The activity of a radioisotope is 3000 counts per minute at one time and 2736 counts per minute 48 hours later, then the half life time is 365 hours.
How do we calculate the half life time?Half life time for the first order reaction will be calculated by uisng the below equation as:
k = 0.693/t, where
t = half life time
k is the rate constant and its value will be calculatedy using the below equation as:
ln(No/N) = kT, where
No = initial concentration of radioisotope = 3000
N = remaining contentration of radioisotope = 2736
T = time require for above change = 48 hours
On putting these values on above equation, we get
k = ln(3000/2736) / 48 = 0.0019
Now putting this value in the first equation, we get
t = 0.693/0.0019 = 364.7 = 365 hours
Hence half life time is 365 hours.
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In a titration of sulfuric acid against sodium hydroxide, 32.20 mL of 0.250 M NaOH is required to neutralize 26.60 mL of H2so
Answer:
About 0.151 M.
Explanation:
Because 32.20 mL of 0.250 M NaOH was used, determine the number of moles of NaOH consumed:
[tex]\displaystyle 32.20\text{ mL} \cdot \frac{0.250\text{ mol NaOH}}{1\text{L}} \cdot \frac{1\text{ L}}{1000\text{ mL}} = 0.00805\text{ mol NaOH}[/tex]
Find the number of moles of sulfuric acid reacted with using reaction stoichiometry:
[tex]\displaystyle 0.00805\text{ mol NaOH} \cdot \frac{1\text{ mol H$_2$SO$_4$}}{2\text{ mol NaOH}} = 0.00402\text{ mol H$_2$SO$_4$}[/tex]
Therefore, the molarity of the original sulfuric acid solution is:
[tex]\displaystyle \ [\text{H$_2$SO$_4$}] = \frac{0.00402\text{ mol}}{26.60\text{ mL}} \cdot \frac{1000\text{ mL}}{1\text{ L}} = 0.151\text{ M}[/tex]
In conclusion, the molarity of the original sulfuric acid solution was about 0.151 M.
How long are hard boiled eggs good for after peeled?.
Answer:
about 1 week
Explanation:
if you want to eat it after that smell it
4. How can you calculate the solubility of a gas in a liquid under different
pressures
The solubility of a gas in a liquid under different pressures can be calculated using Henry's Law.
The solubility of a gas in a liquid under different pressures can be calculated using Henry's Law, which describes the relationship between the pressure of a gas and its solubility in a liquid. According to Henry's Law, at a constant temperature, the solubility (S) of a gas in a liquid is directly proportional to the partial pressure (P) of the gas above the liquid.
Mathematically, Henry's Law is expressed as:
S = k * P
Where:
S = Solubility of the gas in the liquid (usually in mol/L or g/L)
k = Henry's Law constant, which is specific to the gas and the solvent at a given temperature (units depend on the units of pressure and solubility chosen)
P = Partial pressure of the gas above the liquid (usually in atm or kPa)
To calculate the solubility of a gas in a liquid under different pressures, you would typically perform the following steps:
Determine the Henry's Law constant (k) for the specific gas and solvent at the given temperature.
Measure or obtain the partial pressure (P) of the gas above the liquid at the desired pressure conditions.
Use the Henry's Law equation to calculate the solubility (S) of the gas in the liquid:
S = k * P
The solubility will be in units of mol/L (molarity) or g/L, depending on the units used for the Henry's Law constant and partial pressure.
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ii. FILL IN THE BLANK
FILL IN THE BLANK BY USING SUITABLE WORDS:
1. In electron dot structure, the dot represent ................. electrons.
2. Ionic compounds are highly soluble in ...........
3. The bond formed by the mutual sharing of two electrons is called .................. bond.
4. there are ................ bonds in nitrogen molecule.
5. the .......... bonds are non-directional.
6. NaCl is ......... in molten state
7. formula of common salt is ............
8. Oxygen gas is a ..........m molecule.
Answer:
1. In electron dot structure, the dot represent one electrons.
2. Ionic compounds are highly soluble in water.
3. The bond formed by the mutual sharing of two electrons is called covalent bond.
4. there are 3 bonds in nitrogen molecule.
5. the ionic bonds are non-directional.
6. NaCl is taken in molten state
7. formula of common salt is NaCl.
8. Oxygen gas is a diamotic molecule.
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Support gases system are subject to the same hazards as, present in any piped medical gas system with the additional hazard of_________________.
The complete statement will be "Support gases system are subject to the same hazards as, present in any piped medical gas system with the additional hazard of higher pressure"
What are gas systems?Generally, A gas system is simply defined as an assemblage of tubes, used for gas reticulation and circulation.
In conclusion, a higher pressure will be experienced as an additional hazard to the medical gas system.
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Item 16 A sample of gas has a temperature of 200 K. If the speed of every gas molecule in the sample is doubled, what is the new temperature of the gas
If the speed of every gas molecule in the sample is doubled, then the new temperature of the gas is 80K.
What is relation between the speed and temperature?Speed of any molecule of gas is measured in terms of velocity and relation between root mean square velocity and temperature will be calculated as:
V = √3RT/M
Means velocity is directly proportional to the square root of the temperature, and for this question required equation is:
V₁/V₂ = √T₁/T₂
If velocity of the molecule is gets double then equation becomes,
V₁/2V₁ = √200/T₂
T₂ = 800K
Hence resultant temperature of gas is 800K.
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2. Calculate the percentage yield for the production of ammonia if 23g of NH, was made from 56g of nitrogen and 12g of hydrogen. Give your answer to 2 decimal places. N₂ + 3H₂ → 2NH3
Answer:
the science behind this is 45
Explanation:
you times it by 4N²
divide it by ⁶Mn
PLEASE answer! Brainly if more than 2 answers - Liked comment - 5-star rating
Kepler-186f
a. Identify the element that makes up the initial composition of the star.
b. Explain the process of fusion between these atoms that occurs in all stars
what volume of water in ml initially at 85.4 C needs to be mixed with 200 ml of water initally at 29.5 C so that the final temperature of the water is 36.2 C
Answer:
About 27 mL of water.
Explanation:
We can use the heat transfer equation. Recall that:
[tex]\displaystyle q = mC\Delta T[/tex]
Heat is transferred from the water with higher temperature to the water with lower temperature. Hence:
[tex]\displaystyle -q_1 = q_2[/tex]
Substituting yields:
[tex]-m_1C \Delta T_1 = m_2C\Delta T _2[/tex]
We can solve for m₁:
[tex]\displaystyle \begin{aligned} m_1 &= -\frac{m_2 C\Delta T_2}{ C \Delta T_1} \\ \\ & = -\frac{m_2\Delta T_2}{\Delta T _1}\end{aligned}[/tex]
The desired final temperature of water is 36.2 °C. Substitute and evaluate:
[tex]\displaystyle \begin{aligned} m_1 & = -\frac{(200\text{ mL})(36.2\text{ $^\circ$C}-29.5\text{ $^\circ$C})}{(36.2\text{ $^\circ$C}-84.5\text{ $^\circ$C})} \\ \\ & = -\frac{(200\text{ mL})(6.7\text{ $^\circ$C})}{-49.2\text{ $^\circ$C}}\\ \\ & =27\text{ mL}\end{aligned}[/tex]
In conclusion, about 27 mL of water should be added.
Which Barium Salt is insoluble in water?
a) Calcium Bromide b) Potassium Bromide
c) Silver bromide d) Sodium bromide
Answer:
D
Explanation:
What is the molarity of 2.5 liters of solution containing 5 moles of NaCl?
Answer:
2 mol/L
Explanation:
Molarity is Moles/Liters, you just simple divide 5 moles ÷ 2.5 L =2 mol/L
A sample of iron (fe) with a mass of 200.0 g releases 9,840 cal when it freezes at its freezing point. what is the molar heat of fusion for iron? use q equals n delta h.. 2,747.7 cal/mol 2,771.8 cal/mol 2,811.7 cal/mol 3,280.0 cal/mol
The molar heat of fusion for iron with a mass of 200.0g releases 9,840 cal when it freezes at its freezing point is 2,747.7 cal/mol.
How to calculate molar heat of fusion?The heat of fusion of a substance can be calculated by using the following formula:
Q = m∆H
Where:
Q = quantity of heatm = mass∆H = change in temperature of fusionHowever, the quantity of heat has been given as 9840calories. The molar heat of fusion of iron can be calculated by dividing the heat of fusion by the number of moles of iron.
Moles of iron = mass ÷ molar mass
moles = 200g ÷ 55.8g/mol
moles = 3.58moles
molar heat of fusion = 9840 cal ÷ 3.58mol
molar heat of fusion = 2748.6 cal/mol
Therefore, the molar heat of fusion for iron with a mass of 200.0g releases 9,840 cal when it freezes at its freezing point is 2,747.7 cal/mol.
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Answer:
A) 2,747.7 cal/mol
Explanation:
EDGE 2022
if you prepare 25mL of 0.010M NaCl starting with a 0.500 M NaCl solution, how much of the initial solution do you need?
Answer:
The answer is given in the picture
Explanation:
PLEASE MARK ME BRAINLIEST IF MY ANSWER IS CORRECT PLEASEWhat is the molarity of a salt solution made by dissolving 280.Omg of NaCl in 2.00mL of water. Assume the final volume is the same as the volume of the water.
Answer:
The molarity of a solution tells you how many moles of solute you get per liter of solution.Notice that the problem provides you with the volume of the solution expressed in milliliters mL.Right from the start you should remember that you must convert this volume to liters by using the conversion factor1 L=10+3mL
Explanation:
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When the season changes and a bird migrates, the bird is responding to which of these?
an internal cue
an external cue please help
Answer:
Internal Cue
Explanation:
Answer:
an internal cue
Explanation:
just think
What is the molarity of the solution with a volume of 8.26 Liters and 9.870 moles?
Answer: 1.19 M
Explanation:
molarity = (moles of solute)/(liters of solution) = 9.870 / 8.26 = 1.19 M
The purpose of the light dependent reaction is to convert ____ to _____.
Explain how we know that charge is conserved in this
reaction: Li+ CI → Lici
Answer:
Charge is conserved due to the groups in which Lithium and Chlorine are located in the periodic table of the elements.
Explanation:
In the reaction [tex]Li + Cl - > LiCl[/tex], we can examine the groups in which Li and Cl are found in the periodic table of the elements. Lithium appears in Group 1A, or the alkali metals group, indicating that it carries a charge of +1. Chlorine appears in Group 7A, or the halogen group, indicating that it carries a charge of -1. Because LiCl's constituent elements carry the same charges as previously mentioned, LiCl will have an overall charge of 0.
The chemical equation can then be rewritten as [tex]Li^{+} + Cl^{-} - > LiCl[/tex], which, if looking at the individual charges of Li and Cl in lithium chloride, becomes [tex]Li^{+} + Cl^{-} - > Li^{+}Cl^{-}[/tex]. Adding the charges on the reactant and product sides of this chemical equation gives us zero in both locations, meaning that we have a charge of 0 on the reactant side and a charge of 0 on the product side. This indicates that charge is conserved in this reaction.
Another way to look at this is expressed in the valence electrons of Li and Cl. Li has an electron configuration of [tex]1s^{2}2s^{1}[/tex], where the n = 2 electron shell has one of eight total electrons needed to fill the valence shell. This means that Li will easily lose one electron in order to have an electron configuration where the n = 1 electron shell is full, [tex]1s^{2}[/tex], and become the [tex]Li^{+}[/tex] ion. Similarly, Cl has an electron configuration of [tex]1s^{2}2s^{2}2p^{6}3s^{2}3p^{5}[/tex] (or [tex][Ne]3s^{2}3p^{5}[/tex]), meaning that the n = 3 electron shell is one electron away from becoming complete. Cl will easily gain one electron to have the electron configuration [tex][Ne]3s^{2}3p^{6}[/tex] (or [tex][Ar][/tex]) in order to have an electron configuration where the n = 3 electron shell is full, [tex]3s^{2}3p^{6}[/tex], and become the [tex]Cl^{-}[/tex] ion. Thus, when Li and Cl bond, Li will lose the electron [tex][1, 0, 0, +\frac{1}{2}][/tex] and transfer it to Cl, where it will become the electron [tex][3, 1, 1, -\frac{1}{2}][/tex], thus conserving charge, as there is an equal total number of electrons before and after the reaction.
What is the volume of 1.60 grams of O2 gas at STP? (5 points)
1.72 liters
1.45 liters
1.32 liters
1.12 liters
Answer:
1.12 litersExplanation:
Calculating number of moles
Molar mass of O₂ = 32 gn = Given weight / Molar massn = 1.6/32n = 0.05 molesAt STP
One mole of O₂ occupies 22.4 LTherefore, 0.05 moles will occupy :22.4 L x 0.05 = 1.12 L1mol of any gas at STP contains 22.4L
moles of O_2
Given mass/molar mass1.6/320.05molNow
Volume of O_2:-
0.05(22.4)1.120LOption D
When considering metal complexation with EDTA, if you are comparing 2 metals, the metal with a higher ____________ will react with EDTA first.
If you are comparing 2 metals, the metal with a higher Number of free ions will react with EDTA first
What is EDTA ?EDTA is a type of chemical which binds certain metal ions such as calcium and magnesium. some of the functions of EDTA includes:
Preventing blood clotting of blood samplesprevention of the formation of Biofilm by bacteriasThe EDTA will readily react with metals which have a hiogher number of free ions that it can bind with.
Hence we can conclude that If you are comparing 2 metals, the metal with a higher Number of free ions will react with EDTA first.
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Animals that eat only other animals are called ________. (2 points) a carnivores b decomposers c herbivores d omnivores. Giving 27 points
Answer:
The answer is Carnivore
Explanation:
A carnivore eat meat which is other animals.
Explain how the law of conservation of mass allows you to interpret a balanced chemical equation in terms of mass.
Balancing the coefficients means that the number of atoms are the same on each side which means that the masses of reactants and products are equal.
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Water vapor enters a compressor at 35 kpa and 160°c and leaves at 300 kpa with the same specific entropy as at the inlet. What are the temperature and the specific enthalpy of water at the compressor exit? use steam tables.
The initial entropy is obtained from the initial pressure and temperature with data from A-6 using interpolation:
s= 8.2652 kJ/kgK
The final temperature is determined from the entropy and the final pressure with data from A-6 using interpolation:
T₂ = T₁+ T₂ - T₁/ 8₂ - 8₁ ( s - s₁)
= (400 + 500 - 400/8.3271 - 8.0347 (8.2652 - 8))
= 478.83°C
The final enthalpy is determined in the same way:
h₂= h₁ + h₂ - h₁/s₂ - s₁ ( s - s₁)
= ( 3275.5+ 3486.6 - 3275.5/ 8.3271 - 8.0347) (8.265)
= 3441.91 kJ/kg
2. How do you make a solution of lower concentration, using a stock solution of higher concentration.
1) Find the mass of 2.7 moles of NaCl.
Answer:
157. 788 grams
Explanation:
number of moles = mass/molar mass.
hence the mass = molar mass × number of moles
m = 58.44 × 2.7 = 157.788 grams
The term mole concept is used here to determine the mass of sodium chloride. The mass of 2.7 moles of NaCl is 157.78 g.
What is a mole?One mole of a substance is defined as that quantity of it which contains as many entities as there are atoms exactly in 12 g of carbon - 12. The formula used to calculate the number of moles is:
Number of moles = Given mass / Molar mass
The mole concept is a convenient method to express the amount of a substance. The elementary particles in moles may be atoms, ions, molecules etc.
The molar mass of NaCl = 58.44 g/mol
Here the number of moles of NaCl = 2.7
Mass = Molar mass × Number of moles
58.44 g/mol × 2.7 = 157.78 g
Thus the mass of NaCl is 157.78 g.
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Why is only increasing the ph of the ocean not enough to restore the ocean’s equilibrium?.
The increasing pH of an ocean is not enough to restore the equilibrium as seawater becomes more acidic, and the pH of the water drops. This process binds carbonate ions, reducing their abundance.
What is the ocean's equilibrium?Equilibrium is a state where the presence of base and acid is in equal quantity.
Increased pH, leads to more acidity and reduces the number of ions.
Ions are necessary for corals, oysters, mussels, and many other shelled organisms that require building their shells and skeletons.
Thus, increasing pH of an ocean is not enough to restore the equilibrium as seawater becomes more acidic, and the pH of the water drops. This process binds carbonate ions, reducing their abundance.
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Can there be pH measurements greater than 14 or less than zero? Explain.
Answer:
scale does not have fixed limits, so it is indeed possible to have a pH above 14 or below zero.
The difference in temperature of the two glasses of water is 30°C. What is their difference in temperature on the Kelvin scale?
A. 30 K C. 243 K
B. 86 K D. 303 K
Answer:
D
Explanation:
Because 30c is kevin and add 303+30=333-30=303
The difference in temperature of the two glasses of water is 30°C. The difference in temperature on the Kelvin scale is 86 K D. 303 K. Therefore, option B is correct.
What is temperature ?The term temperature is refer to the degree of hotness or coldness of an object.Temperature is measured with a thermometer. Temperature is the measure of average kinetic energy of a system.
There are main three different scales are commonly used to measure temperature that are Fahrenheit (expressed as °F), Celsius (°C), and Kelvin (K).
The difference in temperature of the two glasses of water is 30°C. The difference in temperature on the Kelvin scale is 86 K D. 303 K. Because at 30°c in Kelvin = 273 + 30
= 303 kelvin
Thus, option B is correct.
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what is the difference between biology and anatomy?
Answer:
Biology is the study of nature, like plants and animals, while anatomy is the study of the human body, like our bones and muscles.
Explanation:
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I
A chemical blank
occurs when some substances
change chemically to other substances
Answer:
its a chemical Reaction
Explanation: