Given :
Initial mass , a = 150 gm .
Half time ,
[tex]t_{\dfrac{1}{2}}=36 \ hours[/tex].
Final mass , x = 18.75 gm .
To Find :
The time taken to decay 18.75 gm .
Solution :
We know , time taken is given by :
[tex]t=\dfrac{1}{k}\times ln(\dfrac{a}{a-x})[/tex]
Here , k is a constant given by :
[tex]k=\dfrac{0.693}{t_{\dfrac{1}{2}}}\\\\\\k=\dfrac{0.693}{36}[/tex]
Putting all given value in above equation :
We get :
[tex]t=\dfrac{36}{0.693}\times ln(\dfrac{150}{150-18.75})\\\\t=6.94\ hours[/tex]
Therefore , time taken is 6.94 hours .
Hence , this is the required solution .
basketane is a hydrocarbon that is 90.8% carbon. If the molar mass is between 130-140 g/mol find the molecular formula of the compound.
Answer:
C₁₀H₁₂
Explanation:
90.8% of basketane (Hydrocarbon, contains only C and H) is Carbon, and 100-90.8 = 9.2% of the mass is hydrogen.
The molar mass is between 130-140g/mol, That means the moles of Carbon (Using its molar mass, 12.01g/mol) that are in basketane are between:
140g/mol /12.01g/mol *90.8%= 10.58 moles of C.
130g/mol / 12.01g/mol *90.8%= 9.83 moles of C.
As the moles of carbon must be given in a whole number, There are 10 moles of Carbon.
10 moles C * (12.01g / mol) = 120.1g/mol that are 90.8% of the molar mass. Molar mass of basketane is:
100% * (120.1g/mol / 90.8%) =
132.3g/mol.
The part of the molar mass due hydrogen must be:
132.3 g/mol - 120.1g/mol = 12.2 g/mol
As molar mass of hydrogen is 1g/mol, the moles of hydrogen are 12
And molecular formula is:
C₁₀H₁₂why ice floats on water is a physical change
Answer:
Ice floats on water because it is less dense than water. When water freezes into its solid form, its molecules are able to form more stable hydrogen bonds locking them into positions. Because the molecules are not moving, they're not able to form as many hydrogen bonds with other water molecules. Ice is a unique substance because it is solid-state — ice — is less dense than its liquid state. Because of this property, ice floats in water. Physical properties are characteristics of a substance. They do not change. Ice floats on water because it is less dense than water. When water freezes into its solid form, its molecules are able to form more stable hydrogen bonds locking them into positions.
Question 6
How many significant figures are there in 31.1100?
Answer:
6 sig figs
Explanation:
sig figs are numbers that are more than 0, but in this case, after the decimal, the 0's at the end count as sig figs as well
There are 6 significant numbers in 31.1100.
If there is no decimal point in the figures then it will be 4 but since there is a decimal point then it is 6 significant figures.
Compute the equilibrium constant for the spontaneous reaction between
Ni2+(aq) and Cd(s).
Express your answer using two significant figures.
Answer:
9.8 × 10^21
Explanation:
Equation of the reaction;
Cd(s) + Ni^2+(aq) ----> Cd^2+(aq) + Ni(s)
E°cell= E°cathode - E°anode
E°cathode= -0.25 V
E°anode = -0.40 V
E°cell= -0.25 - (-0.40)
E°cell = 0.65 V
∆G= -nFE°cell
∆G= -(2 × 96500 × 0.65)
∆G = -125450 J
From;
∆G= -RTlnK
lnK = ∆G/-RT
K= e^∆G/-RT
K= e^-[-(125450/8.314 × 298)]
K= 9.78 × 10^21
The human body burns glucose for energy according to this chemical reaction: The products of the reaction are carbon dioxide and water . Interestingly, all of the carbon dioxide and much of the water exits the body through the lungs: on every breath, the average person exhales of air, which is typically enriched to and water vapor by volume. In short, when a person loses weight by dieting, the weight that is lost actually departs his body as a gas, every time he exhales. Each kilogram of body fat lost requires exhaling about of carbon dioxide. Calculate how many breaths it takes an average person to "exhale" of fat. Round your answer to the nearest thousand. You'll need to know that the density of is .
Answer:
The average persons requires 75000 breaths to exhale 1.0 Kg of fat
Explanation:
Note: The question is incomplete. The complete question is given below:
"The human body burns glucose (C6H1206) for energy according to this chemical reaction:
C6H1206 + 602----> 6CO2 + 6H20
The products of the reaction are carbon dioxide (CO2) and water (H20). Interestingly, all of the carbon dioxide and much of the water exits the body through the lungs: on every breath, the average person exhales 500 mL of air, which is typically enriched to 4% CO2 and 5% water vapor by volume. In short, when a person loses weight by dieting, the weight that is lost actually departs his body as a gas, every time he exhales. Each kilogram of body fat lost requires exhaling about 3.0 kg of carbon dioxide. Calculate how many breaths it takes an average person to "exhale" 1.00 kg of fat. Round your answer to the nearest thousand. You'll need to know that the density of CO2 is 2.0 kg/m³”.
Volume of air exhaled on average per breath = 500 mL
Volume of CO2 exhaled per breath = 4/100 × 500 = 20 mL
Since, 1000000 mL = 1 m³;
20 mL = 0.00002 m³
3.0 kg of CO2 is exhaled per Kg of fat.
Density of CO2 = 2.0 Kg/m³
Volume = mass/density
Volume of 3.0 Kg CO2 = 3.0/2.0 = 1.5 m³
Number of breaths that will have a volume of 1.5 m³ = 1.5/0.00002 = 75000 breaths.
How many grams of solid potassium chlorate (KClO 3, 122.55 g/mol) are needed to make 150 mL of 0.50 M solution
Answer:
[tex]m_{solute}=9.19gKClO_3[/tex]
Explanation:
Hello,
In this case, since the molarity is defined as:
[tex]M=\frac{mol_{solute}}{V_{solution}}[/tex]
Whereas the volume of the solution is in liters, we first compute the moles of solute which in this case is the potassium chlorate:
[tex]mol_{solute}=150mL*\frac{1L}{1000mL}*0.50molKClO_3/L \\\\mol_{solute}=0.075molKClO_3[/tex]
Then, by using its molar mass of 122.55 g/mol, we compute the required mass as follows:
[tex]m_{solute}=0.075molKClO_3*\frac{122.55gKClO_3}{1molKClO_3} \\\\m_{solute}=9.19gKClO_3[/tex]
Regards.
1.05 Quiz: Measure Angles
Iron filings are attracted by a magnet. This is a physical property of iron but not of most other materials, including sand. How could you use this difference in physical properties to separate a mixture of iron filings and sand?
Answer:
Direct a magnet towards the mixture of iron and sand. You can observe that only the iron filling is attracted to the magnet and will come in contact with it. Therefore, after this process, you'll be left with iron filling on the surface of the magnet whereas the sand particles are left on the dish
To separate a mixture of iron filings and sand, using the physical property of iron is by using a magnet because a magnet attracts iron, but not sand.
What are physical properties?
Physical properties are those properties that can be seen by seeing an object or a substance. These properties do not change with the change in the composition of matter.
Physical properties are appearance, texture, color, odor, melting point, boiling point, density, solubility, polarity, and many others.
Magnetic properties are the property in which the object attracts to magnets and or iron-containing substances, here it can be used to separate sand and iron.
Thus, using a magnet and the magnetic property of iron—which attracts iron but not sand—one can separate a combination of iron filings and sand.
To learn more about physical properties, refer to the link:
https://brainly.com/question/18327661
#SPJ2
Name the colourless gas that evolves when potassium reacts with water. How will you test this gas?
Answer:
Hydrogen gas
Explanation:
K +H2O=KOH+ H2
Test for hydrogen gas:
Light a splint and put it in the smoke present. If it makes a pop sound, that means hydrogen is present
Write the condensed structural formula for the major organic product of the following reaction in the presence of light (assume that only one mole of Br2 reacted). Name the reaction mechanism and summarize in words the main steps of the mechanism.
(CH3)4C + Br2
Answer:
(CH3)3CCH2Br
Explanation:
This reaction proceeds by the following mechanism;
First, irradiation with light of appropriate frequency leads to the homolytic fission of the bromine molecule to yield two bromine free radicals. This is the initiation step of the reaction.
The free radical now attacks one of the -CH3 groups in neopentane leading to the formation of (CH3)3CCH2Br.
To draw a primary amine, start by drawing the longest carbon atom chain of the molecule. Next, connect the amine functional group according to the location given in the name of the amine. Finally, attach all substituent groups according to the location given in the nomenclature. To draw a secondary or tertiary amine, start by drawing a nitrogen atom with three connecting bonds. Attach each substituent group, listed in the nomenclature by the prefix N-, to the nitrogen atom (two groups if it is a secondary amine and three groups if it is a tertiary amine). For secondary amines, attach a hydrogen atom to the third bond of the nitrogen atom.
A. Draw the structure of 1,4-hexanediamine.
B. Draw the structure of 2,4-difouroaniline.
Answer:
See figure 1 and figure 2
Explanation:
We can analyze each structure:
A. Structure of 1,4-hexanediamine
For this molecule, we must start with a six-carbon chain. Since, in the name of the molecule we have the prefix "hex", then we have to name the carbons. The first carbon will be the one on the right and the sixth on the left. Finally, we must place two amino groups on carbons 1 and 4 (See figure 1).
B. Draw the structure of 2,4-difluoroaniline
For this molecule, we must start with the aniline molecule. In this molecule, we have an amino group attached to a benzene ring. Carbon number 1 will be the carbon that is attached to the amino group, carbon number 2 must be placed in a clockwise direction. Finally, we must place two fluorine atoms on carbons 2 and 4 (See figure 2).
The principal quantum number for the outermost electrons in a Te atom in the ground state is ________.
Answer:
The principal quantum number for the outermost electrons in a Te atom in the ground state is 5
Explanation:
In quantum chemistry, the region of maximum probability of where an electron is located is sometimes referred to as cloud or orbital.
The principal quantum number is used to express the state of an electron
The principal quantum number for the outermost electrons in a Te atom in the ground state is 5
The atomic number of Tellurium Te is Kr 4d¹⁰ 5s² 5p⁴
so quantum no is 5
A 1.44-g sample of an unknown pure gas occupies a volume of 0.335 L at a pressure of and a temperature of 100.0°C. The unknown gas is ________.
Answer:
Xenon
Explanation:
Step 1: Given data
Mass (m): 1.44 gVolume (V): 0.335 LPressure (P): 1.00 atm (I looked it up)Temperature (T): 100.0°CStep 2: Convert the temperature to Kelvin
K = °C + 273.15 = 100.0°C + 273.15 = 373.2 K
Step 3: Calculate the number of moles (n)
We will use the ideal gas equation.
P × V = n × R × T
n = P × V / R × T
n = 1.00 atm × 0.335 L / (0.0821 atm.L/mol.K) × 373.2 K
n = 0.0109 mol
Step 4: Calculate the molar mass of the gas
M = 1.44 g / 0.0109 mol = 132 g/mol
Step 5: Identify the gas
The gas with a molar mass of about 132 g/mol is xenon.
The gas with a molar mass of 132.11g/mol is Xenon. Hence the unknown gas is Xenon
Using the ideal gas equation
[tex]PV=nRT\\n=\frac{PV}{RT}[/tex]
R is the Boltzmann constant = 8.31
V is the volume of the gas = 0.355L
P is the pressure = 1.00atm
T is the temperature of the gas = 100.0°C = 373K
To get the unknown gas, we need to first get the number of moles of gas:
[tex]n=\frac{1.0\times 0.335}{0.0831 \times 373}\\n=0.0109 moles[/tex]
Get the molar mass of the element;
[tex]n=\frac{m}{M}\\0.0109=\frac{1.44}{M}\\M=\frac{1.44}{0.0109}\\M= 132.11g/mol[/tex]
The gas with a molar mass of 132.11g/mol is Xenon. Hence the unknown gas is Xenon
Learn more here: https://brainly.com/question/21912477
An important industrial route to extremely pure acetic acid is the reaction of methanol with carbon monoxide: h5sil950 Use bond energies to calculate the heat of reaction.
