Answer:
The London dispersion force is the weakest intermolecular force. The London dispersion force is a temporary attractive force that results when the electrons in two adjacent atoms occupy positions that make the atoms form temporary dipoles.
A 135 g sample of a metal requires 2.50 kJ to change its temperature from 19.5°C to 95.5°C to 100.0°C?
Answer:
0.23J/g°C
Explanation:
Given parameters:
Mass of sample = 135g
Amount of heat = 2.5kJ
Initial temperature = 19.5°c
Final temperature = 100°C
Unknown:
Specific heat capacity of the metal = ?
Solution:
The specific heat capacity of a substance is the amount of heat required to the raise the temperature of 1g of the substance by 1°C.
H = m C (T₂ - T₁ )
H is the amount of heat
m is the mass
C is the specific heat capacity
T₂ is the final temperature
T₁ is the initial temperature;
2.5 x 10³ = 135 x C x (100 - 19.5)
2500 = 10867.5C
C = [tex]\frac{2500}{10867.5}[/tex] = 0.23J/g°C
7. A student has a 25 g sample of gas in a container at STP and adds another 7
g of the gas while keeping the pressure constant, what is the new temperature in
degrees Celsius?
Answer:
New temperature t2 = [1.28T− 273.15]° C
Explanation:
Given:
Volume v1 = 25 gram
New volume v2 = 25 + 7 = 32 gram
Constant pressure = p
Temperature t1 = T
Find:
New temperature t2
Computation:
Pv1/t1 = Pv2/t2
25 / T = 32 / t2
t2 = 1.28T
New temperature t2 = [1.28T− 273.15]° C
Draw a structural formula for the product formed upon hydroboration/oxidation of the alkene below. CH3CH2CH2CHCH2
Answer:
CH3-CH2-CH2-CH2-CH2-OH. (1-PENTANOL)
Explanation:
The given compound is Pente-1-ne
Hydroboration oxidation reagent - BH3 +H2O2 + OH-
The reaction is initiated by boron hydride which attacks the terminal carbon because the middle carbon + charge will be stabilized by +I effect of the parent carbon chain. This similar process will happen thrice and all the hydrogens of Boron hydride will be lost and carbon chain of Pent-1-ene will be attached to boron and it will form TRIPENTYL BORANE, Then we will add H2O2+ OH- and finally OH- will be attached to the parent carbon chain and
1-PENTANOL will be formed.
CH3-CH2-CH2-CH=CH2 + HBO → CH3-CH2-CH2-CH2-CH2-OH
1-PENTANOL
how is coal usually used
Answer:
Coal is primarily used as fuel to generate electric power in the United States.
Explanation:
write any 5 seasonal plants
Answer:
1. Vinca
2.Zinnia
3.Cornflower
4.Mariglod
4.Geranium
Explanation:
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1. How many moles of water molecules are there in 39 grams of Chlorine?
2. How many molecules are there in 39 grams of Gold?
Answer:
1. There is no moles of water in 39g of chlorine.
2. 1.19x10²³ molecules of Au.
Explanation:
First, we need to remember that molar mass of a compound represents the mass of 1 mole (6.022x10²³ molecules) of molecules.
Molar mass of Chlorine, Cl₂ is 70.9g/mol
Molar mass of gold, Au, is 197g/mol
1. Moles of 39g of Cl₂ are:
39g Cl₂ * (1mol / 70.9g) = 0.55 moles moles of chlorine
But there is no moles of water in 39g of chlorine.
2. First, moles of Au are:
39g Au * (1mol / 197g) = 0.198 moles Au.
Molecules are:
0.198 moles Au * (6.022x10²³ molecules / 1 mol) =
1.19x10²³ molecules of Auwhat is the molarity of a HCI solution if 25.0 ml of 0.185 M Main is required to neutralize 0.0200 L of HCI?
Answer:
Molarity of HCl solution = 0.25 M
Explanation:
Given data:
Volume of NaOH= V₁ = 25.0 mL (25/1000 = 0.025 L)
Molarity of NaOH solution=M₁ = 0.185 M
Volume of HCl solution = V₂ = 0.0200 L
Molarity of HCl solution = M₂= ?
Solution:
M₁V₁ = M₂V₂
0.185 M ×0.025 L = M₂ × 0.0200 L
M₂ = 0.185 M ×0.025 L / 0.0200 L
M₂ = 0.005M.L /0.0200 L
M₂ = 0.25 M
The thermodynamic information for the following reaction is as follows:
HNO3 (g) + H2 (g) → NH3 (g) + H2O (g) △H = −637 kJ
1) Balance the chemical reaction.
2) Identify this reaction as endothermic or exothermic.
3) Calculate how much heat is released when 7.20 g of H2 reacts in this situation.
1. HNO₃ (g) + 4H₂ (g) ⇒ NH₃ (g) + 3H₂O (g)
2. Exothermic.
3. 2293.2 kJ
Further explanationReaction
HNO₃ (g) + H₂ (g) ⇒ NH₃ (g) + H₂O (g) △H = −637 kJ
1. Balance
give coefficient :
HNO₃ (g) + aH₂ (g) ⇒ bNH₃ (g) + cH₂O (g)
H, left=1+2a, right=3b+2c⇒1+2a=3b+2c(eq 1)
N,left=1, right=b⇒b=1
O,left=3, right=c⇒c=3
eq 1 : 1+2a=3.1+2.3⇒1+2a=9⇒2a=8⇒a=4
Balance reaction :
HNO₃ (g) + 4H₂ (g) ⇒ NH₃ (g) + 3H₂O (g)
2. exothermic⇒release heat(negative sign)
3. heat released :
mol H₂ :
[tex]\tt mol~H_2=\dfrac{7.2}{2}=3.6[/tex]
heat released :
[tex]\tt -637\times 3.6=-2293.2~kJ[/tex]
When is expressing numbers using scientific notation useful?
A. When the numbers are very large or very small
B. When the numbers are referring to moles
C. When the numbers are only rough estimates
O D. When the numbers come from scientific data
Answer:
when the numbers are very large or very small
Explanation:
good luck
How many moles of H20 are required to react completely with 7.30 moles of NO2?
3NO2(g) + H200 +
NO(g) + 2HNO3(aq) A
1.86 mol
2.19 mol
2.43 mol
O 6.12 mol
O 7.30 mol
Answer:
2.43 moles of water are require.
Explanation:
Number of moles of water required = ?
Number of moles of NO₂ available = 7.30 mol
Solution:
Chemical equation:
3NO₂ + H₂O → NO + 2HNO₃
now we will compare the moles of NO₂ with H₂O.
NO₂ : H₂O
3 : 1
7.30 : 1/3×7.30 = 2.43 mol
. A 20.0 % by mass solution of phosphoric acid (H3PO4) in water has a density of 1.114 g/mL at 20°C. What is the molarity of this solution?
The molar mass of phosphoric acid (H3PO4) is 97.99 g.
Answer:
2.273M
Explanation:
What is the definition of molarity.
M = mols/L. So that's what we need to determine.
How much does a L weigh? That's
1.114 g/mL x 1000 mL = 1114 grams. Simple enough, eh?
How much of that 1114 g is H3PO4. It says it is 20% by mass, therefore, 1114 g x 0.20 = 222.8 g.
How many mols are there in 222.8 g H3PO4? That's mools = grams/molar mass = 222.8/98 = 2.273 mols.
The definition of M is what? M = mols/L. And you have 2.273 mol/L; that must be the molarity.
The formula is
density g/mL x 1000 mL x mass% x (1/molar mass) = M
1.114 x 1000 x 0.20 x (1/98) = 2.273 M.
Balance each of the following chemical equations.
A) Mg(s)+Br2(l)→MgBr2(s)
Express your answer as a chemical equation. Identify all of the phases in your answer.
B) P4(s)+O2(g)→P4O10(s)
Express your answer as a chemical equation. Identify all of the phases in your answer.
C) Ba(OH)2(aq)+HNO3(aq)→Ba(NO3)2(aq)+H2O(l)
Express your answer as a chemical equation. Identify all of the phases in your answer.
D) Cr2O3(s)+C(s)→Cr(s)+CO(g)
Express your answer as a chemical equation. Identify all of the phases in your answer.
Answer:
Explanation:
The question states that the chemical equations should be balanced and the phases should also be indicated. The abbreviations of the phases have been indicated in the question with
i) (s) meaning the compound is in solid
ii) (aq) meaning the compound is in aqueous form
iii) (l) meaning the compound is in liquid
iv) (g) meaning the compound is in gaseous form
Balanced chemical equation is that in which the number of individual atoms on the reactant side is equivalent to the number of the same individual atoms on the product side.
Only the answer (the balanced chemical equations) will be written below.
A) This reaction is balanced
Mg(s) + Br₂(l) ⇒ MgBr₂(s)
B) P₄(s) + 5O₂(g) ⇒ P₄O₁₀ (s)
C) Ba(OH)₂(aq) + 2HNO₃(aq) ⇒ Ba(NO₃)₂(aq) + 2H₂O
D) Cr₂O₃(s) + 3C(s) ⇒ 2Cr(s) + 3CO(g)
What impact would adding twice as much Na2 CO3 than required for stoichiometric quantities have on the quantity of product produced
Answer:
There will be no observed impact of adding twice as much Na2CO3 on the product
Explanation:
Stoichiometry gives the relationship between reactants and products in terms of mass, mole and volume.
If we consider the stoichiometry of the reaction, we will discover that the reaction occurs in a 1:1 ratio. This implies that use of twice the amount of Na2CO3 will only lead to an excess of Na2CO3 making the other reactant the limiting reactant. Once the other reactant is used up, the reaction quenches.
Hence, use of twice as much Na2CO3 has no impact on the quantity of product produced.
Suppose you had four spoons the same size and shape made out of glass, plastic, steel, and wood. Which spoon handle would get hot the quickest when the spoons are placed in a pan of hot water?
Question 14 options:
A. steel spoon
B. plastic spoon
C. wood spoon
D. glass spoon
Answer:
A. steel spoon
Explanation:
A steel spoon will get hot the quickest from the different given spoon. This is because steel is predominantly made up of a metal which shows metallic properties such as heat conduction.
Metals have low specific heat capacity which is the amount of head needed to raise 1g of a substance by 1°C. By so doing, metals will conduct heat at a very fast rate. The delocalized electron around the central nucleus plays very important role.Other properties originating from metallic bonds are ductility, malleability, luster etc.
What may happen to the human body when exposed to an infectious agent?
A. When infectious agents get into the human body, your body responds by functioning normally.
B. When infectious agents get into the human body, the body gets a surge of energy, causing a slight increase in body temperature, and you feel great.
C. When infectious agents get into the human body, your body responds by raising the core body temperature, causing a fever.
D.Nothing happens when the human body is exposed to an infectious agent.
Answer:
when infectious agents get into the human body your body responds by raising the core body temperature causing a fever
The answer is C it will raise your body temp and cause a fever
how many moles of water are needed to react with 100. g of al4c3
Answer:
8.4 moles
Explanation:
Al4C3 + 12 H2O ---> 4 Al(OH)3 + 3 CH4
100g of Al4C3 = 100/144 = 0.7 moles
from the reaction above,
1 mole of Al4C3 = 12 moles of water
0.7 moles of Al4C3 = x moles of water
x = 12×0.7/1 = 8.4 moles
Therefore 8.4 moles of water is needed to react with 100. g of al4c3
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The moles of water are needed to react with 100. g of al4c3 - 8.34 moles.
The reaction can be expressed as -
Al₄C₃ + 12 H₂O → 4 Al(OH)₃ + 3 CH₄
By the equation, it can be said that 1 equivalent of Al₄C₃ reacts with the equivalent of 12 H₂O to generate 4 Al(OH)₃ and 3 CH₄.
the given mass of Al₄C₃ = 100 gthe molar mass of Al₄C₃ = 143.959the molar mass of H₂O = 18.015the moles = mass + molar mass
then for moles of Al₄C₃ = 100 + 143.959
= 0.6946 moles.
or, 216/143.959
for 100 gram = 21600/143.959
= 150. 0416
moles of H₂O required = [tex]\frac{12\ mole\ of H_{2} O}{1\ mole\ of\ Al_{4} C_{3}}[/tex]
= 150.0416/18
= 8.43 moles.
Thus, the moles of water are needed to react with 100. g of al4c3 - 8.34 moles.
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Question 1 (Worth 3 points)
(02.04 MC)
The diagram shows four different locations in an atom.
A shaded circle is shown, labeled nucleus. Two small points labeled two and three are shown inside this shaded circle. A lighter shaded concentric circle is shown with a radius more than double the radius of the inner circle. A point labeled one is shown inside a section of this circle which does not overlap with the inner circle. A flower petal like shaded region is shown above and below these circles. A point labeled four is shown inside the lower petal.
Which locations are likely to have subatomic particles with the least mass?
1 and 2
2 and 3
1 and 4
3 and 4
Answer:
answer C) 1 and 4
Explanation:
Answer:
C) 1 and 4
Explanation:
I took the test. Hope this helps!
A peak elutes from an HPLC column 17.7 cm in length in 11.1 min. What would be the width at half‑height of the peak (in seconds) if the plate height were 8.68 μm?
Answer:
10.98 s
Explanation:
To solve this problem we first use the formula:
H = L/NWhere:
H = Plate height (8.68 μm, or 8.68x10⁻⁶m)L = Column length (17.7 cm, or 0.177 m)N = Number of theoretical plates (unknown)And solve for N:
N = 0.177 m / 8.68x10⁻⁶mN = 20392 platesThen we use the formula:
N = 5.54*[tex](\frac{t_r}{W_{0.5}})^2[/tex]Where:
N is the number of theoretical plates previously calculated. tr is the retention time (11.1 min, or 666s)W₀.₅ Is the width at half-height (unknown)And solve for W₀.₅:
W₀.₅ = 10.98 sWhich is an example of a beneficial mutation?
one that changes the color of a rabbit, allowing it to hide from predators.
one that results in lighter flower petal colors without changing the plant’s ability to reproduce
one that causes a person’s body to produce thick mucus that clogs the lungs
one that makes it easier for a corn plant to contract a disease
Answer:
A
Explanation:
Answer: a
Explanation: one that changes the color of a rabbit, allowing it to hide from predators.
Fill in the best answer for each of the following:
An ionic bond forms when atoms ______ electrons.
Another name for an ionic compound is a _____.
Instead of forming molecules, ionic compounds form ____.
Crystals are 3 dimensional arrays of positive and negative ions in a _____ pattern.
The formula for an ionic compound is called a(n) _____ formula.
The formula for an ionic compound always indicates the _____ whole number ratio of positive to negative ions within the crystal.
Ionic compounds do not conduct electricity in the _____ state, but do conduct electricity in the and states.
The ______ state means that the compound is dissolved in water.
Answer:
donate? *transfer* (gain/lose, not share)
crystal
crystals (lattices)/ formula units
repeating (alternating) pattern (of +/- charges, like NaCl)
empirical
smallest
solid (...bc of strong bonds)
aqueous
Explanation:
An ionic bond forms when atoms transfer electrons.
Another name for an ionic compound is a crystal.
Instead of forming molecules, ionic compounds form.
Crystals are 3-dimensional arrays of positive and negative ions in a repeating pattern.
The formula for an ionic compound is called an empirical formula.
The formula for an ionic compound always indicates the smallest whole number ratio of positive to negative ions within the crystal.
Ionic compounds do not conduct electricity in the solid-state but do conduct electricity in the and states.
The aqueous state means that the compound is dissolved in water
An ionic bond is a bond that's formed when there's an electrostatic attraction between the oppositely charged ions. In this case, ionic bond forms when atoms transfer electrons.
It should also be noted that another name for an ionic compound is a crystal. Instead of forming molecules, ionic compounds form crystals.
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You have a solution that is 18.5% (v/v) methyl alcohol. If the bottle contains 1.64 L of solution, what is the volume (V) in milliliters of methyl alcohol
Answer:
303.4 millimeters
Explanation:
Just multiply 1.64 by 0.185. then convert that answer to millimeters
An aqueous solution is made by dissolving 26.4 grams of barium sulfide in 349 grams of water.
