Answer:
The number of its protons and electrons are 82 each
Explanation:
Atomic no of an element = 82
Atomic no = No of protons
⇒ No of protons = 82
Electrons are negatively charged particle and Protons are positively charged particles.
No of electrons = 82
Hence, the element is Lead with 82 protons and electrons
1)Fluorine-21 has a half life of approximately 5 seconds. If you start with 100g, how much
would remain after 10 seconds?
What’s the answr
Answer:
25 g
Explanation:
The following data were obtained from the question:
Half life (t½) = 5 s
Original amount (N₀) = 100 g
Time (t) = 10 s
Amount remaining (N) =..?
Next, we shall determine the decay constant for the disintegration. This can be obtained as follow:
Half life (t½) = 5 s
Decay constant (K) =.?
K = 0.693 / t½
K = 0.693 / 5
K = 0.1386 s¯¹
Finally, we shall determine the amount of the isotope that remained after 10 s as follow:
Original amount (N₀) = 100 g
Time (t) = 10 s
Decay (K) = 0.1386 s¯¹
Amount remaining (N) =..?
Log (N₀/N) = kt /2.303
Log (100/N) = (0.1386 × 10) / 2.303
Log (100/N) = 1.386 / 2.303
Log (100/N) = 0.6018
Take the anti log of 0.6018
100/N = antilog (0.6018)
100/N = 4
Cross multiply
100 = N × 4
Divide both side by 4
N = 100/4
N = 25 g
Therefore, the amount remaining after 10 s is 25 g
what is write out the following number as a decimal number
[tex]1.2 \times {10}^{5} [/tex]
Answer:
120000Explanation:
I hope this helps
Which statement best describes balancing equations and the law of conservation of mass?
O There are more atoms in the reactants than in the products, and the total mass is the same in the
reactants and in
the products
O The number of atoms is the same in the reactants and in the products, and the total mass is the same in the
reactants and in the products
O There are fewer atoms in the reactants than in the products, and the total mass is less in the reactants than in the
products
There are more atoms in the reactants than in the products, and the total mass is higher in the reactants than in
Toms
the products
Answer:
The number of atoms is the same in the reactants and in the products, and the total mass is the same in the reactants and in the products.
The statement best describes balancing equations and the law of conservation of mass is the number of atoms is the same in the reactants and in the products, and the total mass is the same in the reactants and in the products. Therefore, option B is correct.
What is the law of conservation of mass ?According to the law of conservation of mass or principle of mass conservation, any system that is closed to all transfers of matter and energy must maintain a constant mass over time since the system's mass cannot vary and neither more nor less amount can be added or subtracted.
This law states that no matter what physical or chemical change occurs, the overall mass of the products and reactants remain identical.
Understanding and producing different chemical reactions depend heavily on this law. Researchers might anticipate how much the result would be if they knew the identities and quantities of the reactants for each reaction.
Thus, option B is correct.
To learn more about the law of conservation of mass, follow the link;
https://brainly.com/question/20635180
#SPJ6
If the reaction yield is 88.2%,what mass in grams of hydrogen is produced by the reaction of 7.73 g of magnesium with 1.31 g of water
Mg + 2h2o >>mg(oh)2+h2
Answer:
Mass of hydrogen produced is 0.07g.
Explanation:
Given data:
Mass of magnesium = 7.73 g
Mass of water = 1.31 g
Reaction yield = 88.2%
Mass of hydrogen produced = ?
Solution:
Chemical equation:
Mg + 2H₂O → Mg(OH)₂ + H₂
Number of moles of water:
Number of moles = mass/ molar mass
Number of moles = 1.31 g / 18 g/mol
Number of moles = 0.07 mol
Number of moles of magnesium:
Number of moles = mass/ molar mass
Number of moles = 7.73 g / 18 g/mol
Number of moles = 0.43 mol
Now we will compare the moles of water and magnesium with hydrogen.
Mg : H₂
1 : 1
0.43 : 0.43
H₂O : H₂
2 : 1
0.07 : 1/2×0.07 = 0.035
Mass of hydrogen:
Mass = number of moles × molar mass
Mass = 0.035 mol × 2 g/mol
Mass = 0.07 g
Answer: 0.064 grams is the answer
Explanation:
at the end you must multiply 88.2/100*0.073=0.064
What is the mass number of Carbon–12, which has 6 protons and 6 neutrons?
Answer:
It has the atomic mass of 12.
Planets that will sink in water ?
Answer:
Any planet that is made up of mostly rock.
What is the charge on an electron?
Answer:
Electrons have a negative charge
hope this was helpful (plz vote brainliest, I would appreciate it!) :)
A___ change occurs when a substance changes phase.
Answer: chemical change
Explanation:
A physical change occurs when a substance changes phase. For example, boiling pure water (H₂O) is physical change of substance (from liquid to gaseous state).
As a seed plant grows, the roots grow downward due to the force of
Answer:
As a seed plant grows, the roots grow downward due to the force of Gravity
Explanation:
A seed is planted upside-down, but the roots still grow in the direction of gravity.
Answer:
Obviously, it's gravity
Explanation:
Because when saying moving downward, it means an object is moving down, and that is caused by gravity.If there is no gravity then it is called 0 gravity, meaning free from the ground.Which statement best Describe the people in Mississippi period
Answer:Explanation:
The statement that best describes the people of the Mississippian Period is that they were farmers who used simple tools to grow their food in small gardens. They would also fish and gather food such as muscles, in order to create a large enough food supply in addition to produce from these gardens and farms.
The circular flow model interacts between which sectors of the economy? Select THREE answers.
Private
Government
Foreign
Tech
Households
Answer:
2,3,5
Explanation:
A deck of cards has dimensions 8.9cm x 5.72cm x 1.82 cm. What is the volume of the deck in cubic centimeters?
The volume of the deck having dimensions 8.9cm x 5.72cm x 1.82 cm is 92.65 cubic centimeters.
How to find the volume of the Cube ?The volume of a cube is obtained by multiplying its side three times. The formula of volume of the cube can thus be given as, Volume of cube = s³, where s is the side length of the cube.
Given ;
Length : 8.9cmBreadth : 5.72cmHeight : 1.82 cmFormula used ;
Volume = Length x Breadth x Height
= 8.9cm x 5.72cm x 1.82 cm.
= 92.65 cm³ i.e, 92.65 cubic centimeters
Learn more about volume here ;
https://brainly.com/question/1578538
#SPJ1
Describe the “Doppler Effect.” Explain how it is used in Astronomy in term of red shift and blue shift
Answer:
This apparent change in the pitch (or frequency) of sound is called Doppler shift. ... You see these stretched-out light waves as having a lower frequency. Since red is at the low-frequency end of the visible spectrum, we say that light from a receding star is shifted toward red, or red shifted.
Explanation:
How much valence electrons does xenon have
8 valence electrons.
After filling up all the rings, Xenon has 8 electron in the very outer ring
Answer:
hope thiss will helps u
Explanation:
8 valence electrons
There are a total of 22 valence electrons in the Lewis structure for XeF2. The Lewis structure for XeF2 is a bit tougher since you have to take formal charges into account to find the best Lewis structure for the molecule. Remember that Xenon can have more than 8 valence electrons.
Some Reactions are endothermic
How does the temperature and energy change in an endo thermic reaction?
temperature change
energy change
А
decreases
energy taken in
B
decreases
energy given out
С
increases
energy taken in
increases
energy given out
D
increases
energy given out
Answer:
endothermic means energy is taken in and temperature increases.
Will give Brainiest if you can answer fast
Answer:
280 m/s
Explanation:
What is the oxidation number of Oxygen?
-1
........... ..............
Given that one mole occupies 22.4 L at STP, show that R = .082 (atm * L)/(mol*K)
A scientist plants two rows of corn for experimentation. She puts fertilizer on row 1 but does not put fertilizer on row 2. Both rows receive the same amount of sun and water. She checks the growth of the corn over the course of five months.
Q9) What is the independent variable in this experiment? Why is this variable independent?
Q10) What is the dependent variable in this experiment? Why is this a dependent variable?
Q11) What variables are controlled in this experiment? Why are/is these/this variable control variable(s)?
Answer:
Q9. The independent variable in this experiment is the fertilizer. It is independent because she manipulating the variable to compare the growth.
Q10. The dependent variable in this experiment is the amount of growth of the corn. It is this because the growth depends on what the scientist did on the corn.
Q11. The variable controlled in this experiment is the amount of sun and water. These two variables never change so this is why it is the control.
Explanation:
Answer:
Explanation:
independent - 5 months dependent - sun controlled - water and the fertilizer
Each orbit of an atom contains a set number of..........
Answer:
I'm pretty sure it's electrons
Acetylsalicylic acid (C9H8O4) is a monoprotic acid commonly known as aspirin. A typical aspirin tablet, however, contains only a small amount of the acid. In an experiment to determine its composition, an aspirin tablet was crushed and dissolved in water. It took 14.40 mL of 0.1466 M NaOH to neutralize the solution. Calculate the number of grains of aspirin in the tablet. (One grain = 0.0648 g and the molar mass of aspirin = 180.2 g/mol.)
Answer:
6 grains
Explanation:
The equation of the reaction between NaOH and aspirin is;
C9H8O4(aq) + NaOH (aq) ------>C9H7O4Na(aq) + H2O(l)
Amount of NaOH reacted = concentration × volume = 0.1466 M × 14.40/1000 L = 2.11 × 10^-3 moles
Given that aspirin and NaOH react in a mole ratio of 1:1 from the balanced reaction equation above, the number of moles of aspirin reacted is 2.11 × 10^-3 moles
Hence mass of aspirin reacted = 2.11 × 10^-3 moles × 180.2 g/mol = 0.38 g
If 1 grain = 0.0648 g
x grains = 0.38 g
x= 0.38 g/0.0648 g
x= 6 grains
Is it true or false that the Temperature is a direct measurement of the energy stored in a substance?
Identify 3 pieces of safety equipment commonly found in the science lab.
Answer: googles, fire extinguisher, fire blanket
Explanation:
Balance the following equation. ZnCl2 + (NH4)3PO4 ->__Zn3(PO4)2 + NHACI
Answer:
3ZnCl2 + 2(NH4)3PO4 → Zn3(PO4)2 + 6NH4Cl
Explanation:
Zinc Chloride + Tribasic Ammonium Phosphate = Zinc Phosphate + Ammonium Chloride
Reaction Type
Double Displacement (Metathesis)
Reactants
Zinc Chloride - ZnCl2
Zinc(II) Chloride Zinc Chloride, Anhydrous Dichlorozinc Butter Of Zinc Zinc Chloride Zn-65
Molar Mass of ZnCl2 Oxidation State of ZnCl2
Tribasic Ammonium Phosphate - (NH4)3PO4
Ammonium Phosphate
Molar Mass of H12N3O4P Oxidation State of H12N3O4P
Products
Zinc Phosphate - Zn3(PO4)2
Zinc(II) Phosphate
Molar Mass of O8P2Zn3 Oxidation State of O8P2Zn3
Ammonium Chloride - NH4Cl
Amchlor Ammoneric Ammonium Muriate Darammon Sal Ammonia Sal Ammoniac Salammonite Salmiac
Molar Mass of ClH4N Oxidation State of ClH4N
What does the name "atom" mean in
Greek?
It means indivisible
Answer:
The Greek root of atom is atomos, which means "indivisible," since the scientists who first gave the atom its name imagined it couldn't be split or divided into smaller pieces.
Explanation:
If two atoms are the same element, which statement can never be true?
1: they can have different number of protons.
2:they can have different number of electrons.
3:they can have different number of neutrons
Answer:
The answer is number 3: They can have different number of neutrons
Explanation:
What is the major threats to Philippines' aquatic biomes? As a student how can you help in preventing or combating this/these threat/s?
Answer:
Overfishing
Explanation:
The aquatic biomes of the Philippines' are rich in coral reefs and other aquatic animals but they are under major threat due to pollution and overfishing.
Pollution is caused by industrial factories and coastal developments. Industrial factories fed all it waste in the aquatic biomes and coastal developments due to the increasing population of the Philippines causes mass pollution by the dumping of waste materials and sedimentation.
Overfishing exploits the fish species and also affects the food cycle in aquatic biomes.
As a student, we can spread awareness by conducting awareness campaigns and can take the help of news channels to let people know the consequences of aquatic biomes exploitation. We can also use social media which is popular nowadays to introduce facts about the causes and consequences of aquatic biomes exploitation.
HELPP
35. A catalyst:
a. actually participates in the reaction.
b. changes the equilibrium concentration of the products.
c. decreases the rate for a reaction.
d. increases the activation energy for a reaction.
The following is a list of common errors encountered in research laboratories. Categorize each as a determinate or an indeterminate error, and further categorize determinate errors as instrumental, operative, or methodic:
(a) An unknown being weighed is hygroscopic.
(b) One component of a mixture being analyzed quantitatively by gas chromatography reacts with the column packing.
(c) The tip of the pipet used in the analysis is broken.
(d) In measuring the same peak heights of a chromatogram, two technicians each report different heights.
Answer:
An unknown being weighed is hygroscopic. - operative error
One component of a mixture being analyzed quantitatively by gas chromatography reacts with the column packing. - methodic error
The tip of the pipet used in the analysis is broken. - instrumental error
In measuring the same peak heights of a chromatogram, two technicians each report different heights - operative error
Explanation:
In chemical analysis, operative errors are that largely introduced into the measurement because of variation of personal judgements of analysts. It is also a personal error that emanates solely due to the analyst.
A methodic error arises as a result of adopting defective experimental methods. For example, a column packing that reacts with a component of the mixture is used in the gas chromatography.
Instrument error refers to the error of a measuring instrument, for instance, the use of a pipette with a broken tip.
Which element has an outer(ending) electron configuration of s2p4?
The question is in complete, the complete question is:
Which element has an outer electron configuration of s 2 p4 ?
(A) Ca (B) Cr (C) Ge (D) Se
Answer:
(D) Se
Explanation:
The outer electronic configuration of an atom reflects the group to which it belongs in the periodic table. Each group has its unique outermost electron configuration and number of electrons found in the outermost shell of the atoms of elements in the group.
s 2 p4 is the unique outermost electron configuration of group 16 elements. Group 16 elements have six electrons in their outermost shell. If we consider the options, only Se is a member of group 16. Hence it is only Se that has the outermost electron configuration s 2 p4 .
An element which has an outer (ending) electron configuration of [tex]s^2p^4[/tex] is: Oxygen.
Electron configuration can be defined as a formula that is used to denote the distribution of the atoms of a chemical element in an atomic orbital.
Basically, electron configuration uses four (4) main letters to illustrate the distribution of atoms in an atomic orbital:
spdfThe electron configuration of [tex]s^2p^4[/tex] indicates that the chemical element is in Group 6 and has six (6) electrons in its outermost shell.
Hence, a chemical element such as Oxygen (O) or Selenium (Sn) in Group 6 of the periodic table would have an electron configuration of [tex]s^2p^4[/tex].
Read more: https://brainly.com/question/18214726