Answers
A= 0.5, B = 0.25 , C = 0.125, D = 0.015625 and E = 0.00390625
What is a hypothesis?A research hypothesis is a statement of expectation or prediction that will be tested by research. Before formulating your research hypothesis, read about the topic of interest to you.
Half life of a substance is defined as the amount of time taken by the substance to reduce to half of its original amount.
Here n represents the number of half lives.
The amount of substance that remains after n half lives can be calculated using the given formula,
So when we have n =1,
Fraction of substance that remains = 0.5¹ = 0.5.
That means after first half life over, the amount of substance that remains is 0.5 times that of original.
Therefore we have A = 0.5
When n = 2, we have 0.5² = 0.25
So when 2 half lives are over, the amount of substance that remains is 0.25 times that of original
Therefore B = 0.25
When n = 3, we have 0.5³ = 0.125
So when 3 half lives are over, the amount of substance that remains is 0.125 times that of original.
Therefore we have C = 0.125
When n = 6 , we have 0.5⁶ = 0.015625
So D = 0.015625
When n = 8, we have 0.5⁸ = 0.00390625
Therefore E = 0.00390625
The values for A, B, C, D and E are 0.5, 0.25, 0.125, 0.015625 and 0.00390625 respectively.
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Related Questions
3. In a chemical reaction, the final amount of the products is determined by the
A. Universal Gas Law
B. catalysts involved
C. air pressure
D. temperature
E. limiting reactant
Answers
If you run out of the limiting reactant you cannot make anymore of a product.
Give the name of the ion with 13 protons and 10 electrons
Answers
Answer:
Explanation:
aluminum
Answer: The aluminum ion
Explanation:
5.86 ■ Liquid oxygen for use as a rocket fuel can be produced by cooling dry air to −183°C, where the O2 condenses. How many liters of dry air at 25°C and 750 torr would need to be processed to produce 150 L of liquid O2 at −183°C? (The mole fraction of oxygen in dry air is 0.21, and the density of liquid oxygen is 1.14 g/mL.)
Answers
Approximately 631.5 liters of dry air at 25°C and 750 torr would need to be processed to produce 150 liters of liquid \(O_2\) -183°C.
To solve this problem, we need to consider the ideal gas law and the molar volume of gases.
First, we can calculate the number of moles of oxygen in 150 L of liquid \(O_2\) at -183°C. To do this, we divide the mass of liquid oxygen by its molar mass:
Mass of liquid oxygen = volume of liquid oxygen * density of liquid oxygen = 150 L * 1.14 g/mL = 171 g
Molar mass of oxygen (O2) = 32 g/mol
Number of moles of oxygen = mass of oxygen / molar mass of oxygen = 171 g / 32 g/mol ≈ 5.34 mol
Since the mole fraction of oxygen in dry air is given as 0.21, we can calculate the total moles of dry air needed to produce 5.34 mol of oxygen:
Moles of dry air = moles of oxygen / mole fraction of oxygen = 5.34 mol / 0.21 ≈ 25.43 mol
Now, we can use the ideal gas law to calculate the volume of dry air at 25°C and 750 torr (convert to atm) that corresponds to 25.43 mol:
PV = nRT
P = 750 torr * (1 atm / 760 torr) ≈ 0.987 atm
V = volume of dry air (unknown)
n = 25.43 mol
R = 0.0821 L·atm/(mol·K)
T = 25°C + 273.15 = 298.15 K
Solving for V:
V = nRT / P = (25.43 mol)(0.0821 L·atm/(mol·K))(298.15 K) / 0.987 atm ≈ 631.5 L
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Assume the trials listed below with Equilibrium constants!
Need help with the table graphing questions (in answers b, c, d, I need to explain my answer which I'm a little confused about -> how do you actually go about solving?)
Answers
The value of Kc for the reaction at 25°C is 11.25.
The equilibrium constant expression for the reaction:
2NO(g) + \(Cl_2\)(g) ⇌ 2NOCl(g)
is Kc = \(([NOCl]^2)/([NO]^2[Cl_2])\), where [NO], [\(Cl_2\)], and [NOCl] are the molar concentrations of NO, \(Cl_2\), and NOCl, respectively, at equilibrium.
At 25°C, if the concentration of NO and \(Cl_2\) are 0.2 M and the concentration of NOCl is 0.3 M, then we can substitute these values into the equilibrium constant expression to find the value of Kc:
Kc =\(([NOCl]^2)/([NO]^2[Cl_2])\)
Kc = \((0.3^2)/(0.2^2*0.2)\)
Kc = 11.25
Therefore, the value of Kc for the reaction at 25°C is 11.25.
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--The complete Question is, Assuming trials with equilibrium constants, what is the equilibrium constant expression for the reaction:
2NO(g) + Cl2(g) ⇌ 2NOCl(g)
and what is the value of Kc at 25°C if the concentration of NO and Cl2 are 0.2 M and the concentration of NOCl is 0.3 M? --
What is the molar concentration (molarity, M) of a 450 mL solution that contains 2.00 mol of FeCl₂?
Answers
Answer:
3.50 Mol/L or M
Explanation:
450 mL / 1000 = 0.45 L
1 mole ------- 126.751 g
? mole ------- 200 g
moles = 200 * 1 / 126.751
moles = 200 / 126.751
= 1.57789 moles FeCl₂
M = n / V
M = 1.57789 / 0.45
= 3.50 Mol/L or M
TiCl4 + O2
What is the predicted product
Answers
Answer: Titanium dioxide
Using standard heats of formation, calculate the standard enthalpy change for the following reaction.
H2(g) + C2H4(g)--------C2H6(g)
Answers
Answer:
\(\Delta _rH=-136.27kJ/mol\)
Explanation:
Hello,
In this case, for the given reaction, the enthalpy of reaction is computed in terms of the enthalpies of formation as:
\(\Delta _rH=\Delta _fH_{C_2H_6}-\Delta _fH_{C_2H_4}-\Delta _fH_{H_2}\)
Whereas hydrogen, ethene and ethane enthalpies of formation are 0 kJ/mol, 52.47 kJ/mol and -83.8kJ/mol respectively. Therefore, we compute:
\(\Delta _rH=-83.8kJ/mol-52.47kJ/mol-0kJ/mol\\\\\Delta _rH=-136.27kJ/mol\)
Best regards.
Complete the table below by deciding whether a precipitate forms when aqueous solutions A and B are mixed. If a precipitate will form, enter its empirical formula in the last column.
Answers
1) A precipitate called \(Fe(OH)_{2}\)
2) A precipitate is formed called \(Mg(CH_{3} COO)_{2}\)
What is a precipitate?The term precipitate is used to describe the product that is formed when there is a reaction between two aqueous phase reactants that leads to the formation of a solid product from the reaction as we can see from the image that is attached.
we now have to look at the reactions as we can see them in the mage that is attached. We must note that we can only say that a precipitate has been formed if the product is solid after we have mixed the aqueous phase reactants.
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When 1.00-gram sample of baking soda is heated, a gas is formed. The solid that remains weighs less than 1.00 g and does not have the same properties as the original sample. Is baking soda an element or compound?
Answers
Answer:
Compound
Hope it helps!
which type of mutation could have the most drastic effect
on a gene a chromosomal mutation? Back up your choice.
Answers
Answer:
we need to know the definitions of the two types of mutations:
A chromosomal mutation is a change in the structure or number of chromosomes, which are the structures that carry genes. Examples of chromosomal mutations are deletions, duplications, inversions, and translocations.A gene mutation is a change in the sequence of nucleotides, which are the building blocks of DNA and RNA. Examples of gene mutations are substitutions, insertions, and deletions.Looking at the definitions, we can see that a chromosomal mutation can affect many genes at once, while a gene mutation can affect only one or a few nucleotides. Therefore, a chromosomal mutation could have the most drastic effect on a gene, because it could alter or delete an entire gene or multiple genes, resulting in major changes in the phenotype or function of an organism. A gene mutation could also have significant effects on a gene, but it could also be silent or minor depending on the location and type of the mutation. Therefore, the answer is a chromosomal mutation. One possible way to back up this choice is to give an example of a chromosomal mutation that causes a genetic disorder, such as Down syndrome or Turner syndrome.
____________Polar regions get less of the sun's direct rays, they are the coldest climates on Earth. A because , B although, C Howerer, D Consequently / what best word fits in the blank space what makes sense.
Answers
Answer:
Because Polar regions get less of the sun's direct rays, they are the coldest climates on Earth.
Explanation:
100.0 mL of a 0.695 M solution of KBr is diluted to 500.0 mL. What is the new concentration of the solution?
Answers
Answer:
0.116 M
Explanation:
(Step 1)
Calculate the amount of moles using the molarity ratio.
100.0 mL / 1,000 = 0.1000 L
Molarity = moles / volume
0.695 M = moles / 0.1000 L
0.0695 = moles
(Step 2)
Calculate the new molarity using the moles and new volume.
500.0 mL / 1,000 = 0.5000 L
Molarity = moles / volume
Molarity = 0.0695 moles / (0.1000 L + 0.5000 L)
Molarity = 0.0695 moles / (0.6000 L)
Molarity = 0.116 M
prop-1-yne + 2HBr/H2O2 = A;
A + 2H2O = B;
B + K2CO3(aq) = C;
C + heat = D;
D + HBr = E.
find the compounds A, B, C, D and E
Answers
Based on the given reactions, the compounds are as follows:
A: The specific product formed from the reaction between prop-1-yne and either 2HBr or H2O2.
B: The product formed when compound A reacts with 2H2O.
C: The product formed when compound B reacts with K2CO3(aq).
D: The product formed from the heat-induced reaction of compound C.
E: The product formed when compound D reacts with HBr.
Based on the given reactions, let's analyze the compounds involved:
Reaction 1: prop-1-yne + 2HBr/H2O2 = A
The reactant prop-1-yne reacts with either 2HBr or H2O2 to form compound A. The specific product formed will depend on the reaction conditions.
Reaction 2: A + 2H2O = B
Compound A reacts with 2H2O (water) to form compound B.
Reaction 3: B + K2CO3(aq) = C
Compound B reacts with K2CO3(aq) (potassium carbonate dissolved in water) to form compound C.
Reaction 4: C + heat = D
Compound C undergoes a heat-induced reaction to form compound D.
Reaction 5: D + HBr = E
Compound D reacts with HBr (hydrobromic acid) to form compound E.
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The diagrams to the right show the distribution and arrangement of gas particles in two different containers. According to kinetic-molecular theory, which of the following statements is true? Check all that apply. If the temperatures of both containers are equal, container A has greater pressure than container B. If the volume of container A decreased, its pressure would decrease. If the pressure in both containers is equal, container A has a lower temperature than container B. Two containers are shown. Container A is square, and Container B is the same height, but is about twice as wide. Each container holds 6 gas particles distributed randomly.
Answers
The kinetic-molecular theory's true assertions are as follows:
If both containers' temperatures are the same, container A will have a higher pressure than container B.
Container A has a lower temperature than container B if the pressure in both containers is equal.
What is the kinetic theory of molecules?The molecules that make up a gas are always moving randomly, colliding with one another and the container walls, according to the kinetic molecular hypothesis. Remember that high temperature and low pressure are the only conditions in which perfect gases can exist.
The kinetic-molecular theory's true assertions are as follows:
If both containers' temperatures are the same, container A will have a higher pressure than container B.
If both are under pressure
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What is the acceleration of a jogger who moves in a straight line and increases her speed by 1 mile per hour every 0.5 hours?
A. 0.5 miles/h
B. 2 miles/h2
C. 1 mph a
Answers
If you need to design a technological solution to lack of water availability in a developing country, which of the following should you do before proposing a solution? invest the money to test your most promising design select the best of several possible designs build a model to test research scientific principles involved in water availability
Answers
Anwser:
Research scientific principles involved in water availability.
Explanation:
Before building or investment you always want to see and know what your up against and what the best way to help or solve is. Researching why there's a problem in water availability or/and the principals to water availability will help you see what the problem is with what's happening to and around the process and it's environment.
An organic compound (CaHbNcOdCle) was synthesized and a sample of it was analyzed and found to contain only C, H, N, O, and Cl. It was observed that when a 0.150-g sample of the compound was burned, it produced 0.138 g CO2 and 0.0566 g H2O. All the nitrogen in a different 0.200-g sample of the compound was converted to NH3, which found to weigh 0.0238 g. Finally, the chlorine in a 0.125-g sample of the compound was converted to Cl- and by reacting it with AgNO3, all the chlorine was recovered as AgCl. The AgCl, when dried, was found to weigh 0.251 g. Calculate the weight percent of each element in the compound.
Answers
The mass percent of each element is:
mass percent of C is 24%
mass percent of H is 4%
mass percent of Cl is 50%
mass percent of N is 9.8%
Mass percent of oxygen is 12.2%
What is the mass of each of the constituent elements in a sample of the compound?The mass of each of the constituent elements in a sample of the compound is determined as follows:
mass of C:
1 mole of C is present in 1 mole of CO₂
The mass of C in 0.138 g of CO₂ will be:
0.138 g / 44 g * 12 g = 0.0368 g
mass of H:
2 moles of H are present in 1 mole of H₂O
The mass of H present in 0.0566 g H₂O will be:
0.0566 g / 18 * 2 * 1 = 0.00628 g
mass of Cl;
1 mole of Cl is present in 1 mole of AgCl
The mass of Cl in 0.251 g of AgCl will be:
0.251 g / 143.5 g * 35.5 g = 0.0621 g
mass of N:
1 mole of N is present in 1 mole of NH₃
The mass of N in 0.251 g of NH₃ will be:
0.0238g / 17.0 g * 14 g = 0.0196 g
Mass percent of each element will be:
mass percent of C:
mass percent = 0.0368/0.15 * 100
mass percent = 24%
mass percent of H:
mass percent = 0.00628 / 0.15 * 100%
mass percent = 4%
mass percent of Cl;
mass percent of Cl:
mass percent = 0.0621 / 0.125 * 100%
mass percent = 50%
mass percent of N:
mass percent = 0.0196 / 0.2 * 100%
mass percent = 9.8%
Mass percent of oxygen = 100 - (24 + 4 + 50 + 9.8)
Mass percent of oxygen = 12.2%
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Why is there an imbalance in the carbon cycle?
Answers
What would be the volume in liters of an 25.15 liter sample of gas at 201 °C and 2.31 atm if conditions were changed to STP?
Answers
The volume of the gas at STP would be 23.93 liters.
The volume of gas at STP (Standard Temperature and Pressure), we need to use the Ideal Gas Law, which states that PV = nRT, where P is pressure, V is volume, n is the number of moles of gas, R is the gas constant, and T is temperature. First, we need to calculate the number of moles of gas in the initial sample. We can use the formula n = PV/RT, where P is the initial pressure, V is the initial volume, R is the gas constant, and T is the initial temperature.
n = (2.31 atm) x (25.15 L) / [(0.0821 L atm/mol K) x (201 + 273.15 K)]
n = 1.067 moles
Now, we can use the molar volume of gas at STP, which is 22.4 L/mol, to calculate the volume of gas at STP.
V = n x 22.4 L/mol
V = 1.067 moles x 22.4 L/mol
V = 23.93 L
Therefore, the volume of the gas at STP would be 23.93 liters.
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12.5 mL of 0.280 M HNO3 and 5.0 mL of 0.920 M KOH are mixed. Is the resulting solution acidic, basic or neutral?
Answers
Answer:
The resulting solution is basic.
Explanation:
The reaction that takes place is:
HNO₃ + KOH → KNO₃ + H₂OFirst we calculate the added moles of HNO₃ and KOH:
HNO₃ ⇒ 12.5 mL * 0.280 M = 3.5 mmol HNO₃KOH ⇒ 5.0 mL * 0.920 M = 4.6 mmol KOHAs there are more KOH moles than HNO₃, the resulting solution is basic.
