The pH at the equivalence point for the titration of 0.25 M HCOOH versus 0.25 M NaOH is 8.5.
Let's consider the following neutralization reaction.
HCOOH + NaOH ⇒ HCOONa + H₂O
At the equivalence point, 0.25 M HCOOH completely reacted with 0.25 M NaOH to form 0.25 M HCOONa.
HCOONa undergoes hydrolysis. The net ionic equation is:
HCOO⁻(aq) + H₂O(l) ⇄ HCOOH(aq) + OH⁻(aq)
Given the concentration of HCOO⁻ is 0.25 M (Cb) and the basic dissociation constant of HCOO⁻ is 4.8 × 10⁻¹¹ (Kb), we can calculate the concentration of OH⁻ using the following expression.
[tex][OH^{-} ] = \sqrt{Kb \times Cb } = \sqrt{(4.8 \times 10^{-11} ) \times 0.25 } = 3.5 \times 10^{-6} M[/tex]
The pOH of the solution is:
[tex]pOH = -log [OH^{-} ] = -log (3.5 \times 10^{-6} ) = 5.5[/tex]
The pH of the solution is:
[tex]pH = 14 -pOH = 14 -5.5 = 8.5[/tex]
The pH at the equivalence point for the titration of 0.25 M HCOOH versus 0.25 M NaOH is 8.5.
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True or false? Suppose you have two identical birthday balloons, with one filled with the gas helium and the other blown up by you. Assuming they're both filled to the same amount, these balloons will have the same number of molecules.
Answer:
True!
Explanation:
Avogadro’s law means that if we compare the number of helium molecules and the number of air molecules needed to inflate the same balloon, we would find the numbers the same.
The balloon filled with helium air, and the one blown by oneself with the same amount of air have the equivalent number of molecules. Thus, the given statement is true.
What is the relation between moles and atoms?The moles are given as the mass of the compound with respect to the molar mass. According to the Avogadro's law, the 1 mole of a substance has the presence of the atoms equivalent to the Avogadro number.
In the balloons filled with oneself and individual there is same amount of gas, thus have same moles and thereby the number of molecules will be same in both the balloons. Thus, the given statement is true.
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I need help solving the picture
Answer:
213 kJ-1704 kJ852 kJ (ignore what's on my paper, accidentally added a negative)Explanation:
These problems are pretty easy, you just need to do to the enthalpy what is done to the equation itself. Numbers one and 3 are reversed, so they become positive values. When a coefficient changes in the equation, you multiply the enthalpy by that number. I have attached my work below. Let me know if there is any confusion left.
Hope this helped! :^)
What is measurement??
0000000000
measurement is the process of finding the value of any Unknown physical quantities in standard value.
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Measurement has been defined as the concept widely used in math and science to quantify an object. It is used to denote the quantification of the event or the object with respect to other or individually.
Hence, the definition of measurement is the process of determining the size or smallness of a physical amount by comparing it to a reference quantity of the same kind as the object.
It has been used to determine the quantity to be small or large based on some predetermined standard or values. It compares the physical quantity like mass can be estimated using kilograms or grams.
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how to draw ethyl structural formula?
Answer:
c2H5
Explanation:
H. H
|. |
C-C- H
|. |
H. H
14. What type of materials are spun together to make yarns?
Answer:
cotton
Explanation:
which is typically spun into fine yarn for mechanical weaving or knitting into cloth.
Which statement best describes a covalent bond?
a
A chemical bond in which no electrons are shared.
b
A chemical bond that involves sharing a pair of electrons between
atoms in a molecule.
с
A chemical bond in which four or more electrons are shared.
A chemical bond in which one atom loses an electron to form a
d positive ion and the other atom gains an electron to form a negative
ion.
Answer:
B
Explanation:
Option B best describes covalent bonds.
How many grams are contained in the quantity 0.34 mol Ca
Answer:
13.6272 Grams
Explanation:
Moles of Calcium × atomic weight = Grams
0.34 × 40.08 = 13.6272
0.34 Moles of Calcium = 13.6272 Grams
Identify the movements of the glenohumeral joint that occur with contraction of the infraspinatus and teres minor.
Answer: adduction of the arm
lateral rotation of the arm
Explanation:
A student performs titration to find the concentration of acetic acid. Titrant was sodium hydroxide. He went beyond the indicator color change by adding too much titrant. How will his experimental error affect the calculated value for the concentration of unknown acetic acid
Answer:
A student performed titration to find the concentration of acetic acid. Titrant was sodium hydroxide. He went beyond the indicator color change by adding too much titrant.
Explanation:
hope it helps you
A piece of potato had an original mass of 3.2g and after being left in a sugar solution for 24 hours it then had a mass of 2.8g. Calculate the percentage mass decrease of the potato.
Answer: -13% to 3 sig figs
Explanation:
A piece of potato had an original mass of 3.2g and after being left in a sugar solution for 24 hours it then had a mass of 2.8g. Calculate the percentage mass decrease of the potato.
the change in mass is 2.8 -3.2 = -0.4 gm
the % change fro the origial piece is ( -0.4/3.2) X 100 = -12.5%
or -13% to 3 sig figs
45.0 g of CaCl2 are dissolved in enough water so that the molarity of the solution is 1.15 M. What is the volume in mL of the solution?
Answer:
[tex]\boxed {\boxed {\sf 353 \ mL}}[/tex]
Explanation:
We are asked to find the volume in milliliters of a solution, given the mass of solute and molarity of the solution.
Molarity is a measure of concentration in moles per liter.
[tex]molarity = \frac {moles \ of \ solute}{liters \ of \ solution}[/tex]
1. Moles of SoluteWe are given the mass of the solute. We must convert the mass to moles using the molar mass (the mass of 1 mole of a substance). These values are found on the Periodic Table. They are equal to the atomic masses, but the units are grams per mole instead of atomic mass units.
Look up the molar masses of the individual elements in calcium chloride.
Ca: 40.08 g/mol Cl: 35.45 g/molThe chemical formula, CaCl₂, has a subscript of 2. There are 2 moles of chlorine in 1 mole of calcium chloride. We must multiply chlorine's molar mass by 2 before adding calcium's molar mass.
Cl₂ = 35.45 *2 = 70.9 g/mol CaCl₂= 40.08 + 70.9 = 110.98 g/molSet up a conversion factor using the molar mass.
[tex]\frac {110.98 \ g \ CaCl_2}{1 \ mol \ CaCl_2}[/tex]
Multiply by 45.0 grams of calcium chloride.
[tex]45.0 \ g \ CaCl_2 *\frac {110.98 \ g \ CaCl_2}{1 \ mol \ CaCl_2}[/tex]
Flip the conversion factor so the units of grams of calcium chloride cancel.
[tex]45.0 \ g \ CaCl_2 *\frac{1 \ mol \ CaCl_2} {110.98 \ g \ CaCl_2}[/tex]
[tex]45.0 \ *\frac{1 \ mol \ CaCl_2} {110.98}[/tex]
[tex]\frac {45.0}{110.98} \ mol \ CaCl_2= 0.405478465 \ mol \ CaCl_2[/tex]
2. Liters of SolutionNow we can find the liters of solution.
[tex]molarity = \frac {moles \ of \ solute}{liters \ of \ solution}[/tex]
molarity = 1.15 mol CaCl₂/L moles of solute = 0.405478465 mol CaCl₂liters of solution =xSubstitute the values into the formula.
[tex]1.15 \ mol \ CaCl_2/L = \frac{0.405478465 \ mol \ CaCl_2}{x}[/tex]
Cross multiply.
[tex]\frac {1.15 \ mol \ CaCl_2 /L}{1}= \frac{0.405478465 \ mol \ CaCl_2}{x}[/tex]
[tex]{1.15 \ mol \ CaCl_2 /L}*x= {0.405478465 \ mol \ CaCl_2} * 1[/tex]
Divide both sides of the equation by 1.15 moles of calcium chloride to isolate the variable x.
[tex]\frac {1.15 \ mol \ CaCl_2/L *x}{1.15 \ mol \ CaCl_2 /L}= \frac{0.405478465 \ mol \ CaCl_2 * 1 }{1.15 \ mol \ CaCl_2/L }[/tex]
[tex]x=\frac{0.405478465 \ mol \ CaCl_2 * 1 }{1.15 \ mol \ CaCl_2 /L}[/tex]
The units of moles of calcium chloride cancel.
[tex]x=\frac{0.405478465 }{1.15 \ L }[/tex]
[tex]x=0.35258997 \ L[/tex]
3. Convert to millilitersThere are 1000 milliliters in 1 liter.
[tex]\frac {1000 \ mL}{1 \ L}[/tex]
[tex]0.35258997 \ L * \frac{1000 \ mL}{ 1 \ L}[/tex]
[tex]0.35258997 * 1000 \ mL=352.58997 \ mL[/tex]
The original measurements of mass and molarity have 3 significant figures, so our answer must have the same. For the number we found, that is the ones place. The 5 in the tenth place tells us to round the 2 up to a 3.
[tex]353 \ mL[/tex]
The volume of the solution is approximately 353 milliliters.
five differences between true solution and false solution
Answer:
k im silly frrr lol have a great day
Why do some hockey players go flying when they are checked?
Limestone is used in industry as a raw material in the production of slaked Ca (OH) 2.
1) Write the equations of the chemical reactions that characterize the transformations carried out in the production process!
CaCO3 -> CaO -> Ca (OH) 2
The first reaction equation is how calcium oxide can be obtained from calcium carbonate.
The second reaction equation - how calcium oxide can be obtained from calcium oxide.
Answer:
i k ow its not the exact anwser but ih ope this helps
Explanation:
Energy plays a key role in chemical processes. According to the modern view of chemical reactions, bonds between atoms in the reactants must be broken, and the atoms or pieces of molecules are reassembled into products by forming new bonds. Energy is absorbed to break bonds, and energy is evolved as bonds are made. In some reactions the energy required to break bonds is larger than the energy evolved on making new bonds, and the net result is the absorption of energy. Such a reaction is said to be endothermic if the energy is in the form of heat. The opposite of endothermic is exothermic; in an exothermic reaction, energy as heat is evolved. The more general terms exoergic (energy evolved) and endoergic (energy required) are used when forms of energy other than heat are involved.
A great many common reactions are exothermic. The formation of compounds from the constituent elements is almost always exothermic. Formation of water from molecular hydrogen and oxygen and the formation of a metal oxide such as calcium oxide (CaO) from calcium metal and oxygen gas are examples. Among widely recognizable exothermic reactions is the combustion of fuels (such as the reaction of methane with oxygen mentioned previously).
What equipment is generally used to make lyophilized medications suitable for administering to the patient? a) Test tubes or sterile ampules b) Petri dishes and sterile droppers c) Sterile syringes or graduated cylinders d) Measuring cups and clean, warm water
Answer:
B) Sterile droppers and petri dishes
How do the elements beryllium, carbon, and oxygen produce stars such as the Sun?
Answer:
Beryllium, carbon, and oxygen do not create stars like the sun. The sun is a massive cluster of hydrogen atoms being fused into helium atoms and heavier metals like Beryllium, carbon, and oxygen through the process of nuclear fusion. The more mass a star has in its core the more fusions that can occur and the heavier the metals inside can be fused into.
Explanation:
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What is the concentration of chloride ions in solution after the reaction of 5.8 mL 0.12 M ammonium chloride with 3.2 mL 0.21 M silver nitrate
Answer:
ok
Explanation:
Indicate how CaCO3 neutralizes soil acidity. In other words, indicate how calcium carbonate chemically removes hydrogen from soil solution.
Answer:
Soil acidity can be corrected easily by liming the soil, or adding basic materials to neutralize the acid present. ... As lime dissolves in the soil, calcium (Ca) moves to the surface of soil particles, replacing the acidity. The acidity reacts with the carbonate (CO3) to form carbon dioxide (CO2) and water (H2O).
Explanation:
What is a solution?
A. A mixture of two solids blended together
B. A compound that is in liquid and gas states
C. A liquid with something dissolved in it
OD. A clear liquid with nothing dissolved in it
aufbau principle
what is the meaning of the principle
Answer:
The meaning of this principle is building-up.
Explanation:
The Aufbau principle asserts that electrons occupy lower-energy atomic orbitals before filling higher-energy ones (Aufbau is German for "building-up") (Aufbau is German for "building-up"). By using this method, we may forecast the electron configurations for atoms or ions.
How does the structure of compounds determines the properties of the compounds?
All of these properties are due to the chemical structure of the compound. The chemical structure includes the bonding angle, the type of bonds, the size of the molecule, and the interactions between molecules. Slight changes in the chemical structure can drastically affect the properties of the compound.
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Answer:
sorry wala din akong sagot niyan sorry talaga
Nancy rides her bike 114.8 miles in 8.2 hours. What is her average speed in miles per hour
The answer to the question is 14 no cap
What is the difference between melting and burning a substance? Is mass conserved in either process?
Answer:
Explanation:
First Question:
Melting is a physical process that involves the phase transition of a substance from its solid to its liquid state. Burning, on the other hand, is a chemical process that involves a substance being broken down and changed into different substances. It's still the same substance, though: water.
Second Question:
Mass is therefore never conserved because a little of it turns into energy (or a little energy turns into mass) in every reaction. But mass+energy is always conserved. Energy cannot be created out of anything.
2. What is the temperature (°C) of 1.50 moles of gas stored in a 10.0 L container at 1558 mm
Hg? (R=0.082 L atm/ mol K, 1.00 atm = 760 mm Hg
(4 points)
Answer:
-106°C
Explanation:
1558 mmHg / 1 × 1 atm / 760. mmHg = 2.05 atm
PV = nRT
2.05 atm (10.0 L) = 1.50 mol (0.082 atmL/molK) T
20.5 atmL = (0.123 atmL/K) T
K/0.123 atm L × 20.5 atmL = (0.123 atmL/K) T × K/0.123 atmL
166.666 K = T
167 K = T (sig figs)
K = °C + 273
167 - 273 = °C - 273
-106 = °C
HELPP
explain the difference between molecular and empirical formulas. Which types of compounds are described by the terms formula mass and molecular mass. Use an example to show the steps in calculating the formula mass for K2CO3
Answer:
In the previous section, we discussed the relationship between the bulk mass of a substance and the number of atoms or molecules it contains (moles). Given the chemical formula of the substance, we were able to determine the amount of the substance (moles) from its mass, and vice versa. But what if the chemical formula of a substance is unknown? In this section, we will explore how to apply these very same principles in order to derive the chemical formulas of unknown substances from experimental mass measurements.
Explanation:
tally. The results of these measurements permit the calculation of the compound’s percent composition, defined as the percentage by mass of each element in the compound. For example, consider a gaseous compound composed solely of carbon and hydrogen. The percent composition of this compound could be represented as follows:
\displaystyle \%\text{H}=\frac{\text{mass H}}{\text{mass compound}}\times 100\%%H=
mass compound
mass H
×100%
\displaystyle \%\text{C}=\frac{\text{mass C}}{\text{mass compound}}\times 100\%%C=
mass compound
mass C
×100%
If analysis of a 10.0-g sample of this gas showed it to contain 2.5 g H and 7.5 g C, the percent composition would be calculated to be 25% H and 75% C:
\displaystyle \%\text{H}=\frac{2.5\text{g H}}{10.0\text{g compound}}\times 100\%=25\%%H=
10.0g compound
2.5g H
×100%=25%
\displaystyle \%\text{C}=\frac{7.5\text{g C}}{10.0\text{g compound}}\times 100\%=75\%%C=
10.0g compound
7.5g C
×100%=75%
Question 3 of 10
Which event indicates an endothermic chemical reaction?
A. Decrease in temperature
B. Release of heat
C. Increase in thermal energy
D. Production of light
Plz help
Answer:
A. Decrease in temperature
Explanation:
The statement indicates an endothermic chemical reaction is "Decrease in temperature".
What is endothermic reaction?Endothermic reactions generate products by absorbing heat energy from the environment.
The temperature of the reaction mixture rises as energy is released in an exothermic process. The temperature drops when energy is absorbed in an endothermic reaction. A thermometer can be used to monitor temperature changes in the reaction mixture.
An endothermic reaction happens when the temperature of an isolated system drops while the temperature of its surroundings rises. The overall heat of reaction in endothermic reactions is positive (q > 0).
Hence the correct option is A.
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A very long tube with a cross-sectional area of 1.00 cm2 is filled with mercury to a height of 76.0 cm. At what height would water stand in this tube if it were filled with a mass of water equal to that of the mercury? (The density of mercury is 13.60 g/cm3 and the density of water is 1.00 g/cm3.)
The water would stand at a height of 1033.6 cm
If the mass of the mercury, m equals the mass of the water, m' at its height,h', then the weight of the mercury W equals the weight of the water, W'
So, W = W'
mg = m'g
ρV = ρ'V' where ρ = density of mercury = 13.60 g/cm³, V = volume of mercury = Ah where A = cross-sectional area of tube = 1.00 cm and h = height of mercury = 76.0 cm, ρ' = density of water = 1.00 g/cm³, V = volume of water = Ah' where A = cross-sectional area of tube = 1.00 cm and h' = height of water.
So, ρV = ρ'V'
ρAh = ρ'Ah'
h' = ρAh/ρ'A
h' = ρh/ρ'
Substituting the values of the variables into the equation, we have
h' = ρh/ρ'
h' = 13.60 g/cm³ × 76.0 cm/1.00 g/cm³
h' = 13.60 × 76.0 cm
h' = 1033.6 cm
So, the water would stand at a height of 1033.6 cm
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Which best explains why nanofiltration is an important new technology?
A. It can be used to help regions that have a short supply of usable water.
B. It can be used as an energy source to produce electricity in regions with limited coal.
C. It recycles wastewater to be reused for geothermal energy.
D. It collects solar energy to generate electrical power.
Explanation:
Our Direct Nanofiltration (dNF) membranes offer the unique combination of a low fouling hollow fiber configuration with the ability to remove organics and salinity (hardness) from water in one simple step. Other than a strainer, no further pre-treatment is required. We manufacture our membranes with a patented layer-by-layer process, where multiple nano-scale layers are deposited on a membrane support. This method enables very precise and controlled rejection and flux properties of the membrane. A unique solution for troubled water.
375cm³ of a gas has a pressure of 770 mm Hg, find it Volume if the pressure is reduced to 750 mm Hg
Answer:
Explanation:
Givens
v1 = 375 cm^3
P1 = 770 mm Hg
V2 = ?
P2 = 750 mm Hg
Formula
V1 P1 = V2 P2
Solution
375 * 770 = V2 * 750 Combine the left
288750 = V2 * 750 Divide both sides by 750
288750/750 = V2
V2 = 385