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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guys help me, please
Answer:
radiation, conduction, convection, conduction
Answer:
radiation , conduction, convection, conduction
Test I. Write the specialized body structures of the following animals that can enable them adapt in the land
1. snake
Answer: specialized body structures of Snakes
Explanation:
Snakes have many adaptations that allow them to move, hunt, eat and survive in their environments. Many animals have developed specific parts of the body adapted to survival in a certain environment. Among them are webbed feet, sharp claws, whiskers, sharp teeth, large beaks, wings, and hooves. In most aquatic animals, swimming is a must. To aid swimming, many animals have adapted and evolved with webbed feet.
how does agriculture contribute to the global population in relation to health and food supplies?
Answer:
We present a quantitative analysis of global and regional food supply to reveal the flows of calories, protein and the micro-nutrients vitamin A, iron and zinc, from production through to human consumption and other end points. We quantify the extent to which reductions in the amount of human-edible crops fed to animals and, less importantly, reductions in waste, could increase food supply. The current production of crops is sufficient to provide enough food for the projected global population of 9.7 billion in 2050, although very significant changes to the socio-economic conditions of many (ensuring access to the global food supply) and radical changes to the dietary choices of most (replacing most meat and dairy with plant-based alternatives, and greater acceptance of human-edible crops currently fed to animals, especially maize, as directly-consumed human food) would be required. Under all scenarios, the scope for biofuel production is limited. Our analysis finds no nutritional case for feeding human-edible crops to animals, which reduces calorie and protein supplies. If society continues on a ‘business-as-usual’ dietary trajectory, a 119% increase in edible crops grown will be required by 2050.
Explanation:
For the given reactions determine if the entropy increases or decreases.
A) 2 KClO3 (s)⇌2 KCl (s)+3 O2 (g)
B) CoCl2 (s)+6 H2O (g)⇌CoCl2⋅6H2O
Entropy increases in reaction 1 due to increase in the number of particles while entropy decreases in reaction 2 due to decrease in the number of particles.
Entropy refers to the degree of disorderliness in a system. The higher the entropy, the more disorderly the system is and the lower the entropy, the less disorderly the system is. We must note that entropy increases with increase in the number of particles.
In the reaction, 2 KClO3 (s)⇌2 KCl (s)+3 O2 (g), entropy increases because one of the products is a gas and the number of particles increases from left to right. In the second reaction, CoCl2 (s)+6 H2O (g)⇌CoCl2⋅6H2O, entropy decreases because the number of particles decreases.
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4. Use the atomic model to answer the following questions
A. How many protons?
B. How many neutrons?
C. What is the name of this atom?
Answer:
´protons: 16
neutrons: 16
name: sulfur
Explanation:
Draw the skeletal structure of 3-octanethiol
found a picture hope this helps
Page No. Date Chemistry traignment Scientific Notation Covert 0.00000046 in to Scientific Notation
Answer:
answer is 4.6×10 with exponent 7
Answer:
[tex]4.6\times10^{-7}[/tex]
Explanation:
Remember that if the decimal point is to the right then the exponent is a negative.
[tex]4.6\times10^{-7}[/tex]
Move the decimal point to the left:
[tex].0.0.0.0.0.0.4.6[/tex]
[tex].0.0.0.0.0.0.4.6=0.00000046[/tex]
Hope this helps
1. Which member of each pair is more stable? a. 2-Methyl-1-butene or 3-Methyl-1-butene b. 2-Methyl-1-butene or 2-Methyl-2-butene c. 2.3-dimethyl-1-butene or 2.3-dimethyl-2-butene
Answer:
c. 2-dimethyl-2-butene or 3-dimethyl-1-butene
g Element X is an element in period 4. Identify X given that in the molecule XH3. It exhibits hybridization sp3. WHat is the element
Answer:
XF3 is our compound. X is unknown For the problem I am using the periodic table at this ...
Explanation:Solution for Element X is an element in period 3. Identify X given that in the molecule XH3, it exhibits hybridization sp2 . Indicate the symbol and not ...
Two or more than two atoms with different physical or chemical properties can not combine together to form an element. The element X in period 4 with covalency 3 is Arsenic (As).
What is element?Element generally consist of atoms or we can atoms combine to form element. Atoms of an element is always same, means all the properties of all atoms of one type of element is same. The periodic table is divided into groups and periods. depending on the number of valence electrons and the number of outermost orbit respectively.
In the given compound XH[tex]_3[/tex], the covalency of X is 3, means the valence electrons in the outermost shell of element X is 3. The only group that have valence electron 3 is group 15 that is nitrogen family. In the fourth period of group 15 we find Arsenic element.
Therefore the element X in period 4 with covalency 3 is Arsenic (As).
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Lookup, verify and write down the correct Lewis dot structure for tartaric acid. How many total lone pairs are there in one molecule of tartaric acid
Which of the following is true about the actinide series?
Answer:
All of the elements are radioactive and contain the transuranium elements.
Explanation:
N/A
If the pressure of 50.0 mL of oxygen gas at 100°C increases from 735 mm Hg to 925 mm Hg, what is
the final volume? Assume temperature remains constant.
Answer: .039L
Explanation:
Atomic mass is an average of the elements_____.
Specific chemical element
Answer:
The atomic mass of an element is the average mass of the atoms of an element measured in atomic mass unit (amu, also known as daltons, D). The atomic mass is a weighted average of all of the isotopes of that element, in which the mass of each isotope is multiplied by the abundance of that particular isotope.
Explanation:
How many grams of sodium acetate NaCH3COO, , must be dissolved to prepare 200. mL of a 0.216 M aqueous solution of the salt? g
Answer:
Explanation:
You have to find the mass in the mole before the molarity and then in the mole.
Chemistry
Help me please.
Answer:
4:6
Explanation:
An object's mass is less on
the Moon than it is on Earth.
Answer:
The mass of objects remains constant throughout the universe. This is because an object is made of he same amount of matter (atoms), no matter where you take it in the universe. If you take an object from the Earth to the moon, only the weight will change.
Explanation:
Did cellular respiration occur in trial 3 with the yeast and sugar?
PLEASE HELP ITS DO RIGHT NOWW
Answer:
In summary, yeast is a single-celled fungus that uses cellular respiration, which converts glucose and oxygen into carbon dioxide and ATP. ... Aerobic respiration makes the most ATP, between 36 and 38. Fermentation is anaerobic respiration and happens without oxygen.
HELP I BEG
What are two ways the atmosphere helps protect living things?
A. It traps enough energy from the Sun to keep Earth warm.
I B. It keeps Earth cold enough that most of the water is frozen and
can't evaporate.
O C. Most meteoroids bounce off its outer layers instead of striking
Earth's surface.
OD. It contains oxygen gas and carbon dioxide gas, which living things
need.
Answer:
I would say D and A
But i might be wrong
Answer:
A and D
Explanation:
Now try marking the other guy as brainiest.
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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In an acid/base titration where NaOH(aq) is the titrant and HCl(aq) is the analyte, what is true about the moles of each reactant present in the reaction flask at the equivalence point?
A. The moles of NaOH are equal to moles of HCl.
B. There are more moles of NaOH than HCl.
C. There are more moles of HCl than NaOH.
D. The concentrations are needed to determine moles.
[tex]\huge{\color{magenta}{\fcolorbox{magenta}{black}{\huge{\color{white}{\fcolorbox{aqua}{black}{✿ᴀɴsᴡᴇʀ✿}}}}}}[/tex]
A) The moles of NaOH are equal to moles of HCl.
Explanation:
NaOH + HCl ↦NaCl + H20
Natural gas is almost entirely methane. A container with a volume of 2.65L holds 0.120mol of methane. What will the volume be if an additional 0.182mol of methane is added to the container under constant temperature and pressure? Give your answer in three significant figures.
The final volume of the methane gas in the container is 6.67 L.
The given parameters;
initial volume of gas in the container, V₁ = 2.65 Linitial number of moles of gas, n₁ = 0.12 moladditional concentration, n = 0.182 molThe total number of moles of gas in the container is calculated as follows;
[tex]n_t = 0.12 + 0.182 = 0.302 \ mol[/tex]
The final volume of gas in the container is calculated as follows;
[tex]PV = nRT\\\\\frac{V}{n} = \frac{RT}{P} \\\\\frac{V_1}{n_1} = \frac{V_2}{n_2} \\\\V_2 = \frac{V_1 n_2}{n_1} \\\\V_2 = \frac{2.65 \times 0.302}{0.12} \\\\V_2 = 6.67 \ L[/tex]
Thus, the final volume of the methane gas in the container is 6.67 L.
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1 year = 365 days
1 day = 24 hours
How many years is 1,000,000 hours?
Has to be dimensional analysis
Using the Kf value of 1.2×109 calculate the concentration of Ni2+(aq) and Ni(NH3)62+ that are present at equilibrium after dissolving 1.47 gNiCl2 in 100.0 mL of NH3(aq) solution such that the equilibrium concentration of NH3 is equal to 0.20 M.
Express your answers in moles per liter to two significant figures separated by a comma.
This problem is describing the equilibrium whereby the formartion of a complex is attained when 1.47 g of nickel(II) chloride is dissolved in 100.0 mL of ammonia so that the latter's equilibium concentration is 0.20 M. Thus, it is asked to calculate the equilibrium concentrations of both nickel(II) ions and that of the complex.
Firstly, we can write out the chemical equation to be considered:
[tex]Ni^{2+}+6NH_3\rightleftharpoons Ni(NH_3)_6^{2+}[/tex]
Next, we can calculate the initial concentration of nickel(II) ions by using the concept of molarity:
[tex][Ni^{2+}]=\frac{1.47gNiCl_2*\frac{1molNiCl_2}{129.6g}*\frac{1molNi^{2+}}{1molNiCl_2} }{0.1000L}=0.113M[/tex]
Afterwards, we set up an equilibrium expression for this chemical reaction:
[tex]Kf=\frac{[Ni(NH_3)_6^{2+}]}{[Ni^{2+}][NH_3]^6}[/tex]
Which can be written in terms of the reaction extent, [tex]x[/tex]:
[tex]Kf=\frac{x}{(0.113-x)(0.2)^6}[/tex]
Now, for the calculation of [tex]x[/tex], we plug in Kf, and solve for it:
[tex]1.2x10^9=\frac{x}{(0.113-x)(0.2)^6}\\\\1.2x10^9=\frac{x}{(0.113-x)(6.4x10^{-5})}\\\\7.68x10^4(0.113-x)=x\\\\x=0.112999 M[/tex]
Which is about the same to the initial concentration of nickel(II) ions because the Kf is too large.
Thus, the required concentrations at equilibrium are about:
[tex][Ni(NH_3)_6^{2+}]=0.113M[/tex]
[tex][Ni^{2+}]=0M[/tex]
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https://brainly.com/question/13043707Compare the alkali metals and alkaline earth metals with respect to (i) Ionization enthalpy (ii) basicity of oxides (iii) solubility of hydroxide
Answer:
Ionization enthalpy
Explanation:
that should be right
Which is larger? 12 milligrams or 12 kilograms
Answer:
12 kilograms is larger.
Explanation:
Of the three units, the kilogram is the largest and the milligram is the smallest. The prefix “kilo” means a thousand and “milli” means one-thousandths. A gram is the basic unit of mass.
What are the steps to Photosynthesis
Answer:
Step 1-Light Dependent. CO2 and H2O enter the leaf.
Step 2- Light Dependent. Light hits the pigment in the membrane of a thylakoid, splitting the H2O into O2.
Step 3- Light Dependent. ...
Step 4-Light Dependent.
Step 5-Light independent.
Step 6-Light independent.
4. A system contracts from an initial volume of 15.0 L to a final volume of 10.0 L under a constant external pressure of 0.800 atm. The value of w, in J, is?
The value of the work done in joule is 405.3 J.
We know that the work done is obtained using the relation;
w = PΔV
Where;
w = work done
P = pressure
V = volume
Now, substituting values,
w = 0.800( 15.0 - 10.0)
w = 4 atm L
Since;
1 L atm = 101.325 J
4 atm L = 4 atm L × 101.325 J/1 L atm
= 405.3 J
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Oil does not dissolve in water because
Answer:
Because oil have apolar molecules, while water have polar molecules
How many federal agencies are responsible for managing land resources in the United States?
2
4
ОООО
6
10
The answer would be 4.
The agencies are:
Department of Agriculture's Forest Service (AFS)
Department of the Interior's Bureau of Land Management (BLM)
Fish and Wildlife Service (FWS)
National Park Service (NPS)
These four agencies cover around 95% of the land and are the only federal agencies.
I learned about these agencies in school.
To what pH should you adjust a standard hydrogen electrode to get an electrode potential of -0.128 V ? (Assume that the partial pressure of hydrogen gas remains at 1 atm.) Express your answer using two decimal places.\
The pH of the standard hydrogen electrode that has electrode potential of -0.128 V is 4.3.
The equation of the hydrogen electrode is;
2H^+(aq) + 2e ⇄ H2(g)
The standard electrode potential of hydrogen is 0.00 V
Using the Nernst equation;
Ecell = E°cell - 0.0592/n log Q
Now;
E°cell = 0.00 V
n = 2
Q = 1/[H^+]
-0.128 = 0.00 - 0.0592/2 log 1/[H^+]
-0.128 = 0.00 - 0.0296 log 1/[H^+]
-0.128 = - 0.0296 log 1/[H^+]
-0.128/ - 0.0296 = log 1/[H^+]
1/[H^+] = Antilog (4.32)
[H^+] = 4.79 × 10^-5
Now;
pH = -log[H^+]
pH = -log (4.79 × 10^-5)
pH = 4.3
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