Answer:
2290 . 75 J absorbed
Explanation:
The copper changed from 21 to 28 degrees= 7 degrees
.85 kg = 850 gm
850 gm * 7 degrees * .385 J / g-degree) = 2290.75 j
Which buffer can be suitable to prepare a solution that needs to be buffered at ph 4?
Answer:
For pH= 4.00 :
Add 0.1 ml of 0.1 molar NaOH to 50 ml of 0.1 molar potassium hydrogen phthalate .
A
Calculate the number of C atoms in 0.524 mole of C.
B
Calculate the number of SO2 molecules in 9.87 moles of SO2
C
Calculate the moles of Fe in 1.40x10^22 atoms of Fe
D
Calculate the moles of C2H6O in 2.30x10^24 molecules of C2H6O
The number of C atoms in 0.524 moles of C is 3.15 atoms.
The number of [tex]SO_2[/tex] molecules in 9.87 moles [tex]SO_2[/tex] is 59.43 molecules.
The moles of Fe in 1.40 x [tex]10^{22}[/tex] atoms of Fe is 0.23 x [tex]10^{-1}[/tex]
The moles of [tex]C_2H_6O[/tex] in 2.30x[tex]10^{24}[/tex] molecules of [tex]C_2H_6O[/tex] is 3.81.
What are moles?A mole is defined as 6.02214076 × [tex]10^{23}[/tex] of some chemical unit, be it atoms, molecules, ions, or others. The mole is a convenient unit to use because of the great number of atoms, molecules, or others in any substance.
A. The number of C atoms in 0.524 mole of C:
6.02214076 × [tex]10^{23}[/tex] x 0.524 mole
3.155601758 atoms =3.155 atoms
B. The number of [tex]SO_2[/tex] molecules in 9.87 moles of [tex]SO_2[/tex]:
6.02214076 × [tex]10^{23}[/tex] x 9.87
59.4385293 molecules= 59.43 molecules
C. The moles of Fe in 1.40 x [tex]10^{22}[/tex] atoms of Fe:
1.40 x [tex]10^{22}[/tex] ÷ 6.02214076 × [tex]10^{23}[/tex]
0.2324754694 x [tex]10^{-1}[/tex] moles.
0.23 x [tex]10^{-1}[/tex] moles.
D. The moles of [tex]C_2H_6O[/tex] in 2.30x[tex]10^{24}[/tex] molecules of [tex]C_2H_6O[/tex]:
2.30x[tex]10^{24}[/tex] ÷ 6.02214076 × [tex]10^{23}[/tex]
3.819239854 moles=3.81 moles
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What type of reaction is illustrated?
Answer:
Synthesis
Explanation:
Carbon + Difluorine = Tetrafluoromethane.
1 mole of Carbon [C] reacts with 2 moles of Difluorine [F2] to form 1 mole of Tetrafluoromethane [CF4]
For the reaction below determine the ▲H for the reaction and state whether the reaction was endothermic or exothermic. Show your work.
C2H5OH + 3 O2 → 2 CO2 + 3H2O
C-C = 83 kcal; C-H = 99 kcal; C-O = 84 kcal; O-H = 111 kcal; C=O 192 kcal; O=O = 119 kcal
I got stuck on this and need help please, thank you so much!
Answer:exothermice
Explanation: it is relaeing heat not keeping it in
In the laboratory you dissolve 12.2 g of iron(II) iodide in a volumetric flask and add water to a total volume of 500 mL.
What is the molarity of the solution?
M.
What is the concentration of the iron(II) cation?
M.
What is the concentration of the iodide anion?
M.
In the laboratory you dissolve 16.8 g of iron(III) sulfate in a volumetric flask and add water to a total volume of 250 mL.
What is the molarity of the solution?
M.
What is the concentration of the iron(III) cation?
M.
What is the concentration of the sulfate anion?
M.
You wish to make a 0.271 M hydrobromic acid solution from a stock solution of 12.0 M hydrobromic acid. How much concentrated acid must you add to obtain a total volume of 50.0 mL of the dilute solution?
mL
Question 1
1) The formula of iron(II) iodide is [tex]\text{FeI}_{2}[/tex] and has a formula mass of 309.654 g/mol. This means that in 12.2 grams, there are
12.2/309.654 = 0.039398812868557 mol.So, the molarity is (0.039398812868557)/(0.5) = 0.0788 M (to 3 sf)
2) In 0.039398812868557 mol of iron(II) iodide, there are 0.039398812868557 moles of iron(II) iodide cations, and thus the molarity is still 0.0788 M (to 3 sf)
3) In 0.039398812868557 mol of iron(II) iodide, there are
2(0.039398812868557) = 0.078797625737114 moles of iodide anionsThus, the molarity is (0.078797625737114)/(0.5) = 0.158 M (to 3 sf)
Question 2
1) The formula of iron(III) sulfate is [tex]\text{Fe}_{2}\text{(SO}_{4})_{3}[/tex] and has a formula mass of 399.9 g/mol. This means that in 16.8 grams, there are
16.8/399.9 = 0.042010502625656 molSo, the molarity is (0.042010502625656)/(0.25) = 0.168 M (to 3 sf)
2) In 0.042010502625656 moles of iron(III) sulfate, there are 2(0.042010502625656)=0.084021005251312 moles of iron(III) cations, so the molarity is:
0.084021005251312/0.25 = 0.336 M (to 3 sf)3) In 0.042010502625656 moles of iron(III) sulfate, there are 3(0.042010502625656)=0.12603150787697 moles of sulfate anions, so the molarity is:
0.12603150787697/0.25 = 0.504 M (to 3 sf)Question 3
Since we need 50.0 mL of solution at 0.271 M,
0.271 = (moles of HBr)/(0.05) moles of HBr = 0.01355 molSo, we need this from 12.0 M HBr so, meaning that:
12.0 = (0.01355)/(liters of 12.0 M HBr stock solution)liters of 12.0 M HBr stock solution = 0.0011291666666667 L = 1.13 M (to 3 sf)25. What is the equilibrium constant expression for the following? 2Hg (g) + O₂(g) → 2HgO (s) A. K= [Hg] [0₂]. B. K= [HgO]/([Hg]²[0₂]) M C. K=[2HgO]/([2Hg][0₂]). D. K=1/([Hgl [02]) 25. What is the equilibrium constant expression for the following ? 2Hg ( g ) + O₂ ( g ) → 2HgO ( s ) A. K = [ Hg ] [ 0₂ ] . B. K = [ HgO ] / ( [ Hg ] ² [ 0₂ ] ) M C. K = [ 2HgO ] / ( [ 2Hg ] [ 0₂ ] ) . D. K = 1 / ( [ Hgl [ 02 ] )
Answer:
2 Hg (g) + o2 ---> 2 H2o
equilibrium constant
K = (c) (d) / (a)(b)
K= ( H2o)²/(He) ²(o2)
Under which conditions of temperature and pressure, the real gas behave ideally?
Answer:
A real gas will act as an ideal gas under high temperature and at a low pressure.
Real gases are non-ideal gases whose molecules occupy space and have interactions, consequently, they do not adhere to the ideal gas law.
An ideal gas has molecules that occupy negligible space and have no interactions, and which consequently obeys the gas laws exactly.
Explanation:
explain how magic numbers are related to nuclear stabilize
Answer:
A magic number is a number of nucleons (either protons or neutrons, individually) that form complete bands within the atomic nucleus. As a result, atomic nuclei with a magic number of protons or neutrons are significantly more persistent than other nuclei.
37) Which chemical equation is correctly balanced?
a) Al(OH)3(s) → Al₂O3(s) + 2 H₂O(g)
b) KI(aq) + Pb(NO3)2(aq) → KNO3(aq) + 4 Pbl₂(aq)
c) 2 Na3PO4(aq) + 3 CaCl₂(aq) →6 NaCl(aq) + Ca3(PO4)2(aq) to S
d) CsH12) +6 O₂(g)→ 5 CO₂(g) + 6 H₂O(g)
0 (0
Answer: c) [tex]2\text{Na}_{3}\text{PO}_{4}+3\text{CaCl}_{2} \longrightarrow 6\text{NaCl}+\text{Ca}_{3}\text{(PO}_{4})_{2}[/tex]
Which data are shown on topographic maps?
Answer:
Topographic maps generally shows Natural features such as Rivers and Lakes.
sometimes they also show some features made by humans like brodges, elevations etc.
Answer:
Topographic maps show contours, elevation, forest cover, marsh, pipelines, power transmission lines, buildings, and various types of boundary lines such as international, provincial, and administrative, and many others.
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Why is a low concentration of CO2 in our blood good while a high concentration is bad?
Carbon dioxide in your blood usually causes no problems. But if you have too much or too little of it, you may have a disease or a health emergency.
What is carbon dioxide?Carbon dioxide (CO2) is an odourless, colourless gas.
A high concentration can displace oxygen in the air. If less oxygen is available to breathe, symptoms such as rapid breathing, rapid heart rate, clumsiness, emotional upsets and fatigue can result.
As less oxygen becomes available, nausea and vomiting, collapse, convulsions, coma and death can occur.
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How many grams of solid barium sulfate form when 32.0 mL of 0.160 M barium chloride reacts with 70.0 mL of 0.065 M sodium sulfate? Aqueous sodium chloride forms also.
Considering the reaction's stoichiometry and the notion of molarity, 1.167 grams of solid barium sulfate form when 32.0 mL of 0.160 M barium chloride reacts with 70.0 mL of 0.065 M sodium sulfate.
The balanced reaction is:
BaCl₂(aq) + Na₂SO₄(aq) → BaSO₄(s) + 2 NaCl(aq)
What is a Limiting Reagent?The reactant that is consumed first in a chemical reaction is the limiting reagent because it stops any more reactions from taking place. The limiting reagent controls how much product is produced during the reaction.
Utilizing the reaction stoichiometry and the estimated number of moles, it is possible to identify the limiting reagent.
According to reaction stoichiometry, which describes the proportions of reagents and products in a chemical reaction, the following numbers of moles of each component are involved in the reaction:
BaCl₂: 1 moleNa₂SO₄: 1 moleBaSO₄: 1 moleNaCl: 2 molesMolarity, on the other hand, refers to how many moles of solute are dissolved in a certain volume.
Molarity is determined by the expression:
[tex]Molarity=\frac{number of moles of solute}{volume}[/tex]
Molarity is expressed in units[tex]\frac{moles}{L}[/tex].
In this case, 32.0 mL= 0.032L (being 1000 mL= 1 L) of barium chloride reacts. So, by definition of molarity, the number of moles that participate in the reaction is calculated as:
[tex]0.160 M=\frac{No. of moles of solute}{0.032L}[/tex]
No of moles of barium chloride(solute) = 0.160M × 0.032L
No of moles of barium chloride(solute) = 0.00512moles
On the other side,70.0mL= 0.070 L of 0.065 M sodium sulfate reacts. So, by definition of molarity, the number of moles that participate in the reaction is calculated as:
[tex]0.065 M =\frac{No of moles of solute}{0.070L}[/tex]
No of moles of Sodium sulfate= 0.065M × 0.070L
No of moles of Sodium sulfate = 0.0045moles
if by stoichiometry 1 mole of barium chloride reacts with 1 mole of sodium sulfate, 0.00512moles of barium sulfate reacts with how many moles of sodium sulfate?
No. of moles of sodium sulfate=
[tex]\frac{ 0.00512moles of barium sulfate * 1 mole of sodium sulfate}{1 mole of barium chloride}[/tex]
amount of moles of sodium sulfate= 0.00512 moles
But 0.00512moles of sodium sulfate are not available, 0.0045moles moles are available. Since you have fewer moles than you need to react with 0.00512moles of barium chloride, sodium sulfate will be the limiting reagent.
Then, it is possible to determine the number of moles of barium sulfate produced by another rule of three: if by stoichiometry 1 mole of sodium sulfate produces 1 mole of barium sulfate, 0.00512 moles of sodium sulfate produces how many moles of barium sulfate?
[tex]Amt of mole of barium sulfate=\frac{0.00512 moles of sodium sulfate* 1mole of barium sulfate}{1 mole of sodium sulfate}[/tex]
amount of moles of barium sulfate= 0
Being the mass molar of barium sulfate is 233.34 g/mole, the mass-produced of the compound is calculated as:
= [tex]\frac{0.00512 moles * 233.34 gm}{1 mole}[/tex]
=1.167 gm
Hence, 1.167 gm of solid barium sulfate is formed.
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Determine the mass of SO₂ that contains 6.075 × 10^26 S atoms.
Avogadro's law states that in a mole of any substance, there are [tex]6.022 \times 10^{23}[/tex] atoms. This means that in the given sample, there are
[tex]\frac{6.075 \times 10^{26}}{6.022 \times 10^{23}}=1008.8010627 \text{ mol}[/tex]
The atomic mass of sulfur is 32.06 amu.The atomic mass of oxygen is 15.9994 amu.So, the atomic mass of sulfur dioxide is
[tex]32.06+2(15.9994=64.0588 \text{ g/mol}[/tex]
Therefore, the mass is:
[tex](64.0588)(1008.8010627)=\boxed{64620 \text{ g (to 4 sf)}}[/tex]
Which of the following alkali metal is expected to melt if the room temperature
rise to 30oc (a) Na (b) K (c) Rb (d) Cs
You need to measure out exactly 6.7 mL of water for an experiment. Which of the following would be the best tool for the job?
a. A 250 mL beaker
c. A 50 mL graduated cylinder
b. A 10 mL graduated cylinder
d. A 150 mL Erlenmeyer flask
Answer:
The answer for this problem would be "b. A 10 mL graduated cylinder".
Explanation:
The reason for this is because with a instrument that is closer to the value you're trying to measure, the more precise it will be.
For example using a teaspoon to measure something rather than a cup.
Explain how to get it Thanks
The Ammonia present in 2.5 mole of Ammonia is 42.5grams.
What is a mole ?A mole is a measuring unit in Chemistry to measure the number of atoms in certain molar mass of a substance.
It is given that 2.5 mole of Ammonia is present
Grams of Ammonia present in 2.5 mole of Ammonia = ?
Molecular weight of Ammonia = 17 grams.
1 mole of Ammonia = 17 grams of Ammonia
2.5 mole of Ammonia = 17 * 2.5
= 42.5 grams
Therefore 42.5 grams of Ammonia is present in 2.5 mole of Ammonia.
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If a utility burned 7.57 million tons of coal that was 2.00% sulfur by weight, how many tons of sulfur dioxide were emitted? Answer in scientific notation.
So mass of sulphur
[tex]\\ \rm\Rrightarrow 0.02\times 757\times 10^{6}[/tex]
[tex]\\ \rm\Rrightarrow 1514\times 10^4[/tex]
S+O_2–≥SO_2Moles =64/32=2
So
So tons of sulphur dioxide
[tex]\\ \rm\Rrightarrow 2(1516)10^4[/tex]
[tex]\\ \rm\Rrightarrow 3032\times 10^4ton[/tex]
Explanation:
2% of 2million tons of sulphur=
2÷100×7.57E9
That is;
[tex] \frac{2}{100} \times 7.57 \times 10 {}^{6} = 0.02 \times 7.57 \times 10 {}^{6} \\ = 2 \times 10 {}^{ - 2} \times7.57 \times 10 {}^{6} = 2 \times 7.57(10 {}^{ - 2 + 6}) \\ = 15.14 \times 10 {}^{4} (for \: sulphur) \\ for \: sulphur \: dioxide = so2 \\ the \: molar \: mass \: of \: so2 = 64g.mol {}^{ -1} \\ if \: 32grams \: of \: sulphur \: weighs \: 15.14 \times 10 {}^{4} tones \\ 64grams \: will \: weigh \: \frac{64}{32} \times 15.14 \times 10 {}^{4} \\ = 2 \times 15.14 \times 10 {}^{4} \\ = 30.28 \times 10 {}^{4} \\ or = 3.028 \times 10 {}^{5} tones[/tex]
An unknown compound contains only C , H , and O . Combustion of 6.80 g of this compound produced 16.0 g CO2 and 4.37 g H2O . What is the empirical formula of the unknown compound?
Answer:
I am a small palm-sized pointing device
Use the chemical equation to answer the question.
2H₂(g) + O₂(g) → 2H₂O(1)
Which statement describes the breaking and forming of bonds in the reaction?
The reaction requires breaking one H-H bond and two O=O bonds, and then forming four O-H bonds.
The reaction requires breaking one O=O bond and two H-H bonds, and then forming four O-H bonds.
The reaction requires breaking four O-H bonds, and then forming one H-H bond and two O=O bonds.
The reaction requires breaking four O-H bonds, and then forming one O=O bond and two H-H bonds
Answer: The reaction requires breaking one O=O bond and two H-H bonds, and then forming four O-H bonds.
Chromium (III) oxide reacts with hydrogen sulfide gas to form chromium (III) sulfide and water. To produce 421 g of cr2s3, how many moles of cr2o3 and grams of cr2o3 are required?
Cr₂O₃ ( s ) + 3H₂S ( g ) → Cr₂S₃ ( s ) + 3H₂O ( l )
mol Cr₂S₃ = 421 : 200.19 g/mol = 2.103
mol Cr₂O₃ ≈ mol Cr₂S₃ = 2.103 ( equivalent coefficient)
mass Cr₂O₃ = 2.103 x 151.99 g/mol = 319.63 gr
Use Table B in your Student Guide to answer the questions about ion concentrations.
A solution with a pH = 13 has approximately how many moles of OH ions per liter?
How many moles of H* would this same solution have per liter?
(Use the decimal form of your answer.)
A different solution with an H+ concentration of 1.0 x 10-4 would have a pH =
Question 1
[tex]\text{pH}=-\log(\text{H}^{+})\\\\13=-\log(\text{H}^{+})\\ \\ \text{[H}^{+}]}=1 \times \boxed{10^{-13} \text{ moles per liter}} \\ \\ \text{[H}^{+}] \times \text{[OH}^{-}] =1 \times 10^{-14} \text{ M}\\\\\text{[OH}^{-}]=\boxed{1 \times 10^{-1} \text{ moles per liter}}[/tex]
Question 2
[tex]\text{pH}=-\log(\text{H}^{+})\\\\\text{pH}=-\log(1.0 \times 10^{-4})=\boxed{4}[/tex]
Write and balance molecular equations for the following reactions between aqueous solutions. You will need to decide on the formulas and phases of the products in each of the cases.
An aqueous solution of barium hydroxide is mixed with an aqueous solution of sulfuric acid.
Answer:
Ba(OH)2(aq) + H2SO4(aq) ----> BaSO4(s) + 2H2O(l)
A doctor prescribed a tablet to a patient suffering from iron deficiency. The tablet does not look like iron. Explain.
Answer:
Tablets are made from salts of iron hence it does not look like iron.
Explanation:
Select the correct answer.
In a given chemical reaction, the energy of the products is greater than the energy of the reactants. Which statement is true for this reaction?
A. Energy is absorbed in the reaction.
B. Energy is released in the reaction.
C. No energy is transferred in the reaction.
D. Energy is created in the reaction.
E. Energy is lost in the reaction.
Which of the following statements about carbon dioxide is not true?
Increased carbon dioxide in the atmosphere increases the Greenhouse Effect.
Carbon dioxide is a greenhouse gas.
Atmospheric carbon dioxide levels have slowly declined over the last 50 years.
Burning fossil fuels can increase carbon dioxide levels in the atmosphere.
Question 26 of 30
For a reaction, AH = -75 kJ/mol and SO = -0.081 kJ/(K.mol). At what
A
temperatures is this reaction spontaneous?
O A. T<930 K
OB. At all temperatures
C. T< 100 K
OD. T> 930 K
Answer: B
Explanation:
Determine how many kilojoules are absorbed when 341 g of Ca(OH)2 reacts via the following reaction:
Ca(OH)2(s)→CaO(s)+H2O(l),ΔH=+65.3kJ
305.6KJ are absorbed when 341 g of [tex]Ca(OH)_2[/tex]reacts via the following reaction.
What is enthalpy?The sum of the internal energy and the product of the pressure and volume of a thermodynamic system.
Given data:
[tex]Ca(OH)_2[/tex] (s) → [tex]CaO(s)+H_2O(l)[/tex], ΔH=+65.3kJ
Moles of [tex]Ca(OH)_2[/tex]= [tex]\frac{mass}{molar \;mass}[/tex]
Moles of [tex]Ca(OH)_2[/tex] = [tex]\frac{341 g }{74g/mol}[/tex] =4.68 moles
Since, 1 mol [tex]Ca(OH)_2[/tex] absorbs 65.3kJ.
Therefore, 4.68 moles [tex]Ca(OH)_2[/tex] produce energy = 65.3kJ X 4.68 moles
=305.6KJ
Hence, 305.6KJ are absorbed when 341 g of [tex]Ca(OH)_2[/tex] reacts via the following reaction.
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Which of these reactions are acid-base reactions?
Answer:
The fifth answer choice (NH3 + H2O = NH4+ + OH-)
Explanation:
An acid-base reaction occurs when an acid and base combine, and the acid, (which is H2O in this case) "donates" a proton, or an H+ to the base. In this reaction, H2O gave one of its H+ to NH3, to make NH4+ and OH-. NH4+ now has a positive charge because it gained a positive ion, while OH- now has a negative charge because it gained a negative ion.
How would you draw the ionic compound Beryllium Arsenide lewis structure?
Answer:
[Na]^+ [Cl]^-
Explanation:
Lets say its sodium, its number of electrons is 11, but when its stable (an ion), it is 10. and chloride, number of electrons is 17, but when its stable (an ion) it is 18. So the lewis structure for that is, remember with the straight brackets (not sure what it's called, but you know what I mean I guess) its this one: [ ]
Sodium will be + because it has more protons (11-10 = +1), and chloride will be - because it gained an electron, so has more electrons than protons (17-18 = -1)
So the lewis structure would be:
[Na]^+ for sodium
and
[Cl]^- for chlorine
Sodium chloride:
[Na]^+ [Cl]^-
Also just to add, only 1 of each atom (Na and Cl) was needed for the bonding, but if let's say example; 2 Cl was needed to bond with sodium, there would be 2 Cl (same) and 1 Na.
Question 3
What part of a water molecule is the negatively charged side?
Answer:
The oxygen atom in water has a negative charge.
Definitions:Polar molecule: A molecule in which the centroid of the positive charges is different from the centroid of the negative charges.
Oxygen: A colorless, odorless, gaseous element constituting about one-fifth of the volume of the atmosphere and present in a combined state in nature. It is the supporter of combustion in air and was the standard of atomic, combining, and molecular weights until 1961, when carbon 12 became the new standard. Symbol: O; atomic weight: 15.9994; atomic number: 8; density: 1.4290 g/l at 0°C and 760mm pressure.
Water: A transparent, odorless, tasteless liquid, a compound of hydrogen and oxygen, H2O, freezing at 32°F or 0°C and boiling at 212°F or 100°C. that in more or less impure state constitutes rain, oceans, lakes, rivers, etc.: it contains 11.188 percent hydrogen and 88.812 percent oxygen, by weight.
Hydrogen: A colorless, odorless, flammable gas that combines chemically with oxygen to form water: the lightest of the known element. Symbol: H; atomic weight: 1.00797; atomic number: 1; density: 0.0899 g/l at 0°C and 760 mm pressure.
Atom: Am atom is the smallest constituent particle of a chemical element which has the properties of that element. They re comprised of at least an electron and a portion, as is the case for Hydrogen. Atoms of all other elements however, contain at least one neutron.
Proton: A positively charged elementary particle that is a fundamental constituent of all atomic nuclei. It is the lightest and most stable baryon, having a charge equal in magnitude to that of the electron, a spin of 1/2, and a mass of 1.673 × 10-27kg. Symbol: P.
Electron: An elementary particle that is a fundamental constituent of matter, having a negative charge of 1.602 × 10-19 coulombs, ha mass of 9.108 × 10-31 kilograms, and spin of 1/23, and existing independently or as the component outside the nucleus of an atom.
Neutron: An elementary particle having no charge, mass slightly greater than that of a proton, and spin of 1/2: a constituent of the nuclei of all atoms except those of hydrogen. Symbol: n.
What is a negative charge?A object has a negative charge when it consists of more electrons than protons.
With a partial positive charge on 2 Hs and a partial negative charge on oxygen, water molecules are polar molecules.
Actually, two hydrogen atoms and the core oxygen atom of water are covalently connected. Due to its greater electronegative nature than hydrogen, oxygen pulls the bound electron pair in the middle of the atom toward it.
When illustrating higher electron densities over oxygen, partial negative charge is used, whereas partial positive charge is used to illustrate lower densities over hydrogen atoms.
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