Since the sample size is below 30, in this case we use the t statistic. The formula for t score is:
t = (x – u) / (σ / sqrt n)
where,
x = the level l = unknown
u = sample mean = 120 mg / dl
σ = standard deviation = 20 mg / dl
n = sample size or number of results = 5
Using the standard distribution tables for t, we can find the value of t given the probability (P = 0.15) and degrees of freedom (DOF).
t = 1.036
Going back to the formula for t score:
1.036 = (x – 120) / (20 / sqrt 5)
x = 129.27 mg / dl = l
Final answer:
To find the glucose level such that the probability of the mean of 5 tests being above it is 0.15, we calculate the reduced standard deviation for the mean of the tests, find the corresponding z-score for a cumulative probability of 0.85, and apply the formula for the mean's distribution. The level l is found to be 129.267 mg/dl.
Explanation:
The question asks for the level l such that there is only a 0.15 probability that the mean glucose level of 5 test results falls above l, given that Sheila's glucose level after a sugary drink follows a normal distribution with a mean (μ) of 120 mg/dl and a standard deviation (σ) of 20 mg/dl.
To solve for l, we first need to recognize that the distribution of the mean of several test results (in this case, 5) will also be normally distributed, with the same mean but with a reduced standard deviation that is equal to the original standard deviation divided by the square root of the number of tests (σ/√n). For 5 tests, the new standard deviation (σnew) is 20/√5 = 8.9443 mg/dl.
The next step involves determining the z-score that corresponds to a probability of 0.85 (since 1 - 0.15 = 0.85) in the standard normal distribution. Consulting a z-table or using statistical software, we find that the z-score corresponding to 0.85 is approximately 1.036. Using the formula l = μ + z σnew, we calculate:
l = 120 + (1.036)(8.9443) = 120 + 9.267 = 129.267 mg/dl.
Therefore, the level l such that there is a probability of only 0.15 that the mean glucose level of 5 test results falls above l is 129.267 mg/dl.
Which of the following reactions is a neutralization reaction? A. ZnCl2(aq) + CaCrO4(aq) → ZnCrO4(s) + CaCl2(aq) B. HNO3(aq) + LiOH(aq) → H2O(l) + LiNO3(aq) C. 2NaOH(aq) + MgCl2(aq) → Mg(OH)2(s) + 2Na+(aq) + 2Cl−(aq) D. 4Fe(s) + 3O2(g) → 2Fe2O3(s)
A neutralization reaction is a chemical reaction between an acid and a base that results in water and a salt. Option B, HNO3(aq) + LiOH(aq) → H2O(l) + LiNO3(aq), is an example of this as it involves the reaction between an acid (Hydrogen Nitrate) and a base (Lithium Hydroxide) to form water and a salt (Lithium Nitrate).
Explanation:In chemistry, a neutralization reaction is a type of chemical reaction where an acid and a base react to form a salt and water. Looking at the provided options, the reaction B. HNO3(aq) + LiOH(aq) → H2O(l) + LiNO3(aq) is a neutralization reaction. This is because Hydrogen Nitrate (HNO3) is an acid and Lithium Hydroxide (LiOH) is a base. The result of their interaction is water (H2O) and a salt (LiNO3).
A neutralization reaction is characterized by an acid reacting with a base and forming water and a salt, which is what happens in this reaction. Hence, option B depicts a neutralization reaction.
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If Uranium-234 decays via alpha emission, what is the likely product of radioactive decay? (U, atomic no. = 92)
An alpha emission is one in which an atomic nucleus emits an alpha particle (helium nucleus). Therefore in this reaction, the products of the decay are Helium and another element X. Helium has an atomic mass and atomic number of 4 and 2 respectively, therefore the complete reaction is:
U-234 (92) ---> He-4 (2) + X
Since atomic mass and number must be conserved therefore X = X-230 (90)
U-234 (92) ---> He-4 (2) + X-230 (90)
The element with atomic number of 90 is Thorium. Therefore the other product is Thorium-230 (90).
U-234 (92) ---> He-4 (2) + Th-230 (90)
What type of graph shows the relationship between two quantities as those quantities are changing?
Which analogy can best be likened to the activation energy of a chemical reaction?
The density of a gas is 1.49 g/l at a temperature of 24 âc and a pressure of 0.787 atm . calculate the molar mass of the gas.
The molar mass of the gas is approximately [tex]47.56 \text{ g/mol}[/tex]
To calculate the molar mass of the gas, we can use the Ideal Gas Law, which is given by:
[tex]\[ PV = nRT \][/tex]
where:
- [tex]\( P \)[/tex] is the pressure of the gas,
- [tex]\( V \)[/tex] is the volume of the gas,
- [tex]\( n \)[/tex] is the number of moles of the gas,
- [tex]\( R \)[/tex] is the ideal gas constant, and
- [tex]\( T \)[/tex] is the temperature of the gas in Kelvin.
First, need to convert the temperature from Celsius to Kelvin:
[tex]\[ T(K) = T(\°C) + 273.15 \] \[ T(K) = 24 + 273.15 = 297.15 K \][/tex]
The density [tex]\( \rho \)[/tex] of the gas is given as 1.49 g/L. The density is the mass [tex]\( m \)[/tex] divided by the volume [tex]\( V \)[/tex]:
[tex]\[ \rho = \frac{m}{V} \][/tex]
express the mass in terms of the molar mass [tex]\( M \)[/tex] and the number of moles [tex]\( n \)[/tex]:
[tex]\[ m = M \cdot n \][/tex]
Substituting this into the density equation gives:
[tex]\[ \rho = \frac{M \cdot n}{V} \][/tex]
Now, can rearrange the Ideal Gas Law to solve for [tex]\( n \)[/tex]:
[tex]\[ n = \frac{PV}{RT} \][/tex]
Substituting this expression for [tex]\( n \)[/tex] into the density equation gives:
[tex]\[ \rho = \frac{M \cdot PV}{RTV} \][/tex]
[tex]\[ \rho = \frac{M \cdot P}{RT} \][/tex]
Now, can solve for the molar mass [tex]\( M \)[/tex]:
[tex]\[ M = \frac{\rho RT}{P} \][/tex]
know that the ideal gas constant [tex]\( R \)[/tex] is 0.0821 L·atm/(mol·K), so we can plug in the values:
[tex]\[ M = \frac{1.49 \text{ g/L} \cdot 0.0821 \text{ L\·atm/(mol\·K)} \cdot 297.15 \text{ K}}{0.787 \text{ atm}} \] \[ M = \frac{1.49 \cdot 0.0821 \cdot 297.15}{0.787} \] \[ M = \frac{37.41}{0.787} \] \[ M \approx 47.56 \text{ g/mol} \][/tex]
Therefore, the molar mass of the gas is approximately 47.56 g/mol.
Air contains water in a gaseous form called _____.
Air contains water in a gaseous form called water vapor
You are given 450.0 g of a 0.7500 molal solution of acetone dissolved in water. how many grams of acetone are in this amount of solution?
To find the grams of acetone in the given solution, we can use the formula for molality and calculate the mass of acetone based on the molality, molar mass of acetone, and mass of the solvent.
Explanation:The mass of the solution is given as 450.0 g and the molality is given as 0.7500 molal. To find the grams of acetone in the solution, we can use the formula for molality:
Molality (m) = moles of solute / mass of solvent (in kg)
Since 0.7500 molal corresponds to 0.7500 mol of acetone per 1 kg of water, we can calculate the mass of acetone by multiplying the molality by the molar mass of acetone and the mass of the solvent:
Mass of acetone = 0.7500 molal * (58.08 g/mol) * (0.4500 kg)
Therefore, there are 22.52 grams of acetone in this amount of solution.
If you are given a 1.0 L (1000mL) of an unknown liquid which has the mass of 500 grams it is most likely which of the above substances? Show work to back up your answer. Distilled water density 1.0 g/cm^3 propane density 0.494 g/cm^3 salt water density 1.025 g/cm^3 liquid gold density 17.31g/cm^3
Which statement correctly describes an electrode in a voltaic cell of copper and hydrogen?
A. Copper atoms become copper ions at the anode because the SRP is more positive.
B. Hydrogen ions become diatomic hydrogen at the cathode because hydrogen is always reduced in a voltaic cell.
C. Copper ions become copper atoms at the cathode because copper is always reduced in a voltaic cell.
D. Diatomic hydrogen becomes hydrogen ions at the anode because the SRP is more negative.
Which pair of elements is most apt to form a molecular compound with each other?
How is gamma radiation different from other types of electromagnetic radiation
How tall would a stack of 1000 pennies in centimeters
Final answer:
To find the height of a stack of 1000 pennies, multiply the thickness of one penny (1.52mm) by 1000, resulting in a stack 1520mm tall, which is 152 centimeters.
Explanation:
The question concerns how tall a stack of 1000 pennies would be in centimeters. To answer this, we must know the thickness of one penny. If we assume the thickness of a single penny is approximately 1.52mm (0.0598 inches), we can calculate the height of 1000 pennies by multiplying the thickness of one penny by the number of pennies in the stack. Since there are 10 millimeters in 1 centimeter, we'll need to convert millimeters to centimeters.
Here is the calculation:
Thickness of one penny = 1.52mmHeight of 1000 pennies = 1000 x 1.52mm = 1520mmHeight in centimeters = 1520mm / 10 = 152cmHELP! I will give brainliest for correct answer
In the important industrial process for producing ammonia (the Haber Process), the overall reaction is:
N2(g) + 3H2(g) → 2NH3(g) + 100.4 kJ
A yield of NH3 of approximately 98% can be obtained at 200°C and 1,000 atmospheres of pressure. What is the ΔH in kJ of heat released per mole of NH3(g) formed?
A.)50.2 kJ
B.)50.2 kJ
C.)4 kJ
D.)4 kJ
Cu(NO3)2 + Zn (s) → Cu (s) + Zn(NO3)2 is an example of which type of reaction?
Combustion
Decomposition
Single-displacement
Double-displacement
Answer:
Single-displacement
Explanation:
How many bonding electrons are in the lewis structure of carbon monoxide, co?
Answer:
6
Explanation:
The Lewis structure represents the valence electrons at the atoms, which ones are shared and the lone pairs. Carbon is at group 4 at the periodic table, and so has 4 electrons in the valence shell; oxygen is at group 6, and so has 6 electrons at the valence shell.
That compound is an exception of the octet rule. A triple bond is done between the atoms, and so, 3 electrons of carbon are shared and 3 electrons of oxygen are shared. Thus, there are 6 bonding electrons, as shown below in red.
The polar portion of a cholesterol molecule, which forms hydrogen bonds with the polar heads of neighboring phospholipids and glycolipids, consists of a
Which type of chemical bond involves the sharing of valence electrons between two atoms?
Answer:
Nonpolar Covalent
based on the nebular Theory, which of these is a step in the formation of a new planetary system?
A) evaporation of water
B) nuclear fission of gases
C) repulsion of gaseous masses
D) change of gases into liquids
Final answer:
The formation of a new planetary system involves the condensation of solid particles, accretion and collision of planetesimals, and the formation of protoplanets.
Explanation:
The formation of a new planetary system according to the nebular theory involves several steps. One important step is the condensation of solid particles from the solar nebula, which leads to the formation of planetesimals. The planetesimals then continue to accrete and collide with each other, gradually growing in size. This process eventually results in the formation of protoplanets, which are still in the process of forming into fully developed planets. Therefore, the correct answer is C) repulsion of gaseous masses.
A student performs an experiment that produces solid sodium chloride. He uses four different catalysts and lets the reaction run for two minutes, and then removes the sodium chloride product. Which is the best way for him to make a consistent measurement that would show the different amounts of sodium chloride produced?
Answer:
☆☆ Measure the four products separately, but using the same scale each time. option C
Explanation:
He cannot do this without affecting at the same time the evolution of the reaction, and of course by doing it on one sample only he will not be able to compare.
Find the no. Of electron involved in the electro deposition of 63.5g of cu from a solution of cuso4
In the reaction n2 + 3h2 ---> 2nh3, how many grams of nh3 are produced if 25.0 g n2 reacts with excess h2? question 10 options:
H2O has a Hvap = 40.7 kJ/mol. What is the quantity of heat that is released when 27.9 g of H2O condenses?
Answer:
Quantity of heat released = -63.1 kJ
Explanation:
Given:
Enthalpy of vaporization of water, ΔHvap = 40.7 kJ/mol
Mass of water, m = 27.9 g
To determine:
The amount of heat (Q) released
Explanation:
The reaction is: H2O(g) ↔ H2O(l)
The amount of heat evolved during condensation which involves a phase transition from vapor to liquid is given as:
[tex]Q = n*\-Delta Hvap[/tex]
n = moles of water
Since this is a condensation process: ΔHcond = -ΔHvap
[tex]Q = \frac{27.9 g}{18 g/mol} * -40.7 kJ/mol = -63.1 kJ[/tex]
Which of the following statements is not true regarding physical properties and changes?
A. Physical changes include evaporating, boiling, and dissolving.
B. Physical changes can change compounds into elements.
C. Physical properties can be observed without any change in the substance's identity.
D. A series of physical changes, such as filtration and heating, can be used to separate substances with different physical properties.
Answer: Option (B) is the correct answer.
Explanation:
Physical properties and changes are defined as the property or changes that does not cause any change in the chemical composition of a substance.
For example, cutting a piece of sodium with knife is a physical change.
Whereas boiling point, density, melting point etc are all physical changes.
On the other hand, changes that bring change in chemical composition of a substance are known as chemical changes.
For example, reactivity, toxicity etc are all chemical changes.
Hence, we can conclude that the statement physical changes can change compounds into elements, is not true regarding physical properties and changes.
When sodium chloride reacts with silver nitrate, silver chloride precipitates. what mass of agcl is produced from 75.00 g of agno3?
To calculate the atoms of an element in a given molecule, we need to multiply stoichiometry by the number that is written on the foot of that element. Therefore, the mass of AgCl produced from 75.00 g of AgNO[tex]_3[/tex]. is 63.0g.
What is stoichiometry?Stoichiometry is a part of chemistry that help us in making relationship between reactant and product from quantitative aspects.
The balanced reaction is
NaCl + AgNO[tex]_3[/tex] → NaNO[tex]_3[/tex] + AgCl
Mass of AgNO[tex]_3[/tex]=75.00 g
Molar mass of AgNO[tex]_3[/tex]=169.87 g/mol
Moles of AgNO[tex]_3[/tex]=0.44mol
From 1 mole of AgNO[tex]_3[/tex], 1 mole of AgCl is produced.
So, from 0.44 of AgNO[tex]_3[/tex], 0.44 mole of AgCl is produced.
Mass of AgCl =Molar mass of AgCl ×moles of AgCl
Mass of AgCl =143.32 g/mol ×0.44 mole
Mass of AgCl =143.32 g/mol ×0.44 mole
Mass of AgCl =63.0g
Therefore, the mass of AgCl produced from 75.00 g of AgNO[tex]_3[/tex]. is 63.0g.
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What is the concentration of k+ ions in a 0.045 m k2co3 solution assuming complete dissociation?express the concentration in molarity?
Answer: The concentration of [tex]K^+[/tex] ions in the solution is 0.09 M
Explanation:
We are given:
Concentration of [tex]K_2CO_3[/tex] = 0.045 M
The chemical equation for complete dissociation of potassium carbonate follows:
[tex]K_2CO_3(aq.)\rightarrow 2K^+(aq.)+CO_3^{2-}(aq.)[/tex]
By stoichiometry of the reaction:
1 mole of potassium carbonate produces 2 moles of potassium ions and 1 mole of carbonate ions.
So, the concentration of potassium ions in the given solution = [tex](2\times 0.045M)=0.09M[/tex]
Hence, the concentration of [tex]K^+[/tex] ions in the solution is 0.09 M
How did the discoveries of scandium (sc) and germanium (ge) affect mendeleevâs work?
they showed mandeleeves predictions were correct
A hurricane track gives the probability of a hurricane following a specific path. What type of scientific model is this?
Determine the ka of an acid whose 0.294 m solution has a ph of 2.80. 1.2 x 10-5 8.5 x 10-6 2.7 4.9 x 10-7 5.4 x 10-3
1)
Calculate [H+] from the pH:
pH = log { 1 / [H+] } = - log [H+]
=> [H+] = 10 ^ (-pH)
=> [H+] = 10 ^ (-2.80) = 0.00158
2) Assume the stoichiometry 1:1
=> HA aq ---> H(+) aq+ A(-) aq
=> [A-] = [H+] = 0.00158
[HA] = 0.294 – 0.00158 = 0.29242
3) Calculate Ka
Ka = [H+] *[A-] / [HA] = (0.00158)*(0.00158) / 0.29242 =8.54 * 10^ -6
Answer: 8.5 * 10^ -6
We have that the acid dissociation constant(Ka) is mathematically given as
Ka=8.54e-6
The acid dissociation constant(Ka)Question Parameters:
Generally the equation for the H+ pH value is mathematically
pH = log { 1 / [H+] }
[tex][H+] = 10 ^{-pH}[/tex]
[H+]= 0.00158
Where the stoichiometric ratio is 1:1
HA aq ---> H(+) aq+ A(-) aq
[H+] = 0.00158
[HA] = 0.294 – 0.00158
[HA]= 0.29242
Therefore
[tex]Ka =\frac{ [H+] *[A-]}{ [HA] }\\\\Ka=\frac{ (0.00158)*(0.00158)}{0.29242}[/tex]
Ka=8.54e-6
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3. The bonds between hydrogen and oxygen in water differ from the bonds between hydrogen and carbon in carbohydrates. How and why do these bonds differ?
How many moles are there in a 1.40 kg bottle of water?