Answer:
Hope it helps.
Explanation:
The lanthanide (/ˈlænθənaɪd/) or lanthanoid (/ˈlænθənɔɪd/) series of chemical elements[1] comprises the 15 metallic chemical elements with atomic numbers 57–71, from lanthanum through lutetium.[2][3][4] These elements, along with the chemically similar elements scandium and yttrium, are often collectively known as the rare earth elements.
The informal chemical symbol Ln is used in general discussions of lanthanide chemistry to refer to any lanthanide. All but one of the lanthanides are f-block elements, corresponding to the filling of the 4f electron shell; depending on the source, either lanthanum or lutetium is considered a d-block element, but is included due to its chemical similarities with the other 14.[5] All lanthanide elements form trivalent cations, Ln3+, whose chemistry is largely determined by the ionic radius, which decreases steadily from lanthanum to lutetium.
They are called lanthanides because the elements in the series are chemically similar to lanthanum. Both lanthanum and lutetium have been labeled as group 3 elements, because they have a single valence electron in the 5d shell. However, both elements are often included in discussions of the chemistry of lanthanide elements. Lanthanum is the more often omitted of the two, because its placement as a group 3 element is somewhat more common in texts and for semantic reasons: since "lanthanide" means "like lanthanum", it has been argued that lanthanum cannot logically be a lanthanide, but IUPAC acknowledges its inclusion based on common usage.[6]
In presentations of the periodic table, the lanthanides and the actinides are customarily shown as two additional rows below the main body of the table,[2] with placeholders or else a selected single element of each series (either lanthanum and actinium, or lutetium and lawrencium) shown in a single cell of the main table, between barium and hafnium, and radium and rutherfordium, respectively. This convention is entirely a matter of aesthetics and formatting practicality; a rarely used wide-formatted periodic table inserts the lanthanide and actinide series in their proper places, as parts of the table's sixth and seventh rows (periods).
The 1985 International Union of Pure and Applied Chemistry “Red Book” (p. 45) recommends that "lanthanoid" is used rather than "lanthanide". The ending “-ide” normally indicates a negative ion. However, owing to wide current use, “lanthanide” is still allowed.
Answer:
D. Europium
Explanation:
I got this as a correct answer on apex
A solution containing a mixture of lactic acid and lactate was found to have a pH of 4.26. Calculate the ratio of the lactate concentration to the lac
Given :
pH of solution of mixture of lactic acid and lactate is 4.26 .
To Find : [tex]log( \dfrac{[ \text{Conc. of lactate}]}{[\text{Conc . of lactic acid }]}) = 0.4[/tex]
The ratio of the lactate concentration to the lactate .
Solution :
We know , pKa of lactic acid is :
pKa = 3.86 .
Now , the solution of lactic acid and lactate is a buffer solution .
So , pHof buffer acid is given by :
[tex]pH=pKa+log(\dfrac{[Salt]}{[Acid]})[/tex]
Putting all given values :
[tex]log( \dfrac{[ \text{Conc. of lactate}]}{[\text{Conc . of lactic acid }]}) = 0.4[/tex]
Taking anti log both the sides , we get :
[tex]\dfrac{[ \text{Conc. of lactate}]}{[\text{Conc . of lactic acid }]} = 2.51[/tex]
Therefore , the ratio of the lactate concentration to the lactate is 2.51 .
Hence , this is the required solution .
5(3x)-7y2=?,when x=3 and y =2
Answer:
17
Explanation:
We are given the equation:
[tex]5(3x)- 7y^2[/tex]
and asked to solve when x=3 and y=2. Therefore, we must plug 3 in for x and 2 in for y.
[tex]5(3(3))-7(2)^2[/tex]
Solve according to PEMDAS: Parentheses, Exponents, Multiplication, Addition and Subtraction.
Solve the exponent first.
⇒ (2)²= 2*2=4
[tex]5(3(3))-7(4)[/tex]
Multiply 3 and 3.
⇒3*3=9
[tex]5(9)-7(4)[/tex]
Multiply 5 and 9.
⇒5*9=45
[tex]45-7(4)[/tex]
Multiply 7 and 4.
⇒ 7*4=28
[tex]45-28[/tex]
Subtract 28 from 45.
[tex]17[/tex]
5(3x)-7y² when evaluated for x=3 and y=2 is 17
What is the mass of a neutron?
A) 1/2,000 amu
B) 1 amu
C) 2,000 amu
D) 1/200 amu
Answer:
B) 1 amu
Explanation:
What would it take for Americans today to favor a greater reliance on nuclear power as a source of electricity
Answer:
yes
Explanation:
mmmm
If an automobile slows from 26 m/s to 18 m/s in a period of 4.0 s, what was the average acceleration? a. %005.7 m/s2 b. 4.0 m/s2 c. 7.0 m/s2 d. %002.0 m/s2
Answer:-2.0
Explanation:
If an automobile slows from 26 m/s to 18 m/s in a period of 4.0 s, the average acceleration is 2.0
what is acceleration ?Acceleration can be defined as the vector quantity and has both magnitude and direction, it is a second derivative of position with respect to time and it is the first derivative of velocity with respect to time.
The change in the velocity of an object called as acceleration and the Velocity is a vector quantity with both magnitude and direction.
Acceleration can be a change in the direction of an object. For example, while pressing the accelerator of car makes the car go faster.
Acceleration(a)= final velocity(v) –initial velocity(u) time(t)
The velocity at the beginning was ‘u′, and the increased to velocity, ‘v′, after "t" time .
Learn more about acceleration , here:
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The following properties are either physical or chemical. Which one is different from the rest based on those two categories?
Answer:
Boiling point: physical
Density: physical
Ductility: physical
Heat of combustion: chemical
Explanation:
Chemical properties can only be analyzed by putting the substance through a chemical reaction, such as combustion.
Physical properties can be analyzed without altering the substance chemically. With that in mind:
Boiling point is the physical property, density is the physical property, ductility is also a physical property but combustion of heat is a chemical property.
What is physical and chemical property?A physical property is the characteristic of a substance or compound that is observed without any change in the identity of the particular substance.
The physical properties of a substance is its colour, hardness, density, and melting as well as boiling points.
A physical property is a characteristic of matter that involves in physical change and physical changes are reversible and there is no production of any new substance.
The chemical change is the property of a substance due to which new substances are formed and it is non reversible change.
The chemical properties are flammability, toxicity, heat of combustion, coordination number, enthalpy of formation, and oxidation states.
Therefore, Boiling point is the physical property, density is the physical property, ductility is also a physical property but combustion of heat is a chemical property.
Learn more about physical and chemical property here:
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what is symbol, molecule, electrovalent compound?
Answer:
the abbreviation form of full name is called symbol.
the smallest unit of cimpound is called molecule.
Which of these is a property of acids? Question 1 options: They taste sour. They turn litmus paper blue. They feel slippery. They typically contain an -OH group.
Answer:
C , They taste sour
Answer:
They taste sour
Explanation:
I know it's late but i couldnt help it i just took the test
Convert 48.66 L to daL
Can someone help me with this i don't understand it.
Answer:
The subscript next to the letter "C" will always tell you the number of carbon atoms.
13. A sample of copper has a volume of 14.75 cm3. The density of copper is 8.96 g/cm3. What is the mass of this sample?
Answer:
The answer is
132.16 gExplanation:
The mass of a substance when given the density and volume can be found by using the formula
mass = Density × volumeFrom the question
volume of copper = 14.75 cm³
Density = 8.96 g/cm³
The mass is
mass = 8.96 × 14.75
We have the final answer as
132.16 gHope this helps you
Help please! List the six steps in the scientific method. Beside them list the nine components of a lab report.
Air is a mixture because it is colorless when unpolluted. Why is this statement
wrong?
Explanation:
Air is indeed a mixture but the reason is wrong. It is because there can be different concentrations of gases in the air to give the mixture of air, such as nitrogen, oxygen and carbon dioxide.
Answer:
The statement is wrong because air is already colorless when unlimited because when it is polluted.it is not air but it is carbon and methane with oxygen so we cannot say it air.
The independent variable has control and affects the
Answer:
The independent variable is the condition that you change in an experiment. It is the variable you control.
Explanation:
It is called independent because its value does not depend on and is not affected by the state of any other variable in the experiment. Sometimes you may hear this variable called the "controlled variable" because it is the one that is changed.
What is the TLV for sodium hydroxide? Will mark brainliest!
Answer:
you could've googled it but here.
Explanation:
The former OSHA limit for sodium hydroxide (also known as caustic soda or Iye) was 2 mg/m3 as an 8-hour TWA. OSHA proposed a 2-mg/m3 ceiling limit for sodium hydroxide, based on the ACGIH- and NIOSH-recommended limits.
A wind turbine is used to convert wind energy into electricity. If you want to increase the efficiency of the turbine, which of these would most likely help increase the speed of the turbine?
Answer:
Wind turbines work on a simple principle: instead of using electricity to make wind—like a fan—wind turbines use wind to make electricity. ... water) or a generator can convert this mechanical power into electricity.
Explanation:
I hope this helps!
what method is suitable to determine whether barium is more reactive than calcium
Answer:
by looking at the number of electrons in the outermost shell of an atom determines its reactivity (the number on top of the column)
Explanation:
calcium and barium are both in column 2, since barium is located further in the column, it's more reactive
plus barium also have a larger mass than calcium
What is the density of a 700 kg object with a volume of 649 m3? (Density: D = D = m over v.) 0.927 kg/m3 .4543 kg/m3 1.079 kg/m3 4.543 kg/m3
Answer:
.4543
Explanation:
Answer:
0.927 i just did it on edg. 2020
Explanation:
What is the answer: 20°C to °F?
Answer:
68 degrees fahrenheit
Explanation:
Which statement describes how chemical formulas, such as H2O, represent compounds
Answer: B
Explanation:
Answer:
They show the elements that make up a compound.
Explanation:
Got it right 100% right
How many grams are in 160 lbs ?
Put 5.1 x 10^-7 into standard notation.
Answer:
My answer to the question is 0.00000051
Answer:
0.00000051
Explanation:
Comprised of protons, neutrons, and electrons.
Answer:
The atom
Explanation:
The following properties are either physical or chemical. Which one is different from the rest based on those two category? A.) Density B.) Appearance C.) Color D.) Reactivity
Answer:
A.)physical B.)physical C.)physical D.)chemical
A florist prepares a solution of nitrogen-phosphorus fertilizer by dissolving 5.66 g of NH4NO3 and 4.42 g of (NH4)3PO4 in enough water to make 17.0 L solution. What is the molarity of NH4+ in the solution?
Answer:
9.39x10⁻³M NH₄⁺
Explanation:
To find molarity of NH₄⁺ we need to calculate moles of NH₄⁺ that comes from NH₄NO₃ and (NH₄)₃PO₄
Moles from NH₄NO₃ (Molar mass: 80.043g/mol):
5.66g * (1mol / 80.043g) = 0.0707 moles NH₄NO₃ = Moles NH₄⁺
Moles from (NH₄)₃PO₄ (Molar mass: 149.09g/mol):
4.42g * (1mol / 149.09g) = 0.0296 moles (NH₄)₃PO₄ * 3 = 0.0889 moles NH₄⁺
Total moles NH₄⁺:
0.0707 moles + 0.0889 moles = 0.1596 moles NH₄⁺ in 17.0L
Molarity: 0.1596 moles / 17.0L =
9.39x10⁻³M NH₄⁺Determine which physical properties are being described.
a. Copper wire is used to transfer electricity.
b. There are 19.3 grams of gold in one cubic centimeter.
c. Iron turns to liquid at 1,534.85°C. Silver is very easy to bend.
d. Fluorite is a green crystal.
Answer:
Explanation:
a. Copper wire is used to transfer electricity.
Physical property : Electrical conductivity .
b. There are 19.3 grams of gold in one cubic centimeter.
Physical property : Density
c. Iron turns to liquid at 1,534.85°C.
Physical Property : Melting point
d. Fluorite is a green crystal.
Physical property : Colour .
Answer:
Explanation:
A: Conductivity
B: Density
C: Melting point
D: Hardness
E: Color
b. 239/94 Pu 4/2 He +
Answer:
im thinking its 362x
Explanation:
A mixture is made by combining 1.17 lb of salt and 3.54lb of water.What is the percentage of salt (by mass) in this mixture?
Answer:
The percentage of salt in the mixture 24.84%
Explanation:
In this problem we are required to solve for the percentage of salt in the mixture of salt and water
Step one :
We can proceed by first solving for the total mass of the mixture
Which is given as
mass of mixture =mass of salt +mass of water
Mass of mixture = 1.17+3.54
Mass of mixture = 4.71 lb
Step two :
Now let us calculate the percentage of salt present in the mixture which is
=(mass of salt/mass of mixture) *100
=(1.17/4.71)*100
=0.248*100
=24.84%
Why did the Boeing 767 crew need to do a density calculation? What was wrong
with theircalculation?
Answer:
Their calculation was way too off to the actual one.
Explanation:
Answer:
They need a density calculation so they can get the right vaule. Their calculation was way off compare to the acutal vuale.
Explanation:
Express the following numbers in scientific notation:
1. 0.00125
2.
2,000,000,000
3. 796,000
Express the following numbers in scientific notation