The question is incomplete, the complete question is:
Standardization of a Borax solution (Na2B4O7). A student titrates a 20.00 mL sample of an aqueous borax solution with 1.044 M H2SO4. It takes 2.63 mL of acid to reach the equivalence point. Knowing it takes 1 H2SO4 to neutralize 2 Na2B4O7, what was the concentration of this Borax solution?
Answer: The concentration of borax solution is 0.069 M.
Explanation:
To calculate the concentration of borax solution, the formula used is:
[tex]n_1C_1V_1=n_2C_2V_2[/tex] ....(1)
where,
[tex]n_1, C_1\text{ and }V_1[/tex] are the n-factor, concentration and volume of sulfuric acid
[tex]n_2,C_2\text{ and }V_2[/tex] are the n-factor, concentration and volume of borax solution.
We are given:
[tex]n_1=1\\C_1=1.044M\\V_1=2.63mL\\n_2=2\\C_2=?M\\V_2=20mL[/tex]
Putting values in equation 1, we get:
[tex]1\times 1.044\times 2.63=2\times C_2\times 20\\\\C_2=\frac{1\times 1.044\times 2.63}{2\times 20}\\\\C_2=0.069M[/tex]
Hence, the concentration of borax solution is 0.069 M.
What is the pH of a solution with a concentration of 4.2 x 10−5 M H3O+? (4 points)
Select one:
a. 2.31
b. 4.38
c. 5.62
d. 6.87
What is the pH of a solution with a 4.60 x 10−4 M hydroxide ion concentration? (4 points)
Select one:
a. 0.663
b. 3.33
c. 10.1
d. 10.7
Answer:
1) b. 4.38
2) d. 10.7
Explanation:
1) The problem tells us that [H₃O⁺] = 4.2x10⁻⁵ M, and keeping in mind that [H₃O⁺]= [H⁺], we can calculate the pH of the solution:
pH = -log[H⁺] = 4.382) First we calculate the pOH of the solution:
pOH = -log[OH⁻] = -log(4.6x10⁻⁴) = 3.33Then we calculate the pH using the following formula:
pH = 14 - pOH = 14 - 3.33pH = 10.7The pH of a solution with a concentration of 4.2x10⁻⁵ M H₃O⁺ ion is 4.38 and of a solution with a concentration of 4.6x10⁻⁴ OH⁻ ion is 10.7.
What is pH and pOH?pH of any solution is define as the negative log of the concentration of H⁺ ions and pOH is define as the negative log of the concentration of OH⁻ ions.
Given that concentration of H⁺ ions in solution = 4.2x10⁻⁵ M
pH for this solution is calculated as:
pH = -log(4.2x10⁻⁵) = 4.38
Also given that concentration of OH⁻ ions in solution = 4.6x10⁻⁴
pOH = -log(4.6x10⁻⁴) = 3.33
We know that, pH + pOH = 14.
pH = 14 - 3.33 = 10.7
Hence, value of pH & pOH is 4.38 and 10.7 respectively.
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Q1: Give the letter of a substance that is a solid at 20 °C
Q2: Give the letter of a substance that is a liquid at 50 °C
Answer:
A1: Z
A2: Y
Explanation:
Q1: Z is the only one with a melting point high than 20 °C.
Q2: Y is the only substance with both a melting point lower than 50 °C and a boiling point higher than 50°C
Give an example of a reaction where the following are involved:
(a) Heat
(b) Light
(c) Electricity
(d) Close contact
(e) Solution
(f) Pressure
(g) Catalyst
Explanation:
everything can be found in the picture
what mass of water will be formed when 3g of hydrogen react with 30g of oxygen?
Answer: Write down the chemical equation first;
2H2 + O2 —-> 2H2O
2. Since the mass is given, use it to calculate the mole for each reactant;
mole = mass / molar mass
mole of H2 : 8/2 = 4 mole
mole of O2 : 30/16(2) = 0.9375 mole
Now, if you're not sure which reactant to use to calculate the mass of H2O using ratio since both answer are different, find the limiting reactant.
From the equation;
2 mol of H2 -> 2 mol of H2O
4 mol of H2 -> (4*2)/2 = 4 mol of H20
______________________________________
1 mol of O2 -> 2 mol of H2O
0.9375 mol of O2 -> (0.9375*2)/1 = 1.875 mol of H2O
Let's take a look at both numbers. Since H2 produces more water than O2, O2 will be the limiting reactant as it has the least mole of H2O. So now we are going to use O2 as our limiting reactant. Use the formula to calculate mass of water using mole.
mass of H2O : 1.875*(16+2) = 33.75 g
Thats it. Correct me if im wrong
Explanation:
What type of force are you exerting when you lie on a bed?
A. Electric force
B. Magnetic force
C. Compression
D. Tension
Answer:
C. Compression
Explanation:
I'm pretty sure it's compression
What is a prism?
A. Something that measures the energy of light wavelengths
B. Something that raises electrons to higher energy levels
c. Something that combines colors into a single source
D. Something that splits up light into different colors
Answer:
D. Something that splits up light into different colors
Explanation:
A prism separates light into various different colors. Thus, D is correct. :)
Gas occupies 30 Liters at 2.0 atm pressure and 27° Celsius. How many moles of gas are present
Explain and describe how the photoelectric effect occurs on an atomic level in terms of protons, neutrons, and electrons
Answer:
The photoelectric effect is the emission of electrons when electromagnetic radiation, such as light, hits a material. Electrons emitted in this manner are called photoelectrons.
Based on the wave model of light, physicists predicted that increasing light amplitude would increase the kinetic energy of emitted photoelectrons, while increasing the frequency would increase measured current.
What kind of pattern can you see about elements in the same period with respect to electron
structures?
Answer: A pattern of same atomic orbitals can be seen about elements in the same period with respect to electron structures.
Explanation:
The horizontal rows in a period table are called periods.
Elements present in the same period will have same atomic orbitals.
For example, electronic distribution of Na is 2, 8, 1 and it is a third period element.
Similarly, electronic distribution of Cl is 2, 8, 7 and it is also a third period element.
Hence, both Na and Cl will have K, L, M shells, that is, they have three atomic orbitals.
Thus, we can conclude that a pattern of same atomic orbitals can be seen about elements in the same period with respect to electron structures.
What is the volume of 2 mol of chlorine gas at STP?
2.0 L
11.2 L
22.4 L
44.8 L
Answer:
44.8 L
Explanation:
Using the ideal gas law equation:
PV = nRT
Where;
P = pressure (atm)
V = volume (L)
n = number of moles (mol)
R = gas law constant (0.0821 Latm/molK)
T = temperature (K)
At Standard temperature and pressure (STP);
P = 1 atm
T = 273K
Hence, when n = 2moles, the volume of the gas is:
Using PV = nRT
1 × V = 2 × 0.0821 × 273
V = 44.83
V = 44.8 L
Answer:
44.8L
Explanation:
Se puede inferir que el órgano de los sentidos que contiene un mayor número de terminaciones nerviosas debido a su extensión es *
Answer:
La piel.
Explanation:
La piel es el órgano que forma el límite del cuerpo con el mundo exterior. La piel sirve para varios propósitos. Protege al cuerpo de influencias externas como el calor, el frío, la radiación o las bacterias y ayuda a mantener un ambiente interno estable. La piel está fuertemente atada a los huesos y tejidos. Por lo general, la piel alberga más de 100 especies bacterianas diferentes y algunas investigaciones sugieren que la mayoría de estas bacterias son beneficiosas y aumentan la probabilidad de que se evite la infestación de parásitos.
What properties can be used to identify substance and why?
Answer:
All substances can be characterized by their unique sets of physical and chemical properties. Properties that can be determined without changing the composition of a substance are referred to as physical properties. Characteristics such as melting point, boiling point, density, solubility, color, odor, etc.
Which of the following illustrates a single-replacement reaction?
A. CaCl2 + Na2CO3 → CaCO3 + 2Naci
O B. 2Fe + 3Br2 → 2FeBr3
O C. Ba(NO3)2 + NISO4 → BaSO4 + Ni(NO3)2
D. Fe + CuSO4 → Cu + FeSO4
The equation Fe + CuSO₄ → Cu + FeSO₄ illustrates the single displacement reaction. Hence Option (D) is the correct answer.
What is Single replacement reaction ?
A single replacement reaction, sometimes called a single displacement reaction, is a reaction in which one element is substituted for another element in a compound.
The starting materials are always pure elements, such as a pure zinc metal, iron or hydrogen gas, plus an aqueous compound.
Therefore, the equation Fe + CuSO₄ → Cu + FeSO₄ illustrates the single displacement reaction. Hence Option (D) is the correct answer.
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Gatorade has the conductivity of 3296 µS, Powerade has 4502 µS, and Vitamin Water is 657 µS. What does this data tell you about the dissolved ions in these solutions?
Answer:
Powerade has the most dissolved ions, followed by Gatorade and lastly vitamin water
Explanation:
How conductive a certain solution is, is based on the kind of ions that are present or dissolved in the solution. Hence, we have it that, the higher the concentration of the ions that are present in a solution, the better it will conduct.
There is thus, a direct relationship between what is dissolved or the kind of present ions and how conductive the solution is.
A solution with more dissolved ions is a better conductor of electricity and thus has a conductivity value that is higher
Thus, we can conclude that Powerade has more dissolved ions, Gatorade has less and Vitamin water has the least
How does an indicator show the difference between an acid and an alkali?
Explanation:
When a base dissolves in water it is an alkali and makes an alkaline solution.
...
Litmus.
Red Litmus Blue Litmus
Acidic solution Stays red Turns red
Neutral solution Stays red Stays blue
Alkaline solution Turns blue Stays blue
When copper is heated in air, the solid product that is formed has a greater mass than the original copper. When calcium carbonate is heated in air, the solid product that is formed has less mass than the original
calcium carbonate. Why is the mass of the solid product greater in one reaction but less in the other reaction?
Answer:
When heated, oxygen reacts with copper to form copper oxide. If this reaction occurs in a sealed container, will the mass of the container and everything in it increase, decrease, or stay the same and why? The mass will increase because a new kind of molecule is formed.
Explanation:
As above, carbonates decompose upon heating to give the metal oxide and carbon dioxide. The mass is lost as carbon dioxide.
To solve this we must be knowing each and every concept related to mass. Therefore, Carbon dioxide is released as the mass is depleted when carbonates are heated.
What is mass?Mass defines the quantity of a substance. It is measured in gram or kilogram. Average mass is the mass of atoms of an element that are isotopes.
When copper was heated in the air, the resulting solid product has a larger mass than the initial copper. When calcium carbonate was heated in air, the resulting solid product has much less mass than the initial calcium carbonate. When carbonates are heated, they breakdown into metal oxides and carbon dioxide. Carbon dioxide is released as the mass is depleted.
Therefore, Carbon dioxide is released as the mass is depleted.
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PLEASE HELP ME!
-The compound dissolves in water to form a solution with pH > 7.
- The compound has a low boiling point.
The elements P, Q, R and S have proton number of 1, 7, 11 and 17.
Which of the following pair of elements will react to form a compound with the characteristics stated in the table above?
A. P and Q
B. R and S
C. Q and R
D. P and S
Answer:
C
Explanation:
Q and R forms a nitrate. When dissolved in water it will form a solution with a pH greater than 7 because the solution is alkaline.
what creates an ionic bond?
a: The attraction between neutral ions
b: The checks between similarly charged ions
c: the attraction between oppositely charged ions
d: the attraction between neutral atoms
Answer:c
Explanation: it’s c
what mass of small stones would be needed to make the strongest concrete? give a reason for your awnser.
Answer:
For a good consert mix aggregate needed to the clean hard strong partical free of absorb chemicals or coating clay and other fine materials
types of molecular forces
Answer:
Hydrogen bonds
Covalent bonds
Van Der Walls Forces
Ionic Bonding
London Dispersion forces
Metallic bonding
Chemical bonds
Secondary succession can only occur as a transition from primary succession.
Answer:
false
Explanation:
edge 2022
Calculate the poH of a solution at 25°C which contains
1 x 10^-10 M of hydronium ions.
Answer:
4.000 hope this helps :)
please help in all 3 questionnn
Answer:
Explanation:
a) photosynthesis
b) Substances used: water, sun, gas and nutrients. Products: glucose and flowers
c) there will be no sunlight or no open environment
Is the number of electrons in different shells of an atom fixed or unlimited ? Explain by giving an example.
Answer:
the number of electrons in a particular shell is given by the formula 2n^2 . However an electron when gets very exicited loose energy in the forms of radiation and comes in high energy level shell.
What effect does the pH of water have on radish seed germination?
Answer:
High pH negatively affected the germination rate of seeds from most species, but had no effect on the per cent germination of any of the species. The higher concentration of the nutritious solutions affected negatively the germination level and rate
Explanation:
what is the pound mole of co2
How many places after the decimal should your measurements contain?
Answer:
Minimum 2. ( Thats how I do, and till now there is no probs)
Thank You'
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The chart shows the bids provided by four contractors to complete a job. Which contractor is the most cost-effective? Joshua Carmen Dante Alicia
Chart for question attached
Answer:
Joshua
Explanation:
By cost-effective here, we mean the contractor that does the job best at the shortest time and lowest money cost. To get this, we calculate total cost for each contractor and then consider time for completion of the job:
Joshua charges $25 per hour for 5 hrs
Carmen charges $20 per hour for 7 hrs
Dante charges $30 per hour for 6 hrs
Alicia charges $20 per hour for 8 hrs
Joshua's cost= $25×5=$125 in 5 hours
Carmen's cost = $20×7= $140 in 7 hours
Dante's cost= $30×6=$180 in 6 hours
Alicia's cost= $20×8= $160 in 8 hours
From the above we can see that Joshua is the most cost-effective contractor given that he completes the job in less time and with less money.
Which of the following is not a reason why actual yield is less than theoretical yield?
A. presence of impure reactants
B. conservation of mass
C. competing side reactions
D. loss of product during purification
The option that isn't a reason why the actual yield is less than theoretical yield is B. conservation of mass.
It should be noted that the formula for the percent yield is given as:
= Actual yield / Theoretical Yield × 100
The actual yield is experimentally determined, and it's the quantity of a product that is gotten from a chemical reaction.The theoretical yield is the amount of product that can be obtained from a reaction when the reactants are changed to products.Actual yield can be less than theoretical yield due to the presence of impure reactants ,competing side reactions, and loss of product during purification.
In conclusion, the correct option is B.
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What is the product of
Mg(NO3)2 + Na2CO3?
Answer:
MgCO3 + 2 NaNO3
Explanation:
