Answer:
0.9375 grams
Explanation:
As we know half life is the time period in which quantity of a substance reduces to half of its original value.
The formula to calculate amount of substance left after n half life is [tex]x/2^n[/tex]
where x is the amount of original substance
n is the no of half life.
_________________________________________
Given
No. of half lives = 4
amount of original substance = 15 gram
thus,
n = 4
x = 15 grams
amount of radioisotope left after 4 half life = [tex]x/2^n = 15 \ gram/2^4 = 15 \ grams / 16 = 0.9375 \ grams\\[/tex]
Thus, only 0.9375 grams of radioisotope are left after 4 half lives.
5.0 x 104 ml of gasoline is added to a boat that weighs
4.5 kg. What will be the mass of the boat with the added gasoline?
Answer:
ml can not be kg because ml is volume
Which of the following are examples of chemical changes?
change in composition
a substance decomposing
burning
melting
Answer:
change in composition
a substance decomposing
burning
Explanation:
A chemical change is one in which a new kind of matter is formed. It is always accompanied by energy changes (evolution or absorption of energy in form of heat or light or both).
This process is often irreversible.
Chemical changes involves changes in mass. It requires considerable amount of energy. It leads to the production of new kinds of matterNow, processes such as burning and decomposition are chemical changes and are not easily reversible.
Since new kind of matter is formed, there is a change in composition.
Melting is a physical change that is easily reversed.
Other examples of chemical changes are rusting of iron, precipitation and souring of milk.
Answer: 1 change in composition 2 a subtance decomposing 3 burning
(Brainliest) Please Help! Please do not give me a random, gibberish answer or I will report you and give you a low rating therefore dropping your popularity. Also, if you don't know the answer you can put your guess in the comments. I will give a Brainliest and 50 points!
What mass of KBr is present in 20.0 mL of 15.5% (m/v) KBr solution?
Answer:
3.10g
Explanation:
Please see the attached picture for the full solution.
Neon (Ne) is in group 18. This element
1. has 18 electrons
2. has 18 electron shells
3. is very stable
4. forms a salt when combined with a metal
Answer:
option 3
Explanation:
Neon is one of the noble gases. Noble gases don't react with any element because of their stability. Elements of Group 18 in Periodic Table are inert gases.
Answer:
is very stable
Explanation:
How would this be written as a formula? 6 molecules of water *
Answer:
either 1 or 3
Explanation:
brain
What’s the answer????
Answer:
DNA
Explanation:
solid liquid gas or plasma
Answer:
I believe its gas
Explanation:
because it has no symbolic bonds
I am not sure with the answer but I think the answer is solid.
When you are conducting a controlled experiment, what variable are you as the scientist manipulating and testing?
A. independent variable
B. dependent variable
C. controlled variable
D. uncontrolled variable
Answer: It’s A because you change the independent variable to conduct an experiment and get accurate results.
Explanation:
Answer:
The correct answer would be A
Explanation:
I did the test :)
Which of the following questions could best be answered by the work of
Charles Kuen Kao?
According to the law of conservation of matter, how must a chemical equation be written?
Question 6 options:
The subscript of every element must be the same on each side of the equation.
An equal number of compounds must appear on each side of the equation.
The same coefficient must be applied to every molecule in the equation.
An equal number of atoms must be on both sides of the equation.
Answer:
An equal number of atoms must be on both sides of the equation.
Explanation:
Which of these elements would have the largest atomic radius?
Answer:
It is Li FOR SURE
Explanation:
Answer:it’s Li
Explanation:
Where on the table would a group's
ionization energy be the greatest?
Answer:
upper left
Explanation:
it is a trend on the periodic table. Ionization energy increases from left to right(->) I t also increases down to up
Answer:
right
Explanation:
If you are doing this on usatestprep its on the right side
An atom has atomic number 11 and mass number 23. How many electrons does the atom have?
Answer:
11
Explanation:
The number of electrons is the same as the number of protons. Protons are the atomic number.
What mass of aluminum is required if 40.0 grams of iron (III) oxide is to be completely consumed as
shown in the following reaction? (NO CALCULATOR) Fe2O3(s) + 2Al(s) → 2Fe(l) + Al2O3(s) (A) 13.5 g (B) 27.0 g (C) 40.0 g (D) 67.0 g
Answer:
13.5
Explanation:
Molar mass of Fe2O3 = 2*56 + 16*3 = 112 + 48 =160 approximate value
Number of moles of Fe2O3 = mass/molar mass = 40/160 = 0.25 mol
The reaction is balanced. Fine
1 mol of Fe2O3--------> 2 mol of Al
0.25 mol--------> 0.25*2 = 0.5 mol of Al
Mass of Al required = Number of moles * Molar mass
= 0.5 * 27 = 13.5 g
can a sample of methane contain 1577 atoms?
URGENT This is due at 8:30! Help fast !!!!!!!
Gold has a density of 19.3 g/cm^3, and a volume of 17.78 cm x 9.21 cm x 4.45 cm. What is the mass of 3 gold bars ? Please explain your answer
m/v=19.3
m/17.78×9.21×4.45=19.3
19.3×17.78×9.21×4.45=m
3m=2,186.11323g
Which would be an example of a compound?
oxygen
carbon dioxide
sand
carbon
Answer:
carbondioxide is an example of compound.
Covalent bond occur between which groups of elements?Immersive Reader
a-Non-metals and Metalloid
b-Metals and Non-metals
c-Non-metals and Non-metals
d-Metals and Metalloid
Ionic bond is found between Immersive Reader
A- Non-metals with Non-metals
B- Non-metals and Metalloids
C-Metals and Non-metals
D- Metals and Metalloids
Answer:
A
Explanation:
I hope this helps. A because two non-metals can form together.
What is the acceleration of a 10kg object if a force of 3N is applied to it
Answer:
0.3kg/min
Explanation:
The formula for acceleration is a = f/m where f = force and m = mass.
a = 3/10
a = 0.3
Best of Luck
I need help plsssssssssssssss
Answer:
B
Explanation:
The work-energy theorem states that the work done on an object is equal to a change in which quantity?
O kinetic energy
O displacement
O potential energy
Omass
Answer :
A.) Kinetic energy
Explanation:
When work is either added to or taken away from a system, it forces the kinetic energy to change.
The work-energy theorem states : change in kinetic energy of an object is equal to the work done on the object
[ I took the quiz already on Edgenuity and received 100% ]
Hope this helped ! :)
Answer:
Kinetic energy
Explanation:
Edge 2020
What is the electron configuration of the element in period 2 that has 5 valence electrons (valence electrons are the electrons in the outermost shell) *
Answer:
Nitrogen
Explanation:
N= is the symbol
electronic configuration
1s2 2s2 2p3
How many grams of AlCl3 can be prepared from 3.5 moles of HCl gas?
Answer:
156 g of AlCl₃ will be produced from 3.5 moles of HCl.
Explanation:
Given data:
Number of moles of HCl = 3.5 mol
Grams of AlCl₃ produced = ?
Solution:
Balanced Chemical equation:
3HCl + Al(OH)₃ → AlCl₃ + 3H₂O
Now we will compare the moles of AlCl₃ with HCl from balanced chemical equation.
HCl : AlCl₃
3 : 1
3.5 : 1/3×3.5 = 1.17 mol
Mass of AlCl₃ produced:
Mass = number of moles ×molar mass
Mass = 1.17 mol × 133.341 g/mol
Mass = 156 g
Thus 156 g of AlCl₃ will be produced from 3.5 moles of HCl.
Determine the number of moles of oxygen gas (O2) that are needed to react with 0.725 moles of aluminum (Al).
4Al (s) + 3O2 (g) ⟶ 2Al2O3 (s)
Given :
Oxygen gas ([tex]O_2[/tex]) that are needed to react with 0.725 moles of aluminum (Al).
[tex]4Al(s)+3O_2(g)->2Al_2O_3(s)[/tex]
Solution :
4 moles of Aluminium react with 3 moles of oxygen,
Let, moles of oxygen react with 0.725 moles of Al is x.
[tex]x=\dfrac{0.725\times 3}{4}\\\\x=0.54375\ moles[/tex]
Hence, this is the required solution.
The number of moles that should be required to react is 0.54375 moles.
Calculation of the number of moles:Since There are 0.725 moles of aluminum (Al)
And, there is the chemical equation 4Al (s) + 3O2 (g) ⟶ 2Al2O3 (s)
The above equation represent 4 moles of Aluminium should be react with 3 moles of oxygen.
So, the number of moles should be
= 0.725 * 3/4
= 0.54375 moles
Therefore, The number of moles that should be required to react is 0.54375 moles.
Learn more about moles here: https://brainly.com/question/19462659
An igneous rock is found on the ground and has no identifiable crystals. What is the most likely origin of this rock?
Answer:
Its a Extrusive Igneous Rock
Explanation:
They form on the surface where they cool.
Answer: Rock was eroded by surrounding rocks
Explanation: my teacher said that but i think it is wrong-
What is SI unit and it's advantage
could anyone give me the answer to this plz 20 points
How many atoms of each element are in 4Na3PO4?
3 sodium, 1 phosphorus, 4 oxygen
4 sodium, 4 phosphorus, 4 oxygen
12 sodium, 1 phosphorus, 4 oxygen
12 sodium, 4 phosphorus, 16 oxygen
Answer:
12 sodium, 4 phosphorus, 16 oxygen
Explanation:
4Na3PO4
Has (4X3) Na ,( 4X1) P ,(4X4) O
Answer:
12 sodium, 4 phosphorus, 16 oxygen
DDDDDDDDDDDDD
Explanation:
Sam has a sample of water and a sample of carbon dioxide gas. Which sample is compressible?
Carbon dioxide
Neither
both
Water
Answer:
Carbon Dioxide
Explanation:
