Answer:
The answer is
1.204 × 10²⁴ atoms of BExplanation:
To find the number of entities of a substance given it's number of moles we use the formula
N = n × Lwhere n is the number of moles
N is the number of entities
L is the Avogadro's constant which is
6.02 × 10²³ entities
From the question
n = 2.0 moles
We have
N = 2 × 6.02 × 10²³
We have the final answer as
1.204 × 10²⁴ atoms of BHope this helps you
Number of moles of boron (B) = 2
To Find :We have to find number of atoms present in the given amount of boron[tex].[/tex]
Solution :➤ We know that 1 mole of substance contains 6.022×10²³ particles (atoms/molecules).
Avogadro's no. = 6.022 × 10²³★ Number of atoms present in B :
⭆ N = n × [tex]\sf{N_A}[/tex]
N denotes number of atomsn denotes mole number[tex]\sf{N_A}[/tex] denotes avogadro's number⭆ N = 2 × 6.022 × 10²³
⭆ N = 12.044 × 10²³
⭆ N = 1.2 × 10²⁴
Hope It Helps!3. What is SI system? Why has SI system been developed? Give reasons
Consider an element X that has two naturally occurring isotopes with the following percent abundances: the first isotope has a mass number of 84.912 and is 72.17% abundant; the second isotope has a mass number of 86.909 and is 27.83% abundant. What is the average atomic mass for element X?
the order of particle in all substance is the same
A True
B false
Answer:
false false false false
Katie needs to measure water for a recipe she is using to cook dinner she should measure the liquid in...
A. inches
B. pints
C. pounds
D. yards
Answer:
pints
Explanation:
Answer:
B: pints
fl.oz.
Explanation:
If this decay has a half life of 2.60 years, what mass of 72.5 g of sodium 22 will remain after 15.6 years
Sodium-22 remain : 1.13 g
Further explanationThe atomic nucleus can experience decay into 2 particles or more due to the instability of its atomic nucleus.
Usually, radioactive elements have an unstable atomic nucleus.
General formulas used in decay:
[tex]\large{\boxed{\bold{N_t=N_0(\dfrac{1}{2})^{T/t\frac{1}{2} }}}[/tex]
T = duration of decay
t 1/2 = half-life
N₀ = the number of initial radioactive atoms
Nt = the number of radioactive atoms left after decaying during T time
half-life = t 1/2=2.6 years
T=15.6 years
No=72.5 g
[tex]\tt Nt=72.5.\dfrac{1}{2}^{15.6/2.6}\\\\Nt=72.5.\dfrac{1}{2}^6\\\\Nt=1.13~g[/tex]
What is meant by the statement "Atoms are electrically neutral"?
Answer:
They have the same number of electrons as protons.
Explanation:
Atoms are electrically neutral means that all the charges within the atom are balance to equal neutral. An atom has the same number of protons as it does electrons, therefore the charge is neutral.
An ion has a different number of electrons than protons, making the ion either positively or negatively charged.
Answer:
Hi! I am currently taking AP Chemistry, I'll try to help you out.
That quote basically just means that the atom as a whole is not positively or negatively charged. Atoms are made up of protons, neutrons, and electrons. Neutrons are neutrally charged. Protons are positively electrically charged. And electrons are negatively electrically charged. In atoms, if there is an even number of protons and electrons, they can cancel each other's charges out, which results in the atom as a whole being electrically neutral.
Hope this helps! Feel free to mark me Brainliest if you feel this helped. :)
PLEASE HELP ASAP How many moles are there in 2.25 x 10^25 atoms of Zinc?
How many atoms are there in 9500.0 mg of Fluorine?
Answer:
There are 6.023 x 10^23 fluorine atoms.
Explanation:
Please help me!! Look at the picture to understand the question please!
Which of these red outlined elements is most similar to Chlorine (CL)?
A. He
B. I
C. AI
Answer:
C. I
Explanation:
The elements are categorized in groups and periods. The periods are horizontal and the groups are vertical. The elements in the same group (vertical) have very similar characteristics.
HELP ME ASAP PLEASE BIG POINTs
Answer:
1.cation
2.anion
Explanation:
the plus is always cation and the negative is anion
Answer:
1. cation
2. anion
Explanation:
A positive ion is always cation and the negative ion is anion
17 POINTS!!! JUST DO A B C D PLS!!!! PLS DONT COMMENT IF YOU DONT KNOW IT ITS DUE BY TOMORROW AND I CANT KEEP WASTING POINTS PLS
Answer:
A B C D E
Explanation:
Which term names the longest geologic time frame?
Answer:
Precambrian
Explanation:
Answer:
An Eon
Explanation:
epcohs are the shortest geologic time frame, which make up periods, that make up eras, that make up eons.
5.) You bought a new car and estimated that your monthly payment would be $312. However, your actual
payment amount is $325. How much error was in your estimate?
a large office building is 1.07x10^2m long,31m wide. and 4.25x10^2m high. what id the volume?
If a large office building is 1.07 x 10^2 meters long, 31 meters wide. and 4.25 x 10^2 meters high, then the volume of the building would be 1409725 meters cube.
What is density?It can be defined as the mass of any object or body per unit volume of the particular object or body. Generally, it is expressed as in gram per cm³ or kilogram per meter³.
As given in the problem we have to calculate the volume of a large office building having the dimensions of 1.07 x 10 ^2 meters long, 31 meters wide, and 4.25 x 10^2 meters high.
The volume of the office building = length × width × height
=107 × 31 × 425
=140925 meters cube
Thus, the volume of the building would be 140925 meters cube.
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What happened to the rate of the reaction when the concentration was increased?
Explain the effect of concentration on reaction rate in terms of collision theory. Your answer should include at least four complete sentences.
Answer:
If you increase the concentration of a reactant, there will be more of the chemical present. More reactant particles moving together allow more collisions to happen and so the reaction rate is increased. The higher the concentration of reactants, the faster the rate of a reaction will be.
If u have time pls help...
How is it that the chair is a solid, the water is a liquid, and the air you're breathing a solid if the entire room is the same temp? What about the substances make them different states at the same temperature?
Answer:
the internal force of attraction between the particle or molecules.
In solids the force is max.
In liquid it is intermediate.
And least in the gases..
True/False (A= True & B =False) 46. Blood is a tissue. 47. Elastic cartilage is found in the ears, nose, epiglottis and larynx. 48. If you have a neoplasm you hope it is benign. 49. All cancers are neoplasms but not all neoplasms are cancer. 50. Plasma cells produce Histamine 51. The liver is one organ that can partially regenerate because it is made of epithelial cells 52. Keratin is a waterproofing protein found in epithelial cells
Answer:
46.A 47.B 48.B 49.A.50.A.51.B.52.B
The answer of the questions serially is true, false,false ,true,true,false and false where blood is a tissue which circulated by the pumping organ that is heart.
What is heart?
Heart is a muscular organ which is present in most of the animals , it is responsible for pumping blood via the blood vessels to the entire body.The blood which is pumped carries oxygen and nutrients along with it.Along with it on it's way back to heart it carries carbon dioxide to the lungs.
Heart has an approximate size of a closed fist and is present between the lungs in the middle compartment of the chest. It is divided in to for chambers , the upper chambers called atria and lower ones called ventricles.
The wall of the heart is made up of three layers : epicardium,myocardium and endocardium. It pumps blood with a rhythm which is determined by a group of cells which are called the pacemaker cells present in the sinoatrial node.
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they are located between each of the atrium and ventricle to prevent blood from flowing backwards, what is it?
What is the relationship between a white dwarf and black dwarf?
Answer:
No longer emitting heat or light, the white dwarf will become a black dwarf. Because it emits no radiation, it is nearly impossible to see. However, the black dwarf would still retain its mass, allowing scientists to detect the effects produced by its gravitational field.
Explanation:
Answer:
white dwarfs are hot, black dwarfs are cold
Explanation:
a white dwarf is a slowly burning and aging corpse of a main sequence star such as our sun. they are up to 40 times hotter then the sun, ranking among one of the hottest objects in the universe, except their luminosity is so low that all their heat stays in them basically forever.
On the other hand, a black dwarf is a theoretical ending to a white dwarf, over the course of trillions of years, white dwarfs cool down into black dwarfs. black dwarfs rank among the coldest possible temperature. We aren't sure if these are really a thing, because we still haven't given white dwarfs enough time to cool down.
What are the main characteristics for the definition of work?
Answer:
1-There Must be some displacement in the direction of force. 2-Angle between force and displacement is 0°.
Which expression represents the number 0.00017 written in scientific notation?
A.1.7 x 10-3
B.1.7 x 103
C.1.7 x 104
D. 1.7 x 10-4
Answer:
D
Explanation:
Move the decimal and count the places
name the elements that determine the weather of a place....
Which one of the following is an alkane?
A. C2H4
B. C5H10
C. C3H8
D. C4H6
how do convection currents form ?
Answer:
Convection currents occur when a fluid is near a heat source.
Explanation:
Heat sources provide energy to their surroundings. When fluid receives this energy, molecules inside it move around more, spacing out from each other and lowering the density.
We know from helium balloons that things with lower densities than their surroundings are pushed upwards. Therefore, the fluid close to the heat source moves upwards, as it is hotter than the rest.
As this fluid moves up, cooler molecules drift down, succumbing to gravity.
As hot molecules move up and further from the heat source, they cool down, and drop. As colder molecules drop and move towards the heat source, they heat up, and begin rising.
This results in a circular motion called a convection current. It is present in the strong winds at the seaside and in the magma in the Earth's mantle.
Use the information below to explain why the atomic radius decreases across a period.
Answer:
Detail is given below.
Explanation:
Atomic radius trend along period:
As we move from left to right across the periodic table the number of valance electrons increases. The atomic size tend to decrease in same period of periodic table because the electrons are added with in the same shell. When the electron are added, at the same time protons are also added in the nucleus. The positive charge is going to increase and this charge is greater in effect than the charge of electrons. This effect lead to the greater nuclear attraction. The electrons are pull towards the nucleus and valance shell get closer to the nucleus. As a result of this greater nuclear attraction atomic radius decreases and ionization energy increases because it is very difficult to remove the electron from atom and more energy is required.
we can see in picture A there is one positive charge and force of attraction is 2.30×10⁻⁸ N
In picture D there are 2 positive charge and force of attraction is 4.60×10⁻⁸ N
So by increasing the positive charge force of attraction also increases.
In F we can see there is more positive charge thus force of attraction is also greater.
What is the correct formula for calcium dihydrogen phosphate?
A) CaH2PO4
B) Ca(H2PO4)2
C) Ca(H2HPO4)2
D) Ca2H2PO4
Answer:
B) Ca(H2PO4)2
Explanation:
To solve this we must be knowing each and every concept related to chemical formula. Therefore, the correct option is option B among all the given options.
What is chemical formula?The chemical formula is indeed a means of expressing information about just the chemical proportion of atoms that comprise a certain chemical compound as well as molecule through the use of chemical element numbers and symbols.
Furthermore, the molecular formula does not contain any words and does not serve as a chemical name. However, it just indicates basic chemical structures and is not the same as the entire chemical structural formula. The correct formula for calcium dihydrogen phosphate is Ca(H[tex]_2[/tex]PO[tex]_4[/tex])[tex]_2[/tex].
Therefore, the correct option is option B among all the given options.
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Definition of periodic trends
The half life of iodine-125 is 60 days. What was the initial amount of iodine-125 if you have 4.5 grams after 360 days?
Answer:
288 grams
Explanation:
The amount of any radiative substance left after some time is calculated by
amount left = [tex]x/2^n[/tex]
where x is the initial amount of substance
n is the number of half lives
one half live is the time in which amount of substance reduce to half of its initial value.
------------------------------------------------------
amount left = 4.5 grams
half life of iodine-125 = 60 days
total time in which substance reduced to 4.5 grams = 360 days
thus,
number of half life in 60 days = 360/60 = 6
thus, there are period of 6 half lives
in each half life the amount of substance reduces to its previous half
let the initial amount be x grams
using the formula
amount left = [tex]x/2^n[/tex]
[tex]4.5 = x/2^6 \\ 4.5 = x/64\\x = 4.5*64 = 288[/tex]
Thus, 288 grams was the initial amount of iodine-125
45.761 g - 42.98 = ___________
I believe your answer would be
2.781
Mrs. K is trying to rearrange her living room. She uses 150 N of force to move a 600 g table. The table does not move. How much work is done?
90,000 J
4 J
600 J
0 J
Answer:
0J
Explanation:
Work = Force * Distance
Since the distance (or the displacement) in this problem is 0, hence, no work is done. W = 150*0 = 0. The mass of the object is just trying to trick you. Hopes this helps!
How many mL are in 7.3 dL?
Answer:
730 mL which is .73 L
Explanation: