Answer:
3.13%.
Explanation:
The following data were obtained from the question:
Original amount (N₀) = 0.15
Half life (t½) = 2 mins
Number of half-life (n) = 5
Fraction of sample remaining =.?
Next, we shall determine the amount remaining (N) after 5 half-life. This can be obtained as follow:
Amount remaining (N) = 1/2ⁿ × original amount (N₀)
NOTE: n is the number of half-life.
N = 1/2ⁿ × N₀
N = 1/2⁵ × 0.15
N = 1/32 × 0.15
N = 0.15/32
N = 4.69×10¯³
Therefore, 4.69×10¯³ is remaining after 5 half-life.
Finally, we shall the fraction of the sample remaining after 5 half-life as follow:
Original amount (N₀) = 0.15
Amount remaining (N) = 4.69×10¯³
Fraction remaining = N/N₀ × 100
Fraction remaining = 4.69×10¯³/0.15 × 100
Fraction remaining = 3.13%
How many sulfur atoms are present in 100 grams of this compound? Report your answer to three significant figures.
Answer:
1.88 × 10²⁴ atoms
Explanation:
Step 1: Given data
Mass of sulfur: 100 g
Step 2: Calculate the moles corresponding to 100 g of sulfur
The molar mass of sulfur is 32.07 g/mol. The moles corresponding to 100 g of sulfur are:
100 g × (1 mol/32.07 g) = 3.12 mol
Step 3: Calculate the number of atoms in 3.12 moles of sulfur
We will use Avogadro's number: there are 6.02 × 10²³ atoms of sulfur in 1 mole of sulfur.
3.12 mol × (6.02 × 10²³ atoms/1 mol) = 1.88 × 10²⁴ atoms
HELP HELP
why are more common bone fractures among senior citizens than among young people
PLEASE HELP! WILL DO BRAINLIEST! What do scientists call all of the compounds that contain carbon and are found in living things?
organic
inorganic
acidic
nonacidic
Answer:
acidic because of electrical issues and the body of electrical equipment
What is the mass, in grams, of 8.65 x 1025 atoms of oxygen?
Answer:
Mass = 2304 g
Explanation:
Given data;
Number of atoms of oxygen = 8.65×10²⁵
Mass in gram = ?
Solution:
The given problem will solve by using Avogadro number.
It is the number of atoms , ions and molecules in one gram atom of element, one gram molecules of compound and one gram ions of a substance. The number 6.022 × 10²³ is called Avogadro number.
For example,
1 mole = 6.022 × 10²³ atoms
8.65×10²⁵ atoms of oxygen× 1mol /6.022 × 10²³ atoms
1.44×10² mol
144 mol
Mass in grams of oxygen:
Mass = number of moles × molar mass
Mass = 144 mol × 16 g/mol
Mass = 2304 g
Sustainable forestry is managing forests so they harvested regularly without harming or reducing the future supply of timber. What is one practice you might observe in a sustainably-managed forest?
A) clear cutting
B) selective cutting
C) land reclamation
D) crop rotation
Answer:
I think option D
I hope my answer is helpful to you
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Calculate the mass of glucose metabolized by a 60.0 −kg person in climbing a mountain with an elevation gain of 1550 m . Assume that the work performed in the climb is about four times that required to simply lift 60.0 kg by 1550 m . (ΔfH∘ of C6H12O6(s) is -1273.3 kJ/mol.) w = mgh (mass in kg, g = 9.8 m/s2, h in meters)
Answer:
Mass of glucose = 515.34 g
Explanation:
We are given;
Mass; m = 60 kg
Elevation; h = 1550 m
Acceleration due to gravity; 9.8 m/s²
Now, work performed to lift 60kg by 1550m is given by the formula;
W = mgh
W = 60 × 9.8 × 1550
W = 911400 J
We are told the actual work is 4 times the one above.
Thus;
Actual work = 4W = 4 × 911400 = 3,645,600 J
Now,
Molar mass of Glucose(C6H12O6) = 180 g/mol
We are given standard enthalpy of combustion = -1273.3 KJ/mol = -1273300
Moles of glucose = 3645600/1273300 = 2.863mol
Mass of glucose = 2.863 mol × 180 g/mol
Mass of glucose = 515.34 g
What does this image represent?
a) alcohol group
b) carbonyl group
c) ether group
d) hydroxyl group
Explanation:
It represent Alcohol group (—OH)
Which profile best shows the topography alone line AD
Which of the following is NOT an example of deposition?
sand dune
river delta
cave crystal
valley
This science btw
Answer:
Cave Crystal
Explanation:
I believe it's cave crystal because sand dunes, river deltas, and valleys are all examples of deposition.
explain the reason each step of the separation is performed with three portions of the solvent rather than with a single poriton of solvent
Answer:
Several extractions is more effective than a single extraction.
Explanation:
When extraction is carried out multiple times, for instance, in this case, the extraction was carried out with three portions of the solvent rather than with just a single portion of the solvent, the amount of material left in the residue will be lower, because the extraction is more complete.
Several extractions with smaller volumes of solvent are more effective than a single extraction with a large volume of solvent.
What is the value of E0 for the spontaneous reaction resulting from a suitable combination of these half reactions?
Standard Potentials E0
Fe2+ --> Fe3+ + e- -0.77 V
2Hg --> Hg2+ + 2e- -0.79 V
a. +0.02 V.
b. +0.36 V.
c. -1.56 V.
d. -0.02 V.
e. +1.56 V.
Answer:
+0.02 V
Explanation:
For the reaction to be spontaneous, iron must be the cathode and Mercury the anode
Given that the standard cell potential is obtained from;
E°=E° cathode - E° anode
Since;
E° cathode = -0.77V
E° anode = 0.79 V
E°cell = -0.77 -(-0.79)
E°cell = +0.02 V
The half-life of cesium-137 is 30 years. Suppose that we start with 70 grams of cesium-137 in a storage pool. How many half-lives will it take for there to be 10 grams of cesium-137 in the storage pool?
Answer:
Explanation:
Let n be number of half lives taken .
10 = 70 x ( 1/2 )ⁿ
1/7 = ( 1/2 )ⁿ
2ⁿ = 7
n ln2 = ln 7
n = ln7 / ln2
= 1.9459 / .693
= 2.8
So 2.8 half lives will be required .
Volume of HCl used 25.0mL 4 l
Initial burette reading 0.50mL
Final burette reading 25.60mL
Concentration of KOH 1.0M
the molarity
HCl solution
Calculate
Answer:
1.0 M
Explanation:
Reaction equation;
KOH(aq) + HCl(aq) -----> KCl(aq) + H2O(l)
Concentration of acid CA = ?
Concentration of base CB = 1.0 M
Volume of base VB = 25.60 - 0.50 = 25.1 ml
Volume of acid VB = 25.0 ml
Number of moles of acid NA = 1
Number of moles of base NB =2
CAVA/CBVB =NA/NB
CAVANB = CBVBNA
CA = CBVBNA/VANB
CA = 1 * 25.1 * 1/25.0 *1
CA = 1.0 M
3. What is the Limiting Reactant in the following equation if you start with 3 moles of NH3 with 6 moles of O2?
4NH3 (g) + 5O2 (g) 4NO (g) + 6H2O(g)
4. How many grams of NO can be made from the previous equation and quantities?
Answer:
3. NH3 is limiting
4. 90 g NO
Explanation:
3. To find the limiting reactant, you have to convert from moles of reactant to moles of product. In this case, because we need to know how many grams of NO in the second question, we will use NO as our product. We use the ratios found in the chemical formula.
[tex]3 mol NH3*\frac{4 molNO}{4 mol NH3} = 3molNO[/tex]
[tex]6 mol O2*\frac{4 molNO}{5 mol O2} = 4.8molNO[/tex]
Because NH3 makes less moles of NO, it is the limiting reactant.
4. Now we need the molar mass to convert the moles of NO into grams of NO. The molar mass of NO is 30.01g/mol. This is the equation.
[tex]3 mol NO*\frac{30.01g NO}{1 mol NO} = 90.03gNO[/tex]
Because there are is only one significant figure in the original numbers, we round to one significant figure = 90 g NO.
what might happen to variables in a science experiment that would lead to unusable results?
Answer:
ejeb094
Explanation:
nnb3neneie9eei rje
Lewis based his theory of bonding on? Is this correct
Question: Describe how molecules would
move in a piece of ice.
Answer:
The molecules in the liquid are moving past one another. The hydrogen end of one water molecule is attracted to the oxygen end of another but only for a short time because they are moving. The molecules in ice are further apart than in liquid water. The molecules in ice are in fixed positions but still vibrate.
Explanation:
As you are cleaning out the shared refrigerator in the kitchen of your apartment at the end of the school year, you find an unlabeled, clear plastic container in the back, left there by one of your roommates. This container is half-filled with something that you notice has separated into two layers: the top one is a dark yellow color, the bottom layer is more greenish. You assume that this biphasic mixture has an aqueous layer and some type of organic layer. Without tasting, smelling, or removing either layer from the container, how can you determine which layer is the aqueous layer using just material found in a typical kitchen
Answer:
See explanation
Explanation:
The organic layer is always found at the top of the mixture while the aqueous layer is found at the bottom of the mixture.
Therefore, if I use any piece of rod and an empty container found in the kitchen to perform a simple decantation, the top layer that comes out first is the organic layer. The other layer that remains after the top layer has been successfully decanted is the aqueous layer.
I2(g) + Br2(g) ↔ 2 IBr(g) What is the equilibrium concentration of IBr (in M to 4 decimal places) if 0.200 mol of I2 and 0.100 mol Br2 in a 5.00 L vessel if Kc = 29 at 150°C?
Answer:
The equilibrium concentration of IBr is 0.0360 M or 0.1032 M
The equilibrium concentration of IBr is 0.752 mol
Explanation:
Mathematically, concentration = number of moles/volume
For Iodine molecule, concentration = 0.2/5 = 0.04 M
For the bromine molecule, concentration = 0.1/5 = 0.02 M
We need to set up an ICE table ( Initial, change, equilibrium) to get the concentrations of the molecules at equilibrium.
Please check this table in the attachment.
From the table, we can see that the equilibrium concentration of Iodine is (0.04-x), that of Bromine is (0.02-x) while that of IBr is 2x
Now, we need to get the equilibrium constant using the equilibrium concentration of the molecules
With the given chemical reaction, we can represent the equilibrium constant in terms of pressure as follows;
Kc = [IBr]^2/[Br2][I2]
Thus;
Kc = (2x)^2/(0.04-x)(0.02-x)
Kc = 4x^2/(0.04-x)(0.02-x)
From the question, Kc = 29 , so substitute this;
29 = 4x^2/(x^2-0.06x+0.008)
Cross multiply
29((x^2-0.06x+0.008) = 4x^2
29x^2 - 1.74x +0.0232 = 4x^2
Thus;
25x^2 - 1.74x + 0.0232 = 0
Solving this quadratic equation, we get two values for x which are x = 0.0516 and 0.0180
The equilibrium concentration is either (2 * 0.018) or (2 * 0.0516) which is 0.0360 or 0.1032
Quick electron emissions are called
Automobile air bags inflate following a serious impact. The impact triggers the following chemical reaction.
2NaN3(s)->2Na(s)+3N2(g)
If an automobile air bag has a volume of 11.9 L, what mass of NaN3 (in g) is required to fully inflate the air bag upon impact? Assume STP conditions.
Answer:
Explanation:
To determine the molar volume of the gas according to the equation at stp;
1 mole = 22.4 dm³
2 moles = 44.8 dm³
To determine the mass of NaN₃ inflated according to the equation
2NaN₃ (where Na = 23g and N = 14) = (2 × 23) + 2(14 × 3)
= 130 g
Hence, if 130g of NaN₃ is required to inflate 44.8 dm³ airbag upon impact
what mass of NaN₃ is required to fully inflate the air bag upon impact;
130g ⇒ 44.8 dm³
? ⇒ 11.9 dm³ (dm³ is same as L)
? = 130 × 11.9/44.8
? = 34.5g
34.5g of NaN₃ is required to fully inflate 11.9 L of air bag upon impact
Can you guys answer question 4 on new substance for Chemistry tysm
The answer is a bevasue it then becomes a chemical compound
Answer:
a
Explanation:
this would result in a compound and compounds are chemical changes so i think im right....
A first-order decomposition reaction has a rate constant of 0.00140 yr−1. How long does it take for [reactant] to reach 12.5% of its original value? Be sure to report your answer to the correct number of significant figures.
Reactants take 504.87 yr to reach 12.5% of their original value in first-order decomposition reaction.
Equation for the first-order decomposition reaction:-[tex]A_{t} =A_{0} e^{-kt}[/tex]....(1)
Here, [tex]A_{t}[/tex] is the final concentration, t is the time, [tex]A_{0}[/tex] is the initial concentration, and k is the rate constant.
Given:-
[tex]A_{t} =0.125A_{0}[/tex]
k= [tex]0.00140yr^{-1}[/tex]
Substitute the above value in equation (1) as follows:-
[tex]0.125A_{0} =A_{0} e^{-kt} \\0.125A_{0} =A_{0} e^{-k\times0.00140 yr^{-1} }\\ln(0.125)/(-0.00140)=t\\t=504.87 year[/tex]
So, 504.87 yr does it take for the reactant to reach 12.5% of its original value.
Find more information about first- order decomposition reaction here:-
brainly.com/question/20607444
what element has a higher ionization energy carbon or silicon
The oxidation of glucose to carbon dioxide and water is represented by the following reaction, whether the oxidation occurs by combustion in the laboratory or by biological oxidation in living cells: C6H12O6+6O2⇌6CO2+6H2O When combustion is carried out under controlled conditions in the laboratory, the reaction is highly exothermic, with an enthalpy change (ΔH) of −673kcal/mol. As you know, ΔG for this reaction at 25∘C is −686kcal/mol, so the reaction is also highly exergonic. Part A Explain what the ΔH and ΔG values mean. What do the negative signs mean in each case? Drag the terms on the left to the appropriate blanks on the right to complete the sentences. Terms can be used once, more than once, or not at all.
Answer:
See explanation
Explanation:
∆H is known as the change in enthalpy. When the change in enthalpy is negative, it simply means that heat is given out during the reaction. Therefore, we refer to the reaction as an exothermic reaction.
Similarly, ∆G is known as change in free energy. When the change in free energy is negative, it implies that the reaction is spontaneous as written. This is called an exergonic reaction.
A certain chemical reaction releases of heat for each gram of reactant consumed. How can you calculate the heat produced by the consumption of of reactant? Set the math up. But don't do any of it. Just leave your answer as a math expression. Also, be sure your answer includes all the correct unit symbols.
Complete Question
The complete question is shown in the first uploaded image
Answer:
So the math expression is
[tex]heat = \frac{ 35. 7 KJ * 1900 \ gram }{ 1 \ gram }[/tex]
Explanation:
From the question we are told that
The heat released for 1 gram of reactant consumed is [tex]H = 37.5 \ KJ/g [/tex]
The mass of reactant considered is [tex]m = 1.9 \ kg = 1900 \ g[/tex]
So if
[tex]37.5 \ KJ [/tex] is produced for 1 gram
Then
x kJ is produced for 1900 g
=> [tex]x = \frac{ 35. 7 KJ * 1900 \ gram }{ 1 \ gram }[/tex]
So the heat released is
[tex]heat = \frac{ 35. 7 KJ * 1900 \ gram }{ 1 \ gram }[/tex]
Georgia discovered a piece of metal. She measured its mass as 14 grams and its volume as 2 cm3. Georgia then compared the metal she found with the metals in the table below.
DENSITY OF METALS
Which type of metal did Georgia most likely find?
A.Gold
B.Lead
C.Silver
D.Zinc
Answer:
try dividing the grams and the volume and see what number matches up with your answer
Explanation:WhatGiven the particle diagram:
Which type of matter is represented by the particle diagram?
(1) an element
(2) a compound
(3) a homogeneous mixture
(4) a heterogeneous mixture
Answer:
A compound
Explanation:the mixture can vary
How do balanced chemical equations thon the
conservation of mass?
They show that the atoms in the products
may be different than the readarts as long
as the mass does not change,
They show that the atoms in the products are
the same as in the reactants, but the number
of atoms must change,
They show that the number of atoms of each
element is the same in the products and
reactants
Answer:
They show that the number of atoms of each element is the same in the products and reactants
Explanation:
Balanced chemical equations show the conservation of mass in that the number of atoms of each element is the same in the products and reactants.
In balancing chemical equation, the idea is to conform with the law of conservation of mass. It states that "during a chemical reaction, atoms are neither created nor destroyed but they simply combine to form new products". In chemical reaction, the atoms are still the same but new compounds ensue. The atoms still maintain their number.Answer:
C (They show that the number of atoms of each element is the same in the products and reactants.)
For the next question: C (2H2(g) + O2(g) → 2H2O(g))
Explanation:
For Edge
Write a balanced equation for the double-replacement precipitation reaction described, using the smallest possible integer coefficients. A precipitate forms when aqueous solutions of lead(II) nitrate and sodium hydroxide are combined.
Answer: [tex]Pb(NO_3)_2(aq)+2NaOH(aq)\rightarrow 2NaNO_3(aq)+Pb(OH)_2(s)[/tex]
Explanation:
A double displacement reaction is one in which exchange of ions take place. The salts which are soluble in water are designated by symbol (aq) and those which are insoluble in water and remain in solid form are represented by (s) after their chemical formulas.
The balanced chemical equation for a precipitate forms when aqueous solutions of lead(II) nitrate and sodium hydroxide are combined is:
[tex]Pb(NO_3)_2(aq)+2NaOH(aq)\rightarrow 2NaNO_3(aq)+Pb(OH)_2(s)[/tex]
