9. How long will it take 120 grams of Strontium-90 to decay to 7.5 grams?
with steps pls
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
pls asap figure it out pls I will mark brainliest
Answer:
NaCl (Na is a metal and Cl is a nonmetal) MgO (Mg is a metal and O is a nonmetal) Al2O3, NaF, Na2O
Explanation:
You have to have a metal and a non metal together for it to be ionic
Someone please answer this...
Answer:
5446.8 J
Explanation:
From the question given above, the following data were obtained:
Mass (M) = 50 g
Initial temperature (T₁) = 70 °C
Final temperature (T₂) = 192.4 °C
Specific heat capacity (C) = 0.89 J/gºC
Heat (Q) required =?
Next, we shall determine the change in the temperature. This can be obtained as follow:
Initial temperature (T₁) = 70 °C
Final temperature (T₂) = 192.4 °C
Change in temperature (ΔT) =?
ΔT = T₂ – T₁
ΔT = 192.4 – 70
ΔT = 122.4 °C
Finally, we shall determine the heat required to heat up the block of aluminum as follow:
Mass (M) = 50 g
Specific heat capacity (C) = 0.89 J/gºC
Change in temperature (ΔT) = 122.4 °C
Heat (Q) required =?
Q = MCΔT
Q = 50 × 0.89 × 122.4
Q = 5446.8 J
Thus, the heat required to heat up the block of aluminum is 5446.8 J
True or False, plz don't answer if you don't know the correct answer
Answer:
The answer is true
Explanation:
Hope this can help
You have a stock solution of HNO3 with a concentration of 4.5 x 10^-4 M. However, you need 275 ml of a 2.50 x 10^-5 M solution. How much of the stock solution will you need?
Answer:
15.28 mL
Explanation:
From the question given above, the following data were obtained:
Molarity of stock solution (M₁) = 4.5x10¯⁴ M
Volume of diluted solution (V₂) = 275 mL
Molarity of diluted solution (M₂) = 2.5×10¯⁵ M
Volume of stock solution (V₁) needed =.?
The volume of the stock solution needed can be obtained by using the dilution formula as illustrated below:
M₁V₁ = M₂V₂
4.5x10¯⁴ × V₁ = 2.5×10¯⁵ × 275
4.5x10¯⁴ × V₁ = 0.006875
Divide both side by 4.5x10¯⁴
V₁ = 0.006875 / 4.5x10¯⁴
V₁ = 15.28 mL
Therefore, the volume of the stock solution needed is 15.28 mL
what water has 97% of water
Answer:
ocean
Explanation:
because its easy
Could someone pls help me if you know it!!
Answer:
Beautiftul, begging under F
honest, beginning in thrid line under A
hopeful, fifth line under F
Explanation:
18. Which statement about photosynthesis is FALSE?
a
Tilmy green pigment chlorophyll captures light
energy
b Oxygen is needed as a reactant to produce
glucose
The process converts light energy from the
csun into chemical energy in the bonds of
glucose.
d
Carbon dioxide is needed as a reactant to
produce glucose.
Which statement about photosynthesis is FALSE?
Answer:
b. Oxygen is needed as a reactant to produce
glucose is the incorrect statement here
Explanation:
plants uses simple raw materials to prepare their food , which includes water ( H2O ) and Carbon dioxide ( CO2 ).
and traps sunlight by Green pigments known as chlorophyll and stores these energy in bonds of glucose molecules
so ,
after this reaction glucose and oxygen is formed as products
● hence we conclude that Oxygen is not needed as a reactant to produce glucose , oxygen is the bi product formed during photosynthesis.
help me with cience for brainest:) its easy:)
Answer:
Stronger
And its science
Explanation:
Answer:
stronger for top.
weaker for bottom.
passed all sciences in freshman year :D
"You learned about mixtures, especially solutions and the factors that affect their makeup and properties. Why is it important to know the properties of both solutes and solvents when preparing a solution that is expected to meet a certain need?
Does this involve a chemical change or a physical change? Explain."
Can u pls help me
Answer:
its due to the solvents being factored. to be prepared for the solution you would need a chemical change as the solvents get factored so this will mean that it will have a chemical reaction. in this case its slightly different so it will be called a chemical change as 2 different chemicals change and evolve.
Explanation:
No one answers my Questions :(
Please help its my last one:
Name three sources of atmospheric carbon dioxide. (Write in complete sentences and be very detailed.)
This is science.
First and best answer gets 5 stars, a thanks, and a brainliest!
Doing this because I know I'm kickass at Chemistry.
One source would be human emissions. As humans, we use a lot of machines (like power plants) that produce large amounts of carbon dioxide into the atmosphere. The ocean also produces a lot of carbon dioxide via the evaporation cycle. Polluted waters eventually will go into the atmosphere. Volcanoes, even when not erupted, emit a lot of carbon dioxide as well. Dormant underground magma releases carbon dioxide through the Earth's pores, and even when a volcano erupts, it produces carbon dioxide as well.
What is the molecular formula of a compound that is 51.02 % carbon, 13.80 % hydrogen, and 35.18 %
oxygen? The molecular mass is 88.0 g/mol.
Answer:
Molecular formula = C₄H₁₂O₂
Explanation:
Given data:
Percentage of hydrogen = 13.80%
Percentage of carbon = 51.02%
Percentage of oxygen = 35.18%
Molecular formula = ?
Solution:
Number of gram atoms of H = 13.80 / 1.01 = 13.6
Number of gram atoms of O = 35.18 / 16 = 2.2
Number of gram atoms of C = 51.02 / 12 = 4.25
Atomic ratio:
C : H : O
4.25/2.2 : 13.6/2.2 : 2.2/2.2
2 : 6 : 1
C : H : O = 2 : 6 : 1
Empirical formula is C₂H₆O.
Molecular formula:
Molecular formula = n (empirical formula)
n = molar mass of compound / empirical formula mass
Empirical formula mass = C₂H₆O = 46 g/mol
n = 88 / 46
n = 2
Molecular formula = n (empirical formula)
Molecular formula = 2 (C₂H₆O)
Molecular formula = C₄H₁₂O₂
I've decided that i still want to have some orange juice
Answer:
Oh thats great..
But I hate juice :(
WHICH OF THE FOUR COMPOUNDS HAS BONDS WITH THE GREATEST DEGREE OF POLARITY (MOST POLAR)?
Answer:
I NEED TO KNOW THIS TOO
Explanation:
IVE BEEN LOOKING FOR THE ANSWER
what is tetra atomic molecules?
Answer:
Explanation:
They are the molecules that are formed when four atoms chemically bond together.
A student is drinking a cup of hot chocolate as they sit by a campfire on a chilly evening. They know that the cup of hot chocolate transfers thermal energy to the surrounding air. The heated air over their cup of hot chocolate expands and rises and is replaced by cooler, denser air.
This method of energy transfer is —
Answer:
A student is drinking a cup of hot chocolate as they sit by a campfire on a chilly evening. They know that the cup of hot chocolate transfers thermal energy to the surrounding air. The heated air over their cup of hot chocolate expands and rises and is replaced by cooler, denser air.
This method of energy transfer is
Explanation:
Answer:
radiation
Explanation:
radiation is when an existing heat source spreads heat to its surroundings
what is the charge on a calcium (Ca) atom that contains 18e?
Answer:
Ca2+
Explanation:
which personal trait do scientists mainly depend upon when they design an experiment
Answer:
creativity is the personal trait that scientists mainly depend upon when they design an experiment.
How many moles are present in 5.24 x 1023 molecules of CH4?
Answer:
0.807 moles
Explanation:
No of molecules = No of mole × Avogadro's number
No of mole = No of molecules / Avogadro's number
No of mole = 5.24×10^23/6.02×10^23
0.870 moles
What is true about a chemical reaction
Answer: energy is transferred, but it can go to the products or the reactants.
Explanation: in a chemical reaction, the atoms and molecules that interact with each other are called reactants.
what is the temperature in the fahrenheit?
How can mutations occur in cells? Submi Save and Exit Next Mark this and return
by rounding them to the neerest 10
when is light produced during e- configuration
Why does forming bonds release energy? *
What is the percent composition of Phosphorus in Li3PO3
Answer:
you will get 17.983 g of lithium for every 100 g of lithium phosphate.
Explanation:
69.7% is the percent by mass of Lithium in Li[tex]_3[/tex]PO[tex]_3[/tex]. A percent is obtained by multiplying the result by 100.
One approach to show the concentration for an element within a compound or component in a combination is as a mass percentage. The mass percentage is computed by dividing the total weight of the combination by the mass of each component and multiplying the result by 100%. The mass percent is calculated by dividing the mass that contains the compound and solute by the mass for the element or solute.
99.795g/mol = molar mass of Li[tex]_3[/tex]PO[tex]_3[/tex]
6.94g/mol = molar mass of Li
mass percentage of Li=(molar mass of Li/molar mass of Li[tex]_3[/tex]PO[tex]_3[/tex])× 100
=(6.94/99.7)× 100
=69.7%
To know more about mass percentage, here:
brainly.com/question/32197511
#SPJ6
The photo shows wires made of pure copper, an element
What would the smallest piece of copper be?
A. Copper atom
B. Mixture of different kinds of metallic elements
C. Copper molecule
D. Compound containing two or more elements
Answer:
B
Explanation:
I hope its right. I'm pretty sure.
Answer:
Explanation:
Copper Atom
Please select the word from the list that best fits the definition.
Science lab, bring water and sodium
a) term calendar
b) weekly schedule
c) daily organizer
Answer:
C. Daily Organizer. Also called an agenda. We usually write notes in them for school related things so the answer is pretty self explanatory.
Give two limitations of law of Constant Composition
Answer:
1.The law does not hold true if the different isotopes of the element are involved in making chemical compound.
2.The law is not applicable when elements combine in the same ratio but different compounds are formed.
Newton's first law of motion explains how
affects an object's motion. According to
Newton's first law, an obiect at rest will stay at
Answer:
rest until and unless an external force is applied.
Any two difference between short sightedness and long sightednes
Explanation:
tala it is also called myopia lekhnu hai
Äni Arko MA it is also called hypermetropia .