Answer:
This is an exothermic reaction.
Explanation:
You can calculate the reaction using the calculation below:
ΔH reac= 3(413Kj/mol) +358Kj/mol +467 Kj/mol +1070 kj/mol = 3134 kj/mol
ΔH prod = 3(413 kj/mol) + 347 kj/mol + 358kj/mol +467kj/mol +745 kj/mol = 3156kj/mol
ΔH = 3134 kj/mol - 3156kj/mol = -22 Kj/mol
Negative results indicate an exothermic reaction.
An image of the reaction is attached below.
The heat of the reaction has been -22 kJ/mol. The negative sign has been the indication of the exothermic reaction.
The heat of reaction has been given as the amount of energy absorbed or released by the system to form the products.
The heat of reaction has been given by:
[tex]\Delta H=\Delta H_{reactant}-\Delta H_{product}[/tex]
The heat of reaction has been calculated based on the bond energies. The energy constituent by each bond in the reactant has been the heat of the reactant, and the energy of product has been the heat of product.
The heat of reactant has been given as:The reactant molecules have been [tex]\rm CH_3OH[/tex] and [tex]\rm C\equiv O[/tex].
The bond energy of the reactant has been:
[tex]\Delta H_{reactant}=3\;\times \;\text {C-H}\;+\;\text{C-O + O-H}+\;\text C\equiv \text O\\ \Delta H_{reactant}=3\;\times \;413\;+\;358+467+1070\;\text{kJ/mol}\\ \Delta H_{reactant}=3134\;\text{kJ/mol}[/tex]
The heat of reactant has been 3134 kJ/mol.
The heat of product has been given as:The product molecule has been [tex]\rm CH_3COOH[/tex]
The bond energy of the product has been:
[tex]\Delta H_{product}=3\;\times \;\text {C-H}\;+\;\text{C-O + O-H +\;C-C}+\;\text C=\text O\\\Delta H_{reactant}=3\;\times \;413\;+\;358+467+\;347\;+\;745\;\text{kJ/mol}\\\Delta H_{reactant}=3156\;\text{kJ/mol}[/tex]
The heat of product has been 3156 kJ/mol.
The heat of reaction has been given as:
[tex]\Delta H=\Delta H_{reactant}-\Delta H_{product}\\ \Delta H=3134-3156\;\text{kJ/mol}\\ \Delta H=-22\;\rm kJ/mol[/tex]
The heat of the reaction has been -22 kJ/mol. The negative sign has been the indication of the exothermic reaction.
Learn more about bond energy, here:
https://brainly.com/question/26141360
You need to show how the time it takes for a rat to finish a maze changes in different age
groups. What chart or graph should you use?
O Line Graph
Bar Chart
O Pie Chart
O Histogram
O Scatter Plot
I would give brainly
If 27.50 mL of 0.120 M NaOH neutralizes 0.248 g of HAA, what is the molar mass of unknown amino acid
Answer:
75.15 g/mol
Explanation:
First, let us look at the equation of reaction;
[tex]NaOH + HAA --> NaAA + H_2O[/tex]
From the balanced equation of reaction, 1 mole of NaOH is required to completely neutralize 1 mole of HAA.
Recall that: mole = molarity x volume.
Therefore, 27.50 mL, 0.120 M NaOH = 0.0275 x 0.120 = 0.0033 moles
0.0033 mole of NaOH will therefore requires 0.0033 moles of HAA for complete neutralization.
In order to find the molar mass of the unknown amino acid, recall that:
mole = mass/molar mass, hence, molar mass = mass/mole.
Therefore, molar mass of HAA = 0.248/0.0033 = 75.15 g/mol
0.0075 mole of calcium trioxocarbonate(IV) is
added to 0.015 mole of a solution of hydrochloric
acid. The volume of gas evolved at stp is?
Answer:
0.0075÷0.015=0.5 not so sure lol
For the reaction A + 3B → 2C, the rate of disappearance of B given by (Δ[B]/Δt) may also be expressed as
Answer:
[tex]r_B=k[A][B]^3[/tex]
Explanation:
Hello,
In this case, in order to represent the rate disappearance of B, we need to consider the rate law as:
[tex]r_B=k[A][B]^3[/tex]
Whereas k is the rate constant the third power corresponds to B's stoichiometric coefficient as well as the concentrations of A and B because they are involved in the overall rate too.
Regards.
Solid sodium chloride decomposes into chlorine gas and solid sodium . Write a balanced chemical equation for this reaction.
Answer:
2NaCl > Cl2 + 2Na
Explanation:
2 moles of sodium chloride is irreversible to chlorine gas plus 2 moles of solid sodium
Solid sodium chloride decomposes into chlorine gas and solid sodium balanced chemical equation will be 2NaCl → [tex]2 Na^{+} + 2Cl^{-}[/tex].
What is balanced chemical equation?An equation with equal proportions of each kind of atom from both ends of the arrow would be called a balanced chemical reaction. A written symbolic description of a chemical reaction will be known as a chemical equation. The reactant chemical(s) were listed on the left, while the product chemical(s) were listed on the right.
What is chemical equation?Chemical equation is just the presentation of a chemical reaction using symbols and equations for the ingredients.
Solid sodium chloride decomposes into chlorine gas and solid sodium balanced chemical equation will be 2NaCl → [tex]2 Na^{+} + 2Cl^{-}[/tex].
To know more about balanced chemical equation
https://brainly.com/question/8062886
#SPJ2
Which of the following addresses the economic question of how to produce?
a growing corn instead of potatoes
b. requiring individuals to complete specific types of work
c. producing more capital goods and fewer consumer products
d. selling natural resources to other countries
Answer:
b
Explanation:
The correct answer would be requiring individuals to complete specific types of work.
A question of how to produce deals with the processes of production itself. There are several small processes that eventually aggregate together to lead to the production of goods or services. Some of these small processes will definitely require that individuals within the production unit complete specific types of work.
The option of growing corn instead of potatoes and producing more capital goods and fewer consumer products address what to produce while the option of selling natural resources to other countries has to do with for whom to produce.
Correct option: b
g A sample of chlorine gas occupies 1550 mL at 0.945 atm and 50 C. What is the mass of the sample
Answer:
THE MASS OF THE SAMPLE IS 25.37 g
Explanation:
Using PV = m RT / Mm
P = 0.945 atm
V = 1550 mL = 1.55 L
R = 0.082
T = 50 C
m = unknown
Mm = molar mass = 35.5 * 2 = 71 g/mol
Re-arranging the formula by making m the subject of the equation, we have:
m = PV Mm / RT
m = 0.945 * 1.55 * 71 / 0.082 * 50
m = 103.99725 / 4.1
m = 25.37 g
The mass of the sample is therefore 25.37 g
When the reaction A → B + C is studied, a plot 1/[A]t vs. time gives a straight line with a positive slope. What is the order of the reaction?
Answer:
Second order
Explanation:
Given that:
When the reaction A → B + C is studied, a plot 1/[A]t vs. time gives a straight line with a positive slope.
From the integration method for the second order of reaction.
Suppose that:
rate = k₂[A]²
∴
[tex]\dfrac{1}{A}=\dfrac{1}{A_0}+k_2t[/tex]
Therefore, a plot of the linear function [tex]\dfrac{1}{A}[/tex] versus t will be linear with a positive slope k₂ and the intercept on the concentration axis will be [tex]\dfrac{1}{A_o}[/tex]
The linear plot for a second order reaction can be seen in theimage attached below.
Q 11.8: Exposure of 2-methyl-2-butene to oxymercuration-demercuration conditions provides which product?
Answer:
Exposure of 2-methyl-2-butene to oxymercuration-demercuration conditions provides 2-methyl-2-butanol.
Explanation:
Please see the attachments below
Indicate the ionic species that predominates at pH 4, 8, and 11 for (a) ammonia and (b) phosphoric acid.
D. The density of cork is approximately 0.24 g/cm^ 3 Convert this density to nanograms per cubic millimeter
Answer:
D
Explanation:
Because jwbahaggagqhhwjwjja
How many mmoles are in 8.34 mol ?
Answer:
8.34 moles
Explanation:
We are given 8.34 moles.
We need to find moles: 8.34
Calculate the percentrage of neutral form of aspirin that is present in the stomach ph 1.
Answer:
The 99.68% of the aspirin is present in the neutral form
Explanation:
Aspirin, Acetylsalicylic acid, is a weak acid with pKa = 3.5
Using Henderson-Hasselbalch equation:
pH = pKa + log [A⁻] / [HA]
Where [A⁻] is the ionized form and HA the neutral form of the acid
Replacing with a pH of stomach of 1.0:
1.0 = 3.5 + log [A⁻] / [HA]
-2.5 = log [A⁻] / [HA]
3.16x10⁻³ = [A⁻] / [HA] (1)
A 100% of aspirin is = [A⁻] + [HA]
100 = [A⁻] + [HA] (2)
Replacing (2) in (1)
3.16x10⁻³ = 100 - [HA] / [HA]
3.16x10⁻³[HA] = 100 - [HA]
1.00316 [HA] = 100
[HA] = 99.68%
The 99.68% of the aspirin is present in the neutral formA piece of metal with a mass of 150 g is placed in a 50 mL graduated cylinder. The water level rises from 20 mL to 45mL. What is the volume of the metal? and what is the density of the metal
Answer:
volume = 15
density = 10
Explanation:
mass = 150 grams
volume = 45 - 20 = 15
density = mass / volume
density = 150 / 15 = 10
Calculate the heat (in calories) required to freeze 35.0 g of water.
Answer:
-2.79 × 10³ cal
Explanation:
Step 1: Given data
Mass of water (m): 35.0 gLatent heat of fusion of water (L): -79.7 cal/gStep 2: Calculate the heat required to freeze 35.0 g of water
We have 35.0 g of liquid water and we want to freeze it, that is, to convert it in 35.0 g of ice (solid water), at 0 °C (melting point). We can calculate the heat (Q) that must be released using the following expression.
Q = L × m
Q = -79.7 cal/g × 35.0 g
Q = -2.79 × 10³ cal
The heat in calories required to freeze 35.0g of water of water is 2.79 × 10³ cal.
HOW TO CALCULATE HEAT:The heat of a water in the mass of water can be calculated as follows:Q = L × m
Where;
Q = quantity of heat (calories)L = latent heat of fusion of waterm = mass of waterAccording to this question;
Mass of water (m): 35.0 gLatent heat of fusion of water (L): -79.7 cal/gQ = L × m
Q = -79.7 cal/g × 35.0 g
Q = -2.79 × 10³ calories
Therefore, the heat in calories required to freeze 35.0g of water of water is 2.79 × 10³ cal.
Learn more about how to calculate heat at: https://brainly.com/question/21122443
Plzzz fastttt answerrr
Which answer choices correctly describe why the number of known elements more then doubled by 1861
Answer:
- Communication between scientists increased.
- Technological advancements were made.
Explanation:
The complete question is
Which answer choices correctly describe why the number of known elements more than doubled by 1861?
Select all that apply.
- Metalworkers began using new metals.
- Communication between scientists increased.
- The American Civil War started.
- Technological advancements were made.
Technological advancement allowed more elements to be properly analysed and classified, and knowledge sharing between scientist by means of communication made it possible for the known number of elements to double by 1861