Answer:
207.2
Explanation:
One mole of lead weighs 207.2 g. Thus, number of moles in 454 g of lead is determined by dividing the given mass by atomic mass that is ., 2.19 moles.
What is lead ?Lead is 82nd element in periodic table. It is in 14th group. Lead is classified among non-metals but it is a heavy metal in nature. Lead have many naturally stable isotopes of which two are radioactive.
A substance containing 6.02 × 10²³ atoms is called its one mole. This number is called Avogadro number. Hence, one mole of every elements contains Avogadro number of atoms. The mass of one mole of an element is called its atomic mass.
Atomic mass of lead (Pb) = 207. 2 g/mol
thus, number of moles in 454 g of Pb = given mass/atomic mass
no.of moles = 454 /207.2 = 2.19 moles.
Therefore, the number of moles of Pb in 454 g is 2.19.
Find more on lead:
https://brainly.com/question/11999159
#SPJ2
Number of energy levels containing electrons in iodine.
Answer:
First Energy Level: 2
Second Energy Level: 8
Third Energy Level: 18
Fourth Energy Level: 18
Element: Iodine
Group: 17
No. of electrons/shell: 2, 8, 18, 18, 7
Which substances have Delta. Hf = 0 kJ/mol by definition? Select all that apply. O2(g) N(g) H2O(l) Br2(l) Fe(s) He(g).
The substances that have Delta Hf = 0 kJ/mol are O2(g), Br2(l), He(g), Fe(s).
What is delta Hf = 0?Delta Hf = 0 is the standard enthalpy of any element in its most stable form is equal to zero.
When enthalpy is negative, the delta Hf is minus zero, which means the system releases heat.
When the system gains heat, the delta Hf is positive.
Thus, the substances are O2(g), Br2(l), He(g), Fe(s).
Learn more about Delta Hf, here:
https://brainly.com/question/25912291
Answer:
1,4,5,6
Explanation:
When you measure the temperature of hot soup you're measuring the
Answer:
Amount of Thermal Energy
Explanation:
Pure maple syrup has a high sugar content. Its composition is 70% sucrose (C12H2011). If you heat maple
syrup what will happen to its viscosity?
answer : It will decrease
Answer:
it will decrease
Explanation:
Answer:
A. it will decrease
Explanation:
trust
Explain why hydrogen, not sodium, is formed at the cathode.
Answer:
because of its electro affinity
Explanation:
it is electro positive
A 6. 0 L container holds a sample of hydrogen gas at 150 kPa. The pressure increases to 2 atm and the temperature remains constant. What will the volume be? 0. 22 L 0. 44 L 2. 26 L 4. 50 L.
The volume of the container will be 0.45L.
What is Boyle's law?This law states that the product of volume and its pressure is constant for any gas.
Given, the Volume 1 of container 6.0L
V2 =?
Pressure 1 is 150 kPa
Increased pressure 2 is 2 atm
Temperature is constant.
By Boyle's law:
P1V1 = P2V2
[tex]150 \times 6 = 2\times V2 = 450[/tex]
Thus, V2 = 0.45 L.
Learn more about volume, here:
https://brainly.com/question/1578538
what is the area of the face of a rectangle crystals that has a widlth (w) measuring 3.4 cm and a length (1) measuring 4.2 cm?
Answer:
14.28 [tex]cm^{2}[/tex]
Explanation:
Multiply length by width to get area: 3.4 x 4.2 = 14.28
The answer will be in units of cm x cm = [tex]cm^{2}[/tex]
A 5.00 kg weight is placed on a digital scale. The scale reads 4.98 kg. What
is the error of the scale measurement?
The error of this scale measurement is equal to 0.02 kg.
Given the following data:
Actual measurement = 5.00 kg.Measured value = 4.98 kg.To calculate the error of the scale measurement:
What is measurement?Measurement can be defined as an act (process) through which the weight, size, magnitude or distance traveled by an object or body is taken, especially for the purpose of an experiment.
Mathematically, the error of a scale measurement is given by this formula:
[tex]Error = Actual \;measurement-Measured \;value[/tex]
Substituting the given parameters into the formula, we have;
[tex]Error = 5.00-4.98[/tex]
Error = 0.02 kg.
Read more on measurement here: https://brainly.com/question/26374907
How many moles of iron are present in 3.15 × 1024 atoms of iron?
Answer:
5.23 moles
Explanation:
Hope this helps!
A buffered solution has a pH of 7.5. What would happen to the pH if a small
amount of acid were added?
A. The pH would stay at about 7.5.
B. The pH would become less than 7.0.
C. The pH would increase to greater than 7.5.
D. The pH would decrease to 7.0.
For this buffered solution with a pH of 7.5, B. The pH would become less than 7.0.
What is pH?In Science, pH literally means the power of hydrogen ions and it can be defined as a measure of the molar concentration of hydrogen ions in a particular solution. Thus, it is typically used to specify the acidity, neutrality or basicity of any chemical solution.
On a pH scale, a solution with a pH of 7 is neutral while a solution with a pH below 7 is acidic and it's basic (alkaline) when its pH is above 7.
In this scenario, a buffered solution with a pH of 7.5 would become less than 7.0 when a small amount of acid is added to it.
Read more on power of hydrogen here: https://brainly.com/question/24242819
How many moles is 2.80 × 1024 atoms of silicon? A. 4.65 mol B. 0.465 mol C. 2.15 mol D. 6.02 mol
Answer:
A) 4.65mol
Explanation:
[tex]\frac{2.80x10^{24}atoms }{1} *\frac{1 mol}{6.02x10^{23}atoms } =4.65mol[/tex]
empirical or molecular? (C12H6)
empirical or molecular? (C2H4O)
empirical or molecular? (C8H8S4)
Answer:
C12H6 : Molecular
C2H4O : Empirical
C8H8S4 : Molecular
Explanation:
Molecular formula : tells you the exact number of atoms of each element are in a compound. If the number of elements can be simplified it is molecular.
Empirical formula : tells you the most reduced ratio of elements in a compound. If the number of elements is already in it's simplest form it's likely empirical.
C12H6 - this is molecular because C12H6 can further be simplified to C2H
C2H4O - this is empirical because C2H4O cannot further be simplified
C8H8S4 - this is molecular because C8H8S4 can further be simplified to C2H2S
1)
Create a new species of a plant and an animal that is well-suited
for living in the tundra ecosystem. Make a drawing of each, then
list and describe three characteristics that help each organism
thrive in its environment. Don't forget to name your plant and
animali
An organism that is well-suited for living in the tundra ecosystem should ideally be adapted to cold conditions. These organisms should take advantage of the growing season and survive in low humidity conditions.
What is a tundra ecosystem?Tundra is a special type of ecosystem characterized by low temperatures, a short growing season, and low humidity.
In consequence, any organism (either plant or animal) living in a tundra should exhibit adaptation to these climate conditions.
For example, plants in the tundra are able (i.e., they are adapted) to perform photosynthesis in extremely cold temperature conditions.
Learn more about the tundra here:
https://brainly.com/question/4125133
List one symbol for an element that forms an oxidation number of
-2?
Answer:
Sulfur
Explanation:
S+2e−→S2−
Why should we turn of the main switch when there is a short circuit in your home
Explanation:
It is the safest way to shut down a circuit by switching off the main switch. If you haven't switched off the main switch and started directly working on it you are open to all kinds of harm one being electrocuted (since high current flows through the electric circuits due to the short circuit or overloading, the fuse wire heats and melts down) other methods of avoiding being electrocuted after turning the main switch off is by using insulating tools such as tools made of wood.
One mole of gas at STP occupies a volume of
a 22.0L
b 20.0L
c 224
d 25.0 L
Answer: 22.4 L
Explanation:
the constant for one mol of gas at STP is always 22.4 L and this constant is used in equations when converting from L to mol or mol to L
hope this helps :)
Imagine that the sun disappeared from the universe tomorrow. Which sphere or spheres would this affect?(1 point)
The earth and other planets start drifting into space.
What happen if sun disappear?If the sun disappear from the universe, then Earth would be drawn to a new center of gravity. The gravity of Earth and the other planets of the solar system adversely affected due to no constant supply of energy from the sun which leads to drifting of earth into space.
In conclusion, the earth and other planets start drifting into space.
Learn more about universe here: https://brainly.com/question/805395
Question 10(Multiple Choice Worth 5 points)
(04.05 LC)
During which of the following processes would carbon most likely be required?
O Breaking of rocks
O Generation of electricity
O Making of glucose
O Running of cars
I’m lost
Answer:
O Generation of electricity
Explanation:
because the others dont make sense to me and tbh carbon is used everyway and everywhere
Someone help out plz?
What is the percentage of oxygen in carbon dioxide?.
Answer:
72.7%
Explanation:
The first thing you need to do here is to figure out the mass of oxygen in
1 mole of carbon dioxide. To do that, you must use the compound's molar mass.
Now, carbon dioxide has a molar mass of 44.01 g mol−1. This means that 1 mole of carbon dioxide has a mass of 44.01 g. Oxygen has a molar mass of 16.0 g mol−1, so 1 mole of oxygen atoms has a mass of 16.0 g.
This means that if you take 44.01 g of carbon dioxide, you know for a fact that it will contain: 32g oxygen.
This means that 100 g of carbon dioxide will contain:
100gCO2 × 32gO2 / 44.01gCO2 = 72.7 g Oxygen
Therefore, carbon dioxide has a percent composition of 72.7% oxygen, i.e. for every 100 gof carbon dioxide you get 72.7 g of oxygen.
What are some of the difficulties in identifying particular drugs? Why is it important for forensic scientists to be able to identify particular drugs?
Answer:
The forensic scientist must be able to tell the difference between the substances.
Explanation:
It is important for forensic scientists to be able to identify particular drugs so they have evidence for the case that a certain drug was present.
The goal of forensic drug chemistry is to determine whether the material submitted contains an illegal substance.
number of protons in nucleus of magnesium atom????
A chemist carefully measures the amount of heat needed to raise the temperature of a sample of from to. The experiment shows that of heat are needed. What can the chemist report for the molar heat capacity of ? round your answer to significant digits.
Answer:
Are there any options or starting points for this question?
Explanation:
Which fatty acids are considered essential fatty acids?.
Answer:
alpha-linolenic acid and linoleic acid
Explanation:
Hope this helps!
PLease help my imma mark brainlist plsss
Did the chemical reaction absorb or release energy? How do you know?
Answer:
Chemical reactions that absorb (or use) energy overall are called endothermic. In endothermic reactions, more energy is absorbed when the bonds in the reactants are broken than is released when new bonds are formed in the products.
If 20 grams of NaF are used to make a 3.0 Liter solution. What is the concentration
(Molarity) of the solution?
7M
0.23 M
0.16 M
62 M
Answer: 0.16 M
Explanation:
molarity is a way to measure the concentration of solutions, the equation is the amount of solute in mol / liter of solution:
mol (solute) / L (solution)
the first thing you want to do is convert grams to moles:
20g NaF • 1 mol
———— = 0.47632464 mol
41.98817 g (molar mass of NaF)
then you just want to follow with the rest of the equation:
0.47632464 mol NaF / 3.0 L = 0.15877488 or 0.16 M (sigfigs)
hope this helps :)
Why do you not fill you car tires with just oxygen?
Answer:
in text
Explanation:
But the main reason for using pure nitrogen is resistance to leakage. Nitrogen molecules find it harder to sneak out through the tire past the rubber molecules than oxygen molecules. This makes nitrogen a good bet for race car, aircraft and heavy-duty equipment where precise or constant pressure is critical.
BRAINLIEST PLEASE !!!!
50 points
PLEASE HELp this dropped most of grade but I don’t understand at all
Answer:
that number formula units of mole that meansis You need to learn it on Yt
Example:
There are 6.022×1023 in 1 mole of anything, including formula units. You need to determine the number of moles in 0.335 g CaO . Once you know the number of moles of CaO , you can determine the number of formula units by multiplying the number of moles by 6.022×1023
Which equation below is an example of a single-replacement reaction?
A.6CO2(g) + 6H2O(l) → C6H12O6(aq) + 6O2(g)
B.H2SO4(aq) + 2NaOH(aq) → Na2SO4(aq) + 2H2O(l)
C.Ca(OH)2(s) Δ→ CaO(s)+ H2O(l)
D.Zn(s) + 2HCl(aq)→ ZnCl2(aq) + H2(g)
The equation that depicts a single replacement reaction would be: Zn(s) + 2HCl(aq)→ ZnCl2(aq) + H2(g)
Single replacement reactionsThey are also known as single displacement reactions.
They are reactions in which one element takes the place of another in a compound. That is, one element replaces another in a compound.
Looking at all the reactions from A - D, one can see that the only reaction that exemplifies a single replacement reaction is D.
Here, Zn replaced H in HCl.
More on single replacement reactions can be found here: https://brainly.com/question/13328989
someone helppp pleaseee
Answer:
Top LineNebula → Average Star → Red Giant → Planetary Nebula → White Dwarf
Bottom LineNebula → Massive Star → Red Supergiant → Supernova → Neutron Star or Black Hole (for the second box)
-TheUnknownScientist 72
Answer:
top- nebula average star, reg giant, planetary nebula, white dwarf
bottom- nebula, massive star, red supergiant, supernova, neutron star-black dwarf