The molality of barium sulfide in the solution is ______
m.
Answer:
Molality = 0.43 m
Explanation:
Given data:
Mass of barium sulfide = 25.4 g
Mass of water = 349 g (349 g/1000 = 0.349 Kg)
Molality of water = ?
Solution:
Number of moles of barium sulfide:
Number of moles = mass/molar mass
Number of moles = 25.4 g/169.39 g/mol
Number of moles = 0.15 mol
Molality:
Molality = number of moles o f solute/ Kg of solvent
Molality = 0.15 mol / 0.349 Kg
Molality = 0.43 m
2. As elements go down a group, they have a whole
additional energy level of electrons more than the
element above them in the periodic table. Does atomic
size increase or decrease down a group?
Answer:
Increases
Explanation:
Atomic size is the amount of space between the nucleus of an atom and the outermost electron. So, as each additional energy level is added, the overall amount of space between the nucleus and the outermost electron increases because there is now an extra shell of electrons that is farther out.
10g of Compound X with molecular formula are burned in a constant-pressure calorimeter containing 45g of water at 25. The temperature of the water is observed to rise by 2.432. (You may assume all the heat released by the reaction is absorbed by the water, and none by the calorimeter itself.) Calculate the standard heat of formation of Compound at .
Complete Question
10 g of Compound X with molecular formula [tex]C_4 H_8[/tex] are burned in a constant-pressure calorimeter containing 45g of water at [tex]25^oC[/tex]. The temperature of the water is observed to rise by 2.432. (You may assume all the heat released by the reaction is absorbed by the water, and none by the calorimeter itself.) Calculate the standard heat of formation of Compound at [tex]25^oC[/tex]
Answer:
The value is [tex]\Delta H^o_f =-2571 \ J /mol[/tex]
Explanation:
From the question we are told that
The mass of compound X is [tex]m = 10 \ g = 0.010 \ kg[/tex]
The mass of water is [tex]m_w = 45 \ g = 0.045 \ kg[/tex]
The temperature of water is [tex]T_w = 25^oC[/tex]
The change in the temperature of water is [tex]\Delta T = 2.432 ^oC[/tex]
Generally the heat adsorbed by water is mathematically represented as
[tex]Q_{w } = c * m _w * \Delta T[/tex]
Here c is the specific heat of water with value [tex]c = 4186 \ J/kg\cdot ^oC[/tex]
[tex]Q_{w } = 4186 * 0.045 * 2.432[/tex]
=> [tex]Q_{w } = 458.1 \ J[/tex]
Given that the total heat that was generated by the reaction is absorbed by water then
[tex]\Delta H _{rxn} = -Q_w[/tex]
The negative sign shows that the heat was absorbed
[tex]\Delta H _{rxn} = -458.1 \ J[/tex]
Generally the number of moles of the compound X available is mathematically represented as
[tex]n = \frac{m}{Z}[/tex]
Here Z is the molar mass of compound X the value is [tex]Z = 56.11 \ g/mol[/tex]
[tex]n = \frac{m}{Z}[/tex]
=> [tex]n = \frac{10}{56.11}[/tex]
=> [tex]n = 0.1782 \ mols[/tex]
Generally the standard heat of formation of Compound X is mathematically represented as
[tex]\Delta H^o_f = \frac{\Delta H_{rxn} }{ n}[/tex]
=> [tex]\Delta H^o_f = \frac{-458.1 }{ 0.1782}[/tex]
=> [tex]\Delta H^o_f = \frac{-458.1 }{ 0.1782}[/tex]
=> [tex]\Delta H^o_f =-2571 \ J /mol[/tex]
please help me
four facts..please
Determine how many moles of O2 are required to react completely with 4.6 mol of C4H10
Answer:
29.9 moles
2C²H¹⁰ needs 13 moles of O²
4.6 C⁴H¹⁰ needs X moles of O²
X= 13× 4.6 ÷ 2 = 59.8 ÷ 2 = 29.9 moles
29.9 moles of O2 are required to react completely with 4.6 mol of C4H10.
2C²H¹⁰ needs 13 moles of O²
4.6 C⁴H¹⁰ needs x moles of O²
x= 13× 4.6 ÷ 2
= 59.8 ÷ 2
= 29.9 moles
What is a mole?A mole is described as the quantity of a substance that contains exactly 6.02214076 X1023 primary entities of the given substance. as a result, a mole of a substance is referred to as the mass of a substance containing the equal wide variety of essential gadgets as atoms in exactly 12.000 g of 12C.
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a 500 ml aqueous solution of na3po4 was prepared using 82g of the solute. what is the molarity
Answer:
1 M
Explanation:
The molarity of a solution, M, is a measure of the concentration of that solution and it refers to the number of moles of solute (mol) per liter (L) of solution. The molarity (M) can be calculated using the formula:
M = number of moles (n) /volume (V)
In this question, a 500 ml aqueous solution of Na3PO4 was prepared using 82g of the solute.
Molar mass of Na3PO4 = 23(3) + 15 + 16(4)
= 69 + 31 + 64
= 164g/mol
Mole = mass/molar mass
mole = 82/164
mole = 0.5 mol
Volume in Litres (L) = 500 ml ÷ 1000 = 0.500L
Therefore, Molarity (M) = 0.5/0.500
Molarity = 1 M or 1 mol/L
The molarity of the solution is 1 M
From the question,
We are to determine the molarity of the solution.
First, we will determine the number of moles of the solute (Na₃PO₄) present
Mass of Na₃PO₄ = 82 g
Using the formula
[tex]Number\ of\ moles = \frac{Mass }{Molar\ mass}[/tex]
Molar mass of Na₃PO₄ = 163.94 g/mol
∴ Number of moles of Na₃PO₄ present = [tex]\frac{82}{163.94}[/tex]
Number of moles of Na₃PO₄ present = 0.500 moles
Now, for the molarity of the solution
Using the formula
[tex]Molarity = \frac{Number\ of\ moles}{Volume}[/tex]
Volume of the solution = 500 mL = 0.5 L
∴ Molarity of the solution = [tex]\frac{0.500}{0.5}[/tex]
Molarity of the solution = 1 M
Hence, the molarity of the solution is 1 M
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2. What would charge would you expect a magnesium atom to form?
O 2+
017
2
Answer:
-2
Explanation:
Magnesium usually has a negative charge.
Answer:
+2
Explanation:
Magnesium has the following electron configuration: 1s^2 2s^2 2p^6 3s^2 or [Ne] 3s2.
You can see that Magnesium contains two electrons in its outermost orbit. It loses these 2 electrons during the chemical reaction and transitions to the closest stable noble gas form. It also generates the Mg2+ ion as it loses two electrons. It has an ionic charge of 2+ as a result.
I hope you now fully comprehend why magnesium has a 2+ charge.
Which is not one of the parts of the cell theory.
All living things are made of cells.
The smallest living things are single cells, and cells are the functional units of multi-cellular organisms.
All cells come from other cells.
Cells appear from nonliving objects
Answer:
Pretty sure the answer is d) cells come from nonliving objects
Explanation:
i just think i remember xd
Which of the following substances would you expect to have a low melting point?
A. carbon dioxide
B. silicon dioxide
C. lithium chloride
D. calcium bromide
Ionic compounds have higher melting point than covalent compounds.
Carbon dioxide have lower melting point (-56.6 °C) among the given compounds.
What is melting point?Melting point is the temperature at which the substance melts into liquid thus at this temperature its solid state and liquid state are in equilibrium. Melting point is depend upon the bond type and mass of the compound.
Ionic bonds are stronger than covalent bonds and hence ionic compounds have higher melting point than covalent compounds. Hence, lithium chloride and calcium bromide have higher melting point.
Silicon is bigger than carbon thus silicon dioxide melts at higher temperature. Carbon dioxide is purely covalent and melts at negative temperatures.
Hence, the compound with lower melting point here is carbon dioxide thus, option A is correct.
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