The resulting solution is basic.
• It is known that KOH is a base and HNO3 is an acid, so when they mix they undergo a neutralization reaction.
• The reaction between there will be,
HNO3 + KOH ⇔ KNO3 + H2O
Based on the given information,
• The volume of HNO3 is 12.5 ml and the molarity is 0.280 M, and the volume of KOH is 5 ml and the molarity is 0.920 M.
Now 1 mole of HNO3 completely reacts with 1 mole of KOH,
The millimoles of HNO3 is,
\(= Molarity * Volume (in ml)\\= 0.280 * 12.5\\= 3.5 mmol\)
The millimoles of KOH is,
\(= Molarity * Volume (in ml)\\= 0.920 * 5.0\\= 4.6 mmol\)
Now it can be seen that 3.5 millimoles of HNO3 completely reacts with 3.5 millimoles of KOH. Now we are left with 4.6-3.5 = 1.1 mmol of KOH.
Thus, KOH is in excess amount present in the solution, and as it is basic in nature, therefore, the resultant solution would be basic in nature.
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Which is true regarding percentage error?
The percentage error is calculated by multiplying the approximation value and the exact value.
The percentage error is a percentage that details how far an approximation is from the exact value after an experiment.
The percentage error is a set of inferences made by human senses and scientific equipment.
The percentage error is a percentage that states how many mistakes were made during an experiment.
Answers
The statement that is true regarding percentage error is as follows: the percentage error is a percentage that details how far an approximation is from the exact value after an experiment (option B).
What is percentage error?Percentage error is the difference between estimated value and the actual value in comparison to the actual value and is expressed as a percentage.
The percentage error in an experiment can be calculated by subtracting the actual value from the estimated value divided by the actual value, then multiplying the result by 100.
Percentage error = (Estimated value - Actual value/ Actual value) × 10
Therefore, the statement that is true regarding percentage error is as follows: the percentage error is a percentage that details how far an approximation is from the exact value after an experiment.
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Most of the elements in the periodic table can be described as:
A. metalloids
B. halogens
c. non-metals
D. metals
Answers
The answer would be metals :)
A can of soda gets left in the car on a hot summer day. When the can was placed in the car it had an internal temperature of 10
and pressure of 2.07 atm. If the can heats up to 47.6 what will the pressure inside the can be? Remember to convert to Kelvin! (Report your answers to 2 decimal places)
Answers
Answer:
2.35 atm
Explanation:
According to the Ideal Gas Equation,
P₁/T₁ = P₂/T₂Here :
P₁ = 2.07 atmT₁ = 10 °C = 283 KT₂ = 47.6 °C = 320.6 KSolving :
P₂ = P₁T₂/T₁P₂ = 2.07 x 320.6 / 283P₂ = 663.642/283P₂ = 2.35 atm (rounded to 2 DP)Which material would conduct heat best?
А.Air
B.Copper
C.Wood
D.Rubber
Answers
Answer:
I believe the best answer is B. Copper.
accurately determine the precise composition of the unknown substance
Answers
Answer:
To accurately determine the precise composition of an unknown substance, a combination of analytical techniques may be used. Here are some steps that can be taken:
Physical examination: Conduct a visual and physical examination of the substance to gather information about its color, texture, odor, and other observable characteristics.
Elemental analysis: Determine the elemental composition of the substance using techniques such as X-ray fluorescence (XRF) spectroscopy or inductively coupled plasma (ICP) spectroscopy.
Chromatography: Use chromatography techniques, such as gas chromatography (GC) or liquid chromatography (LC), to separate and analyze the individual components of the substance.
Spectroscopy: Use spectroscopy techniques, such as infrared (IR) spectroscopy or mass spectrometry (MS), to analyze the molecular structure of the individual components of the substance.
Nuclear magnetic resonance (NMR) spectroscopy: Use NMR spectroscopy to identify the arrangement of atoms in molecules, and thus the molecular structure of the individual components of the substance.
Microscopy: Use microscopy techniques, such as scanning electron microscopy (SEM) or transmission electron microscopy (TEM), to examine the physical and structural characteristics of the substance at a microscale.
