Answer:
1. Draw only the valence electrons.
2. Give every element main group element (except hydrogen) an octet of electrons.
3. Give each hydrogen two electrons.
Explanation:
Lewis structures are used to describe the arrangement or configurations of the valence electrons of molecules and polyatomic ions involved in electronic bonding. A Lewis structure consists of the symbols of the elements in the molecule surrounded by dots with each dot representing each of the elements valence electrons. Also, the electrons shared between two elements are shown by dots between the two elements and these electrons are known as shared electron pairs. The valence electrons on atom that is not involved in bonding is known as lone pairs.
The three general rules for drawing Lewis structures are:
1. Draw only the valence electrons. Only the valence electrons of the atoms of elements are shown since they are the only electrons involved in chemical bonding.
2. Give every element main group element (except hydrogen) an octet of electrons. The complete eight valence electrons of the noble gases is associated with their stability. Thus, the main group elements show a tendency to form enough bonds to obtain eight valence electronsmin order to achieve stability. This is known as the octet rule. However, since the maximum number of valence electrons for elements in the first period of the period table is two, the noble gas helium has completely-filled valence shell containing two electrons known as a duplet. Hydrogen belongs to the first period and is therefore an exception tomthe octet rule.
3. Give each hydrogen two electrons. Hydrogen attains a duplet structure in accordance with the structure of helium
During seafloor spreading, what kind of new earth forms?
Answer:
This bubbled-up magma is cooled by frigid seawater to form igneous rock. This rock (basalt) becomes a new part of Earth's crust. Seafloor spreading occurs along mid-ocean ridges—large mountain ranges rising from the ocean floor.
Explanation:
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GC-mass spectrometry is used to find the ________ of each compound in a ________. Group of answer choices none of these molecular formula, mixture of compounds molecular weight, mixture of compounds B and C molecular formula, mixture of alkanes
Answer:
mixture of compounds molecular weight
Explanation:
Gas Chromatography-mass spectrometry is used to find the mixture of compounds of each compound in a molecular weight. The Gas Chromatography also known as Mass Spectrometry (GC/MS) is an instrument that is used to separate chemical mixtures and identifies the components at a molecular level. It is one of the most accurate tools used for analyzing samples of the environment.
Unknown A melts at 113- 114oC. Known compounds 3-Nitroaniline and 4-Nitrophenol both melt at 112-114 oC. If A is mixed with 3-Nitroaniline and the melting point becomes broad and depressed, what must A be __________A) 3-Nitroaniline B) 4-Nitrophenol C) Both
Answer:
C) Both
Explanation:
Whenever we mix any pure form of a compound with some other form of a compound which is not in the other standard pure state, this results in the melting point of mixture to get dispersed and it becomes broad form.
Thus, when a known compound of 3-Nitroaniline mixes with both 3-Nitroaniline and 4-Nitrophenol, the melting point of the compound becomes depressed and board.
Thus the correct option is (C).
A 14.570 g sample of CaCl2 was added to 12.285 g of K2CO3 and mixed in water. A 3.494 g yield of CaCO3 was obtained.
What is the limiting reagent?
-CaCO3
-K2CO3
-CaCl2
Calculate the percent yield of CaCO3.
yield of CaCO3= %
Answer:
Limiting reagent is the potassium carbonate.
Percent yield of calcium carbonate is: 39.3 %
Explanation:
The reaction is:
CaCl₂ + K₂CO₃ → CaCO₃ + 2KCl
Formula for percent yield is:
(Produced yield / Thoeretical yield) . 100
Firstly we determine the moles of each reactant, in order to say what is the limiting reagent: ratio is 1:1.
1 mol of chloride need 1 mol of carbonate.
14.570 g . 1 mol /110.98 g = 0.131 moles of CaCl₂
12.285 g . 1 mol / 138.2g = 0.0889 moles of carbonate.
Limiting reagent is carbonate. For 0.131 moles of CaCl₂ we need the same amount of carbonate and we have less moles.
Ratio is also 1:1, with calcium carbonate.
1 mol of potassium carbonate produces 1 mol of calcium carbonate
then, 0.0889 moles will produce the same amount of CaCO₃
We convert moles to mass: 0.0889 mol . 100.08g /mol = 8.89 g
That's the theoretical yield; to find the percent yield:
(3.494 g / 8.89g) . 100 = 39.3%
In the periodic table,
have common properties,
periods
both groups and periods
neither groups nor periods
groups
Answer:
both groups and periods
Answer:
groups
Explanation:
Elements in the same group have similar chemical properties because they have the same number of outer electrons and the same valency
This question is concerned with the following oxides
• Sulfur dioxide
• Carbon monoxide
• Lithium oxide
• Aluminum (III) oxide
Which of the above oxides will not react with hydrochloric acid but will react with aqueous
sodium hydroxide?
Answer:
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Answer:
See explanation
Explanation:
For the first question, we can see that the pressure is constant so we apply Charles law;
V1/T1 =V2/T2
V1T2 = V2T1
V1= 4.5 L
T1= 27 + 273 = 300 K
V2= ?
T2= 127 + 273 = 400 K
V2= V1T2/T1
V2= 4.5 × 400/300
V2= 6L
For question 2, Charles law is also used;
V1/T1 =V2/T2
V1T2 = V2T1
T1= 338 K
V1= 0.480 L
T2= ?
V2= 9.2 L
T2= V2T1/V1
T2= 9.2 × 338/0.480
T2= 6478.3 K
Which one of the following statements concerning vitamin B12 is correct?
A\ it is present in plant products.
B\ its deficiency is most often caused by a lack of the vitamin in the diet.
C\ it requires a specific glycoprotein for its absorption.
D\ it is involved in the transfer of amino groups.
E\ the cofactor from is vitamin B12 itself.
Answer:
C it requires a specific glycoprotein for its absorption.
Out of the following statements concerning vitamin B12 the only statement which is correct- it requires a specific glycoprotein for its absorption.
Let's study some facts about vitamin B12:
Vitamin B12 is an essential vitamin found in foods such as meat, fish, and dairy. It requires a specific glycoprotein for its absorption. The body absorbs vitamin B12 from food in a two-step process.⇒First, hydrochloric acid in the stomach separates vitamin B12 from the protein that it's attached to.
⇒Second, the freed vitamin B12 then combines with a protein made by the stomach, called intrinsic factor, and the body absorbs them together.
Deficiency of Vitamin B12 leads to weakness and fatigue.Transport of B12 in extracellular fluids is dependent on three homologous carrier proteins:⇒intrinsic factor, transcobalamin (also known as transcobalamin II), and haptocorrin (also known as the R-protein or transcobalamin I).
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Stomach acid is approximately 0.10 M HCl. How many mL of stomach acid can be neutralized by one regular antacid tablet that contains 500 mg of solid CaCO3 (100.09 g/mol)?
Answer:
100 mL
Explanation:
The reaction that takes place is:
CaCO₃ + 2HCl → CaCl₂ + H₂O + CO₂First we convert 500 mg of CaCO₃ into mmoles, using its molar mass:
500 mg ÷ 100 mg/mmol = 5 mmol CaCO₃Then we convert 5 mmoles of CaCO₃ into HCl mmoles, using the stoichiometric coefficients of the balanced reaction:
5 mmol CaCO₃ * [tex]\frac{2mmolHCl}{1mmolCaCO_3}[/tex] = 10 mmol HClFinally we calculate the volume of a 0.10 M HCl solution (such as stomach acid) that would contain 10 mmoles:
10 mmol / 0.10 M = 100 mLA range of organic molecules can undergo combustion. If pyridine
Answer:
A range of organic molecules can undergo combustion. Pyridine (C5H5 combustion in the unbalanced reaction shown below wtar o 4 CsH5N + O2 +H2O + CO2 + NO a) Write the balanced equation. (2 points) # 41 CH N +170 70 the flow, t- b) Find the percent yield for the reaction if 10.0 g of pyridine dioxide. (2 points)
Explanation:
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Identical wire loops are dipped into Liquid X and Liquid Y, so that a film of liquid forms across the loops (like the bubble solution on a child's bubble blowing wand). The width of each loop is increased slowly and the forces FX and FY needed to make the loops 5% wider are measured.
a. FX will be greater than F Y
b. FX will be less than FY
c. FX will be equal to FY
d. It's impossible to predict whether F X or FY will be greater without more information.
Answer:
a.
Explanation:
Assuming that Liquid X is considered to possess a greater viscosity as well as higher surface tension than liquid Y. Then, liquid X will tend to harbour more pressure inside the liquid.
In addition to that, the greater the surface tension, the greater the force required to expand the liquid's surface area.
This in turn makes the force required to make the loop 5% wider to be greater in FX rather than FY.
Thus, option a is the correct answer.
10. What is the mass of SO3 when -8753 kJ of energy are used according
to the following equation?2S + 302 - 2003 AH = -791.4kJ Is this
Endothermic or Exothermic -8735kJ x mols03/kJ x gSO3/
molSO3
Answer:
Exothermic
1771 g
Explanation:
Step 1: Write the balanced thermochemical equation
2 S(s) + 3 O₂(g) ⇒ 2 SO₃(g) ΔH° = -791.4 kJ
Since ΔH° < 0, the reaction is exothermic.
Step 2: Calculate the moles of SO₃ produced when 8753 kJ of energy are released
According to the thermochemical equation, -791.4 kJ are released every 2 moles of SO₃ that are formed.
-8753 kJ × 2 mol/(-791.4 kJ) = 22.12 mol
Step 3: Calculate the mass corresponding to 22.12 moles of SO₃
The molar mass of SO₃ is 80.06 g/mol.
22.12 mol × 80.06 g/mol = 1771 g
Which of the following could not act as a medium for a mechanical wave?
a) air
b) empty space
c) liquid water
d) a solid rope
Answer:
b) empty space
Explanation:
A mechanical cannot travel through empty space. So option (b) is correct.
A mechanical wave is a wave which needs a material medium for its propagation. For example sound, water waves etc . The medium required by the wave can be a solid, liquid or a gas. Empty space doesn't have any medium, so a mechanical wave cannot travel through empty space.
13. The attraction between water molecules and an Na+
ion or a Cl- ion occurs because water molecules are
A) linear
B) symmetrical
C) polar
D) nonpolar
Answer:
C) Polar
Explanation:
The correct answer is polar
The attraction of sodium and chloride ions by the water is mediated by the polar nature of water. Thus, option C is correct.
What is polarity?The polarity is given as the formation of the partial positive and negative charge over the species in the ionization process.
Water molecule is having one hydrogen bounded with 2 oxygen atoms, and oxygen being more electronegative develops a partial negative charge, while hydrogen develops a partial positive charge.
The positive charge hydrogen and the negative charge oxygen attracts the opposite charge sodium and chloride ions. Thus, the attraction is mediated due to the polar nature of water. Hence, option C is correct.
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Reaction or ionic equation for CuSO4(aq)+CaCO3(aq)
Answer:
CuCo3+CaSo4
Explanation:
when they react they form that compound in the reaction called double displacement.
How many moles of water are produced if 3.30 moles of N20 is
produced? NH4NO3 --> N20 + 2 H2O (mole to mole conversion) 1 step
Answer:
The netto reaction equation is:
2 OH- + 2H+ = 2 H2O
So the answer is 2 moles.
What is nitrogen???? explain!!!
Answer:
It is a colourless, odourless, tasteless gas that is the most plentiful element in Earth's atmosphere and is a constituent of all living matter.
Explanation:
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Answer:
Nitrogen is a gas
Explanation:
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Answer:
482
Explanation:
when nitric acid touches your skin a yellow spot develops what does the spot mean
A student swings back and forth from position A to C, as shown.
Which of the following happens when the swing moves from Position C to Position B?
A. Both potential energy and kinetic energy of the student increase.
B. Both potential energy and kinetic energy of the student decrease.
C. Potential energy of the student decreases and kinetic energy of the student increases.
D. Kinetic energy of the student decreases and potential energy of the student increases.
Answer:
C
Explanation:
KE at B is max and PE is 0
KE at C is 0 and PE is max
so when student swings from C to B
its KE increases
and PE decreases
Which atom has the electron configuration 1s²2s²2p⁶3s²3p⁶4s²3d¹⁰4p⁶5s²4d²? and 1s²2s²2p⁶3s²3p⁶3d⁷4s²?
A student measures her computer keyboard with a meter stick and finds that it has a width of 47.35 cm. Which statement about this measurement is true?
PLZZZZ HELP
A.) All the numbers are certain
B.) The 4 is uncertain
C.) The 5 is somewhat uncertain
D.) The 5 is certain
Humans depend on water from various sources for different reasons. All of these sources are polluted or could be polluted to some extent. Of the following sources, which should humans be most concerned about: lakes, rivers and streams, ocean or groundwater? Explain. answer it no link please anser it a soon as possible pleaseeeeee answer it pleaseee :)
Explanation:
Earth is known as the "Blue Planet" because 71 percent of the Earth's surface is covered with water. Water also exists below land surface and as water vapor in the air. Water is a finite source. The bottled water that is consumed today might possibly be the same water that once trickled down the back of a wooly mammoth. The Earth is a closed system, meaning that very little matter, including water, ever leaves or enters the atmosphere; the water that was here billions of years ago is still here now. But, the Earth cleans and replenishes the water supply through the hydrologic cycle.
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Given the following values for the change in enthalpy (deltaH) and entropy (deltaS), which of the following processes can occur at 298 K without violating the second Law of Thermodynamics?
(a) DeltaH = -84 kj mol-2 (-20 kcal mol-1), DeltaS = +125j mol-2K-1)(+30 cal mol-1 K-1)
(b) DeltaH = -84 kj mol-2 (-20 kcal mol-1), DeltaS = -125j mol-2K-1)(-30 cal mol-1 K-1)
(c) DeltaH = +84 kj mol-2 (+20 kcal mol-1), DeltaS = +125j mol-2K-1)(+30 cal mol-1 K-1)
(d) DeltaH = +84 kj mol-2 (+20 kcal mol-1), DeltaS = +125j mol-2K-1)(-30 cal mol-1 K-1)
Answer:
Option A and B
Explanation:
(a) DeltaH = -84 kj mol-2 (-20 kcal mol-1), DeltaS = +125j mol-2K-1)(+30 cal mol-1 K-1)
Delta G = Delta H – T * DS
Substituting the given values, we get –
Delta G = -84 -298 *(125/1000) = -121.25 KJ/mol
Delta G is negative hence the process is spontaneous and will not violate the second law of thermodynamics
(b) DeltaH = -84 kj mol-2 (-20 kcal mol-1), DeltaS = -125j mol-2K-1)(-30 cal mol-1 K-1)
Delta G =-84 -298 *(-125/1000) = -46.75 KJ/mol
Delta G is negative hence the process is spontaneous and will not violate the second law of thermodynamics
(c) DeltaH = +84 kj mol-2 (+20 kcal mol-1), DeltaS = +125j mol-2K-1)(+30 cal mol-1 K-1)
Delta G = 84 -298 *(125/1000) = +46.75 KJ/mol
Delta G is positive hence the process is non-spontaneous and will violate the second law of thermodynamics
(d) DeltaH = +84 kj mol-2 (+20 kcal mol-1), DeltaS = +125j mol-2K-1)(-30 cal mol-1 K-1)
Delta G = 84 -298 *(-125/1000) = + 121.25 KJ/mol
Delta G is positive hence the process is non-spontaneous and will violate the second law of thermodynamics
Using a mole ratio, find the moles of Cu. You have been given the following
balanced chemical equation, and you have 1.5 moles of Al to start.*
2AI
+
3Cu(SO4)
3Cu
+
Al2(SO4)3n
n 1.5 moles
Answer: 2,25 mol
Explanation: 2Al + 3CuSO4 → Al2(SO4)3 + 3Cu
1,5 mol (1,5*3)/2 mol = 2,25 mol
A solution is formed by dissolving 83.2 grams of copper II chloride (CuCl2) in 2.5 liters of water. The molar mass of CuCl2 is 134.45 g/mol.
What is the molarity of the solution?
Explanation:
the answer is in the above image
Explain why the following is an incorrect IUPAC name. 1,3-Dimethylbutane
a. The longest chain is chosen incorrectly.
b. The name of substituent is given incorrectly.
c. The longest chain is numbered incorrectly.
d. Substituents are not listed in alphabetical order.
Answer:
a. The longest chain is chosen incorrectly.
Explanation:
Hello there!
In this case, according to the given information, it turns out possible for us to firstly draw the structural formula of the 1,3-Dimethylbutane:
[tex]CH_3-CH_2-CH(CH3)-CH_2-CH_3[/tex]
Thus, we can see that the correct name should be 3-methylpentane since the longest chain was chosen incorrectly, as it must have five carbon atoms.
Regards!
Cellular respiration results in a
Answer:
A form of energy that can be used by cells.
Explanation:
When the following oxidation-reduction reaction in acidic solution is balanced, what is the
lowest whole-number coefficient for Rb+ (aq)?
Rb(s) + Sr2+ (aq) → Rb+(aq) + Sr(s)
Answer:
2Rb(s) + Sr^+(aq) → 2Rb^+ (aq) + Sr(s)
Explanation:
In a redox reaction, we must ensure that the number of electrons gained equals the number of electrons lost in the reduction and oxidation half reaction equations respectively.
Having that in mind;
Oxidation half reaction;
2Rb(s) ---->2Rb^+(aq) + 2e
Reduction half equation;
Sr^2+(aq) + 2e---> Sr(s)
Hence, the overall redox reaction equation is;
2Rb(s) + Sr^+(aq) → 2Rb^+ (aq) + Sr(s)
What are the TWO characteristics of an effective collision?
Answer:
the TWO characteristics of an effective collision are:
1.Molecules collide with sufficient energy
2.Molecules collide with the proper orientation.