The mass of KOH reacted is 2.576 g. To have a 10% excess KOH, i need 2.833 g of KOH.
The equation of the reaction is;
2 Al(s) + 2 KOH(aq) + 6H20 (l) --------> 2K+ (aq) + 2 Al(OH)4^- (aq) + 3H2(g)
We are told that 1.25 g of Al was used in the reaction, hence;
Number of moles of Al = 1.25 g/27 g/mol = 0.046 moles
To obtain the amount of KOH required for the reaction;
2 moles of Al reacts with 2 moles of KOH
0.046 moles of Al also reacts with 0.046 moles of KOH
Mass of KOH reacted = 0.046 moles of KOH × 56 g/mol = 2.576 g
To have a 10% excess KOH;
Let the needed mass of KOH be x
x =2.576 g + (0.1 × 2.576 g)
x = 2.833 g
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Assuming you start with 1.25 g of pure aluminum, calculate the following:
1) The amount of potassium hydroxide, KOH, in grams, needed to react with all of the 1.25 g of Al. The reaction is: 2 Al(s) + 2 KOH(aq) + 6H20 (1) ---> 2K+ (aq) + 2 Al(OH)4^- (aq) + 3H2(g) 2) The amount of KOH needed, in grams, in reaction 1 if you want to have 10% excess KOH.How many ML of 0.44 M HCl are needed to dissolve 9.83 g of BaCO3
Answer:
nBACO3=m/M=9,83/197=0,05(mol) ->nHCl=0,05.2/1=0,1(mol) =>VHCl=n/CM=0,1/0,44=0,227(lít)
Explanation:
A substance has a freezing point of –38°C and a boiling point of 356°C. At what temperature would this substance be in its liquid state?
A) -100°C
B) -50°C
C) 80°C
D) 375°C
Answer:
X. 80°
Explanation:
if the substance is below -38 then it is in the solid phase (-100° and -50°) and if it is above 356° it is a gas (375°). Therefore anything in the middle is a liquid, 80°.
Given that the substance freezes at –38°C and boils at 356°C, it will be a liquid at a temperature of 80°C.
What is liquid range?The term liqiid range refers to the temperatire range within which a substance remains in its liquid state. Now we are told that the substance freezes at –38°C and boils at 356°C.
Hence, we expect that this substance will be in the liquid state at a temperature of 80°C.
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Answer question based on the periodic table entry for bromine.
How many protons does bromine have?
a. 35
b. 36
c. 45
d. 80
Complete the paragraph below. Do it using your Science journal or notebook
SUSPENSION IS A KIND OF MIXTURE____________________________
_________________AS IT________________________________AT THE BOTTOM WHEN LEFT UNDISTURBED
Answer:
SUSPENSION IS A KIND OF MIXTURE where particlea are visible to the naked eyes AS IT settled AT THE BOTTOM WHEN LEFT UNDISTURBED.
Some changes in matter may results to 1. _ or 2._ effects in the environment. We have to do our share in maintaining 3. environment. We must 4. too much use of electricity and gasoline. We must also avoid 5. rubber tires and plastics. We must avoid practices that will produce acid rain, increase global temperature, or deplete the ozone layer. pls i need answers
Answer:
C
Explanation:
PLEASE MARK AS BRAINLIEST!!!!!How many grams of O are in 705 g of N2O ?
mass:
g
Answer:
O are in 535 g of N2O
Explanation:
Determine the mass percentage of carbon, C, hydrogen, H, and oxygen, O, in C6H8O7. Refer to the periodic table for the atomic mass of each element.
Answer:
C=37.5% H=4.2% O=58.3%
Explanation:
molar mass of element / molar weight of compound X 100% (for each element)
C mass = 12 x 6 = 72
H mass = 1 x 8 = 8
O mass =16x 7 = 112
Molar weight of compound = 192
72/192(100%)= 37.5% C
8/192(100%) = 4.2 % H
112/192 (100%) = 58.3% O
The mass percentage of carbon, hydrogen, H, and oxygen, O, in C₆H₈O₇ is C = 37.5% H = 4.2% O = 58.3%.
What is the mass percentage?The concentration of an element in a compound or component in a combination is calculated by the mass percentage.
The collective of a component is divided by the entire mass of the mixture to obtain the mass percentage, which is then multiplied by 100%.
Given, finding the mass percentage of carbon, hydrogen, H, and oxygen, O, in C₆H₈O₇
the molar mass of element / molar weight of compound X 100% (for each element
First, calculate the molar mass of the elements given in the compound.
C mass = 12 x 6 = 72
H mass = 1 x 8 = 8
O mass =16x 7 = 112
Molar weight of compound = 192
72/192(100%)= 37.5% C
8/192(100%) = 4.2 % H
112/192 (100%) = 58.3% O
Thus, the mass percentage is C = 37.5% H = 4.2% O = 58.3%.
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What evidence supports the theory of continental drift? Select three.
Question 10 options:
Fossils of plants and animals
Distinctive rock layers and mountain ranges
Glacial scratches on rocks
Volcanic activity along the Ring of Fire
Answer:
fossils of plants and animals
distinctive rock layers and mountain ranges
Glacial scratches on rocks
Explanation: I took the quiz lol
what is the percent by mass of chlorine in potassium chloride
Answer: Originally Answered: A sample of 0.892g of potassium chloride is dissolved in 54.6g of a water. What is the percent by mass of the potassium chloride in this solution?
Well, take the quotient…
0.892∙g0.892∙g+54.60∙g×100% percentage by mass potassium chloride
≈2%
Explanation:
Check all of the following that are mixtures.
A) Water
B) Iron
C) Milk
D)Trail mix
white sugar and iodized salt did the resulting look same throughout?
Because White sugar settles at the bottom of iodized salt. White sugar completely mixed with iodized salt.
what if two objects have the same mass but different sizes which is denser? expain
Answer:
Imagine you have 5 marbles in your hand and 5 marbles spread in front of you on the floor. Each group has the same mass, but one is contained in a smaller space. The marbles in your hand would be denser because there is more "stuff" in a smaller space.
Explanation:
Atomic Theory questions. Will be worth 50 points.
Answer:
1. Option C
2. Option D
3. Option B
4. Option
5. Option
6. Option
7. Option
Kaya is riding her dirt bike eastward on a dirt road. She spots a pothole ahead. Kaya slows from 20.0 m/s to 6 m/s in 6.0 s. What is her acceleration?
[tex]\\ \sf\longmapsto Acceleration=\dfrac{v-u}{t}[/tex]
[tex]\\ \sf\longmapsto Acceleration=\dfrac{6-20}{6}[/tex]
[tex]\\ \sf\longmapsto Acceleration=\dfrac{-14}{6}[/tex]
[tex]\\ \sf\longmapsto Acceleration=-2.3m/s^2[/tex]
The best representation of the ozone molecule incorporates both of the structures that you drew in parts C and D.
Redraw the Lewis structures of an ozone molecule and place a two-ended arrow between the structures, pointing to both
of them. This representation is called a resonance structure.
Answer:
Explanation:
EDMENTUM
The Lewis structure for ozone contains a central oxygen atom that has a double bond to one oxygen atom and a single bond with the other oxygen atom. The resonance structure of the ozone is shown in the attached figure below.
What is the lewis structure of the ozone molecule?The oxygen molecule has a valency of -2. It can form two-sigma bonds or covalent bonds with the other atoms. Oxygen contains three lone pairs to form π bonds with other atoms. Ozone contains all three oxygen atoms and is a dihedral molecule with sp² hybridization.
Lewis structure is generally based on the octet rule which states that there should be eight electrons in the valence shell or orbit of an atom for a stable molecule.
The lone pair on the central oxygen atom repels the electrons in the two side bonds and adopt a bent molecular geometry. The expected geometry is the trigonal planar with a bond angle is 120°.
In an ozone molecule, six valence electrons for each molecule of Oxygen so the total number of valence electrons is 6 × 3 = 18. As both Oxygen atoms on the sides have the same electronegativity, therefore, the double bond keeps on shifting from both causing resonances.
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Why is protection from radiation needed?
Answer:
Because you could die or get seriously burn bad
Answer:
Radiation protection aims to reduce unnecessary radiation exposure with a goal to minimize the harmful effects of ionizing radiation. ... As radiation exposure becomes more prevalent, a thorough understanding of radiation exposure risks and dose reduction techniques will be of utmost importance.
Explanation:
What structure
do plant cells have during
cytokinesis that animal cells
do not have?
Answer: See Explanation
Explanation:
Cytokinesis occurs in mitosis and meiosis for both plant and animal cells. The ultimate objective is to divide the parent cell into daughter cells.
In plants , this occurs when a cell wall forms in between the daughter cells.
In animals , this occurs when a cleavage furrow forms. This pinches the cell in half.
A 125g sample of a mixture of salt and sand contains 12% salt.
a. How much salt (in g) does the sample contain?
b. How much sand (in g) does it contain?
Why was the morning session stopped unsuccessfully?
The reactor was overheating.
The automatic control system was not adjusted properly.
The vernier control rod became stuck.
The emergency rod failed.
Answer:
the reactor was overheating
this one too please lol
Answer:
It looks like 43 to me, so 43 ml?
Explanation:
I'd say that's 43ml
Hope this helps- have a good day bro cya)
answer 3 questions. screenshot
how do you expect the size of the atoms to change as you go from neon to argon to krypton
Answer:
The number of energy levels will increase.
Explanation:
As they are all Noble Gases, they are all in the same family. However, as you go further down the list of Noble Gases, the period number increases. The period number shows the number of energy levels. Hence, an increase in energy levels.
The size of the atoms (atomic radius) would increase down the group from neon to argon to krypton.
What is atomic radius?Atomic radius can be defined as a measure of the size (distance) of the atom of a chemical element, typically from the nucleus to its valence electrons.
The trends of atomic radius.Generally, the atomic radius of a chemical element decreases across the periodic table, from alkali metals (group 1 elements) to noble gases (group 8 elements). Also, the atomic radius of a chemical element increases down each group of the periodic table, typically from top to bottom (column).
In this context, the size of the atoms (atomic radius) would increase down the group from neon to argon to krypton.
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AcipHex is classified as
Answer:
Rabeprazole belongs to a class of drugs known as proton pump inhibitors (PPIs).
Why has the acidity of the ocean increased over the years?
A.Sediment deposits cannot replenish quick enough in order to affect the acidity
B.Not enough basic solutions in the ocean
C. Waste from ocean life
Answer:
I think it's A
Explanation:
Carbon dioxide is added to the atmosphere whenever people burn fossil fuels. ... As the amount of carbon dioxide in the atmosphere rises, the oceans absorb a lot of it. In the ocean, carbon dioxide reacts with seawater to form carbonic acid. This causes the acidity of seawater to increase.
Under what circumstances may a health insurer charge a higher premium to a woman with a genetic disposition to breast cancer? a) Her mother has breast cancer but she doesn't. O b) She has breast cancer. c) Her sister has breast cancer but she doesn't. d) Health insurers can never discriminate based on genetic information in this way.
Answer:
D
Explanation:
No company is allowed to discriminate.
15 and extra credit not 14
State the type of reaction and balance it properly: NaOH + CaBr2 → Ca(OH)2 + NaBr
Answer:
2NaOH(aq) + CaBr2(s) → Ca(OH)2(s) + 2NaBr(aq)
The given chemical equation depicts chemical reaction of double displacement type and it's balanced chemical equation is 2 NaOH + CaBr₂ [tex]\rightarrow[/tex] Ca(OH)₂ + 2 NaBr.
What is chemical equation?Chemical equation is a symbolic representation of a chemical reaction which is written in the form of symbols and chemical formulas.The reactants are present on the left hand side while the products are present on the right hand side.
A plus sign is present between reactants and products if they are more than one in any case and an arrow is present pointing towards the product side which indicates the direction of the reaction .There are coefficients present next to the chemical symbols and formulas .
The first chemical equation was put forth by Jean Beguin in 1615.By making use of chemical equations the direction of reaction ,state of reactants and products can be stated. In the chemical equations even the temperature to be maintained and catalyst can be mentioned.
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For which salt is the aqueous solubility most likely to change by changing the pH of the solution?
a) CaF2(aq)
b) CaCl2(aq)
c) CaI2(aq)
d) CaBr2(aq)
The salt whose aqueous solubility will most likely to change the pH of the solution is CaF2(aq).
The pH of a salt solution depends on the nature of the acid and base that forms the salt.
Salt of a weak acid and a strong base yields a basic solutionSalt of a strong acid and a weak base yields an acidic solutionSalt of a strong acid and a strong base yields a neutral solution.Since HF is a weak acid, its salt CaF2 will be slightly basic when dissolved in water hence the pH of the solution is altered.
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Which of the following correctly orders the
events in atomic history?
A. The atom has a small dense positive
nucleus.
B. The atom was a small dense sphere
C.Electrons exist in orbitals, or the most
probable location
D. The atom at electrons stuck in an overall
positive atom
E. Electrons exist in perfect orbits based on
energy levels.
The history of the atom passed through a certain sequence until our recent interpretation of atomic theory.
The correct sequence of atomic theory is;
The atom at electrons stuck in an overall positive atomThe atom has a small dense positive nucleus. Electrons exist in perfect orbits based on energy levels.Electrons exist in orbitals, or the most probable locationThe beginning of the atomic theory saw the discovery of J.J Thompson which led to the plum - pudding model in which the atom was described as a sphere in which electrons are stuck in an overall positive atom.
This was followed by Rutherford's planetary model in which he concluded that the atom has a small dense positive nucleus. This was followed by the model of Bohr in which the electrons exist in perfect orbits based on energy levels.
Lastly, the contemporary model of the atom is called the wave - mechanical model in which electrons exist in orbitals, or the most probable location.
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Why are mass of atoms called relative masses?
The atomic mass constant (symbol: mu) is defined as being 112 of the mass of a carbon-12 atom. Since both quantities in the ratio are masses, the resulting value is dimensionless; hence the value is said to be relative.