Comparison with known standards: Compare the results obtained from the analytical techniques with those of known standards or reference materials to identify and quantify the individual components of the unknown substance.
Overall, a combination of these analytical techniques may be used to accurately determine the precise composition of an unknown substance. The specific techniques used will depend on the nature of the substance and the analytical capabilities of the laboratory or facility conducting the analysis.
Explanation:
An ionic compound has the formula X3N2. Which one of the following groups is the element X on?
Answers
The element X in the ionic compound from the question belongs to group 2.
What is the ionic compound?An ionic compound is a compound that is formed when there is a combination of two or more atoms that are combined by the transfer of electrons. Now we know that the transfer of the electrons would give rise to the formation of to ions, a cation and an anion. The cation is the specie that lost electrons while the anion is the specie that gained the electrons. Thus the compound is composed actually of an ions pair that are necessarily of opposite charges from each other.
In this case, an ionic compound has the formula\(X_{3} N_{2}\). We can see that the element X has reacted with nitrogen to form a nitride and that the nitrogen has a subscript of 2 as shown.
The fact the nitrogen has a subscript of 2 shows that the element belongs to group 2.
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What is the charge that a Phosphorus atom would likely form?
+1
+2
+3
-1
-2
-3
Answers
Answer:(b) By referring to a periodic table or table of elements, we see that phosphorus (symbol P) has an atomic number of 15. Thus, each atom has 15 protons. The mass number of the ion is 15 + 16 = 31. Because the ion has 15 protons and 18 electrons (three more electrons than protons), its net charge is 3-
Calculate the pH of 500 mL of water to whicha. 20.0 mL of 0.1 M HNO3 has been addedb. 15.0 mL of 1.0 M KOH has been added
Answers
The pH of 500ml of water to which 20ml of 0.1M HNO3 has been added is = 4.8 and The PH of 500ml of water to which 15.0ml of 1.0M KOH has been added is = 10.12
a. The pH of 500 mL of water to which 20.0 mL of 0.1 M HNO3 has been added can be calculated as follows:
First, calculate the volume-to-volume ratio of the HNO3 solution to the water: V_HNO3 / V_water = 20.0 mL / 500 mL = 0.04
Next, calculate the amount of HNO3 added to the water: n_HNO3 = 0.1 M * 20.0 mL * 0.04 = 8.0 x \(10^{5}\) mol
Finally, calculate the new concentration of HNO3 in the solution and use the equation for the pH of a strong acid solution to find the pH: C_HNO3 = n_HNO3 / (V_water + V_HNO3) = 8.0 x \(10^{-5}\)mol / (500 mL + 20.0 mL) = 1.6 x \(10^{-5}\) M pH = -log[H+] = -log(1.6 x \(10^{-5}\)) = 4.8
b. The pH of 500 mL of water to which 15.0 mL of 1.0 M KOH has been added can be calculated as follows:
First, calculate the volume-to-volume ratio of the KOH solution to the water: V_KOH / V_water = 15.0 mL / 500 mL = 0.03
Next, calculate the amount of KOH added to the water: n_KOH = 1.0 M * 15.0 mL * 0.03 = 4.5 x \(10^{-4}\)mol
Finally, calculate the new concentration of OH- in the solution and use the equation for the pH of a strong base solution to find the pH: C_OH- = n_KOH / (V_water + V_KOH) = 4.5 x \(10^{-4}\) mol / (500 mL + 15.0 mL) = 7.5 x \(10^{-5}\) M pH = 14 + log[OH-] = 14 + log(7.5 x\(10^{-5}\)) = 10.12.
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What type of bonding around a central atom would result in a trigonal planar
molecule?
A. Three groups bound to it with no lone pairs
B. One group bound to it with two lone pairs
C. Three groups bound to it with one lone pair
D. Four groups bound to it with no lone pairs
Answers
Explanation:
A. 3 groups bound to it with no lone pairs
Which is a nonmetal that becomes isoelectronic with argon
when it forms its most common ion?
Answers
Answer:sulfur
Explanation: