originates in Russia or its satellite states of Kazakhstan and Uzbekistan. Russian-backed companies are developing fuel that can be placed directly in American reactors.
Explanation:
27. Based on Reference Table S, which of the
following atoms requires the least energy for the
removal of the most loosely bound electron?
A) Br
B) Sr
C) Be
D) Sn
Answer:
This question is incomplete but the correct option is B
Explanation:
This question is incomplete because of the absence of the "Reference Table S", however the question can still be answered in the absence of the table. The energy described in the question is the ionization energy (energy required to remove the most loosely bound electron in an atom). This question seeks to know the atom (from the options provided) with the least ionization energy.
Ionization energy increases from left to right across the period because it's easier to remove a single electron (valence electron) from the outermost shell than to remove two electrons from the same shell; thus the more the valence electrons (in a shell), the higher the ionization energy. Thus, bromine (Br) and tin (Sn) have high ionization energies because they have more number of electrons in there outermost shell.
Berylium (Be) and strontium (Sr) are both in the group 2 of the periodic table because they both have 2 electrons in there outermost shell. Ionization energy decreases down a group. This is because the farther an electron is from the nucleus, the weaker the force of attraction between the nucleus and the electron. Thus, strontium (Sr) would have a lesser ionization energy between the two and would indeed have the least ionization among the options provided. Hence, the correct option is B
Q. Explain why is sulfuric acid a corrosive?
.
.
.
.
.
.
Can we clean a dumb humans brain with windex?if yes then tell me how?
Answer: yes
Explanation: cut open their head and spray their head with windex. THAT SIMPLE
1. Kaleigh notices when she goes to the beach that sometimes the water rises as high as the pier. At other times of the day, the water barely covers the pillars under the pier. These differences in water level are primarily due to the gravitational influence of which of the following?
a. The Earth’s revolution b. The Moon c. asteroids d. comets
How are the cells of the bicep muscle similar to the cells of the heart muscle?
A. They digest food.
B. They make energy.
C. They use carbon dioxide.
D. They form tissue that moves.
Answer:
I believe it's D
Explanation:
they both are worked a lot and it makes the most sense.
The cells in both bicep muscle and heart muscle make energy for contraction and relaxation. Hence, option B is correct.
What is cardiac muscles ?Cardiomyocytes have a rather rectangular form and are short and thin. They have a single nucleus, cell organelles that are identical to those seen in skeletal muscle cells, and many sarcosomes, which supply the energy needed for contraction.
Intercalated discs with gap junctions for diffusion and communication link cardiomyocytes structurally. Myofibrils, which in turn are composed of thick and thin myofilaments, make up the sarcoplasm.
Due to their high energy needs, skeletal muscle cells have many mitochondria that enable them to produce enough ATP. Therefore, the cells in the bicep muscles and cardiac muscles produce energy.
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How many valence electrons does this atom have? (Urgent plz help)
Answer: theres 5
Explanation: valence electrons are the electrons in the outer shell. I took that test a few weeks ago :0
how many atoms are there in 8.08 moles of carbon dioxide
Answer:
145.97×10²³ atoms
Explanation:
Given data:
Number of moles of CO₂ = 8.08 mol
Number of atoms of CO₂ = ?
Solution:
1 mole of CO₂ contain 1 mole C atom.
8.08 mole contain 8.08× 1 = 8.08 mole of C atom.
1 mole of CO₂ contain 2 moles of O atom.
8.08mole contain 8.08×2 = 16.16 mole of O atom.
Total number of moles of atoms = 8.08 mole + 16.16 mole
Total number of moles of atoms = 24.24 mol
Number of atoms of CO₂:
1 mole of any substance contain 6.022×10²³ atoms.
24.24 mol ×6.022×10²³ atoms / 1 mol
145.97×10²³ atoms
How many atoms of S are in the following formula: 3Na(SO4)2
1) 6
2) 8
3) 3
4) 5
Answer:
6
Explanation: