Answer:
See Explanation
Explanation:
Given that;
N/No = (1/2)^t/t1/2
Where;
No = amount of radioactive isotope originally present
N = A mount of radioactive isotope present at time t
t = time taken
t1/2 = half life
N/1000=(1/2)^3/6
N/1000=(1/2)^0.5
N = (1/2)^0.5 * 1000
N= 707 unstable nuclei
Since the value of the initial activity of the radioactive material was not given, the activity of the radioactive material after three months is given by;
Decay constant = 0.693/t1/2 = 0.693/6 months = 0.1155 month^-1
Hence;
A=Aoe^-kt
Where;
A = Activity after a time t
Ao = initial activity
k = decay constant
t = time taken
A = Aoe^-3 *0.1155
A=Aoe^-0.3465
8. What was the original concentration in the BHL sample, if the dilution is 1:500 and the concentration 0.07 mg/ml
Answer:
The original concentration is "35 mg/ml".
Explanation:
According to the question,
The solution is diluted,
= 1:50
The initial volume,
V1 = 1 ml
Final concentration,
= 0.07 mg
then,
The final volume,
V2 = 500 ml
As we know,
⇒ [tex]V_1N_1=V_2N_2[/tex]
or,
⇒ [tex]N_1=\frac{V_2N_2}{V_1}[/tex]
On substituting the values, we get
⇒ [tex]=\frac{500\times 0.07}{1}[/tex]
⇒ [tex]=\frac{35}{1}[/tex]
⇒ [tex]=35 \ mg/ml[/tex]
A 0.07 mg/mL BHL solution was prepared by performing a 1:500 dilution on a 35 mg/mL solution.
A 1:500 dilution was carried out to prepare a 0.07 mg/mL BHL solution. We can find the concentration of the initial solution using the dilution rule.
What is the dilution rule?It is an equation that relates the concentration and volume of a concentrated and a dilute solution. The mathematical expression is:
C₁ × V₁ = C₂ × V₂
where,
C₁ is the concentration of the concentrated solution.V₁ is the volume of the concentrated solution.C₂ is the concentration of the dilute solution.V₂ is the volume of the dilute solution.C₁ = C₂ × (V₂/V₁)
C₁ = 0.07 mg/mL × (500/1) = 35 mg/mL
A 0.07 mg/mL BHL solution was prepared by performing a 1:500 dilution on a 35 mg/mL solution.
Learn more about dilution here: https://brainly.com/question/1615979
When an acid reacts with a strong base which product always forms
Answer:طيزي
Explanation:
7. In science, the process/thing that you examine/focus on is called the ??
and anything outside of this focus is called the ??
Answer:
Subject of the experiment and out of scope
Explanation:
In any research study, the process of thing studied is basically the subject of the experiment on which research is conducted to determine the outcomes. If any thing lies out of the experimental process reach, then it is said to be out of scope of the experiment.
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1. What are the reactants at the start of this chemical reaction? What do you start with?
2. What are the products at the end of this chemical reaction? What do you end with?
3. If the total mass of the reactants equals 150 grams, what would the total mass of the
products be?
Answer:
1.The substance(s) to the left of the arrow in a chemical equation are called reactants. A reactant is a substance that is present at the start of a chemical reaction. The substance(s) to the right of the arrow are called products
2.The substances that go into a chemical reaction are called the reactants, and the substances produced at the end of the reaction are known as the products
3.The law of conservation of mass states that in a chemical reaction, the total mass of reactants is equal to the total mass of products. For example, the mass of sodium plus the mass of chlorine that reacts with the sodium equals the mass of the product sodium chloride.
If only 0.225 g of Ca(OH)2 dissolves in enough water to give 0.100 L of aqueous solution at a given temperature, what is the Ksp value for calcium hydroxide at this temperature
Answer: The [tex]K_{sp}[/tex] value for calcium hydroxide at this temperature is [tex]1.08 \times 10^{-4}[/tex].
Explanation:
Given: Mass of [tex]Ca(OH)_{2}[/tex] = 0.225 g
Volume = 0.100 L
As moles is the mass of substance divided by its molar mass.
So, moles of [tex]Ca(OH)_{2}[/tex] (molar mass = 74 g/mol) is calculated as follows.
[tex]Moles = \frac{mass}{molar mass}\\= \frac{0.225 g}{74 g/mol}\\= 0.003 mol[/tex]
Molarity is the number of moles of substance present in a liter of solution.
Hence, molarity of given solution will be as follows.
[tex]Molarity = \frac{moles}{Volume (in L)}\\= \frac{0.003 mol}{0.1 L}\\= 0.03 M[/tex]
The equation for dissociation of [tex]Ca(OH)_{2}[/tex] is as follows.
[tex]Ca(OH)_{2} \rightarrow Ca^{2+} + 2OH^{-}[/tex]
This means that [tex][Ca^{2+}] = 0.03[/tex] and [tex][OH^{-}] = 2 \times 0.03 = 0.06[/tex]. Hence, [tex]K_{sp}[/tex] value for this reaction is calculated as follows.
[tex]K_{sp} = [Ca^{2+}][OH^{-}]^{2}\\= (0.03) \times (0.06)^{2}\\= 1.08 \times 10^{-4}[/tex]
Thus, we can conclude that the [tex]K_{sp}[/tex] value for calcium hydroxide at this temperature is [tex]1.08 \times 10^{-4}[/tex].
A 750-mL sample of hydrogen exerts a pressure of 822 torr at 325 K. What pressure does it exert if the temperature is raised to 475 K at constant volume
Answer:
1.20 × 10³ torr
Explanation:
Step 1: Given data
Initial pressure (P₁): 822 torrInitial temperature (T₁): 325 KFinal pressure (P₂): ?Final temperature (T₂): 475 KConstant volume: 750 mLStep 2: Calculate the final pressure of the gas
Considering the constant volume, if we assume the gas behaves ideally, we can calculate its final pressure using Gay-Lussac's law.
P₁/T₁ = P₂/T₂
P₂ = P₁ × T₂/T₁
P₂ = 822 torr × 475 K/325 K = 1.20 × 10³ torr
Calculate the volume of 0.07216 M AgNO3 needed to react exactly with 0.3572 g of pure Na2CO3 to produce solid Ag2CO3.
Answer:
93.4 mL
Explanation:
Let's state the reaction:
2AgNO₃ + Na₂CO₃ → Ag₂CO₃ + 2NaNO₃
We determine the moles of sodium carbonate:
0.3572 g . 1mol / 105.98g = 3.37×10⁻³ moles
Ratio is 1:2. We say:
1 mol of sodium carbonate react to 2 moles of silver nitrate
Then, our 3.37×10⁻³ moles of carbonate may react to: 3.37×10⁻³ . 2
= 6.74×10⁻³ moles
If we convert to mmoles → 6.74×10⁻³ mol . 1000 mmol / mol = 6.74 mmol
Molarity is mol/L but we can use mmol /mL
6.74 mol / volume in mL = 0.07216 M
6.74 mol / 0.07216 M = volume in mL → 93.4 mL
please help ASAPPPPPPPPPPPPPPP
Pick the correct statement about the pure water. Group of answer choices Pure water contains no ions. Pure water contains equal amounts of hydroxide [OH-] and hydronium [H3O ] ions. Pure water contains larger amounts of hydroxide [OH-] than hydronium [H3O ] ions. Pure water is an electrolyte. Pure water contains smaller amounts of hydroxide [OH-] than hydronium [H3O ] ions.
Answer:
Pure water contains no ions. TRUE
Pure water contains equal amounts of hydroxide [OH-] and hydronium [H3O+ ] ions. TRUE
Explanation:
This is the equilibrium for pure water:
2H₂O ⇄ H₃O⁺ + OH⁻ Kw
We see that pure water has no Ions. Pure water can not conduct electricity.
Generally ionized water comes from the water tap.
Another feature of pure water is pH.
Definetely pH of pure water is : 7
As pH = 7, [H₃O⁺] = 1×10⁻⁷
Then, [OH⁻] = 1×10⁻⁷
This is reazonable because Kw is 1×10⁻¹⁴ and Kw = [H₃O⁺] . [OH⁻]
In conclussion:
Pure water contains no ions. TRUE
Pure water contains equal amounts of hydroxide [OH-] and hydronium [H3O+ ] ions. TRUE
Pure water contains larger amounts of hydroxide [OH-] than hydronium [H3O+] ions. FALSE
Pure water is an electrolyte. FALSE
Pure water contains smaller amounts of hydroxide [OH-] than hydronium [H3O ] ions. FALSE
I dont understand this
Answer:
me too
Explanation:
How many moles are 2.60 * 10 ^ 27 atoms of Silicon?
Answer:
~4,317.5 moles of Silicon
Explanation:
Using Avogadro's contant we know that:
1mole = 6.022 x 10^23 atoms
So,to calculate the number of moles in 2.60 x 10^27 atoms of Silicon:
=(2.60 x 10^27 x 1)/(6.022 x 10^23)
~4,317.5 moles of Silicon
Hope it helps:)
hydrogen iodide is not produced by the same method is for hydrogen chloride why with reaction
Using Phosphoric acid will work perfectly for producing Hydrogen halides because its not an Oxidizing agent. ...
Using an ionic chloride and Phosphoric acid
H3PO4 + NaCl ==> HCl + NaH2PO4
H3PO4 + NaI ==> HI + NaH2PO4
H2SO4 + NaCl ==> HCl + NaHSO4
This method(Using H2So4) will work for all hydrogen hydrogen halide except Hydrogen Iodide and Hydrogen Bromide.
The Sulphuric acid won't be useful for producing Hydrogen Iodide because its an OXIDIZING AGENT. Whist producing the Hydrogen Iodide... Some of the Iodide ions are oxidized to Iodine.
2I-² === I2 + 2e-
Which piece of glassware shown below is used to hold and dispense a solution of known concentration during a titration?
Answer:
Answer C
Explanation:
Got it off of q**zlet ;)
Answer
Its C confirmed
Explanation:
Just did the test
Predict the effect of an eightfold pressUre increase on the equillbrium composition of the reaction 3 Nalg) + H2lg) 2 NaHlg)
Answer:
See explanation
Explanation:
Given the reaction;
3N2(g) + H2(g) = 2N3H(g).
We know that when a constraint is imposed on a reaction system in equilibrium, the equilibrium position will shift in such a way as to annul the constraint.
In this case, when the pressure is increased eightfold, the equilibrium position will shift towards the direction where there is the least total volumes.
In this particular reaction, the forward reaction has the least total volumes and is favoured by an eightfold increase in pressure.
Hence, when the pressure is increased eightfold, more N3H(g) is obtained.
if you were conducting an experiment with pepsin which has an optimal enzymatic actigity at ph 2.3, wat buffer would be the best choice
Answer: One with a pKa of 1.9
Hope this helps <3
P.S Fun Fact~~
There are only two words in the English language that have all five vowels in order: "abstemious" and "facetious."!
Answer:
Explanation: Is there choises? H3PO4 / NaH2PO4 buffer with equal concentrations would form a buffer solution pH = 2.15
How can we classify the group of elements by just looking at its valence configuration?
Electron configurations
Valence electrons are electrons used in forming bonds and are in the outer shell of an element.
The bond that occurs can be either an ionic bond or a covalent bond
Valence electron determination using electron configurations.
The main group elements usually have valence electron configurations in the s and p subshells
While the transition elements in the subshells (n-1) d
Further explanation
The location of the elemental groups in the periodic system is determined by the number of valence electrons filling the last sub-shell
The period of an element is determined from the valence shell (the biggest main quantum number (n) )
In an atom, there are levels of energy in the shell and subshell
This energy level is expressed in the form of electron configurations.
Writing electron configurations starts from the lowest to the highest sub-shell energy level. There are 4 sub-shells in the shell of an atom, namely s, p, d, and f. The maximum number of electrons for each subshell is
s: 2 electrons
p: 6 electrons
d: 10 electrons and
f: 14 electrons
Charging electrons in the subshell uses the following sequence:
1s², 2s², 2p⁶, 3s², 3p⁶, 4s², 3d¹⁰, 4p⁶, 5s², 4d¹⁰, 5p⁶, 6s², etc.
meaning of alchol in one word
Silver nitrate, AgNO3, reacts with ferric chloride, FeCl3, to give silver chloride, AgCl, and ferric nitrate, Fe(NO3)3. In a particular experiment, it was planned to mix a solution containing 25.0 g of AgNO3 with another solution containing 45.0 grams of FeCl3. Write the chemical equation for the reaction.
Answer:
[tex]\mathbf{FeCl_3 + AgNO_3 \to 3 AgCl+Fe(NO_3)_3}[/tex]
Explanation:
From the given question,
The chemical equation is:
[tex]\mathbf{FeCl_3 + AgNO_3 \to 3 AgCl+Fe(NO_3)_3}[/tex]
We are given that:
mass of [tex]FeCl_3[/tex] = 45 g
number of moles of [tex]FeCl_3[/tex] = 45 g/162.2 g/mol
= 0.28 mol
mass of [tex]AgNO_3[/tex] = 25g
number of moles of [tex]AgNO_3[/tex] = 25/169.87
= 0.147 mol
From the given equation 1 mole of [tex]FeCl_3[/tex] is required to make 3 mole of [tex]AgNO_3[/tex]
0.28 mole of [tex]FeCl_3[/tex] = 0.28 × 3 = 0.84 mol of [tex]AgNO_3[/tex]
Here [tex]AgNO_3[/tex] is the limiting reagent.
Thus,
3 mole of [tex]AgNO_3[/tex] = 3 moles of AgCl
0.147 mole of [tex]AgNO_3[/tex] = 0.147 mole of AgCl produced.
BRAINIEST AND POINTS
Which option below accurately describes the relationship between frequency and wavelength?
A. The higher the frequency the shorter the wavelength.
B. The lower the frequency the shorter the wavelength.
Answer:
Hi, there your answer is A. As the frequency of a wave increases, the shorter its wavelength is.
Explanation:
When frequency increases, wavelength decreases.
Hope this Helps :)
HELP PLS HELP i rlly need help omg
Calculate the percent composition by mass (to 4 significant figures) of all the elements in calcium phosphate [Ca3(PO4)2], a major component of bone.
Answer:
The elements present in calcium phosphate-based on molecular formula are calcium, phosphorus, and oxygen. The molecular mass of Ca or calcium is 40.08 grams per mole, the molecular mass of P or phosphorus is 30.97 grams per mole, and the molecular mass of oxygen is 16.00 grams per mole. So, in combination, the molecular mass of Ca₃(PO₄)₂ is, = (3 × 40.08 + 2 ×3 0.97 + 8 × 16) = 310.18 grams per mole
Now, the mass percent of calcium is, = n × molecular mass of calcium/ molecular mass of Ca₃(PO₄)₂ × 100% = 3 × 40.08 / 310.18 × 100 = 38.76 % Thus, the mass percent of the calcium in calcium phosphate is 38.76%.
The mass percent of phosphorus (P), = n × molecular mass of phosphorus/molar mass of Ca₃(PO₄)₂ × 100% = 2 × 30.97/310.18 × 100 = 19.97% Thus, the mass percent of phosphorus in calcium phosphate is 19.97%.
The mass percent of oxygen (O), = n × molecular mass of oxygen/molar mass of Ca₃(PO₄)₂ × 100% = 8 × 16/310.18 × 100% = 41.27% Thus, the mass percent of oxygen in calcium phosphate is 41.27%.
Now we need to find the amount of NF3 that can be formed by the complete reactions of each of the reactants. If all of the N2 was used up in the reaction, how many moles of NF3 would be produced
The question is incomplete, the complete question is:
Nitrogen and fluorine react to form nitrogen fluoride according to the chemical equation:
[tex]N_2(g)+3F_2(g)\rightarrow 2NF_3(g)[/tex]
A sample contains 19.3 g of [tex]N_2[/tex] is reacted with 19.3 g of [tex]F_2[/tex]. Now we need to find the amount of [tex]NF_3[/tex] that can be formed by the complete reactions of each of the reactants.
If all of the [tex]N_2[/tex] was used up in the reaction, how many moles of [tex]NF_3[/tex] would be produced?
Answer: 1.378 moles of [tex]NF_3[/tex] are produced in the reaction.
Explanation:
The number of moles is defined as the ratio of the mass of a substance to its molar mass.
[tex]\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}[/tex] ......(1)
Limiting reagent is defined as the reagent which is completely consumed in the reaction and limits the formation of the product.
Excess reagent is defined as the reagent which is left behind after the completion of the reaction.
In the given chemical reaction, [tex]N_2[/tex] is considered as a limiting reagent because it limits the formation of the product and it was completely consumed in the reaction.
We are given:
Mass of [tex]N_2[/tex] = 19.3 g
Molar mass of [tex]N_2[/tex] = 28.02 g/mol
Putting values in equation 1:
[tex]\text{Moles of }N_2=\frac{19.3g}{28.02g/mol}=0.689mol[/tex]
For the given chemical reaction:
[tex]N_2(g)+3F_2(g)\rightarrow 2NF_3(g)[/tex]
By the stoichiometry of the reaction:
1 mole of [tex]N_2[/tex] produces 2 moles of [tex]NF_3[/tex]
So, 0.689 moles of [tex]N_2[/tex] will produce = [tex]\frac{2}{1}\times 0.689=1.378mol[/tex] of [tex]NF_3[/tex]
Hence, 1.378 moles of [tex]NF_3[/tex] are produced in the reaction.
Can someone help me with a bio organic questions??♀️
Which of these is NOT a producer in the coral reef ecosystem? *
1. phytoplankton
2. sea grass
3. microalgae
4. coral
Answer:
option number 4. 'coral'
Explanation:
-
When you test starch with Barfoed’s reagent, what would be the answer, positive or negative?
Answer:
It would test positive.
compare and contrast the three types oflevers.
Answer:
The difference between the three classes depends on where the force is, where the fulcrum is and where the load is. In a first class lever, the fulcrum is located between the input force and output force. In a second class lever, the output force is between the fulcrum and the input force. write the class of lever.
Explanation:
solution of alcohol and water
[tex]\huge\mathsf{\red{\underline{\underline{Answer}}}}[/tex]
[tex]{\green{\dashrightarrow}}[/tex]When you mix the rubbing alcohol with water, the latter's molecules make hydrogen bonds with the water molecules. The alcohol dissolves in the water to form a homogenous solution, so you cannot distinguish the alcohol and the water anymore.
What volume of 0.686 M HCl would contain 0.037 moles of solute?
Given :
Molarity of HCl solution, M = 0.686 M.
Number of moles, n = 0.037 moles.
To Find :
The volume of solution.
Solution :
We know, molarity is given by :
[tex]M = \dfrac{Number \ of \ moles \ of \ solute}{Volume \ in \ liter}\\\\0.686 = \dfrac{0.037}{V}\\\\V = \dfrac{0.037}{0.686}\ L\\\\V = 0.053935 \ L \\\\V = 53.94 \ ml[/tex]
Hence, this is the required solution.
A student went to the cafeteria and bought iced tea. He then proceeded to add more sugar to his iced tea. In this solution, the iced tea was the __________ and the sugar was the ____________.
A student enters the canteen and buys iced tea. He then goes on to add more sugar to his iced tea. In this solution, iced tea is the solvent and sugar is the solute.
Plz answer with photo
I need answer just with the form ♀️
l love my life an I am happy with it