Answer: Thus [tex]\Delta H[/tex] for the conversion of gray tin to white tin is -20.9 kJ
Explanation:
According to Hess’s law of constant heat summation, the heat absorbed or evolved in a given chemical equation is the same whether the process occurs in one step or several steps.
According to this law, enthalpy change of the overall reaction is the sum of the enthalpy changes of the intermediate reactions.
The final reaction is
[tex]Sn(s, gray)\rightarrow Sn(s, white)[/tex] [tex]\Delta H=?[/tex]
The intermediate balanced chemical reaction will be,
[tex]Sn(s, gray)+O_2(g)\rightarrow SnO_2(g)[/tex] [tex]\Delta H^0=-582.78kJ[/tex] (1)
[tex]Sn(s, white)+O_2(g)\rightarrow SnO_2(g)[/tex] [tex]\Delta H^0=-580.69kJ[/tex] (2)
substarcting (2) form (1) we get
[tex]\Delta H=\Delta H_1-\Delta H_2[/tex]
[tex]\Delta H=-582.78-(-580.69kJ)[/tex]
[tex]\Delta H=-20.9kJ[/tex]
What kind of reaction has the general form A+B → AB?
O A. Combination
OB. Decomposition
O C. Combustion
O D. Displacement
Pls help ASAP
Answer: combination (it is synonymous with synthesis)
Which of the following describes an atom that is neutral?
15 protons, 14 neutrons, and 14 electrons
15 protons, 14 neutrons, and 15 electrons
15 protons, 15 neutrons, and 14 electrons
15 protons, 14 neutrons, and 16 electrons
Answer:
the answer is the third or fourth one
Can anyone solve the little chart at the bottom?
How can the image be described? Check all that apply.
smaller than the object
real
right-side up
larger than the object
upside down
virtual
Answer:
Smaller than the object
Real
Upside down
Explanation:
The image formed by a convex lens will always be real and smaller. The image formed is smaller than the object, real ,upside down and right side up. Hence, options 1,2,3 and 5 are correct.
What is convex lens?Convex lens is a type of lens, in which one at least one side is curved outside. These lenses have the ability to focus an outside light beam to a spot on the opposite side by converging it.
The focal length of the convex lens is the distance from the lens's center to this point, which is known as the focus. On the other hand, a plano-convex lens has one surface that is flat and the other that is convex.
Convex lenses cause light from an item to bend, creating an upright, smaller, and inverted picture of the original object. As a result, the candle in this instance will be smaller, upside down, and actual.
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14) How many molecules are there in 9.34 kg of water?
Answer:
Water has 18 grams per mole so 9 grams is 0.5 moles of water. There are 6.022* 10^23 molecules in a mole. Each water molecule contains one oxygen and two hydrogens.
To measure the amount of nickel in some industrial waste fluid, an analytical chemist adds 0.110 M sodium hydroxide (NaOH) solution to a 25.0 g sample of the fluid and collects the solid nickel(I) hydroxide (Ni (OH2) product. When no more Ni(OH)2 is produced, he filters, washes and weighs it, and finds that 343. mg has been produced The balanced chemical equation for the reaction is: Ni2+(aq) + 2NaOH(aq) Ni(OH)2(s) + 2 Na.
What kind of reaction is this?
a. precipitation
b. acid-base
c. redox
Answer:
a. precipitation
Explanation:
In the reaction:
Ni²⁺(aq) + 2NaOH(aq)→ Ni(OH)₂(s) + 2 Na⁺
Nickel is precipitated as Ni(OH)₂ producing Na⁺ ions.
In a precipitation two soluble ions react with each other to produce an insoluble salt.
In our problem, Ni²⁺ is reacting with OH⁻ to produce Ni(OH)₂, an insoluble salt
The reaction is a precipitation
In an acid-base reaction, an acid reacts with a base to produce water and a salt. In this problem is a base reacting (NaOH) but there are no acids in the reaction.
And in a redox reaction an ion is been oxidized whereas the other is been reduced (Loosing electrons and gaining electrons).
As you can see, Ni²⁺ still with oxidation number of 2+ in Ni(OH)₂ and Na⁺ is always +1-. Thus, this is not a redox reaction.
Examples of nuclear fusion and fission.
Answer: For example, uranium can fission to yield strontium and krypton. Fusion joins atomic nuclei together. The element formed has more neutrons or more protons than that of the starting material. For example, hydrogen and hydrogen can fuse to form helium.
Explanation:
Hope this helped!
Answer:
Explanation:For example, uranium can fission to yield strontium and krypton. Fusion joins atomic nuclei together. The element formed has more neutrons or more protons than that of the starting material. For example, hydrogen and hydrogen can fuse to form helium.
All of these affect weather except!
A. Air pressure
B. Humidity
C. Barometer
D. Wind speed
Answer:
C.Barometer
Explanation:
Which cools faster, magma or lava?
lava
magma
they both cool in seconds
Answer:
lava
Explanation:
QUE CONTIENE EL CROMO QUE SE UTLIZA EN LAS TINTURAS PARA TATUAJES
Answer:
Hexavalent chromium
Explanation:
For the presentation you will research and provide summaries for manned and unmanned explorations of your choice. The presentation should be about twelve slides in length. Your presentation will include:
Title
Introduction – gives an overview of the presentation
Time line of missions – must include 3 manned and 3 unmanned missions
Description of each of the missions in the timeline (1 mission per slide)
Name and date of mission
Purpose of missions
Results or findings from missions
Scientific advance – describe a scientific advancement that has led to an engineering improvement in space exploration
Engineering advance – describe an engineering advance that has led to greater knowledge about the solar system
Sources – list the websites and other sources you used
Remember to make a list (i.e., bullet points) on each slide. The slides should feature the highlights of the main idea. The bullet points should be short phrases (at most, one sentence) that highlight key points.
Answer:
Thank u ?
Explanation:
i don't get your question can you rephrase it pls
Answer:
Look this up on g00gle it will give it right to you! :)
Explanation:
A solution contains 9.25x103 M copper(II) nitrate and 1.40x102 M manganese(II) acetate. Solid potassium carbonate is added slowly to this mixture.
A. What is the formula of the substance that precipitates first?
B. What is the concentration of carbonate ion when this precipitation first begins?
Answer:
Explanation:
Concentration of Cu⁺² = 9.25 x 10³ M
Concentration of Mn⁺² = 1.4 x 10² M
solubility product of copper carbonate = 7.08 x 10⁻⁹
solubility product of manganese carbonate = 2.24 x 10⁻¹¹
solubility product of later is less so carbonate of manganese will come out first .
B )
[ Mn⁺² ] [ CO₃⁻² ] = 2.24 x 10⁻¹¹
1.4 x 10² [ CO₃⁻² ] = 2.24 x 10⁻¹¹
[ CO₃⁻² ] = 1.6 x 10⁻¹³ .
the concentration of carbonate ion when this precipitation first begins
= 1.6 x 10⁻¹³ M .
Describe a chemical property of iron that you observed.
Answer:
Iron can rust in damp conditions. Or, it can dissolve readily in dilute acids.
Explanation:
what is the effect of molecular weight on melting and boiling point of alkanes??
Answer:
Their melting and boiling points of alkanes are relatively low. The higher the molecular weight (the greater the number of carbons), the higher the boiling point.
consider the reaction between acetylene C2H2 and oxygen in a welding torch 2C2H2 + 5O2 = 4CO2 + 2H2O of 5.4 moles of acetylene react with sufficient oxygen how many grams of CO2 should form
Answer:
C. 4.8*10² g.
Explanation:
Which of the following shows correctly an ion pair and the correct formula for the ionic compound the two ions form?
A) Cu1+, O2–; CuO
B) Cr3+, I–; CrI
C) Sn4+, N3–; Sn4N3
D) Fe3+, O2–; Fe2O3
Answer:
D) Fe³⁺, O²⁻; Fe₂O₃
Explanation:
Option D shows correctly an ion pair and the correct formula for the ionic compound the two ions form.
Ion pairs of iron and oxygen react to form iron (III) oxide. The iron (III) oxide is one of the oxides of iron. The compound is usually attacked by acids and it is often called rust. It is used in the feedstock of the steel and iron industries. This means that the compound is used in the production of iron, steel, and many alloys.
Below are some equations:
4 Fe + 3 O₂→ 2 Fe₂O₃
Fe⁰ + 3O₂⁰ → Fe³⁺O₃²⁻
The reaction of HCl with NaOH is represented by the equation
HCl(aq) + NaOH(aq) → NaCl(aq) + H2O(l)
What volume of 0.417 M HCl is required to titrate 11.9 mL of 0.151 M NaOH?
a. 4.3 mL
b. 2.39 mL
c. 0.749 mL
d. 32.8 mL
e. 11.9 mL
Answer:
a. 4.3 mL
Explanation:
Step 1: Write the balanced neutralization reaction
HCl(aq) + NaOH(aq) → NaCl(aq) + H₂O(l)
Step 2: Calculate the reacting moles of NaOH
11.9 mL of 0.151 M NaOH react.
0.0119 L × 0.151 mol/L = 0.00180 mol
Step 3: Calculate the reacting moles of HCl
The molar ratio of HCl to NaOH is 1:1. The reacting moles of HCl are 1/1 × 0.00180 mol = 0.00180 mol.
Step 4: Calculate the volume of 0.417 M HCl that contains 0.00180 moles of HCl
0.00180 mol × (1000 mL/0.417 mol) = 4.3 mL
According to the question,
Mass,
[tex]M_1 = 0.417[/tex][tex]M_2 = 11.9[/tex]Volume,
[tex]V_1 = ?[/tex][tex]V_2 = 0.151[/tex]As we know the relation,
→ [tex]M_1V_1 = M_2 V_2[/tex]
or,
→ [tex]V_1 = \frac{M_2 V_2}{M_1}[/tex]
By substituting the values, we get
[tex]= \frac{11.9\times 0.151}{0.417}[/tex]
[tex]= \frac{1.7969}{0.417}[/tex]
[tex]= 4.3 \ mL[/tex]
Thus the above answer is right.
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please help this makes no sense to me!!
Answer:
potassium nitrate= KNO3 ---> KNO2 + O2 and a gas evolution reaction
Explanation:
i think
A chemist combine did 3.50g of potassium level with chlorine gas to yield 6.6 7g of potassium for it. Assuming all the potassium was consumed, and that potassium chloride was the only product that formed, what mass of chlorine reacted?
Answer: mass of chlorine reacted is 3.18 g
Explanation:
2 K + Cl2 = 2KCl
no. of moles of K = mass / molar mass
= 3.50 / 39
= 0.0897
no. of moles of KCl = mass / molar mass
= 6.67 / 74.5
= 0.0895
no. of moles of Cl2 required = number of moles of KCl / 2
= 0.0895 / 2
= 0.0448 moles
mass of Cl2 required = no. of moles of Cl2 required x molar mass
= 0.0448 x 71
= 3.1808 g ≈ 3.18 g
Therefore mass of chlorine reacted is 3.18 g
An unknown substance visually appears to be a white powder. The substance is analyzed in the laboratory and its melting point is found to be 264 °C.
What can you predict about the intramolecular forces and intermolecular forces in this substance?
Answer:
See explanation
Explanation:
The substance under analysis must be a polar organic substance of high molecular mass. We must remember that as the magnitude of dispersion forces increases with increase in molecular mass, the melting point increases accordingly. Also polar organic substances have very high melting points due to the presence of polar bonds in the molecule..
Hence the intramolecular forces in the substance are covalent bonds while the intermolecular forces are both dispersion forces and dipole forces.
The substance may likely be 1,2,3,4,6,7,8-Heptachlorodibenzo-p-Dioxin which a white powder and melts at 264 °C.
During which step of this procedure does a chemical change occur?
A. 1
B. 2
C. 3
D. 4
Which balance equation represents a single replacement reaction
Answer: A single replacement reaction looks sort of like this
A + BC —> AC + B
Explanation: It would be a LOT more helpful for us if you had provided the answer choices for this question, but I'll try to help by explaining WHAT single-replacement reactions are.
Single-replacement reactions are reactions in which one ion displaces another to form a new compound . One reactant is an element; one reactant is a compound . One product is an element; one product is a compound . The reactant element is part of the compound product .
I hope this helped!
In the reaction 4Al+__O2→2Al2O3, what coefficient should be placed in front of the O2 to balance the reaction?
Question 2 options:
1
2
3
Density of molecules
Please answer this question for meeeeeeeeeee pleeeeeeeeeease!
Which of the following is an example of chemical energy being used?
A. Battery in a flashlight
B. Ice melting
C. Riding a bicycle
D. Mercury rising in a thermometer
WARNING: Sorry I'm only in 5th grade so if you see my level as collage I had to put that because it would not let me put anything else
Answer:battery in a flashlight so A
Explanation:
................ is the organic molecule that is the main energy source for cell processes and is made with the energy released from the breakdown of glucose.
Answer:
ATP
Explanation:
it is made by breaking glucose down
Answer:
Once the last phosphate group is removed from the ATP molecule by hydrolysis, it will form ADP plus inorganic phosphate. ADP is a lower energy molecule. The release of energy during hydrolysis of ATP can be harnessed by the cell to do work. Living things continuously use ATP but it is renewable and can be recycled.
Explanation:
That was to your second question in the description part
5) How many kilograms are there in 7.50 x 10^26 molecules of sulfuric acid?
Answer:
I think It might be ( 122.5g )
Adaleigh is learning about renewable and non-renewable resources in her science class. She decides to take
a nature walk and makes notes of all the renewable resources that she sees. Which of the following is an
observation that Adaleigh could have made on her walk?
A. The seeds on the ground are going to grow into new trees.
B. The tallest trees had the most seeds around their bases.
C. When trees decay, they could eventually turn into coal.
D. Pine trees are older than oak trees.
Answer:
A. The seeds on the ground are going to grow into new trees.
Explanation:
Trees are renewable resources.
what coefficients used to balance chemical equation below? ___ Ag2O ----> ____ Ag + ___ O2
A 2,4,1
B 2,2,2
C 2,1,2
D 1,1,1
The coefficients used to balance the chemical equation given in the question are 2, 4, 1 (Option A)
What is a chemical equation?Chemical equations are representations of chemical reactions using symbols and formula of the reactants and products.
The reactants are located on the left side while the products are located on the right side.
Reactants —> Products
The balancing of chemical equations follows the law of conservation of matter which states that matter can neither be created nor destroyed during a chemical reaction but can be transferred from one form to another.
How to balance the equationAg₂O —> Ag + O₂
There are 2 atoms of O on the right side 1 on the left. It can be balance by writing 2 before Ag₂O as shown below
2Ag₂O —> Ag + O₂
There are 4 atoms of Ag on the left side and 1 atom on the right side. It can be balance by writing 4 before Ag as shown below
2Ag₂O —> 4Ag + O₂
Now, the equation is balanced.
Thus, the coefficients are: 2, 4, 1
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10 POINTS FOR LZ ANSWER ASAP!!!!!!!
Explain in your own words how competition works
in an ecosystem.
How did the backyard bird feeders in the article
increase competition in that ecosystem?
Answer:
Competition is an interaction between organisms in which both the organisms or species are harmed. Two birds can want the some food from the bird feeder and then they will compete for it.
Explanation: