Answer:
NaCl is an electrovalent compound because the sodium and chlorine atoms give one electron from their outermost shells to each other in order to complete their octets
Explanation:
Make me Brain liest plz );
make a 450 gram solution with the mass by mass concentration of 7% how much salt and water do you need to mix
Question 8 of 10
Which of the following is made of matter?
A. Light
B. Energy
C. The sun
D. Heat
Answer: i Choose the sun
because it has mass
Explanation: matter is anything that has mass and occupies space / Volume
and the sun has mass though it is not a solid one, and is made up of matter
HOPE THIS HELPSS!!!!
Which diagram represents this molecule
Answer:
I think it is C
Explanation:
Hope this helps!! :)
If I'm wrong, then greatest apologies
Which is an advantage of subdividing science into different areas?
Answer:
Explain the advantages of subdividing science into many different areas. Advantages-It allows scientists to delve into a specific topic easier, so that they can go deeper.
hope it helps
Answer:
Science is a vast subject. Scientists have classified it into different areas/branches so that they do not get their concepts mixed or overlapped. We can think of all the sub-branches as different topics studied under one main subject, science. We just divide the main subject so that we can study each of the topic clearly and individually. Science is such a vast subject that most of its sub branches are not even related to each other or interlinked, like computer science and biology. If we did not have subdivisions in science, can you imagine a person studying biology, computer science, chemistry, physics, phycology etc all at the same time, simultaneously? Of course not! That's why, in order to get a clear understanding of each topic, we divide science into different areas.
Hope that helps...
If you hit the surface of Iron with a photon of energy and find that the ejected electron has a wavelength of .75 nm, what is the wavelength of the incoming photon in nanometers?
Answer:
The wavelength of the incoming photon is 172.8 nm
Explanation:
The wavelength of the incoming photon can be calculated with the photoelectric equation:
[tex] KE = h\frac{c}{\lambda_{p}} - \phi [/tex] (1)
Where:
KE: is the kinetic energy of the electron
h: is Planck's constant = 6.62x10⁻³⁴ J.s
c: is the speed of light = 3.00x10⁸ m/s
[tex]\lambda_{p}[/tex]: is the wavelength of the photon =?
Φ: is the work function of the surface (Iron) = 4.5 eV
The kinetic energy of the electron is given by:
[tex] KE = \frac{p^{2}}{2m} = \frac{(\frac{h}{\lambda_{e}})^{2}}{2m} [/tex] (2)
Where:
p: is the linear momentum = h/λ
m: is the electron's mass = 9.1x10⁻³¹ kg
[tex]\lambda_{e}[/tex]: is the wavelength of the electron = 0.75 nm = 0.75x10⁻⁹ m
Hence, the wavelength of the photon is:
[tex] \frac{(\frac{h}{\lambda_{e}})^{2}}{2m} = h\frac{c}{\lambda_{p}} - \phi [/tex]
[tex]\lambda_{p} = \frac{hc}{\frac{h^{2}}{2m\lambda_{e}^{2}} + \phi} = \frac{6.62 \cdot 10^{-34} J.s*3.00\cdot 10^{8} m/s}{\frac{(6.62 \cdot 10^{-34} J.s)^{2}}{2*9.1 \cdot 10^{-31} kg*(0.75 \cdot 10^{-9} m)^{2}} + 4.5 eV*\frac{1.602 \cdot 10^{-19} J}{1 eV}} = 1.728 \cdot 10^{-7} m = 172.8 nm[/tex]
Therefore, the wavelength of the incoming photon is 172.8 nm.
I hope it helps you!
When the volume of a gas is
changed from 250 mL to 425 mL, the temperature will change from 137°C to_____°C.
Answer:
[tex]\boxed {\boxed {\sf 232.9 \textdegree C}}[/tex]
Explanation:
This question asks us to find the temperature change given a volume change. We will use Charles's Law, which states the volume of a gas is directly proportional to the temperature. The formula is:
[tex]\frac {V_1}{T_1}= \frac{V_2}{T_2}[/tex]
The volume of the gas starts at 250 milliliters and the temperature is 137 °C.
[tex]\frac{250 \ mL}{137 \textdegree C}= \frac{V_2}{T_2}[/tex]
The volume of the gas is increased to 425 milliliters, but the temperature is unknown.
[tex]\frac{250 \ mL}{137 \textdegree C}= \frac{425 \ mL}{T_2}[/tex]
We are solving for the new temperature, so we must isolate the variable T₂. First, cross multiply. Multiply the first numerator and second denominator, then multiply the first denominator and second numerator.
[tex]250 \ mL * T_2 = 137 \textdegree C * 425 \ mL[/tex]
Now the variable is being multiplied by 250 milliliters. The inverse of multiplication is division. Divide both sides of the equation by 250 mL.
[tex]\frac{250 \ mL * T_2}{250 \ mL}=\frac{ 137 \textdegree C * 425 \ mL}{250 \ mL}[/tex]
[tex]T_2=\frac{ 137 \textdegree C * 425 \ mL}{250 \ mL}[/tex]
The units of milliliters (mL) cancel.
[tex]T_2=\frac{ 137 \textdegree C * 425 }{250 }[/tex]
[tex]T_2= \frac{58225}{250} \textdegree C[/tex]
[tex]T_2=232.9 \textdegree C[/tex]
The temperature changes to 232.9 degrees Celsius.
Asap please help 15 points
Explanation:
P_H
and
li_n
hope it helps
what is S in the equation G= H-T delta S?
Answer:
C
Explanation:
∂S represents change in entropy.
find the atoms of 52u of helium
Here, we have been given the the amount of helium to be 52 amu.
Thus,
Atomic mass of Helium is 4u = 2 protons + 2Neutrons = 1 atom. No. of atoms in 52u = $ \sf{\frac{52}{4}}$ = 13 atoms.$ \red{\leadsto}$ Hence, the number of atoms will be 13 atoms.
[tex] \\ [/tex]
NaC2H3O2 product or reactant
Answer:
the reaction between vinegar and baking soda, the reactants are vinegar (acetic acid) and baking soda (sodium bicarbonate). The products are sodium acetate, water, and carbon dioxide gas.
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 the pH of a 1.0 x 10-3 M KOH solution?
A. 10
B. 4.0
C. 11
D. 3.0
Answer:
Option C. 11
Explanation:
We'll begin by calculating the concentration of the hydroxide ion [OH¯] in the solution. This can be obtained as follow:
In solution, KOH will dissociate as follow:
KOH (aq) <=> K⁺(aq) + OH¯(aq)
From the balanced equation above,
1 mole of KOH reacted to produce 1 mole of OH¯.
Therefore, 1×10¯³ M KOH will also react to produce 1×10¯³ M OH¯.
Thus, the concentration of hydroxide ion [OH¯] in the solution is 1×10¯³ M
Next, we shall determine the pOH of the solution. This can be obtained as follow:
Concentration of hydroxide ion [OH¯] = 1×10¯³ M
pOH =?
pOH = –Log [OH¯]
pOH = –Log 1×10¯³
pOH = 3
Finally, we shall determine the pH of the solution. This can be obtained as follow:
pOH = 3
pH =?
pH + pOH = 14
pH + 3 = 14
Collect like terms
pH = 14 – 3
pH = 11
PLZ HELP Which of the following is made up of a group of cells with the same function?
A. Organism
B. Body system
C. Organs
D. Tissues
Answer:
tissues is the answer to your question
what is Ka for hno2(aq) = h+(aq) + no2-(aq)?
The ionization constant of an acid is denoted by the symbol Kₐ. The smaller the value of Kₐ for an acid, the weaker will be the acid. Thus the correct option is D.
What is acid dissociation constant?The acid dissociation constant denotes the measure of the extent to which an acid dissociates in the solution. The strength of an acid is represented by the value Kₐ. The less an acid dissociates, smaller will be the value of Kₐ, the stronger the acid, higher will be the value of Kₐ.
The dissociation of HNO₂ is given as:
HNO₂ (aq) ⇄ H⁺ (aq) + NO₂⁻ (aq)
The dissociation constant of HNO₂ is given as:
Kₐ = [H⁺][NO₂⁻] / HNO₂
The value of Kₐ is constant at a particular temperature. We can use this fact to find out the pH of a weak acid at a particular temperature.
Thus the correct option is D.
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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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Chromium forms a complex with diphenylcarbazide whose molar absorptivity is 4.17*10^4 at 540nm. Calculate the absorbance of a 7.68*10^-6 M solution of the complex at 540nm when measured in a 1.00cm cell and the transmittance of the solution.
Answer:
0.32 liters/mole cm.
Explanation:
According to Beer Lambert's law;
A= εcl
ε = molar absorptivity
c= concentration
l= path length
A= 4.17*10^4 × 7.68*10^-6 × 1
A= 0.32 liters/mole cm.
Use VSEPR theory to predict the electron-pair geometry and the molecular geometry of CH3Cl. a. The electron-pair geometry is linear, the molecular geometry is linear. b. The electron-pair geometry is tetrahedral, the molecular geometry is trigonal-pyramidal. c. The electron-pair geometry is trigonal-planar, the molecular geometry is bent. d. The electron-pair geometry is tetrahedral, the molecular geometry is tetrahedral. e. The electron-pair geometry is trigonal-planar, the molecular geometry is trigonal planar. Group of answer choices
Answer:
d. The electron-pair geometry is tetrahedral, the molecular geometry is tetrahedral.
Explanation:
According to Valence Shell Electron Pair Repulsion Theory, the shape of a molecule depends on the number of electrons pairs surrounding the valence shell of the central atom in the molecule.
In CH3Cl, the central atom is carbon. Carbon has four regions of electron density surrounding it and no lone pairs. Lone pairs cause molecules to deviate from the expected geometry.
Since CH3Cl has no lone pairs on the carbon central atom, both the molecular and electron pair geometries are tetrahedral.
In CH₃Cl, the electron-pair geometry is trigonal-planar, and the molecular geometry is bent. Therefore, option C is correct.
According to VSEPR (Valence Shell Electron Pair Repulsion) theory, the electron pairs around the central atom in CH₃Cl will arrange themselves to minimize repulsion, resulting in a specific geometry.
In CH₃Cl, the central atom is carbon (C), and it is surrounded by three hydrogen atoms (H) and one chlorine atom (Cl).
The electron-pair geometry is determined by the arrangement of these electron pairs.
Molecular geometry considers only the atoms around the central atom, not the lone pairs.
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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
I NEED HELP WITH THE LAST 4 BOXES PLEASEEEEEEE
Answer:
0.68°C and 0°C.
Explanation:
The average freezing point of sucrose is 0.68°C whereas the average freezing point is 0°C. Both at these temperatures, turn from liquid into solid state. This point is also called transition point because at this point transition of state occurs of both compounds. When the temperature increases, this solid state is again turn into liquid form so temperature is responsible for this change of states of sucrose and water.
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.
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
hii pls help me to write the ionic equation
Answer:
net ionic equation
[tex]\boxed{ SO_4{}^{2-} {}_{(aq.)} + Ba^{2+} {}_{(aq.)} \rightarrow BaSO_4 {}_{(s)}} [/tex]
PLEASE HELP QUICK!!! How many molecules are there in 4.00 L of
glucose, C6H1206? Please show your work!!
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!! :)
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 action of a catalyst
Answer: A catalyst is a substance that speeds up the rate of a chemical reaction without being used up and remains chemically unchanged itself .
Explanation: For a reaction to take place the particles must collide with enough energy for bonds to break and reaction to occur .
BUT when a catalyst is present the reactants are able to react in a way that requires less energy ,leading to more successful collision so the reaction speeds up without the chemical composition of the catalyst being affected
NOTE: the catalyst must be chosen to suit the particular reaction
HOPE THIS HELPS IF YOU NEED MORE EXAMPLES FEEL FREE TO COMMENT IN THE COMMENT SECTION
How does kinetic energy transform into potential energy?
Draw the following structures and name them :
I. CH3CH2(OH)
II.CH3CH2CH(CH3)C(Cl)2C(l)2CH(F)OH
III.CH3CH(CH3)CHO
IV.CH2=CH(OH)
V.CH3OCH2CH3
Answer:
hope this helps.answer is in the picture
1 mole of alkene CxH2x was fully burnt in oxygen. The products were analysed. 264g of Co2 and 108g of of H20 were produced. Use the information to balance the equation and work out the identity of CxH2x.
CxH2x+ O2--> CO2+H2O
PLEASE CAN SOMEONE EXPLAIN THIS TO ME!!!!!!!!!!!!
Answer:
C6H12
Explanation:
Step 1: Find the molar mass of carbon dioxide and water
MH2O = 2(1.008) + 16.00 = 1.802x10^1 g/mol
MCO2 = 12.01 + 2(16.00) = 4.401x10^1 g/mol
Step 2: Calculate the moles of the products
nH2O = 108g / 1.802x10^1 g/mol = 5.99 or about 6
nCO2 = 264g/ 4.401x10^1 g/mol = 5.99 or about 6
Step 3: Enter moles of carbon dioxide and water into the balanced equation
CxH2x + O2 = 6CO2 + 6H2O
Step 4: Balance
We see how there is six carbon dioxide on the right side which means there are six carbons in the equation.
This means x is equal to 6 in our equation.
If you plug the information into the equation you get:
C6H12 + O2 = 6 CO2 + 6 H2O
Now all that's left is to balance the oxygens
We see how there is 18 oxygens on the right side of the equation which means there must be 18 on the left side.
Because we have oxygen gas we divide 18 by 2 which means there are 9 O2's on the left side
Therefore, the balanced equation is C6H12 + 9O2 = 6 CO2 + 6 H2O
Analyse the temperature versus time graph of water, given below.
Which part of graph represent only liquid state and gaseous state and why?
Answer:
Phase C - Liquid State
Phase E - Gaseous State
Explanation:
Usually, in phases of water, we have the following;
When temperature is less than zero, it is said to be in its solid phase as ice.
When temperature is between 0 to 100, we can say it is in the liquid phase as water.
When temperature is above 100°C, It is said to be in the gaseous phase as vapour.
From the diagram;
Phase C is the only liquid state because it falls between temperature of 0°C and 100°
Also, only phase E is in the gaseous phase because the temperature is above 100°C.
