Answer:
3.11 mol/kg
Explanation:
Molality M = number of moles of solute, n/mass of solvent, m
To calculate the number of moles of glycerol (C₃H₈O₃) in 22.75 g of glycerol, we find its molar (molecular) mass, M',
So, M' = 3 × atomic mass of carbon + 8 × atomic mass hydrogen + 3 × atomic mass of oxygen
= 3 × 12 g/mol + 8 × 1 g/mol + 3 × 16 g/mol = 36 g/mol + 8 g/mol + 48 g/mol = 92 g/mol.
So, number of moles of glycerol, n = m'/M' where m' = mass of glycerol = 22.75 g and M' = molecular mass of glycerol = 92 g/mol
So, n = m'/M'
n = 22.75 g/92 g/mol
n = 0.247 mol
So, the molality of the solution M = n/m
Since m = mass of ethanol = 79.6 g = 0.0796 kg, substituting the value of n into the equation, we have
M = 0.247 mol/0.0796 kg
M = 3.11 mol/kg
So, the molality of the solution is 3.11 mol/kg.
In a solution, the solvent is
ANSWER:
A. always water
B. dissolved in the solute
C. present in larger amount than the solute is
D. always nonpolar
Answer:
dissolved in the solute
Explanation:
A solvent is the component that dissolves the solute and is present in larger amount. The type of solution is determined by the state of the solute and solvent. If you have NaCl, a solid, dissolved in water, a liquid, the type of solution is a solid/liquid solution.
Please helpplease please..help
Answer:
vague symptoms are characteristic of an acute toxin, because of the of the lack of well defined consistency that these symptoms have in relation to the course of the disease progress.
A 250 mL sample of gas at 1.00 atm and has the temperature increased to and the volume increased to 500 mL. What is the new pressure
Answer:
0.53atm = P2
Explanation:
Gas at 1.00atm and 20°C. Temperature increased to 40°C...
We can solve this question using combined gas law:
P1*V1 / T1 = P2*V2 / T2
Where P is pressure, V volume and T absolute temperature of 1, initial state and 2, final state.
Compunting the values of the problem:
P1 = 1.00atm
V1 = 250mL
T1 = 20°C + 273.15 = 293.15K
P2 = ?
V2 = 500mL
T2 = 40°C + 273.15 = 313.15K
1.00atm*250mL / 293.15K = P2*500mL / 313.15K
0.53atm = P2
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Question 1
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Write the symbol for every chemical element that has atomic number less than 14 and atomic mass greater than 23.2 u.
Answer:
8 oxygen. 9 flourine. 10. Neon. 5 Boron
(4.184 J——> 1 calorie ? Take your answer from number 1 and convert to the answer into calories?
Answer:
There are 1.195 calories in 5 J.
Explanation:
The relation between calorie and Joules is as follow :
4.184 J = 1 calorie
or
1 J = (1/4.184) calorie
Let the taken number is 5 J
So,
5 J = (5/4.184) calorie
5 J = 1.195 calorie
So, there are 1.195 calories in 5 J.
A dilute solution of an unknown ionic compound must be identified. Several experiments are run on solutions that contain the possible ions with the results tabulated below. Cation Addition of HCl Heated in hot water Ag+ White precipitate is formed No observable change Pb+2 White precipitate is formed Precipitate dissolves Zn+2 No observable change No observable change Anion Addition of Ca(NO3)2 Addition of HNO3 CO3–2 White precipitate is formed Precipitate dissolves and bubbles form PO4–3 White precipitate is formed Precipitate dissolves A white precipitate is formed when HCl is added to the unknown compound. When the white precipitate is heated in hot water, it does not dissolve. A white precipitate is formed when Ca(NO3)2 is added to the unknown compound. When HNO3 is added to the precipitate, it dissolves and bubbles are formed. What is the chemical formula of the unknown ionic compound?
Answer:
The chemical formula of the unknown ionic compound is Ag₂CO₃.
Explanation:
The method used to identify the ions present in a given solution of an unknown compound is known as qualitative analysis. Specific tests are carried based on the chemical reaction of these ions and the results they give in these reactions, the ions present innthe compound are identified. Some of the results or observations include formation of precipitates on addition of certain reagents, evolution of gases, colour changes, as well as the color changes that are observed in a flame test of a solutionmof these compounds.
In the given question, when testing for cations, a white precipitate is formed when HCl is added to the unknown compound. When the white precipitate is heated in hot water, it does not dissolve.
From the table of observations, both Ag+ and Pb²+ give a white precipitate on addition of HCl but Zn²+ does not. So the cation present is either Ag+ or Pb²+. However, when heated in hot water, the white precipitate does not dissolve as will be observed if Ag+ were the cation present. Thus, the cation is Ag+.
When testing for anions, a white precipitate is formed when Ca(NO3)2 is added to the unknown compound and when HNO3 is added to the precipitate, it dissolves and bubbles are formed.
Now comparing these results with that as observed with CO₃²- and PO₄³-, both form white precipitates on addition of Ca(NO₃)₂, and the precipitate dissolves on addition of HNO₃. However, only CO₃²- dissolves with the production of bubbles when HNO₃ is added. Thus, the anion is CO₃²-.
Therefore, the compound is Ag₂CO₃ which is formed from the cation Ag+ and CO₃²-.
Explain why the balls representing fluorine (teal) and hydrogen (white) have only one peg, while carbon (black) has four.
Answer:
Hydrogen and fluorine form only one bond while carbon forms four bonds to other atoms.
Explanation:
This question brings us to the idea of valency. Fluorine is univalent while carbon is tetravalent.
Univalent means that fluorine can only form one bond to hydrogen while carbon forms as much as four bonds because it is tetravalent.
Hence fluorine and hydrogen have only one peg while carbon has four.
What is the molarity of a solution if 325ml of the solution contains 46.8 grams of NaHCO3?
Answer:
1.714 M
Explanation:
We'll begin by calculating the number of mole in 46.8 g of NaHCO₃. This can be obtained as follow:
Mass of NaHCO₃ = 46.8 g
Molar mass of NaHCO₃ = 23 + 1 + 12 + (3×16)
= 23 + 1 + 12 + 48
= 84 g/mol
Mole of NaHCO₃ =?
Mole = mass / molar mass
Mole of NaHCO₃ = 46.8 / 84
Mole of NaHCO₃ = 0.557 mole
Next, we shall convert 325 mL to L. This can be obtained as follow:
1000 mL = 1 L
Therefore,
325 mL = 325 mL × 1 L / 1000 mL
325 mL = 0.325 L
Thus, 325 mL is equivalent to 0.325 L.
Finally, we shall determine the molarity of the solution. This can be obtained as shown below:
Mole of NaHCO₃ = 0.557 mole
Volume = 0.325 L
Molarity =?
Molarity = mole / Volume
Molarity = 0.557 / 0.325
Molarity = 1.714 M
Therefore the molarity of the solution is 1.714 M
2x^2+8x-7 solve the equation
Answer:
x = (-4 + √30) / 2, or x = (-4 – √30) / 2
Explanation:
x = (-b ± √b² – 4ac) / 2a →
y = ax² + bx + c
given
y = 2x² + 8x – 7 →
x = (-(8) ± √(8)² – 4(2)(-7)) / 2(2) →
x = (-8 ± √64 + 56) / 4 →
x = (-8 ± √120) / 4 →
x = (-8 ± 2√30) / 4 →
x = (-4 ± √30) / 2 →
x = (-4 + √30) / 2, or x = (-4 – √30) / 2
Select the statement that correctly describes an endothermic process.
a. The enthalpy change for the process is negative.
b. Heat is lost by the system, but work is done on the system.
c. The enthalpy of the products is higher than that of the reactants.
d. The temperature change of the products is greater than that of the reactants.
e. Heat is released by the system, to the surroundings.
Answer:
C. The enthalpy of the products is higher than that of the reactants
Explanation:
An endothermic process is any process with an increase in the enthalpy of the system
The enthalpy of the products is higher than that of the reactants describes an endothermic process. Therefore, option (C) is correct.
What is the endothermic process?An endothermic process can be described as any thermodynamic process with an increase in the enthalpy H of the system. In such a process, a closed system commonly absorbs thermal energy from its surroundings.
An endothermic reaction leads to an increase in the temperature of the system and a decrease temperature of the surroundings. A physical process, such as the melting of ice cubes is an endothermic process.
Whether a process can take place spontaneously depends not only on the enthalpy change but also on the entropy change and absolute temperature.
An endothermic process commonly needs a favorable entropy increase (∆S > 0) in the system. In an endothermic process, the energy of the products is higher than that of the reactants.
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43.0 mL of 1.49 M perchloric acid is added to 14.0 mL of calcium hydroxide, and the resulting solution is found to be acidic.
29.1 mL of 0.498 M barium hydroxide is required to reach neutrality.
What is the molarity of the original calcium hydroxide solution?
Answer:
2.29 M
Explanation:
Equation of the reaction;
Ca(OH)2(aq) + 2HClO4(aq) → 2H2O(l) + Ca(ClO4)2(aq)
Concentration of acid CA = 1.49 M
Concentration of base CB= ????
Volume of acid VA= 43.0 ml
Volume of base VB= 14.0 ml
Number of moles of acid NA = 2 moles
Number of moles of base NB = 1 mole
CAVA/CBVB = NA/NB
CAVANB =CBVBNA
CB= CAVANB/VBNA
CB= 1.49 × 43.0 × 1/14.0 × 2
CB= 2.29 M
An object was measured by a worker as 14.6cm long, however, the manufacturer specifications list the length of the object at 14.4cm. What is the percent error in the worker's measurement? A. 1.39%
B. 1.37%
it's 0.2cm different from the expected value, wich was 14.6cm
how many percent that are is calculated in the screenshot.
rounded it's 1.37%
1.Using the absorbance of the spinach extract and the equation of the trendline, determine the concentration of the extract solution. Report the concentration in moles/L (M).
2. Calculate the number of rams of chlorophyll-a in the 25ml, spinach solution.
3. Calculate the concentration of the chloropyhll-a soultion in spinach (mg chlorophyll-a/g spinach)
Trendline: y=1609x + .0055
Absorbance spinach extract lamda max: .329
Absorbacne spinach extract, 750 nm: .023
Corrected absorbance: .306
Mass of Spinach: .1876g Total Volume of spinach: 25mL
Answer:
Explanation:
From the given information:
We are to make use of the spinach absorbance extract which is the corrected absorbance (y) = 0.306
And also the trendline equation:
y = 1609x + 0.0055
where,
x = absorbance of the spinach extract.
∴
0.306 = 1609x + 0.0055
collecting the like terms
0.306 - 0.0055 = 1609x
0.3005 = 1609x
x = 0.3005/1609
x = 1.8676 × 10⁻⁴
x ≅ 0.0002 M
No. of grams for the chlorophyll can be computed as follows:
recall that:
molar mass of chlorophyll = 893.5 g/mol
the volume = 25ml = (25/1000) L = 0.025 L
∴
In spinach solution, the no. of grams for the chlorophyll:
= (0.0002) mol/L × (893.5 g/mol) × (0.025) L
= 0.0044675 g
≅ 0.0045 g
In the spinach, the concentration of chlorophyll = no of grams of chlorophyll/ mass of the spinach
= 4.5 mg/0.1876 g
= 23.987 mg/g
≅ 24 mg/g
From the given information:
We are to make use of the spinach absorbance extract which is the corrected absorbance (y) = 0.306ChlorophyllChlorophyll is any member of the class of the green pigments involved in the photosynthesis process.
And also the trendline equation:
y = 1609x + 0.0055
where,
x = absorbance of the spinach extract.
so 0.306 = 1609x + 0.0055
collecting the like terms
0.306 - 0.0055 = 1609x
0.3005 = 1609x
x = 0.3005/1609
x = 1.8676 × 10⁻⁴
x ≅ 0.0002 M
2. No.of grams for the chlorophyll can be computed as follows:
recall that:
molar mass of chlorophyll = 893.5 g/mol
The volume = 25ml = (25/1000) L = 0.025 L
Therefore:
In spinach solution, the no. of grams for the chlorophyll:
= (0.0002) mol/L × (893.5 g/mol) × (0.025) L
= 0.0044675 g
≅ 0.0045 g
3. In the spinach, the concentration of chlorophyll = no of grams of chlorophyll/ mass of the spinach
= 4.5 mg/0.1876 g
= 23.987 mg/g
≅ 24 mg/g
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11th grade chemistry question will mark brainliest
2.50 g of CO2 gas is confined in a rigid cylinder at a pressure
of 4.65 atm. If 0.42 g of gas is released from the cylinder,
what is the new pressure?
Answer:
3.88 atm
Explanation:
We'll begin by calculating the number of mole of CO₂ in each case. This can be obtained as follow:
For 2.50 g of CO₂:
Mass of CO₂ = 2.5 g
Molar mass of CO₂ = 12 + (2×16) = 44 g/mol
Mole of CO₂ =?
Mole = mass / molar mass
Mole of CO₂ = 2.5 / 44
Mole of CO₂ = 0.06 mole
For 0.42 g of CO₂:
Mass of CO₂ = 2.5 g
Molar mass of CO₂ = 44 g/mol
Mole of CO₂ =?
Mole = mass / molar mass
Mole of CO₂ = 0.42 / 44
Mole of CO₂ = 0.010 mole
Finally, we shall determine the new pressure. This can be obtained as follow:
Initial mole (n₁) = 0.06 mole
Initial pressure (P₁) = 4.65 atm
Final mole (n₂) = 0.06 – 0.010 = 0.05 mole
Final pressure (P₂) =?
NOTE: Temperature and volume is constant.
P₁ / n₁ = P₂ / n₂
4.65 / 0.06 = P₂ / 0.05
Cross multiply
0.06 × P₂ = 4.65 × 0.05
0.06 × P₂ = 0.2325
Divide both side by 0.06
P₂ = 0.2325 / 0.06
P₂ = 3.88 atm
Thus, the new pressure is 3.88 atm.
I don’t want to fail help
I need correct answer if u don’t know I will report
When the researcher compiled information which research method did they most likely utilize?
a) documentary
b) survey
c) participant observation
d) case study
Answer:
a
Explanation:
documentary is best researcher!.
Chloride ion is a strong nucleophile and bromide is a good leaving group. The major product of treating (S)-2-bromobutane with NaCl in CH3C(O)CH3 (acetone) is _________. (1S,2R)-1-chloro-2-bromobutane cis-2-butene (1R,2S)-1-chloro-2-bromobutane (S)-2-chlorobutane trans-2-butene (R)-2-chlorobutane
Answer:
Chloride ion is a strong nucleophile and bromide is a good leaving group. The major product of treating (S)-2-bromobutane with NaCl in CH3C(O)CH3 (acetone) is _________. (1S,2R)-1-chloro-2-bromobutane cis-2-butene (1R,2S)-1-chloro-2-bromobutane (S)-2-chlorobutane trans-2-butene (R)-2-chlorobutane
Explanation:
The reaction of (S)-2-bromobutane with NaCl in CH3C(O)CH3 (acetone) forms the following product:
The answer is (R)-2-chlorobutane.
The reaction take splace through [tex]S_{N} _2[/tex] mechansim and inversion in configuration happens.
What is the difference between conjugate acid-base pair?
a. a H atom. c. a mole water
b. a H+ ion d. a OH– ion
Answer:
b. a H+ ion
Explanation:
The concept of conjugate acid-base pair is related to Bronsted-Lowry acid-base theory and according to this theory, acid is a proton acceptor.
In short,
conjugate base is formed when an acid donates a proton.
conjugate acid is formed when a base accepts a proton.
Which is NOT an indicator of a chemical change?
Answer:
The choice that is not an indicator of a chemical change is "State of matter changes". More common than not, chemical reactions produce energy in the form of light or heat. Along with energy, they also produce a new substance called the product that could be in any state of matter (solid, gas, or liquid).
Explanation:
Question 1 Points 3 23 and Louis immerses his left hand in a beaker containing cold water and immerses his right hand in a beaker containing warm water. Then, he immerses both his hands on a beaker containing water at room temperature. Which of the following statements are true? 1. The hand that was in hot water would feel cold. 2. The hand that was in cold water would feel hot. 3. His two hands will feel the same hotness. Que O2 and 3 0 1 and 2 o 1 and 3 1.2, and 3
Answer:look down below
Explanation:
The statements that are true about hands that are immersed in the water are:
1. The hand that was in hot water would feel cold.
2. The hand that was in cold water would feel hot.
The correct option is B 1. and 2.
What is temperature?
Temperature is the measurement of the hotness or coldness of any object. It is measured in Celsius or kelvin. Our body has nerves that feel the different temperatures of any object. The high temperature is called hot and the low temperature is called cold.
When Louis put his hand in the warm water and one hand in the cold water. He feels the temperature of both glasses of water. Then he put both hands in the normal water.
So the hand that is warm would feel the water as cold and the hand with cold water would feel the water as hot.
Thus, the correct option is B. 1. and 2.
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How much carbon dioxide is released when it is fully combusted with 4Kg of ethanol with more than enough oxygen? How do you work it out?
Answer:
7.640 kg
Explanation:
Step 1: Write the balanced complete combustion equation for ethanol
C₂H₆O + 3 O₂ ⇒ 2 CO₂ + 3 H₂O
Step 2: Calculate the moles corresponding to 4 kg (4000 g) of C₂H₆O
The molar mass of C₂H₆O is 46.07 g/mol.
4000 g × 1 mol/46.07 g = 86.82 mol
Step 3: Calculate the moles of CO₂ released
86.82 mol C₂H₆O × 2 mol CO₂/1 mol C₂H₆O = 173.6 mol CO₂
Step 4: Calculate the mass corresponding to 173.6 moles of CO₂
The molar mass of CO₂ is 44.01 g/mol.
173.6 mol × 44.01 g/mol = 7640 g = 7.640 kg
Which safety feature works to slow down nuclear-fission chain reactions?
A. Proliferation
B. Control rods
C. Cooling rods
D. Fuel rods
Answer:
The answer is
-control rods
Answer:
B. Control Rods.... via A P E X
The Li2+ ion is very similar to the hydrogen atom, in that it has one electron and energy levels similar
to the hydrogen atom. However, the relation = − (
1
2 −
1
2) cannot be used for this ion but
rather the relation = −2+ (
1
2 −
1
2) where the constant 2+=1.96x10-17J.
Use this relation to determine the third ionization energy, which is energy required to remove the last
electron from a Li2+ ion in kJ/mol, if the ion starts off in the ground state (Li2+ → Li3+
+ e-
).
Whate the mass percentage of Sulphure in Na2so4 ?
Answer:
Water H2O + SULPHATE OXIDE
a. Draw 2,3-dichloro octane.
b. Write the lewis structure for H20 molecule.
Answer:
a.draw 2,3 dicholoro octane
Explanation:
mag isip ka kung paano hehe
If 2.18 g of sodium peroxide (Na2O2) react with water to produce sodium hydroxide abs oxygen, how many liters of oxygen will be produced at 17.7 Celsius abs 726 torr?
Answer:
0.350 L
Explanation:
2Na₂O₂ + 2H₂O → 4NaOH + O₂First we convert 2.18 g of Na₂O₂ into moles, using its molar mass:
2.18 g ÷ 78 g/mol = 0.0279 mol Na₂O₂Then we convert 0.0279 moles of Na₂O₂ into moles of O₂, using the stoichiometric coefficients of the reaction:
0.0279 mol Na₂O₂ * [tex]\frac{1molO_2}{2molNa_2O_2}[/tex] = 0.0140 mol O₂Finally we use the PV=nRT formula to calculate the volume of oxygen produced:
P = 726 torrV = ?n = 0.0140 molR = 62.36 torr·L·mol⁻¹·K⁻¹T = 17.7 °C ⇒ 17.7 + 273.2 = 290.9 KInputting the data:
726 torr * V = 0.0140 mol * 62.36 torr·L·mol⁻¹·K⁻¹ * 290.9 KV = 0.350 Lin a breaker of water ,the water -water bonds can properly be called
Answer:
LICK
Explanation:
Cal is titrating 57.7 mL of 0.311 M HBr with 0.304 M Ba(OH)2. How many mL of Ba(OH)2 does Cal need to add to reach the equivalence point?
Answer:
118.06 mL
Explanation:
The neutralization reaction between HBr (acid) and Ba(OH)₂ (base) is the following:
2HBr + Ba(OH)₂ → BaBr₂ + 2H₂O
According to the equation, 2 moles of HBr react with 1 mol Ba(OH)₂. Thus, at the equivalence point the moles of acid and base react completely:
2 moles HBr = 1 mol Ba(OH)₂
We can replace the moles by the product of the molar concentration (M) and volume (V):
2 x (M HBr) x (V HBr) = M Ba(OH)₂ x V Ba(OH)₂
Now, we introduce the data in the equation to calculate the volume in mL of Ba(OH)₂:
V Ba(OH)₂ = (2 x (M HBr) x (V HBr))/M Ba(OH)₂
= (2 x 0.311 M x 57.7 mL)/(0.304 M)
= 118.06 mL
Therefore, 118 mL of Ba(OH)₂ are needed.
How many atoms are in 5.70 x 10^32 mol of Rn?
There are 3.43 × [tex]10^{56}[/tex] atom will be present in 5.70 x [tex]10^{32}[/tex] mol of Rn.
What is atom?The basic number of matter that may be broken even without producing electrically charged molecules is the atom.
Calculation of atom:
It is given that number of mol = 5.70 x [tex]10^{32}[/tex] mol.
Then, the number of atom = 5.70 x [tex]10^{32}[/tex] mol × 6.02 × [tex]10^{23}[/tex].= 3.43 × [tex]10^{56}[/tex] atom.
Therefore, there are 3.43 × [tex]10^{56}[/tex] atom will be present in 5.70 x [tex]10^{32}[/tex] mol of Rn.
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How many alkenes are formed by E2 elimination of HBr from 3-bromo -3,4-dimethylhexane using a strong base such as sodium methoxide (NOTE: draw 3,4-dimethyl as anti configuration)
Answer:
2
Explanation:
2 alkenes are formed by E2 elimination of HBr from 3-bromo -3, 4 - dimethylhexane using a strong base such as sodium methoxide
15. You are interested in separating 4-methylbenzoic acid from 1,4-dimethoxybenzene using a procedure similar to the extraction procedure we used in lab. You plan to use sodium bicarbonate instead of sodium hydroxide. a) Show the reaction between salicylic acid and sodium bicarbonate. Label the acid, base, conjugate acid, conjugate base. b) Give the pKa values of the acid and conjugate acid. c) Which base will work better, sodium hydroxide or sodium bicarbonate
Solution :
a). The separation of 4-methylbenzoic acid from 1,4-dimethoxybenzene will work but it will result in lower recovery.
In the reaction of acid-base to form a sodium 4 - methoxy benzoate, that is soluble in the water, 4-methoxy benzoic acid reacts with the sodium bicarbonate to give sodium 4-methoxybenzoate as well as carbonic acid.
b). The pKa for the 4-methoxybenzoic acid is [tex]4.46[/tex], and that of carbonic acid is [tex]6.37[/tex]
c). The Keq for the reaction is [tex]10(6.37 - 4.46) = 101.91[/tex]
Therefore, the equilibrium lies to the right and also the reaction favors the products and the separation works.
But the recovery will be low when compared to the extraction with Sodium hydroxide as the strong base will drive the equilibrium further to the right position, thus neutralizing all the acids virtually. And the weak base will partially neutralize the acid.
