Answer:
40 kcal
Explanation:
Heat required to melt
1 g
of ice at
0°C
is approximately
80 cal
. This is also called latent heat of fusion of ice.
For
500 g
of ice
Q
=
500
g
×
80
cal
g
=
40000 cal = 40 kcal
Suppose that a 10-mL sample of a solution is to be tested for I− ion by addition of 1 drop (0.2 mL) of 0.13 M Pb(NO3)2.
What is the minimum number of grams of I− that must be present in order for PbI2(s) ( Ksp=8.49×10−9 ) to form?
The minimum number of grams of I that must be present is ; 0.01836 * 10⁻³ mol
Given data :
Volume of solution to be tested for I-ion = 10 mL
Volume of Pb(NO₃)₂ = 0.2 mL
molarity of Pb(NO₃)₂ = 0.13 M
Determine the number of I that must be presentFirst step : calculate conc of PB²⁺ ions in the solution
conc of PB²⁺ ions = ( molarity of Pb(NO₃)₂ * volume of Pb(NO₃)₂ ) / ( total volume )
= ( 0.13 * 0.2 ) / ( 10 + 0.2 )
= ( 0.026 ) / ( 10.2 ) = 0.002549 M
Next step : determine the molarity of I
using the dissociation reaction of PbI₂
PbI₂(s) ---> Pb²⁺ (aq) + 2I (aq)
also; Ksp = [ Pb²⁺ ] [ I ]² ---- ( 1 )
From the question the given value of Ksp = 8.49 * 10⁻⁹
Therefore equation ( 1 ) becomes
8.49 * 10⁻⁹ = ( 0.002549 ) * [ I ]²
[ I ] = √ ( 8.49 * 10⁻⁹ ) / ( 0.002549 )
= 0.0018 M
Final step : Determine the minimum number of grams of I
moles of I = molarity of I * total volume
= 0.0018 M * 10.2 mL
= 0.01836 * 10⁻³ mol
Hence we can conclude that The minimum number of grams of I that must be present is ; 0.01836 * 10⁻³ mol
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Chromium reacts with bromine to produce chromium(iii) bromide
The balanced chemical equation for the reaction between chromium and bromine to produce chromium(III) bromide is:
2 Cr + 3 Br2 → 2 CrBr3
This equation shows that two chromium atoms react with three molecules of bromine to form two molecules of chromium(III) bromide.
What is a redox reaction?A redox reaction is a type of chemical reaction that involves the transfer of electrons between reactants. The term "redox" comes from the combination of two processes during the reaction: reduction, which involves the gain of electrons by a reactant, and oxidation, which involves the loss of electrons by a reactant.
Why is the above reaction an example of a redox reaction?The reaction is an example of a redox reaction, where reduction and oxidation occur simultaneously. Chromium is oxidized, while bromine is reduced. The reaction also shows the importance of balancing the number of atoms on both sides of the equation to ensure that the law of conservation of mass is satisfied.
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• Calculate the entropy change when 1.00 mol of
water at 0°C freezes to form ice. (AHfus for water
is +6.02 kJmoll)
1
Answer:
the enthalpy change of this is 5.02mol
Answer this question lol
Which of the following molecules contains a covalent bond?
Answer:
m
Explanation:
Answer:
CN is your answer.
Explanation:
Hope this helps!!!
the square below has anarea of 49ft2 what is the perimeter of the square
Answer:
28ft
Explanation:
if it's a square then each side is equal
the square root of 49 is 7
each side is 7 ft
7 ft times 4 sides is 28ft
If a Hh mom has an offspring with a hh dad, what is the probability that the offspring will have a dominant phenotype?
Question 2 options:
20%
10%
50%
40%
Answer:
I think 50%
Explanation:
im not really sure
Calculate the pOH for a solution with a hydroxide ion, (OH-) of concentration of 6.49 X 10-11 M.
Calculate the pH.
Note: the answers should have three significant figures
The pOH is: Blank 1
The pH is: Blank 2
Answer:
Calculate the pOH for a solution with a hydroxide ion, (OH-) of concentration of 6.49 X 10-11 M.
Calculate the pH.
Note: the answers should have three significant figures
The pOH is: Blank 1
The pH is: Blank 2
Explanation:
If a metal reacts violently with water, in which group is it likely to be found?
Answer:
Alkali metals (Li, Na, K, Rb, Cs, and Fr)
Explanation:
Answer:
Group 1
Explanation:
Alkali metals such as (Lithium, Sodium, Rubidium, Francium, Cesium, etc.) react violently with waterThey are termed "alkali" due to their nature of forming hydroxides on reacting with waterIn the following acid-base reaction,
HPO42- is the
H2PO4- (aq) + NH3(aq) → HPO42- (aq) + NH4+(aq)
А
B
С
acid
conjugate
acid
conjugate
base
Taking into account the Brønsted-Lowry acid-base theory, HPO₄⁻² is conjugate base of H₂PO₄⁻.
Brønsted-Lowry acid-base theoryThe Brønsted-Lowry acid-base theory (or the Brønsted-Lowry theory) identifies acids and bases based on whether the species accepts or donates protons or H⁺.
According to this theory, acids are proton donors while bases are proton acceptors.
So, reactions between acids and bases are H⁺ proton transfer reactions, causing the acid to form its conjugate base and the base to form its conjugated acid by exchanging a proton.
In other words, a conjugate base is an ion or molecule resulting from the acid that loses the proton, while a conjugate acid is an ion or molecule resulting from the base that gains the proton:
acid + base ⇄ conjugate base + conjugate acid
This caseIn this case, you know:
H₂PO₄⁻ + NH₃ → HPO₄⁻² + NH₄⁺
H₂PO₄⁻ behaves like acid because donates an H⁺ proton while NH₃ behaves like base because accepts an H⁺ proton from the acid.
So, NH₄⁺ is the conjugate acid of the NH₃ and HPO₄⁻² is conjugate base of H₂PO₄⁻.
In summary, HPO₄⁻² is conjugate base of H₂PO₄⁻.
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Which property of water makes it effective in protecting firefighters?
Answer:
water has a high specific heat
Explanation:
this should work as an answer
The weak ionization constant (Ka)
for H2CO3 is equal to:
A
B
(H2CO3]
[H+] [HCO3-)
[H+][HCO3-)
[H2CO3]
Carbonic acid is a weak acid. Its weak ionization constant (Ka) is equal to:
Ka = [H⁺] [HCO₃⁻] / [H₂CO₃]
What is a weak acid?A weak acid is an acid that dissociates partially in the water.
The equation for the acid dissociation of carbonic acid is:
H₂CO₃ ⇄ H⁺ + HCO₃⁻
The weak ionization constant (Ka) is the equilibrium constant for this reaction, that is, the product of the concentration of the products divided by the product of the concentrations of the reactants, all of them raised to their stoichiometric coefficients.
Ka = [H⁺] [HCO₃⁻] / [H₂CO₃]
Carbonic acid is a weak acid. Its weak ionization constant (Ka) is equal to:
Ka = [H⁺] [HCO₃⁻] / [H₂CO₃]
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PLS HELP FAST!! 50 POINTS AND BRAINLEYIST FOR WHOEVER ANSWERS THIS FASTEST.
In one to two sentences, describe the characteristics of a high-pressure system.
In one to two sentences, explain what biome comprises most of Antarctica and why the continent is described as being part of this biome.
ALSO, IF YOU COPY, PLEASE REWORD SENTENCES.
A high pressure system has higher pressure at its center than the areas around it
Scientists that work in Antarctica mostly refer to the majority of the continent as being a cold desert
Explanation:
Help please!
__________ is caused by a bacteria that can be transmitted by a flea bite, contact with an infected person, or via airborne droplets. Symptoms are lymph glands that are swollen and painful ("buboes", red spots that turn black)
A ) Tuberculosis
B ) Syphilis
C ) Botulism
D ) Bubonic Plague
Answer:
Bubonic plague is the correct answer!!!
Explanation:
mark me brainliest
Answer:
The answer is Bubonic Plague
what is safe storage of produced materials
Answer:
Stacking bags and bundles.
Explanation:
Interlock them in rows to ensure they're secure.
Answer:
Material Storage Facilities means an uncovered area used on a permanent basis for outside
Explanation:
Material Storage Facilities means an uncovered area where bulk materials (liquid, solid, granular, etc.) are stored in piles, barrels, tanks, bins, crates, or other means.
Additional Benchmarks for Federal, State, or Municipal Facilities with Incidental Solid De-Icing Material Storage Facilities monitoring under the requirements of subparagraph (D)(ii) above shall not be subject to Benchmark requirements for Chloride or Cyanide.
Directors are fully briefed on all business related matters, risk assessment and new initiatives proposed by the Company.
How many kJ of heat do you need to raise the temperature of 200 g of Aluminum from 80 °C to 100 °C?
Remember to convert your answer to kJ. Round your answer to two decimal places.
Answer:
0.01
Explanation:
100 -80=20
200/20=10/1000=0.01kj
energy contained in the
and
15. The energy transformation in a flashlight is from
battery to
energy in the circuit, to
energy released by the light bulb.
Answer:
yes of course is true the
What is the mass in grams of 5.2 x 1028 atoms of manganese (Mn)?
The mass, in grams, of 5.2 x 10^28 atoms of manganese would be 0.0006833 grams
Mass calculationAccording to Avogadro, 1 mole of any substance contains 6.022 x [tex]10^{23}[/tex] atoms.
Thus, how many moles would be in 5.2 x [tex]10^{28}[/tex]atoms of Mn:
= 6.022 x [tex]10^{23}[/tex] /1 x 5.2 x [tex]10^{28}[/tex]
= 0.00001158 moles
Mass of 0.00001158 moles Mn = 0.00001158 x 54.9
= 0.0006833 grams
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What is The fmu (grams/mole) for disulfur hexachloride *the formula for it is S2Cl6*
Hexasulfur Dichloride
Name: Hexasulfur Dichloride
Formula: S2Cl6
Molar Mass:276.848
Example Reactions:
• S2Cl6 + 4H2O = 2SO2 + 6HCl + H2
How many grams of Na2S will be produced if you react 35.0g sodium
Suggest some ways in which you might determine whether a particular water solution contains an acid or a base.
The use of the pH scale and litmus paper are the ways which can determine whether the solution is an acid or base.
How pH scale and litmus paper tell about acidic and basic solution?The pH scale is the way which determine the acidic or basic nature of a solution. If the pH of a solution is less than 7, it is considered as acidic. If the pH is 7, the solution is neutral and if the pH is greater than 7,the solution is basic.
While on the other hand, litmus paper also tells us about acidic and basic nature of solution. if the litmus paper turns red, it means the solution is acidic whereas if the litmus paper turns blue it means basic.
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To what temperature must a sample of helium gas be cooled from 139ºC to reduce its volume from 3.1 L to 0.71 L at constant pressure?
Answer:
To what temperature must a sample of helium gas be cooled from 22.2 degrees C to reduce its volume from 1.00L to 100cm3 ?
Explanation:
How many moles of sodium hydrogen carbonate are present in 2.61 grams of this compound?
Molar mass of NaHCO_3
23+1+12+3(16)36+4884g/molNow
[tex]\\ \sf\longrightarrow No\:of\:moles=\dfrac{Given\:mass}{Molar\:mass}[/tex]
[tex]\\ \sf\longrightarrow No\:of\; moles=\dfrac{2.61}{84}[/tex]
[tex]\\ \sf\longrightarrow No\:of\:moles=0.0312mol[/tex]
A person is going for a walk in the evening. To make sure that she can be seen walking when it gets dark, she wears a glow stick around her neck. The glow stick can be used as a light source when she bends the stick. Although the stick is sealed, bending the stick allows two chemicals to come in contact and react with each other. During the chemical reaction, light is given off by the glow stick.
When the reaction stops, light is no longer given off. What happens to the mass of the glow stick after the chemical reaction occurs? Explain citing evidence from the prompt and identify the scientific law that supports your explanation.
(give me claim,evidence,reasoning)
From the law of conservation of mass, the mass of the glow stick does not change after the reaction.
Law of conservation of massFrom the law of conservation of mass we know that mass can neither be created nor destroyed but is converted from one form to another. Since the mass of the system must remain unchanged, It then follows that the mass of the glow stick must remian the same.
Therefore, the mass of the glow stick does not change after the reaction following the law of conservation of mass.
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How many moles of carbon are present in 1.50mole of aspirin , C_{9}*H_{8} * O_{4}
Given the molecular formula of aspirin, C₉H₈O₄, in 1.50 moles of aspirin there are 13.5 moles of carbon.
What is a mole?The mole is the SI base unit for the amount of matter. 1 mole of particles contains a number of Avogadro's particles.
We have 1.50 moles of aspirin, C₉H₈O₄. According to the molecular formula, the molar ratio of C₉H₈O₄ to C is 1:9.
1.50 mol C₉H₈O₄ × (9 mol C/1 mol C₉H₈O₄) = 13.5 mol C
Given the molecular formula of aspirin, C₉H₈O₄, in 1.50 moles of aspirin there are 13.5 moles of carbon.
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As soon as the rope breaks in picture 4, the car continues to roll forward on its own. This motion is BEST explained by which of the following laws? A. AN object in constant motion tends to remain in motion unless acted on by and unbalanced force. B. For every action there is an equal and opposite reaction/ C. An unbalanced force acting on an object will cause the object to accelerate. D. The force of gravity will cause an object to accelerate toward the earth at a constant rate.
Answer:
what is picture 4 you need to show it
Calculate the normal concentration of a solution containing 20.8 g in 400 ml.
Answer:
52 g/L
Explanation:
First, 400 mL / 1000 = 0.4 L
20.8 g / 0.4 L = 52 g /L
What is radioactive dating in chemistry?
PLEASE HELP!!!
Describe how distillation process makes water soft
Answer:
Distillation can be used to separate and collect a liquid from a solution. Distillation can also be used to soften water as the water evaporates as it is heated and the ions are left behind. Hard water can be softened by adding sodium carbonate (washing soda) or by passing the water through an ion-exchange column.
Explanation:
14. Calculate the mass in grams of oxygen required to react completly with 0.75 moles of Aluminum.
4Al + 302 → 2Al2O3
a. 32 g of Oxygen
b. 18 g of Oxygen
c. 16 g of Oxygen
d. 9.0 g of Oxygen
Moles of O_2:-
0.75(0.75)0.5625molMass of O_2:-
moles(Molar mass)0.5625(32)18gOption B
As per the given balanced reaction, 0.75 moles of aluminum metal requires 0.56 moles of oxygen gas for completely reaction. One mole of oxygen gas is 32 g. Then, mass of 0.56 moles is 18 g.
What is aluminum oxide ?Metals and metal like elements such as aluminum Al are more reactive towards atmospheric oxygen and forms their oxide layers in the metallic surface.
Al₂O₃ is an essential mineral of aluminum formed by the reaction with oxygen as given in the balanced chemical equation. As per this equation, 4 moles of Al requires 3 moles of oxygen for complete reaction.
The number of moles of oxygen required by 0.75 moles of Al is:
(0.75 × 3) /4 = 0.56 moles.
one mole of oxygen weighs 32 g/mol.
mass of 0.56 moles of O₂ = 32 × 0.56 = 18 g.
Therefore, the mass required by 0.75 moles of Al in the reaction is 18 g.
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