Select all of the following reactions that are endothermic.
½N 2(g) + 3/2H 2(g) → NH 3(g) + 11.0 kcal/mole
H 2(g) + ½O 2(g) → H 2O(g), ΔH = -57.83 kcal/mole
½N 2(g) + O 2(g) + 8.1 kcal → NO 2(g)
½N 2(g) + ½O 2(g) → NO(g), ΔH = +21.6 kcal/mole
NH 3(g) → ½N 2(g) + 3/2H 2(g), ΔH = +11.0 kcal/mole
Answer:
½N 2(g) + O 2(g) + 8.1 kcal → NO 2(g)
½N 2(g) + ½O 2(g) → NO(g), ΔH = +21.6 kcal/mole
NH 3(g) → ½N 2(g) + 3/2H 2(g), ΔH = +11.0 kcal/mole
General Formulas and Concepts:
Thermochemistry
Endothermic vs ExothermicEnthalpyExplanation:
An endothermic reaction would have heat or energy gained in the final stage of the reaction.
This means that our enthalpy would be positive and heat/energy would be added as a reactant.
Out of all the answer choices, we see that only these have heat/energy added in the reactant side or the enthalpy being positive:
½N 2(g) + O 2(g) + 8.1 kcal → NO 2(g)
½N 2(g) + ½O 2(g) → NO(g), ΔH = +21.6 kcal/mole
NH 3(g) → ½N 2(g) + 3/2H 2(g), ΔH = +11.0 kcal/mole
Topic: AP Chemistry
Unit: Thermochemistry
Calculate the number of hydrogen atoms in 33.0 g CH4
Answer:
The number of hydrogen atoms is 4.96x10²⁴.
Explanation:
The number of atoms can be found with the following equation:
[tex] n = N*\eta_{H} [/tex]
Where:
N: is the Avogadro's number = 6.022x10²³ atoms/mol
η: is the number of moles of hydrogen
n: is the number of hydrogen atoms
First, we need to find the number of hydrogen moles. The number of moles of CH₄ is:
[tex] \eta_{CH_{4}} = \frac{m}{M} [/tex]
Where:
m: is the mass of methane = 33 g
M: is the molar mass of methane = 16.04 g/mol
[tex] \eta_{CH_{4}} = \frac{33 g}{16.04 g/mol} = 2.06 mol [/tex]
Now, since we have 4 hydrogen atoms in 1 mol of methane, the number of moles of hydrogen is:
[tex] \eta_{H} = 2.06\: mol\: CH_{4}*4 \frac{mol\: H}{mol \: CH_{4}} = 8.24 mol [/tex]
Hence, the number of hydrogen atoms is:
[tex]n = N*\eta_{H} = 6.022 \cdot 10^{23} \: atoms/mol*8.24 mol = 4.96 \cdot 10^{24} atoms[/tex]
Therefore, the number of hydrogen atoms is 4.96x10²⁴.
I hope it helps you!
CH3 CH2 CH2 OH + H2SO4
Get the product and answer the following questions :
I. A + HCl
II. A --> Combustion ( what product does it form. Write out the equation )
III.A ---> Hydrogenation (what product does it form. Write out the equation )
Note : A represents the product gotten from the reaction between
CH3 CH2 CH2 OH and H2SO4
Answer:
propene and hydrogen is product
When propanol is heated with concentrated sulphuric acid at 443 K, dehydration takes place and prop-1-ene is formed. In this reaction concentrated sulphuric acid acts as a dehydrating agent.
I. A + HCl gives )-gives 2-chloropropane
II. A --> Combustion ( what product does it form. Write out the equation propene ozonide
III.A ---> Hydrogenation (what product does it form. Write out the equation )propanol
How many sodium (NA) Atoms are in Methylene?
None
Explanation:
methylene is an organic compound comprising and of One carbon and two hydrogens
Which one is wrong I did them but it’s saying I got partial credit
Which statement is true about the atoms in helium gas?
They have strong attractions to one another.
They travel in circular paths.
They are arranged in an orderly pattern.
They are not closely packed.
Answer: The answer is they are not closely packed
Explanation: HOPE THIS HELPS!!
Biết độ tan s của AgNO3 ở 60 độ C là 525 gam ở 10 độ C là 170 gam tính lượng AgNO3 tách ra khi làm lạnh 2.500g dung dịch AgNO3 bão hòa ở 60 độ C xuống 10 độ C
Answer:
Can you translate for me please
Which equation is balanced?
2Al+3O2→Al2O3
2Na+F2→2NaF
Mg+O2→2MgO
2Al+F2→2AlF3
the 1st one is balanced, the 2nd isn't (the number of Mg differs from left 1 to right 2).
The third is also not balanced, 2 F left,2*3=6 on the right
which type of reaction this would be: 2KNO₃+ H₂CO₃ → K₂CO₃ + HNO₃
Answer:
It's a double displacement reaction.
movement of water molecules without the use of energy
The answer is ‘Passive Transport’
movement of molecules without the use of energy is due to the shrinkage of water
describe one displacement reaction that is useful and explain why it is useful
Answer:
carbon reaction with iron from its oxide. Why?? Because it is largely used in extraction of metals. It is used in acid indigestion.
Hii pls helpnme to write out the ionic equation
Answer:
CO32-(aq) + 2H+(aq) → CO2(g) + H2O(l)
Explanation:
According to this question, sodium carbonate reacts with sulfuric acid to form aqueous sodium sulfate, carbon dioxide and water. The balanced chemical equation is as follows:
Na2CO3(aq) + H2SO4(aq) → Na2SO4(aq) + CO2(g) + H2O(l)
- Next, split compounds that are aqueous into ions.
2Na+(aq) + CO32-(aq) + 2H+(aq) + SO42-(aq) → 2Na+(aq) + SO42-(aq) + CO2(g) + H2O(l)
- Next, we cancel out the spectator ions, which are ions that remain the same in the reactants and products side of a chemical reaction. The spectator ions in this equation are 2Na+(aq) and SO42-(aq).
CO32-(aq) + 2H+(aq) → CO2(g) + H2O(l)
- Hence, the balanced ionic equation is as follows:
CO32-(aq) + 2H+(aq) → CO2(g) + H2O(l)
please help asap!!!!!!!!
The two waves in the diagram are occupying the same place at the same time. At what time will the interfering waves have an amplitude of zero? 1.0 3.0 4.0 7.0 Mark this and return
Answer: It’s 4.0
Explanation: I just took the test and got it right:)
Can someone help with this
Answer:
I think option (d) is right answer
Answer:
I think that the answer is option(C)
Can someone help me with this question ASAP
Is the graph more accurate with more atoms or less atoms?
Answer:
I would guess more atoms? but there is no graph attached
What is an air mass? Where on Earth might you find a hot and dry air mass?
An air mass is a volume of air whose temperature and humidity are specified. Many hundreds or thousands of square miles are covered by air masses, which adjust to the properties of the land underneath them.
What is an air mass ?An air mass is a volume of air whose temperature and humidity are specified. Many hundreds or thousands of square miles are covered by air masses, which adjust to the properties of the land underneath them. Latitude and their continental or marine source regions are used to categorize them.
There is a temperature and air pressure differential. Storms are caused by abrupt changes in the weather. Two natural wind patterns come into conflict.
The hot and dry continental tropical (cT) air mass is prevalent over subtropical and tropical continents. The world's largest deserts, such the Sahara, Arabian, and Australian, are important source areas.
Thus, Latitude and their continental or marine source regions are used to categorize them. An air mass is a volume of air whose temperature and humidity are specified.
To learn more about an air mass, follow the link;
https://brainly.com/question/28709357
#SPJ2
what is the atomicity of Sulphur?
Answer:
the atomicity of sulphur is 8
Explanation:
hope it helps
A 2.50 L container is filled with 175 g of argon; a. If the pressure is 10 atm, what is the temperature ? b if the temperature is 22K, what is the pressure ?
Answer:
A. 70 K
B. 3.16 atm
Explanation:
We'll begin by calculating the number of mole in 175 g of Ar. This can be obtained as follow:
Mass of Ar = 175 g
Molar mass of Ar = 40 g/mol
Mole of Ar =?
Mole = mass / molar mass
Mole of Ar = 175 / 40
Mole of Ar = 4.375 moles
A. Determination of the temperature.
Mole of Ar (n) = 4.375 moles
Volume (V) = 2.50 L
Pressure (P) = 10 atm
Gas constant (R) = 0.0821 atm.L/Kmol
Temperature (T) =?
PV = nRT
10 × 2.5 = 4.375 × 0.0821 × T
25 = 4.375 × 0.0821 × T
Divide both side by (4.375 × 0.0821)
T = 25 / (4.375 × 0.0821)
T ≈ 70 K
B. Determination of the pressure.
Mole of Ar (n) = 4.375 moles
Volume (V) = 2.50 L
Temperature (T) = 22 K
Gas constant (R) = 0.0821 atm.L/Kmol
Pressure (P) =?
PV = nRT
P × 2.5 = 4.375 × 0.0821 × 22
Divide both side by 2.5
P = (4.375 × 0.0821 × 22) / 2.5
P = 3.16 atm.
Which letter in the diagram represents the transition from liquid to gas?
A
B
C
D
Answer:
D
Explanation:
B is solid and liquid while D is liquid and gas
Answer:
Option ( D) is correct
The phase transition occurs at 100o C (the normal boiling point of water). Liquid water becomes water vapor or steam when it enters the gaseous phase.
Explanation:
A heating curve graphically represents the phase transitions that a substance undergoes as heat is added to it.
The liquid will begin to boil when enough heat has been absorbed by the solution that the temperature reaches the boiling point, where again, the temperature remains constant until all of the liquid has become gaseous water. At the atmospheric pressure of 1 atm, this phase transition occurs at 100o C (the normal boiling point of water). Liquid water becomes water vapor or steam when it enters the gaseous phase. Use the heat of vaporization ([latex]\Delta H_{vap}[/latex] ) to calculate how much heat was absorbed in this process: [latex]q=m\cdot C_{H_2O(g)}\cdot \Delta T[/latex], where m is the mass of the sample of water.
After all of the liquid has been converted to gas, the temperature will continue to increase as heat as added. Again, the heat added that results in a certain change temperature is given by: [latex]q=m\cdot C_{H_2O(g)}\cdot \Delta T[/latex] . Note that the specific heat capacity of gaseous water is different than that of ice or liquid water.
mendeleev's periodic table is studied even though it is considered to be defective
Answer:
This is because Mendeleev arranged the elements in order of increasing relative atomic mass.
Explanation:
Dmitri Mendeleev is one of the scientists that contributed to the development of periodic table in chemistry. He was able to organise elements into rows according to their atomic mass and into columns based on chemical and physical properties. This is the main reason why his periodic table is still studied even though it has some defects which include:
--> Grouping of elements that are not similar chemically: For example Copper and Silver bear no resemblance with the alkali metals, but they have been placed together in the first group.
--> Position of isotopes: According to his periodic table: Isotopes of an element must be given separate places in the periodic table because they have different atomic masses.
--> Electronic arrangement of elements: It failed to explain the electronic arrangement of elements.
--> Separation of chemically similar elements:
Elements that are chemically similar such as Gold and Platinum have been placed in separate groups.
A gas has an initial volume of 52.3 L at 273 Kelvin. What is its temperature when the volume reaches 145.7 L?
Answer:
[tex]\boxed {\boxed {\sf 761 \ K}}[/tex]
Explanation:
We are asked to find the new temperature of a gas after a change in volume. We will use Charles's Law, which states the volume of a gas is directly proportional to the temperature. The formula for this law is:
[tex]\frac {V_1}{T_1}= \frac{V_2}{T_2}[/tex]
The volume is initially 52.3 liters at a temperature of 273 Kelvin.
[tex]\frac {52.3 \ L}{273 \ K}= \frac{V_2}{T_2}[/tex]
The volume reaches 145.7 liters at an unknown temperature.
[tex]\frac {52.3 \ L}{273 \ K}= \frac{145.7 \ L }{T_2}[/tex]
We are solving for the new temperature, so we must isolate the variable T₂. Cross multiply. Multiply the first numerator and second denominator, then the first denominator and second numerator.
[tex]52.3 \ L * T_2 = 273 \ K * 145.7 \ L[/tex]
Now the variable is being multiplied by 52.3 liters. The inverse of multiplication is division. Divide both sides by 52.3 L.
[tex]\frac {52.3 \ L * T_2 }{52.3 \ L}=\frac{ 273 \ K * 145.7 \ L}{52.3 \ L}[/tex]
[tex]T_2=\frac{ 273 \ K * 145.7 \ L}{52.3 \ L}[/tex]
The units of liters cancel.
[tex]T_2=\frac{ 273 \ K * 145.7 }{52.3 }[/tex]
[tex]T_2 = 760.5372849 \ K[/tex]
The original measurements have at least 3 significant figures, so our answer must have 3. For the number we found, that is the ones place. The 5 in the tenths place tells us to round the 0 up to a 1.
[tex]T_2 \approx 761 \ K[/tex]
When the volume reaches 145.7 liters, the temperature is 761 Kelvin.
Pls help!!!
You are given a type of element by a teacher and she asks you to identify it.What should you do?Explain your answer
Answer:
NAO SRESONDEPORR PQUEOU BUOBRRRA IGAD THCAAUSEI
Explanation:
Explain the steps you would follow to make 500 mL of a 0.3 M solution of sucrose
(C12H22011) in the lab.
Answer:
see explanation
Explanation:
Solutions are prepared from one of three solute sources ...
- solid solute from manufacturer,
-liquid solute from manufacturer,
-stock concentrate of solute for dilution to lower concentrations.
In this problem, sucrose is a stock solid with a formula mass of 342.3 grams/mol. The amount of solid needed can be determined using the formula:
mass of solute needed (grams) = (Molarity needed x Volume needed in Liters x formula weight) / (decimal fraction purity of stock solid)
Molarity needed = 0.3M
Volume needed = 500 ml = 0.500 liters
Formula weight = 342.3 grams/mole
Purity factor (assumed) = 100% = 1.00 (should be posted on stock bottle label) For example, a 95% pure stock solid => purity factor of 0.95.
∴ grams of sucrose needed = (0.3M*)(0.500L)(342.3g/mole)/(1.00) =51.345 grams sucrose.
Measure 51.345 grams of sucrose into mixing vessel and add solvent water up to, but not to exceed 500 ml total volume. Mix until homogeneous.
How long does it take, on average, for one centimetre of soil to form
Which of the following is an oxide which is strongly acidic?
(a) Na2O.
(b) MgO
(c) SiO2.
(d) P2O5.
Answer:
answer of your question is 4th
Explanation:
P205
Draw the structure for :
3,3,4-trimethylhex-2-ene
Answer:
answer is in the picture.
ii.
ci
What is the name of the organic compound
Answer.
Hydrocarbons are compounds that contain carbon and hydrogen only
Explanation:
a. c3H4 methane
b.c3H4.propene
c.c5H8
Rank these solutions from the most alkaline (1) to the least alkaline (5).
phosphorus react with carbon
Answer:
Phosphorus atoms can bond with oxygen atoms to form ester groups. These can bond with carbon atoms, yielding a large number of organic phosphorus chemicals. These are found in many important biological processes
