Answer:
116 years
Explanation:
To solve this, we will use the half life equation;
A(t) = A_o(½)^(t/t_½)
Where;
A(t) is the amount of strontium left after t years;
A_o is the initial quantity of strontium that will undergo decay;
t_½ is the half-life of strontium
t is the time it will take to decay
We are given;
A(t) = 7.5 g
A_o = 120 g
From online values, half life of strontium-90 is 29 years. Thus, t_½ = 29
Thus;
7.5 = 120 × ½^(t/29)
Divide both sides by 120 to get;
7.5/120 = ½^(t/29)
0.0625 = ½^(t/29)
In 0.0625 = (t/29) In ½
-2.772589 = (t/29) × (-0.693147)
(t/29) = -2.772589/(-0.693147)
t/29 = 4
t = 29 × 4
t = 116 years
HELP PLEASE
Which of the following BEST describes
the size of asteroids?
A. All of them are smaller than a kilometer in diameter.
B. All of them are larger than 100 kilometers in diameter.
C. They range from smaller than 1 km to about 300 km in
diameter.
D. They range from 1 km to about 100 km in diameter.
I put chemistry because there’s no astronomy
Answer:
I think B is the answer so hope
Answer:
It's C
Explanation:
An object has a density of 40 g/cm3 and a mass of 240 g what is it’s volume
Answer:
6cm^3
Explanation:
240/40=6
6 cm^3
simple device that makes climbing easier
Answer:
inclined plane ; is that device.
DUE VERY VERY VERY SOON
What are the rows of elements called on the periodic table?
Answer:
"The elements are arranged in seven horizontal rows, called periods or series, and 18 vertical columns, called groups."
Explanation:
I GIVE OUT FREE POINTS
What is the conversion for 2.0 m x 5.0 m =
One piece of matter is divided into two pieces of matter. Identify the mass of the two new pieces combined.
A. It's the same as the original piece
B. It is greater than the original piece
C. It is less than the original piece
D. It cannot be measured
PLEASE HELP!! THANK YOU
Answer:
A. It's the same as the original piece
Explanation:
The piece of matter is the same as that of the original piece.
When the mass of the two new pieces are combined, it the same as the single and whole one.
Mass is the amount of matter contained within a substance.
When the whole is broken into two and there is no mass loss, the mass is retained when they are brought together again. In most cases mass is always conserved even physical changes.This data was collected after conducting an experiment about the amount, in liters, of water a specific plant needs per month. An accepted value for the measurement is 6 liters. These are the collected experimental values.
Which values in the collected data are precise? Check all that apply.
ANSWER:
all of them
Explanation:
preciseness is measured by how many decimal places are used not by accuracy. since all of these are to the same decimal place they are all equally precise even if they are inaccurate.
How would you do this
The empirical formula = the molecular formula = C₁₀H₂₀O
Further explanationGiven
m = 0.15 g menthol
V = 0.0337 L
T = 150 +273 = 423 K
P = 100.2 kPa =0.99 atm
Required
molar mass
The molecular formula
Solution
Ideal gas law :
PV=nRT
n=PV/RT
n=0.99 x 0.0337/0.082 x 423
n=9.6 x 10⁻⁴
n = mass/Molar mass
Molar mass = mass/n
Molar mass = 0.15/9.6 x 10⁻⁴
Molar mass = 156.25 g/mol
The empirical formula of Menthol : C₁₀H₂₀O
(The empirical formula)n= molecular formula
(C₁₀H₂₀O)n=156.25
(12.011.10+1,007.20+15,999)n=156.25
(156.25)n=156.25
n=1
What are some properties we can use to describe matter
Answer:
melting point, hardness, odor, temperature
Why do mammals require lungs? Provide 3 reasons.
PLEASE HELP I added some food coloring to some water. The water changed color, but
It's still the same water that I can drink. This is an example of ??
A. Chemical Change
B. Physical Change
Answer:
its definitely a physical change as the way you see it now is different then before
Answer:
b
Explanation:
because it changed colors
What is produced when a strong base reacts with the bicarbonate buffer system in the human body?
a.) carbon dioxide
b.) bicarbonate ions
c.) carbonic base
d.) water
Answer:
The answer is Bicarbonate ions.
Answer:
C. Carbonic base
Explanation:
EDG2021
Why do we round numbers?
Answer:
We round numbers so we can find an answer or an estimate that will be close to the actual answer. Rounding numbers is also another way to get close to an exact answer without the trouble of having to calculate every number.
Answer:
Rounding numbers make the numbers easier and more simple to use . Though they may less accurate because of the changes number . Rounding is mainly used for estimates
1. What is the basic unit of structure and function in a living thing
called?
2. How did the invention of the microscope help scientists learn
more about living things?
3. Who was the first to discover cells?
4. Draw a timeline that shows the dates, discoveries, and
scientists involved in the development of the cell theory.
5. What are the four statements of the cell theory?
6. What are specialized cells? List three examples.
7. What are four similarities that all cells share?
8. List the cell part for each letter on the diagram below. What is
the function of each part?
How many molecules are in 50.00 grams of sucrose, C12H22O11
Answer: Well take this for an example and see if it helps with 50 grams of sucrose
Explanation:
Explanation:
And we have to calculate the number of moles of sucrose present in a
lb
mass of sucrose:
Moles of sucrose
=
454
⋅
g
342.30
⋅
g
⋅
m
o
l
−
1
=
1.33
⋅
m
o
l
.
Now it is a fact that in a
mole
of stuff there are
6.022
×
10
23
individual items of stuff.........
So
1.33
⋅
m
o
l
×
6.022
×
10
23
⋅
m
o
l
−
1
≅
8
×
10
23
individual
sucrose molecules
Plz plz here
A student pours 25.0 mL of water into a graduated cylinder. She drops a plece of unknown metal with a mass of 18.9 g Into the cylinder. The
water level rises to 32.0 mL. The student uses the table to identify the metal
Answer:
Aluminum
Explanation
The volume of the metal is found by subtracting the final volume by the Intel volume giving 7
And the formula for density is mass divided by volume hence minus 7 by 18.9 giving 2.7
PERIODIC TABLE
What element is located at the period 3, group 13?
Answer:
Aluminiun
Explanation:
PLEASE HELPPP!!!!!! ASAP!!!!
Which of the following best describes cations? Question 19 options: A) They're negatively charged because they lost an electron. B) They're positively charged because they gained an electron. C) They're positively charged because the number of electrons remained the same. D) They're positively charged because they lost an electron.
Answer:D
Explanation:trust me bro
Answer:
D
Explanation: I took the test
What is the ability for a substance to flow
The ability for a substance to flow is fluidity.
Which substances show flowing?Only liquid and gaseous substances have the ability to flow from one point to other as they have weak intermolecular force in it.
Fluidity is the quantity which gives idea about the ability of that substance to flow. At normal conditions at room temperature, any substance has the tendency to distort its shape in order to flow or take the shape of the container it is enclosed in.
Hence the ability for a substance to flow is fluidity.
To know more about fluidity, visit the below link:
https://brainly.in/question/466917
#SPJ2
Given the following reaction, how many liters of H2 gas are needed to form 35.5 grams of NH3?
N2 + 3H2 -> 2NH3
Answer:
170.4L
Explanation:
The reaction equation is given as:
N₂ + 3H₂ → 2NH₃
Mass of NH₃ = 35.5g
Problem:
How many liters of H₂ are needed to produce 35.5g of NH₃
Solution:
To solve this problem, let us find the number of moles of NH₃;
Number of moles = [tex]\frac{mass}{molar mass}[/tex]
Molar mass of NH₃ = 14 + 3(1) = 17g/mol
So;
Number of moles = [tex]\frac{35.5}{17}[/tex] = 5.07mole
From the balanced reaction equation:
2 mole of NH₃ will be produced from 3 mole of H₂
5.07mole of NH₃ will produce [tex]\frac{5.07 x 3}{2}[/tex] = 7.61mole of H₂
At STP;
1 mole of gas will occupy 22.4L
7.61 mole of H₂ will occupy 7.61 x 22.4 = 170.4L
The reaction of iron (III) metal with a solution of copper (II) sulfate releases iron ions into the solution through a single displacement reaction.
a. Determine the moles of iron ions produced in this reaction.
b. Name a soluble compound that could be added to precipitate all of the iron ions from the solution.
c. What mass of the soluble compound from part (c) is required to precipitate all of the iron ions you determined in part (b)? HINTs: determine a new chemical reaction with your soluble compound Fe2(SO4)3. Then, use the moles of Fe2(SO4)3 calculated in part (b)
Answer:
. Name a soluble compound that could be added to precipitate all of the iron ions from the solution.
Sodium Hydroxide.
What are groups of particles held tightly together called?
What number of cations is present in 1.17g of sodium chloride ?
Answer:
1.2 × 10^22 atoms.
Explanation:
Firstly, cations refers to the positively charged atom in the ionic compound, which is Na+.
Given the mass of NaCl as 1.17g, the number of moles of NaCl can be calculated this:
Molar mass of NaCl = 23 + 35.5
= 58.5g/mol
Mole = mass/molar mass
Mole = 1.17/58.5
Mole = 0.02moles
Using Avagadro's number, 6.022 × 10^23 atoms of Na+ are in 1 mole of NaCl.
In 0.02 moles of NaCl, there are 0.02 × 6.022 × 10^23 of Na+
0.1204 × 10^23 atoms
1.2 × 10^22 atoms of Na+ (cation)
What are two uses of carbon?
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Carbon fibre is finding many uses as a very strong, yet lightweight, material. It is currently used in tennis rackets, skis, fishing rods, rockets and aeroplanes.Impure carbon in the form of charcoal (from wood) and coke (from coal) is used in metal smelting. It is particularly important in the iron and steel industries.[tex]{\huge{\underline{\small{\mathbb{\blue{HOPE\:HELPS\:UH :)}}}}}}[/tex]
Match each atomic particle with the correct charge.
1. proton neutral
2. neutron positive
3. electron negative
The proton is a postitive charge, therefore, being 1 (proton) matched to positive. Whilst neutron (2) is matched to neutral. Thus electron (3) is matched to negative.
Why is the sun colder in winter?
Answer:
ummm the sun isn’t colder in winter actually the sun continues to get hotter every day?
its colder in winter because were roating further away From the sun…
4. Pb +FeSO, - PbSO, +Fe
Reaction Type:
Answer:Fe
Explanation:
What is chemical structure about?
Answer:
chemical structure determines the molecular geometry of ca compound by prtraying the arrangement of atoms and chemical bonds in the molecule..
Explanation:
hope this helps any <3
define the following terms
A) chemical family
B) period
C) metalloid
Answer:
Chemical Family means a group of elements in the Periodic Table or, more commonly, compounds that share certain physical and chemical characteristics and have a common name.
A period in the periodic table is a row of chemical elements.
metalloid is an element (e.g. arsenic, antimony, or tin) whose properties are intermediate between those of metals and solid nonmetals or semiconductors.
electron configuration for Li
Answer:
the electronic configuration of Li is
=》 2, 1
and in spdf configuration it's 1s^2 2s^1
Answer: [He] 2s1
Explanation:
Electrons per shell: 2,1
Atomic number: 3
Electronegativity: 0.98
Atomic mass: 6.941 u
Discoverer: Johan August Arfwedson
Period: Period 2 element