nguyên tử sắt có điện tích hạt nhân là 26+. trong nguyên tử, số hạt mang điện nhiều hơn số hạt không mang điện là 22. Hãy xác định số khối của nguyên tử sắt
Answer:
I don't know yr language
what is known as a double covalent bond?
Answer:
two atoms
Explanation:
PLEASE HELP QUICK!!! How many molecules are there in 4.00 L of
glucose, C6H1206? Please show your work!!
Why is conical flask used in the freezing point of naphthalene activity?
Pick one below.
A Conical flask is used to hold the boiling tube
B Napthalene is poisonous and needs to be contained
C Freezing point can only be determined inside the conical flash
D To ensure the cooling process is not affected by surrounding temperature
Answer:
D. To ensure the cooling process is not affected by surrounding temperature
Explanation:
The conical flask acts as a temperature jacket.
The conical flask is used in freezing point of the naphthalene activity because to ensure the cooling process is not affected by surrounding temperature.
What is the use of conical flask ?In the freezing point determination of naphthalene, a conical flask is used to hold the naphthalene sample and a thermometer. The conical shape of the flask allows for efficient stirring of the naphthalene as it is heated and cooled, ensuring that the temperature is evenly distributed throughout the sample.
The conical flask is also used to protect the naphthalene sample from any external temperature fluctuations that could affect the cooling process. By placing the flask in an ice bath, the cooling process can be closely monitored and controlled, allowing for accurate determination of the freezing point.
Therefore, the primary reason why a conical flask is used in the freezing point determination of naphthalene is to ensure that the cooling process is not affected by surrounding temperature.
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50cm3 of 0.2mol/dm3 hydrochloric acid was reacted with 0.6g of magnesium. The resulting solution was titrated against sodium hydroxide of concentration 1.67mol/dm3.Calculate the volume of alkaline needed.
Answer:
0.06 liter
Explanation:
First, let us look at the equation of the first reaction:
2HCl + Mg ----> MgCl2 + H2
2 moles of HCl requires 1 mole of Mg for complete reaction.
Mole of HCl available = molarity x volume
0.2 x 50/1000 = 0.1 mole
Mole of Mg available = mass/molar mass
0.6/24.3 = 0.02 mole.
Thus, HCl is in excess by 0.1 mole.
Now, let us look at the second reaction:
HCl + NaOH ----> NaCl + H2O
mole ratio of HCl to NaOH is 1:1
Remember that 0.1 mole HCl is left from the first reaction. Thus, 0.1 mole of the alkaline would also be needed.
Hence, volume of NaOH needed = mole/molarity
0.1/1.67 = 0.06 dm3
The volume of alkaline needed would, therefore, be 0.06 liter.
PLZ HELP According to the atomic model Which particles are found In the same part of the atom
a. protons electrons neutrons
B.protons and neutrons
C.protons and electrons
D.electrons and neutrons
How does kinetic energy transform into potential energy?
Which statement describes conditions in which a mineral can form?
A. Crystals of minerals dissolve in the groundwater in caves.
B. Molten materials are cooled in a metalworks factory.
C. Materials are mined from deposits deep underground,
D. Materials dissolved in seawater crystallize on an ocean bottom.
The statement describes conditions in which a mineral can form is "Crystals of minerals dissolve in the groundwater in caves."
What is Crystals?Atoms of the relatively similar element and atoms of other elements [such as silica (Si) and calcium (Ca)] can make up a crystal, and they are arranged in a predictable, repeating pattern.
What is minerals?A mineral would be an element as well as a chemical compound which has been produced as a result of geological activity and is often crystalline in nature.
The statement describes conditions in which a mineral can form as "Crystals of minerals dissolve in the groundwater in caves."
To know more about minerals and crystals.
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What are the two sources of energy for the Earth system?
How can I solve this using a T chart
Answer:
The answer to your question is given below
Explanation:
The balanced equation for the reaction is given below:
2KClO₃ —> 2KCl + 3O₂
From the balanced equation above,
2 moles of KClO₃ decomposed to produce 2 moles of KCl and 3 moles of O₂.
Next, we shall determine the number of mole of KClO₃ that will decompose to produce 9 moles of O₂. This can be obtained as follow:
From the balanced equation above,
2 moles of KClO₃ decomposed to produce 3 moles of O₂.
Therefore, Xmol of KClO₃ will decompose to produce 9 moles of O₂ i.e
Xmol of KClO₃ = (2 × 9)/3
Xmol of KClO₃ = 6 moles
Thus, 6 moles of KClO₃ is needed for the reaction.
Next, we shall determine the number of mole KCl that will be produced by the decomposition of 6 moles of KClO₃. This can be obtained as follow:
From the balanced equation above,
2 moles of KClO₃ decomposed to produce 2 moles of KCl.
Therefore, 6 moles of KClO₃ will also decompose to produce 6 moles of KCl.
Finally we shall represent the reaction in a chart as illustrated below:
2KClO₃ —> 2KCl + 3O₂
6 moles —> 6 moles | 9 moles
Is this population more likely to grows slowly or quickly in the next 10 years
nobody can say it is uncertain but in my opinion it will grow quickly in the next 10 years
what is skeleton?
Write any two function of skeleton .
what is the molecular weight of potassium ( k2so4)
Answer:
174.259 g/mol
Explanation:
The molecular weight of potassium (K2so4) is 174.259 g/mol .
Hope it is helpful to you
why is Darwins theory of evolution by natural selection not just a theory
Answer:
it talks about reality ..how animals and human came to existence and how they disappear ..this is evolution
the environment chooses those who best fit in it and others are selected ..as in die ..this is referred to as natural selection
and further in this theory .animals produce off springs who survive in the environment
TIMED HELP ASAP
19.11 g of MgSO₄ is placed into 100.0 mL of water. The water's temperature increases by 6.70°C. Calculate ∆H, in kJ/mol, for the dissolution of MgSO₄. (The specific heat of water is 4.184 J/g･°C and the density of the water is 1.00 g/mL). You can assume that the specific heat of the solution is the same as that of water.
Answer:
TIMED HELP ASAP
19.11 g of MgSO₄ is placed into 100.0 mL of water. The water's temperature increases by 6.70°C. Calculate ∆H, in kJ/mol, for the dissolution of MgSO₄. (The specific heat of water is 4.184 J/g･°C and the density of the water is 1.00 g/mL). You can assume that the specific heat of the solution is the same as that of water.
Answer:
-21.03 kJ/mol
Explanation:
∆H is enthalpy. Enthalpy is the total heat content of a system.
So we can establish that ∆H = q (heat)
The formula for heat (q)
q = cm∆T
c = specific heat capacity
m = mass of substance
∆T= change of temperature
Since we are calculating the enthalpy of the SOLUTION. We must account for both the mass of water and the mass of MgSO₄ in our q formula.
All you gotta do is plug and chug at this stage.
∆H = q = cm∆T = (4.184)(19.11+100.0)(6.70) = 3338.986808 Joules
We have now calculated the heat (aka enthalpy) of the solution.
BUT
Remember! The problem asked for enthalpy in kj....
Use this conversion factor.
1000 J = 1 kJ
3338.986808 Joules * 1kJ/1000 J = 3.338986808 kJ
We were asked to find ∆H for the dissolution of MgSO4 in units of kj/mol so we are not finished.
Take the grams of MgSO4 in the problem and convert it into moles using its molar mass.
MgSO4 molar mass = 120.3676 g
1 mol = 120.3676 g MgSO4 <---- Use this as a conversion factor
19.11 g MgSO4 * 1 mol MgSO4/120.3676 g = 0.15876365 mol MgSO4
Now that you've calculated the moles of MgSO4 in this solution. You can divide your heat by it.
q dissolution = 3.338.986808 kJ/ 0.15876365 mol = 21.03 kj/mol
Note that the problem tells us that the temperature of water increases.
This means that the water is experiencing an endothermic process (heat is being absorbed from MgSO4) . Mathematically, this would be indicated by a positive sign. ---> +q
We can assume MgSO4 is losing heat as it is placed into the water. It is experiencing an exothermic process (heat is being lost). Mathematically, this would be indicated by a negative sign. ----> -q
So if we're calculating the enthalpy for the dissolution of MgSO₄ ....the value we've arrived at must be negative.
Answer
∆H = 21.03 kj/mol :)))))
I hope that helped...I feel like my explanation was a bit convoluted.
What is the net ionic equation for the following? :D
1. Al (s) + HCl (aq) -->
Answer:
This is the answer
AlCl3+H2
Exprese la concentración de una solución de H3PO4 al 30 % en masa y con una densidad de 1.39 g/mL en: M, y N.
Respuesta:
4.26 M; 12.8 N
Explicación:
Primer paso: Calcular la concentración volumétrica (Cv)
Usaremos la siguiente expression.
Cv = Cg × ρ
Cv = 30 g%g × 1.39 g/mL = 41.7 g%mL
Segundo paso: Calcular la molaridad
La concentración volumetrica es 41.7 g%mL, es decir, hay 41.7 gramos de soluto cada 100 mL de solución. Usaremos la siguiente fórmula para molaridad.
M = masa de soluto / masa molar de soluto × litros de solución
M = 41.7 g / 97.99 g/mol × 0.1 L = 4.26 M
Tercer paso: Calcular la normalidad
Usaremos la siguiente fórmula.
N = M × Z
donde Z para un ácido es igual al número de protones.
N = M × Z
N = 4.26 mol/L × 3 eq/mol = 12.8 N
Which diagram represents this molecule
Answer:
I think it is C
Explanation:
Hope this helps!! :)
If I'm wrong, then greatest apologies
Name each compound. Do not capitalize element names. An example can be seen
below.
Ex. SF6: sulfur hexfluoride
a. H2O:
b. PC15:
C. SiF4:
d. N20
Answer:
a. H2O: dihydrogen monoxide
b. PCl5: Phosphorus pentachloride
c. SiF4: Silicon tetrafluoride
d. N20: dinitrogen oxide
which atoms are isotope? explain
Which of the following steps correctly converts 1.25 moles of fluorine to an equivalent mass of fluorine in grams? (5 points)
Add 1.25 to the atomic mass of fluorine.
Divide the atomic mass of fluorine by 1.25.
Subtract 1.25 from the atomic mass of fluorine.
Multiply the atomic mass of fluorine by 1.25.
Explanation:
Given the amount of fluorine is ---- 1.25 mol.
What is the mass of given fluorine in grams?
Since
[tex]Number of moles =\frac{given mass of the substance}{its molecular mass}[/tex]
To get the mass of the substance in grams, multiply the given number of moles with the molecular mass of the substance.
Hence, among the given options, the correct answer is the last option that is
Multiply the atomic mass of fluorine by 1.25.
Answer:
Multiply the atomic mass of fluorine by 1.25.
Explanation:
i got it right on the exam!! :)
Sea floor spreading occurs at a mid-ocean ridge true or false
Answer:
False
Explanation:
sea floor spreading is not consistent at all mid ocean ridges.
what is S in the equation G= H-T delta S?
Answer:
C
Explanation:
∂S represents change in entropy.
Calculate the number of moles of calcium hydroxide in a 48.6-g
Explanation:
number of moles=mass/molecular mass
molecular mass of calcium hydroxide=74
n=m/mr
=48.6/74
=0.65g/mol
I hope it helps
The number of moles of calcium hydroxide in a 48.6 g is 0.65 mol
What is Mole concept ?The mole, symbol mol, is the SI base unit of amount of substance.
The quantity amount of substance is a measure of how many elementary entities of a given substance are in an object or sample.
Formula used :
Number of moles = mass / molecular mass
Molecular mass of calcium hydroxide = 74
n = m / mm
= 48.6 / 74
= 0.65 mol
Therefore, The number of moles of calcium hydroxide in a 48.6 g is 0.65 mol
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PLEASE HELP!!
Balance the equation below to answer the question. Suppose you mix 3.25 grams of nitrogen trihydride with 3.50 grams of oxygen gas. How many grams of nitrogen monoxide would you make?
A. 2.63 grams
B. 2.11 grams
C. 4.34 grams
D. 3.45 grams
E. 1.76 grams
Longitude starts at an imaginaryn line running trough greenwich england.Wwhat is the name of immaginary line
Answer:
prime meridian
Explanation:
The meridian that runs through Greenwich, England, is internationally accepted as the line of 0 degrees longitude, or prime meridian. The antimeridian is halfway around the world, at 180 degrees. It is the basis for the International Date Line
national geographic
I need help with these
How are the vapor pressure and boiling point of alkynes affected as the chain length increases?
Answer:
Answer to the following question is as follows;
Explanation:
Alkynes' vapour pressure and normal boiling points are altered when chain length grows, since vapour pressure rises while boiling point falls.
Vapour pressure always include pressure entered by vapour with its condensed phase, pressure include molecules force of attraction include vapour
what is transition state
Answer:
transition state is a point in which electrons been removed from the atom
Answer:
The highest energy structure in the reaction coordinate.
Explanation:
If 30.0 grams of AlC3 is produced in the reaction, how many grams of HCI must have reacted?
Answer:
Al2O3 + 6HCl ==> 2AlCl3 + 3H2O ... balanced equation
moles Al2O3 present = 30.0 g x 1 mol/101.96 g = 0.294 moles
moles HCl present = 30 g HCl x 1 mol/36.5 g = 0.822 moles HCl
HCl is LIMITING as it takes 6 moles HCl for each 1 mol Al2O3 and here that is not enough. It will run out first.
Now, using the limiting reactant, we find the moles and mass of AlCl3 that can be formed.
0.822 moles HCl x 2 moles AlCl3/6 moles HCl = 0.274 moles AlCl3 formed
mass of AlCl3 = 0.274 moles AlCl3 x 133 g/mole = 36.4 g AlCl3 formed
