Answer:
SPDF blocks represents the last electron of particular element entering into valance subshell.
example: oxygen is p block element because (1s2, 2s2 2p4) its last electron is in p block
A block of the periodic table is unified by the atomic orbitals in which valence electrons lie in.
What is the block in the periodic table?A block can be described as a set of elements in which the valence electrons lie in atomic orbitals. Each block in the periodic table is named after its characteristic orbital: s-block, p-block, d-block, and f-block.
The block names (s, p, d, and f) are derived from the value of an electron's azimuthal quantum number: sharp (0), principal (1), diffuse (2), and fundamental (3).
The s-block, where 's' stands for "sharp" and azimuthal quantum number 0, is on the left side of the periodic table. The p-block, where 'p' stands for "principal" and azimuthal quantum number 1, is on the right side of the modern periodic table and elements in groups 13 to 18.
The d-block, where 'd' stands for "diffuse" and azimuthal quantum number 2, is in the middle of the periodic table and elements from groups 3 to 12.
Learn more about the periodic table, here:
https://brainly.com/question/29367588
#SPJ2
2. A 0.2719 g sample containing CaCO3 reacted with 20.00 mL of 0.2254 M HCl. Given that HCI was excess. The excess HCl required exactly 20.00 mL of 0.1041 M NaOH to reach the end-point using phenolphthalein indicator. Determine percentage purity of CaCO3 in the sample. The reraction involved is CaCO3(s) + 2HCl(aq) → CaCl₂(aq) + 2H₂O(l) The titration reaction is HC(aq) + NaOH(aq) NaCl(aq) + H₂O(1)
The percentage purity of the calcium carbonate is 44%. The percentage purity gives the amount of pure CaCO3 in the sample.
What is excess titration?In excess titration or back titration, we neutralize the excess titrand left in a system.
We have the reaction;
CaCO3 + 2HCl ----> CaCl2 + H2O + CO2
Number of moles of HCl = 0.2254 M * 20/1000 L = 0.0045 moles
The reaction of the excess acid is according to the reaction;
HCl + NaOH ----> NaCl + H2O
Number of moles of NaOH = 0.1041 M * 20/1000 = 0.0021 moles
Since the reaction is 1:1, 0.0021 moles of HCl reacted also
Number of moles of HCl that reacted with CaCO3 = 0.0045 moles - 0.0021 moles = 0.0024 moles
If 2 moles of HCl reacts with 1 mole of CaCO3
0.0024 moles of HCl reacts with 0.0024 moles * 1/2
= 0.0012 moles
Mass of pure CaCO3 present = 0.0012 moles * 100 g/mol = 0.12g
Percent purity of the sample = 0.12g/0.2719 g * 100/1
= 44%
Learn more about percent purity: https://brainly.com/question/10962305?
2. A 0.2719 g sample containing CaCO3 reacted with 20.00 mL of 0.2254 M HCl. Given that HCI was excess. The excess HCl required exactly 20.00 mL of 0.1041 M NaOH to reach the end-point using phenolphthalein indicator. Determine percentage purity of CaCO3 in the sample. The reraction involved is CaCO3(s) + 2HCl(aq) → CaCl₂(aq) + 2H₂O(l) The titration reaction is HC(aq) + NaOH(aq) NaCl(aq) + H₂O(1)
The calculated percentage purity of the original sample of calcium carbonate is 44%.
What is excess titration?In the back titration of the excess acid, we neutralize the excess titrand left in a system.
We have the reaction equation;
CaCO3 + 2HCl ----> CaCl2 + H2O + CO2
To get the moles of HCl = 0.2254 M * 20/1000 L = 0.0045 moles
The reaction involving the excess acid occurs thus;
HCl + NaOH ----> NaCl + H2O
Number of moles of NaOH = 0.1041 M * 20/1000 = 0.0021 moles
We have a 1:1 hence 0.0021 moles of HCl reacted also
Number of moles of HCl that reacted with CaCO3 initially = 0.0045 moles - 0.0021 moles = 0.0024 moles
Given the stoichiometry of the reaction, 0.0012 moles of CaCO3 reacted.
Hence;
Mass of pure CaCO3 in the sample= 0.0012 moles * 100 g/mol = 0.12g
Percent purity of the sample = 0.12g/0.2719 g * 100/1
= 44%
Learn more about percent purity: https://brainly.com/question/10962305?
How can Climate Change impact the formation of Hurricanes?
I will give brainlist
When the color changes is it a chemical change or a physical change
physical
It can be chemical but it's usually physical as the molecular structure doesn't change
How are Jupiter, Saturn, and Uranus similiar? How are Jupiter, Saturn, and Uranus similiar?
Question 5 options:
a They are all large, gaseous planetary bodies.
b They are all planets that are the exact same size.
c They are all the same distance from the sun.
d They all have the exact same surface temperature.
Answer:
a
Explanation:
because they all are gasses
if the concentration of H+ ions in a solution is 3.16 x 10^-4 mol/L then what is the concentration of OH- ions
Answer:
10-4mol/l
[H+]=10-7 , which we call a pH of 7.
This means, for example, that a hydrogen-ion concentration of a solution with a pH of 4 is 10-4mol/l, meaning it contains 0.0001 mol of hydrogen ions in a solution of 1 liter.
Explanation:
3.12×10⁻¹⁰M is the concentration of OH⁻ ions. Concentration in chemistry refers to the quantity of a material in a certain area.
What is concentration?
Concentration in chemistry refers to the quantity of a material in a certain area. The ratio of the solvent in the solution to the solvent or whole solution is another way to define concentration. In order to express concentration, mass every unit volume is typically used. The solute concentration can, however, alternatively be stated in moles or volumetric units.
If a formula describing a shape's boundary is known, it is possible to use integral calculus to determine the volumes of more complex shapes. No object in the dimensions of zero, one, or two has volume; in the dimensions of four and above, the hypervolume is a concept similar to the standard volume.
[H⁺] [OH⁻] = 10 ⁻¹⁴
3.16 x 10⁻⁴ × [OH⁻] = 10 ⁻¹⁴
[OH⁻] = 3.12×10⁻¹⁰M
Therefore, 3.12×10⁻¹⁰M is the concentration of OH⁻ ions.
To know more about Concentration, here:
https://brainly.com/question/30862330
#SPJ2
What effect would you expect this to have on CO2 levels in the atmosphere?
expect what to have?!?!?!?
Which of the following correctly describes what happens to the kinetic energy of water when it changes from the liquic
state to the solid state?
• There is no change in the kinetic energy of the molecules.
O The kinetic of energy of the molecules increases.
• The kinetic energy of the molecules increases then decreases.
of O The kinetic energy of the molecules decreases.
Answer:
The kinetic energy decreases
Explanation:
When water freezes, it is losing heat. Heat and energy are interchangeable, meaning it loses energy.
Answer:
The kinetic energy of the molecules decreases.
Explanation:
because when temperature decreases the average kinetic energy of the gas molecules decreases as well.
Order the atoms from largest to smallest: Cs , Si , Sn .
Answer:
Si, Sn, Cs
Explanation:
Atomic no. Atomic radius
Silicon Si_______14___________0.117
Tin Sn______50___________0.140
cesium Cs______55___________0.262
Silicon is the smallest among these
A 50g of ethanol alcohol is cooled. if the amount of heat released is 4880 J, find the change in temperature if the specific heat of ethanol is 2.44 J/g.K?
Answer:
∆ in temperature= 40K
Explanation:
H = mc∆€
m= 50g
c = 2.44 J/g.K
∆€= ?
H= 4880
∆€= 4880/(50×2.44)
∆€= 40K
. Define the term Flame?
Answer:
A hot glowing body of ignited gas that is generated by something on fire.
A gas occupies a volume of 50.0 mL at 27°C. At what temperature, in °C, would the pressure be
101.3 kPa if the volume remains constant?
Answer:
i believe 223
Explanation:
T2 + 500k = 223 C*
A gas made up of homonuclear diatomic molecules escapes through a pinhole 0.378 times as fast as He gas. Write the chemical formula of the gas.
For a gas made up of homonuclear diatomic molecules escapes through a pinhole 0.378 times as fast as He gas, the chemical formula of the gas is mathematically given as
N2(nitrogen gas)
What is the chemical formula of the gas.?Generally, the equation for the rate to molar relationship is mathematically given as
\frac{r1}{r2}=\frac{mm2}{mm1}
Thereofore
\frac{r}{r2}=0.378
Hence
0.378=\sqrt{\frac{4.00268}{Mx2}}
Mx2=28.013g/mol
In conclusion,The name of gas with a molar mass of 28.013g/mol is N2
Therefore, the chemical formula of the gas. is N2
Read more about mass
https://brainly.com/question/15959704
How many kilograms are present in 6.78x1025molecules of Al2(SO4)3? (hint 1kg=103g)
Atomic masses:
Al = 27
S = 32
O = 16
A) 0.891kg
B) 38.5kg
C) Cannot be determined
D) 8.44kg
mol = 6.78 x 10²⁵ : 6.02 x 10²³ = 112.62
MM Al₂(SO₄)₃ = 2.27 + 3.32+12.16 =342 g/mol
mass = 112.62 x 342 = 38516.04 g = 38.5 kg
The total mass of 6.78*[tex]10^{25}[/tex] molecules of [tex]Al_{2}(SO_{4})^3[/tex] is (b) 38.5 Kg.
To calculate the mass, we need to first understand the values given in the question:1 mole of [tex]Al_{2}(SO_{4})^3[/tex] contains 6.02*[tex]10^{23}[/tex] molecules6.78*[tex]10^{25}[/tex]/6.02*[tex]10^{23}[/tex] moles are in the given amount of [tex]Al_{2}(SO_{4})^3\\[/tex]112.62 moles of [tex]Al_{2}(SO_{4})^3[/tex] is availableWeight of 1 mole [tex]Al_{2}(SO_{4})^3[/tex] is 342 gramsHence, weight of 112.62 moles of [tex]Al_{2}(SO_{4})^3[/tex] = 112.62*342 gramsThe total mass is equal to 38516.04 grams, which is equal to 38.5 Kg.Hence, the total weight of 6.78*[tex]10^{25}[/tex] molecules of [tex]Al_{2}(SO_{4})^3[/tex] is (b) 38.5 Kg.
To know more about calculation of mass from number of molecules, refer:
https://brainly.com/question/20905959
#SPJ2
where does the beta particle come from
The motion of gas particles is described by straight line motion, followed by a collision and a change in direction. This is know as
Answer:
It is called the Random Walk, where the next move (as seen through the motion of gas particles) depends on chance.
Explanation:
A reversible exothermic synthesis (combination) reaction produces one mole of gaseous product from two moles of gaseous
reactant. Which set of condtions will shift the reaction farthest toward the products?
A)
low temperature, low pressure
B)
low temperature, high pressure
9
high temperature, low pressure
D)
high temperature, high pressure
A 2.0g piece of Mg reacts with HNO3. Which conditions would produce the GREATEST reaction rate?
Factors that will increase product formation are;
low temperature and high pressure increasing the surface area and concentrationWhat factors affect chemical equilibrium?The position of chemical equilibrium is affected by the following factors:
temperature concentration pressure for gasesWhen equilibrium is altered by an external factor, the reaction shifts to annul the effect of that change.
For the reversible exothermic synthesis, low temperature and high pressure will shift the reaction farthest toward the products.
For the reaction of the 2.0g piece of Mg with HNO3. increasing the surface area of magnesium metal as well as increasing the concentration of HNO3 would produce the GREATEST reaction rate.
Learn more about equilibrium and reaction rate at: https://brainly.com/question/18849238
How many grams of air are required to complete the combustion of 186 g of phosphorus (M= 31 g/mol) to diphosphorus pentoxide, assuming the air to be 23% oxygen by mass?
4P(s) + 5O2(g) — 2P2Os(s)
Answer:
1043.5 g of air to the nearest tenth.
Explanation:
4P + 5O2 ---> 2P2O5
4*31 g P reacts with 5*32 g oxygen
124 g .. .. . .... . 160g oxygen
186 g .. .. .. .. .. (160*186)/124 g oxygen
- so the mass of air required = [(160*186)/124] / 0.23
= 240 / 0.23
= 1043.5 g of air.
What is the mass of 3.011 x 1023 atoms of Ca ?
Answer:
2g is the answer
Explanation:
based on google
An electromagnet _____________
A. is stronger than a permanent magnet
B. points north
C. can be turned on and off
D. makes noise
I need the answer fast PLS
Answer:
C. can be turned on and off
Explanation:
An electromagnet becomes magnetic when it is part of a complete electric circuit. A switch is a part of an electric circuit that completes or break the circuit turning the circuit on and off.
(*) Sorry for my late answer but I hope this helps others that are looking for this.
I got 100% ;)
Moles to mass
HELP PLEASE
15 pts
Explanation:
nose amigo, la verdad yo también tengo dificultades escolares muchísimas gracias, Dios te bendiga en otro idioma por cierto mi anime favorito es cowboy beboop
Mass of 1.5 mole electron is
Mass of 1.5 mole of electron is 0.8229 mg
mass of electron = 9.11 * 10^-31 kg
mass of 1 mole of any substance ( Avagadro number ) = 6.022 * 10^23 /mol
1.5 moles of electron = 1.5 * 6.022 * 10^23 = 9.033 * 10^23 /mol
mass of 1.5 mole of electron = 9.033 * 10^23 * 9.11 * 10^-31
mass of 1.5 mole of electron = 8.229 * 10^-7 kg
mass of 1.5 mole of electron = 8.229 * 10^-4 g
mass of 1.5 mole of electron = 0.8229 mg
Hope it helps.....
A sample 0.5 mole sample of NO2 gas occupies a 0.620 L container at 25 °C. What is the pressure of this gas?
The pressure of the sample of the gas in the container at 25 °C occupying 0.62 L is 19.73 atm
Data obtained from the question Volume (V) = 0.62 L Temperature (T) = 25 °C = 25 + 273 = 298 KGas constant (R) = 0.0821 atm.L/Kmol Number of mole (n) = 0.5 mole Pressure (P) = ?Using the ideal gas equation, the pressure of the gas can be obtained as follow:
PV = nRT
Divide both side by V
P = nRT / V
P = (0.5 × 0.0821 × 298) / 0.62
P = 19.73 atm
Thus, the pressure of the gas is 19.73 atm
Learn more about ideal gas equation:
https://brainly.com/question/4147359
I need help to balance a Balance the redox reaction under basic conditions Fe+2 +MnO4-1 ---> Fe+3 + Mn+2
Answer:
[tex]5{Fe}^{ + 2} +1{MnO_4}^{ - 1} + 8 {H}^{ + } \rightarrow 5{Fe}^{ + 3} + 1{Mn}^{ + 2} + 4H_2O[/tex]
Explanation:
To balance any redox reaction the primary factor is to identify the species undergoing oxidation and reduction.
Below are the steps to identify species undergoing oxidation and reduction:
Calculate the oxidation number of each atom individually of reactants as well as product.find out the change in oxidation number from reactants to products.if the oxidation number of products are greater than reactants then the species undergone oxidation.if the oxidation number of products are lesser than reactants then the species undergone reduction.let's calculate oxidation number,
given reaction
[tex]{Fe}^{ + 2} +{MnO_4}^{ - 1} \rightarrow {Fe}^{ + 3} + {Mn}^{ + 2}[/tex]
Of reactant,
[tex]Fe = +2, {MnO_4}^{ - 1} \\ Let \: oxidation \: of \: Mn \: is \: x \: and \: Oxygen -2 \\ {MnO_4}^{ - 1} \rightarrow \: x + 4 \times ( - 2) = - 1 \\ {MnO_4}^{ - 1} \rightarrow \: x + - 8 = - 1 \\ {MnO_4}^{ - 1} \rightarrow \: x = + 8 - 1 \\ {MnO_4}^{ - 1} \rightarrow \: x = + 7 \\ \fbox{ Mn \: +7, O \: -2}[/tex]
Of product,
[tex]\fbox{Fe \: +3, \: Mn \: +2}[/tex]
Now calculate the change in oxidation number
[tex]Fe = +3-(+2) = +1 \\ Mn = +2-(+7) = -5[/tex]
now balance the increase in oxidation number and decrease in oxidation number,
thus we require 5 Fe for 1 MnO4-,
Now putting these numbers as their coefficient,
[tex]5{Fe}^{ + 2} +1{MnO_4}^{ - 1} \rightarrow 5{Fe}^{ + 3} + 1{Mn}^{ + 2}[/tex]
now balance oxygen atom on product side by adding water,
since there are 4 oxygen atoms in reactants 4 water molecules will be there on product side.
[tex]5{Fe}^{ + 2} +1{MnO_4}^{ - 1} \rightarrow 5{Fe}^{ + 3} + 1{Mn}^{ + 2} + 4H_2O[/tex]
now balance Hydrogen atom on reactant side by adding H+ ion, since there are 4 water molecules on product 8 H+ ion will be in reactants!
[tex]5{Fe}^{ + 2} +1{MnO_4}^{ - 1} + 8 {H}^{ + } \rightarrow 5{Fe}^{ + 3} + 1{Mn}^{ + 2} + 4H_2O[/tex]
━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
Confirming the balanced reaction, by checking number of atoms and charge on reactant vs Product side.
Total number of Fe on reactant and product = 5
Total number of Mn on reactant and product= 1
Total number of Oxygen on reactant and product = 4
Total number of hydrogen on reactant and product= 8
Total charge on reactant side= 5×(+2)-1+8=17
Total charge on product side = 5×(+3)+1×(+2)=17
━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
Thanks for joining brainly community!
13. Subtract 0.291 from 0.4
I need a breakdown of the answer?
-0.109 is the answer :)
You could basically just do column subtraction
100.0 grams of water at 4.0°C is heated until its temperature is 37°C. If the specific heat of water is 4.18 J/g°C, calculate the amount of heat energy needed to cause this rise in temperature.
The amount of heat energy needed to cause the rise in temperature of the water initially at 4 degreess Celsius is 13,794 J.
Heat required to raise the temperature of the water
The quantity of heat required to raise the temperature of the water is calculated as follows;
Q = mcΔθ
where;
m is mass of the waterc is heat capacityΔθ is change in temperatureQ = 100 x 4.18 x (37 - 4)
Q = 13,794 J
Thus, the amount of heat energy needed to cause the rise in temperature of the water initially at 4 degreess Celsius is 13,794 J.
Learn more about heat energy here: https://brainly.com/question/7541718
Why is the r.a.m. value used?
A. The r.a.m. value is used to determine how many isotopes an element has.
B. None of these
C. Atoms are too small for their masses to be measured directly.
D. A single atom cannot be isolated, so only the average size of a group of atoms can be measured.
Answer:
I think the answer is going to be d A single atom cannot be isolated, so only the average size of a group of atoms can be measured. :)
Have an amazing day!!
Please rate and mark brainliest!!
Answer: A. The r.a.m. value is used to determine how many isotopes an element has.
Explanation: Founders Educere Answer
I love you fellow summer school students, good luck.
Please rate and mark brainliest!!
Predict: How do you think you could use the Gizmo to make the color gray? _____________
_________________________________________________________________________
Observe: Change the Red, Green, and Blue values to 90. What color does this produce?
_________________________________________________________________________
The simplest way to make the color gray is by mixing white and black colors, but it can also be created by mixing colors such as red and green.
What is the grey color?This is considered a neutral and cool color that can be naturally found in elements such as rocks.
How can you make this color by mixing other colors?Neutral gray: The eeasiest way to create this color is by mixing black and white. This would give you a very neutral gray.Other shades: It is also possible to make this color by mixing colors that are opposite in the colors scale such as:Yellow and purples.Red and green.This would not be a neutral gray as it will resemble a little bit the original colors.
Learn more about colors in: https://brainly.com/question/19580247
25.88 grams of tin (ll) phosphate reacts with 31.73 grams of zinc.
a write a balanced chemical equation
b. what is the limiting reactant?
c. What is the excess reactant and how many moles of it are left over?
d. How many grams of of the products are produced? (2 answers)
Explanation:
Zn + Sn3(PO4)4 = Zn3(PO4)2 + Sn - Balanced Chemical Equation
4.3 is limiting
is the answer
if you like my answer please like comment and mark me as brilliant
The elements A and B combine to produce two differenr compounds. A3B and AB2. if 0.18 mol of A3B has a mass of 17.7g and 0.18 mol of Ab2 has a mass of 11.3g calculate the molar masses of both elemts a and b.
Taking into account the definition of a system of linear equations and molar mass, the molar masses of elements A and B are 26.778 [tex]\frac{g}{mole}[/tex] and 17.998[tex]\frac{g}{mole}[/tex] respectively.
System of linear equationsA system of linear equations is a set of two or more equations of the first degree, in which two or more unknowns are related.
Solving a system of equations consists of finding the value of each unknown so that all the equations of the system are satisfied. That is to say, the values of the unknowns must be sought, with which when replacing, they must give the solution proposed in both equations.
Definition of molar massThe molar mass of substance is a property defined as its mass per unit quantity of substance, in other words, molar mass is the amount of mass that a substance contains in one mole.
The molar mass of a compound (also called Mass or Molecular Weight) is the sum of the molar mass of the elements that form it (whose value is found in the periodic table) multiplied by the number of times they appear in the compound.
Molar masses of elements A and BBeing the molar masses of the compounds:
A₃B: [tex]\frac{17.7 g}{0.18 moles} =[/tex] 98.33 [tex]\frac{g}{mole}[/tex]AB₂: [tex]\frac{11.3 g}{0.18 moles} =[/tex] 62.77 [tex]\frac{g}{mole}[/tex]and considering the definition of molar mass of a compound, the system of equations to be solved is
[tex]\left \{ {{3mA + mB=98.33\frac{g}{mole} } \atop {mA + 2mB=62.77\frac{g}{mole} }} \right.[/tex]
where mA and mB are the molar masses of elements A and B respectively.
There are several methods to solve a system of equations, it is decided to solve it using the substitution method, which consists of clearing one of the two variables in one of the equations of the system and substituting its value in the other equation.
Isolating the variable mB from the first equation:
mB= 98.33 [tex]\frac{g}{mole}[/tex] - 3mA
and substituting in the second equation, you get:
mA + 2× (98.33 [tex]\frac{g}{mole}[/tex] - 3mA)=62.77[tex]\frac{g}{mole}[/tex]
Solving:
mA + 2× 98.33 [tex]\frac{g}{mole}[/tex] - 2×3mA=62.77[tex]\frac{g}{mole}[/tex]
mA + 196.66 [tex]\frac{g}{mole}[/tex] - 6mA=62.77[tex]\frac{g}{mole}[/tex]
mA - 6mA=62.77[tex]\frac{g}{mole}[/tex] - 196.66 [tex]\frac{g}{mole}[/tex]
(-5)mA= - 133.89 [tex]\frac{g}{mole}[/tex]
mA= (- 133.89 [tex]\frac{g}{mole}[/tex] )÷ (-5)
mA= 26.778 [tex]\frac{g}{mole}[/tex]
Remember that mB= 98.33 [tex]\frac{g}{mole}[/tex] - 3mA, replacing the value of mA:
mB= 98.33 [tex]\frac{g}{mole}[/tex] - 3×(26.778 [tex]\frac{g}{mole}[/tex])
mB= 80.334 [tex]\frac{g}{mole}[/tex]
mB= 17.998 [tex]\frac{g}{mole}[/tex]
Finally, the molar masses of elements A and B are 26.778 [tex]\frac{g}{mole}[/tex] and 17.998[tex]\frac{g}{mole}[/tex] respectively.
Learn more about
system of equations:
brainly.com/question/14323743
brainly.com/question/1365672
brainly.com/question/20533585
brainly.com/question/20379472
molar mass:
brainly.com/question/5216907
brainly.com/question/11209783
brainly.com/question/7132033
brainly.com/question/17249726