The time taken for 0.240 mole sample of radiuim to decay to 1.88×10¯³ mole is 79.8 days
We'll begin by calculating the number of half-lives that has elapsed.
Original amount (N₀) = 0.240 mole
Amount remaining (N) = 1.88×10¯³ mole
Number of half-lives (n) =?N = 1/2ⁿ × N₀
1.88×10¯³ = 1/2ⁿ × 0.240
Cross multiply
1.88×10¯³ × 2ⁿ = 0.240
Divide both side by 1.88×10¯³
2ⁿ = 0.240 / 1.88×10¯³
2ⁿ = 128
2ⁿ = 2⁷
n = 7Thus, 7 half-lives has elapsed
Finally, we shall determine the time.Number of half-lives (n) = 7
Half-life (t½) = 11.4 days
Time (t) =?t = n × t½
t = 7 × 11.4
t = 79.8 daysTherefore, the time taken for 0.240 mole sample of radiuim to decay to 1.88×10¯³ mole is 79.8 days
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A strand of DNA has the following string of bases:
TAACGTCG
What is the order of bases of the RNA molecule that is built from this DNA?
The genetic makeup of the majority of these organisms is either RNA or DNA. For instance, some viruses' genetic material may be RNA whereas others' genetic material may be DNA. RNA is present in the Human Immunodeficiency Virus (HIV), which after adhering to the host cell, transforms into DNA.
DNA is a collection of molecules that is in charge of transporting and passing genetic information from parents to children. A ribonucleic acid called RNA aids in the body's production of proteins. In the human body, new cells are created as a result of this nucleic acid.
Instead of thymine, uracil is present in RNA. All other bases are same as DNA like adenine, guanine and cytosine. The order of bases in RNA is:
UAACGUCG.
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HELP ME OUT PLEASE!!
Which model represents the chemical formula NO2, nitrogen dioxide?
A) A.
B) B.
C) C.
D) D.
Answer:
C
Explanation:
The answer is C, because nitrogen is in purple, and oxygen is in blue, and in NO2 you have 2 oxygen atoms.
If 38.6 grams of iron react with an excess of bromine gas, what mass of FeBr2 can form?
Answer:
›› FeBr2 molecular weight. Molar mass of FeBr2 = 215.653 g/mol. This compound is also known as Iron(II) Bromide. Convert grams FeBr2 to moles or moles FeBr2 to grams. Molecular weight calculation: 55.845 + 79.904*2 ›› Percent composition by element
Explanation:
If 38.6 grams of iron react with an excess of bromine gas, the mass of FeBr2 can form is 149 grams.
What is mass?Mass is defined as a way to gauge how much matter there is in a substance or thing. The kilogram (kg) is the fundamental SI unit of mass, while lower masses can also be measured in grams (g). Atoms make up everyday matter. A majority of an atom's mass is contained in its nucleus.
Given Fe = 38.6 g.
Fe has a molar mass = 55.845 g/mol.
Given mass/molar mass equals 38.6g/55.845gmol-1, or 0.6912 moles of iron.
The reaction is described as Fe + Br2 FeBr2.
One mole Fe yields 1 mole of FeBr2.
FeBr2 would be produced from 0.6912 moles of Fe.
FeBr2 has a molar mass of 215.65 g/mol.
Moles of FeBr2 x Molar mass of FeBr2
= 215.65 g/mole x 0.6912 mole
= 149.06 g FeBr2 produced is the formula.
Thus, if 38.6 grams of iron react with an excess of bromine gas, the mass of FeBr2 can form is 149 grams.
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Which of the following has the greatest mass?
A) One mole of mercury
B) One mole of barium
C) One mole of gold
D) They all have the same mass
Answer:one mole of gold
Use the diagram below to answer 3 questions
Answer:
The element X is sulfur.
Sulfur will gain 2 electrons to become an ion.
The charge of sulfide ion is (2-).
Explanation:
In a reaction, 0.209 moles of gas is evolved. Given that the pressure is 0.669 atm and the volume of the gas is 7.30 L, calculate the
temperature of the gas in Kelvin, giving your answer to three significant figures.
The value of R is 0.0821 L'atm-K-1.mol-1
Temperature =
Kelvin
Complete and balance the following redox reaction in basic solution
Cr2O7^2-(aq) + Hg(l) ----> Hg^2+(aq) + Cr^3+(aq)
Answer:
balanced in ACID not BASE
Cr2O7^2-(aq) +3Hg(l) +14 H^1+ ----> 3Hg^2+ + 2Cr^3+(aq) + 7H2O
Answer
Cr2O7^2-(aq) +3Hg(l) +14 H^1+ ----> 3Hg^2+ + 2Cr^3+(aq) + 7H2O
Explanation:
Cr2O7^2-(aq) + Hg(l) ----> Hg^2+(aqH) + Cr^3+(aq)
add H^1+ (acid) to capture the O and make 7 water molecules
Cr2O7^2-(aq) + Hg(l) + H^1+ ----> Hg^2+(aqH) + Cr^3+(aq) + 7H2O
Cr goes from +6 to +3 by gaining 3 e
Hg goes from 0 to +2 by losing 2 e
we need 3 Hg for every 2 Cr
so
Cr2O7^2-(aq) +3Hg(l) +14 H^1+ ----> 3Hg^2+ + 2Cr^3+(aq) + 7H2O
2 Cr on the right and left
Net 12 positive charges on the right and the left
3 Hg on the right and left
14 H on the right and left
the equation is balanced
we cannot balance the equation in a basic solution with OH^1-
we have plenty of O in the dichromate ion. we need to convert it to water which take free H^1+ from the acid
Glucose can be found in foods like honey. What happens to glucose in the body?
OA. It goes through chemical reactions with carbon dioxide, which provides oxygen and energy for cells.
ОВ.
It goes through a physical change in the cell's nucleus to produce oxygen.
OC.
It uses carbon dioxide in the cell's nucleus to produce a larger sugar molecule.
OD.
It goes through chemical reactions with oxygen, which forms new molecules and provides energy for cells. Will Give Brainliest No
Links
Answer:It goes through chemical reactions with oxygen, which forms new molecules and provides energy for cells.
A buffer was prepared by mixing 1.00 mole of ammonia and 1.00 mole of ammonium chloride to form an aqueous solution with a total volume of 1.00 liter. To 500 mL of this solution was added 30.0 mL of 1.00 M NaOH. What is the pH of this solution?
Answer:
Idek sorry
Explanation:
So sorry i think its 1.00
Calculate the percent by mass of each element in LiClO2.
% Li:
% Cl:
% O:
ok done. Thank to me :>
Answer: Mass percent of Li: total mass Li = 6.94 g/mol. % Li = mass Li mass LiClO 2 × 100 % Li = 6 . ...
Mass percent of Cl: total mass Cl = 35.45 g/mol. % Cl = mass Cl mass LiClO 2 × 100 % Cl = 35 . ...
Mass percent of O: total mass O = 32.00 g/mol.
Explanation:
what is the final volume (L) of each of the following diluted solutions? a 0.70 M HCl solution prepared from 25 mL of a 6.0 M HCl solution
The final volume of diluted solution is 214.39 mL
From the question given above, the following data were obtained:
Molarity of diluted solution (M₂) = 0.7 M
Molarity of stock solution (M₁) = 6 M
Volume of stock solution (V₁) = 25 mL
Volume of diluted solution (V₂) = ?M₁V₁ = M₂V₂
6 × 25 = 0.7 × V₂
150 = 0.7 × V₂
Divide both side by 0.7
V₂ = 150 / 0.7
V₂ = 214.39 mLTherefore, the volume of the diluted solution is 214.39 mL
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Which of the following is NOT a property of gases?
Which of the following is NOT a property of gases?
a. Constant shape
b. Fill their container
c. Have mass
d. Easily compressed
Answer:
a. Constant shape
An example of kinetic energy being converted into heat energy
Answer:
if you drop a water balloon onto the ground, its kinetic energy is converted mostly to thermal energy. If the balloon weighs 1 kilogram and you drop it from about 2 meters, it will heat up by less.
Explanation:
As you say, kinetic energy of large objects can be converted into this thermal energy. For example, if you drop a water balloon onto the ground, its kinetic energy is converted mostly to thermal energy. If the balloon weighs 1 kilogram and you drop it from about 2 meters, it will heat up by less than.
How could you tell if a substance has undergone a physical change or a chemical one?
Answer: Chemical changes occur when a substance combines with another to form a new substance, called chemical synthesis or, alternatively, chemical decomposition into two or more different substances. These processes are called chemical reactions and, in general, are not reversible except by further chemical reactions.
A physical change is are changes affecting the form of a chemical substance, but not its chemical composition. Physical changes are used to separate mixtures into their component compounds, but can not usually be used to separate compounds into chemical elements or simpler compounds.
please Help me !! NO LINKS! fill this chemical reaction please
Answer:
see the above attachment.
Explanation:
hope this helps you.
A chemist heats the block of copper as shown in the interactive, then places the metal sample in a cup of oil at 25.00 °C instead of a cup of water. The temperature of the oil increases to 27.33 °C . Calculate the mass of oil in the cup. The specific heat of copper is 0.387 J/g⋅°C and the specific heat of oil is 1.74 J/g⋅°C .
When the oil is added to the heated copper, the energy in the system is
conserved.
The mass of the oil in the cup, is approximately 64.73 grams.Reasons:
The question parameters are;
Temperature of the oil in the cup = 25.00°C
Final temperature of the oil and copper, T₂ = 27.33 °C
Specific heat of copper, c₂ = 0.387 J/(g·°C)
Specific heat capacity of oil, c₁ = 1.74 J/(g·°C)
Required:
The mass of oil in the cup.
Solution:
The mass of the copper, m₂ = 17.920 g
Temperature of copper after heating, T₂ = 65.17°C
Temperature of the copper after being placed in the cup of oil, T₂ = 27.33°C
Heat lost by copper = Heat gained by the oil
m₂·c₂·(T₂ - T₃) = m₁·c₁·(T₃ - T₁)Therefore, we get;
17.920 × 0.387 × (65.17 - 27.33) = m₁ × 1.74 × (27.33 - 25)
262.4219136 = 4.0542·m₁
m₁ ≈ 64.73
The mass of the oil in the cup, m₁ ≈ 64.73 gLearn more here:
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Possible part of the question obtained from a similar question online, are;
The mass of the copper, m₂ = 17.920 g
Temperature of copper after heating = 65.17°C
Why did you place each biotic factor in the model where you did?
Answer:
Biotic and abiotic are the two essential factors responsible for shaping the ecosystem. The biotic factors refer to all the living beings present in an ecosystem, and the abiotic factors refer to all the non-living components like physical conditions (temperature, pH, humidity, salinity, sunlight, etc.) and chemical agents (different gases and mineral nutrients present in the air, water, soil, etc.) in an ecosystem. Therefore, both the abiotic and biotic resources affect survival and reproduction process.
Furthermore, both these components are reliant on each other. Suppose if one of the factors is removed or altered, its repercussions will be faced by the entire ecosystem. Without a doubt, abiotic factors directly affect the survival of organisms. Read on to explore what role do abiotic and biotic resources play in the ecosystem.
The two primary forces influencing the ecosystem are biotic and abiotic. The terms "biotic factors" and "abiotic factors" describe the various living and non-living elements of an ecosystem, respectively.
What is biotic factor ?A living thing that alters its surroundings is referred to as a biotic factor. Examples of organisms found in a freshwater habitat include algae, fish, amphibians, and aquatic plants. A particular ecosystem is the result of the interaction of biotic and abiotic components.
All living things, including people, fungi, and bacteria as well as animals and plants, are considered to be biotic factors. For each species to reproduce and to meet basic needs like food, the interactions between numerous biotic variables are vital.
Due to the fact that these organisms "create" food using inorganic materials and energy sources, the producers are biotic elements that are crucial to an ecological system. Without them, life might not be able to exist.
Thus, The two primary forces influencing the ecosystem are biotic and abiotic.
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i want help with these questions thanks !
Answer:
I will give you hints, as follows:
Explanation:
- two words: climate change
- methane smells funny
- the number of electric cars sold each year is increasing
- there´s a reason they´re call "renewable"
- GEOmetry, GEOlogy, GEOthermal
Hope this helps!
5. If 10.0 gram of aluminum chloride are decomposed, how many molecules of Cl, are
produced?
Answer: 6.77*1022 Molecules
Explanation: :)
The distance between two adjacent peaks on a wave is called the wavelength. (2pts) a. The wavelength of ultraviolet light is 255nm. What is the wavelength in meters? b. The wavelength of a beam of red light is 683nm. What is its wavelength in angstroms?
Answer:
a.2.55e-7
b.6830
Explanation:
9. Calculate the pOH and pH of a 0.35 M solution of the weak acid HCN.
Ka HCN = 4.8 x 10-10
Answer:
=0.35hcn20 4.7 x hcn(poh) =hcnty sa pointd
Plaseee ASAP
In an experiment hydrochloric acid is added drop by drop to solid sodium sulfite (Na2SO3). A gas is evolved and collected. Half of the collected gas is added to Lugol solution (I2 dissolved in KI solution), the other half of the gas is added to hydrogen sulfide solution. Write the equation of the reactions, discuss the observations that can be seen during the reactions and explain the changes. In your answer, also discuss the followings:
a) What gas is liberated during the reaction between HCl and Na2SO3? Why can it be liberated this way? Write an equation for the reaction.
b) What ability of the gas is
demonstrated in the reactions with Lugol solution and with H2S? Write equations and use oxidation numbers to prove it. What makes it possible for the substance to act differently in the two reactions?
c) What other properties of the gas evolved can you recall?
d) What are the environmental implications of the gas evolved? Write the appropriate equation for the reaction.
SO2 acts both as an oxidizing and a reducing agent depending on the conditions of the reaction. It also leads to acid rain.
The reaction of HCl with Na2SO3 occurs as follows;
Na2SO3 + 2HCl ------> 2NaCl + SO2 + H2O
The gas evolved in the reaction is SO2. It is liberated because sulfites react with acids to liberate sulfur IV oxide.
The ionic equation of the reaction is; [tex]SO3^2-(aq) + 2H^+(aq) ----> SO2(g) + H2O(l)[/tex]
The reaction of SO2 with Lugol solution occurs as follows;
SO2 +I2 + 2H20→ H2SO4 + 2HI. This demonstrates oxidation because sulfur is oxidized from +4 to +6 state from left to right. This shows SO2 as a reducing agent.
With H2S, the gas reacts as follows;
2H2S + SO2 → 3S (s) + 2H2O
The oxidation number of sulfur decreases from +4 to zero. This demonstrates the gas as an oxidizing agent. SO2 can act as oxidizing or reducing agent because it can change its oxidation state to +6(oxidation) by electron loss or gain electrons to decrease its oxidation state as low as -2.
The gas SO2 is an acid gas. It dissolves in water to yield an acid solution. Also SO2 is a bleaching agent. The major environmental impact of SO2 is that it leads to acid rain as follows; 2SO2 + O2 + 2H2O⇌2H2SO4.
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What is caused by temperature differences in the mantle resulting in plate movement?
Crust
Convection Currents
Lithosphere
Answer:
Convection Currents
Explanation:
What happens to the particles of air inside a ball it warms in the sun?
Answer:
The particles start moving faster and expand making the ball expand.
Explanation:
How many double bonds does CCL2H2 have?
Disadvantage and advantage of iodine ?
- umoren sŭm..
THE ADVANTAGE OF IODIN
IODINE CAN LEAD TO GOITER AND OTHER THYROID PROBLEMS.THE DISADVANTAGE OF IODIN
IODIN MAY LEAD TO THYROIDITIS AND THYROID PAPILLARY CANCER6. How will you obtain ? (a) Magnesium oxide from magnesium. (b) Silver chloride from silver nitrate. (c) Nitrogen dioxide from lead nitrate. (d) Zinc chloride from zinc. (e) Ammonia from nitrogen. Also give balanced equations for the reactions.
plx answer this question
Answer:
a) reaction with oxygen
2mg +o2---------2mgo
b) Agno3+NaCl ----------AgCl+NaNo3
An atom from the column 1 can form an iconic compound with another from column 18
True
Or
False
pls help see attached pic for the question.
Answer: Evaporation and sublimation.
Explanation: Evaporation is the process of changing from liquid to gas, and sublimation is the process of changing from solid to gas.
What mass of aluminium chloride can be obtained when 0.48mols of aluminium is completely reacted with dilute hydrochloric acid?
Equation for this reaction:
2Al + 6HCl 2AlCl3 + 3H2
Answer:
Explanation:
we will do ratio method
Aluminum chloride : Aluminum
2 : 2
0.48 : x
(cross multiply)
0.48 x 2 / 2 = 0.48 moles of aluminum
mass = 1 mole of aluminum chloride x moles
mass = 133.33 x 0.48
mass = 63.9984g (round off) = 64g
I hope this helps.