Answer: Option (a) is the correct answer.
Explanation:
A substance that does not get consumed in a chemical reaction and helps in increasing rate of the reaction by lowering the activation energy is known as a catalyst.
Hence, when the chemist finds that reaction speeds up when platinum is added into the reaction then the chemist must calculate or measure the mass of platinum before and after the completion of reaction.
This is because if there occurs change in the mass of platinum then it means that platinum is not acting as a catalyst in the reaction.
Thus, we can conclude that chemist must measure the mass of the platinum to determine whether it is a catalyst.
the steps of scientific method in order are?
a. purpose , experiment, hypothesis , analysis , conclusion
b. purpose , hypothesis , experiment , analysis, conclusion
c. hypothesis , experiment , analysis, conclusion .
d. purpose, hypothesis, experiment , conclusion
Which of the following is an example use of a noble gas? a. Making steel drums c. Camera batteries b. Fluorescent light tubes d. Xerox machines
What cellular process converts solar energy into chemical energy
exhaled air contains 16% oxygen by volume. Assuming you exhale like the average person does during strenuous exercise (that is, you exhale 1L of air per breath and you exhale 40 breaths per minute) ad assuming the dive will take 90 minutes, what volume of oxygen will you end up exhaling?
Give the chemical symbol of an element in the third period (row) of the periodic table with three valence electrons. Express your answer as a chemical symbol
how many molecules are in 12.5g of water (H20)
The number of molecules in 12.5 g water is equal to 4.18 × 10²³ molecules.
What is Avogadro's number?Avogadro’s constant can be defined as the proportionality constant that uses to count the number of constituents such as ions, molecules, and atoms in the amount of substance in a sample.
Avogadro's constant can be defined as the approximate number of nucleons per gram of substance. The value of the Avogadro number is the mass of 1 mole of a compound, in grams, and is equal to the number of nucleons in 1 constituent particle.
The value of Avogadro’s constant is experimentally found to be approximately equal to 6.022×10²³ per mole.
The mass of the water = 12.5 g
The molar mass of the water = 18 g
The number of moles of the water = 12.5/18 = 0.694 mol
The number of molecules of water in one mole = 6.022 × 10²³
Number of molecules of water in 0.694 mol = 6.022 × 10²³× 0.694
= 4.18 × 10²³ molecules
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Which of these reactions involves an acid and a covalent base?
A. HF + KOH → H2O + KF
B. H2SO4 + 2NaOH → Na2SO4 + 2H2O
C. HNO3 + Al(OH)3 → Al(NO3)3 + H2O
D. H2SO4 + 2H2O → 2H3O+ + SO42–
E. chemical equilibrium
What is the mass of exactly 1 mol of the following elements osmium, Cesium, krypton?
In an experiment, a student gently heated a hydrated copper compound to remove the water of hydration. the following data was recorded:
1. mass of the crucible, cover and contents before heating 23.4g.
2. mass of empty crucible and cover.
3. mass of crucible, cover, and contents after heating to constant mass 20.94g
How many significant figures are there in the measurement 0.003 kg? A. 1 B. 2 C. 3 D. 4
The modern periodic table is organized by:___________?
Possible Answers: atomic number,number of protons in each element,atomic weight,chemical properties,
The modern periodic table is largely organized by the atomic number of each element. Although atomic weight and chemical properties also play a role, they come secondary to atomic number.
Explanation:The modern periodic table is primarily organized on the basis of the atomic number of each element. The atomic number is equal to the number of protons in the nucleus of an atom of an element. While other factors such as atomic weight and chemical properties are also significant, they are considered secondary in the structure. For example, Hydrogen has an atomic number of 1, hence it is the first element in the Periodic Table. Similarly, Helium with an atomic number of 2 is the second element and so on.
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Because solubility is a characteristic property of matter, it can be used to help identify a substance. t or f
This is a true statement.
Which statement best describes the process that the diagrams show?
A.) A solid loses kinetic energy to become a liquid and then becomes a gas.
B.) A solid gains kinetic energy to become a liquid and then becomes a gas.
C.) A gas loses kinetic energy to become a liquid and then becomes a solid.
D.) A gas gains kinetic energy to become a liquid and then becomes a solid.
B. This looks like ice turning to water then to steam
Answer is: B.) A solid gains kinetic energy to become a liquid and then becomes a gas.
Stage 2 is melting (from solid to liquid) and Stage 2 is boiling (from liquid to gas).
In solid, molecules are closely packed, stiff and do not changes of shape or volume. Solid object does not take on the shape of its container.
Liquids have definite volume, but no fixed shape.
Gases not have definite volume and fixed shape, it depends on its container.
Manuel wants to determine how fast a toy car will move across different surfaces. He lines 3 ramps with different surface covers including wax paper, sandpaper, and smooth carpet and runs the same car down each ramp to determine how long it takes for the car to reach the bottom. What is Manuel's independent variable in this experiment
Which of the following represents a purely covalent bond?
Ne – Ne
Na – Na
N – N
Ni – O
How much energy is required to melt a 500. gram block of iron? The heat of vaporization is 6090 J/g and the heat of fusion is 247 J/g.
Violent shaking from an earthquake can cause soil and rock on slopes to fall and cause a _____.
CH2 - CH2 - CH3
|
CH3 - CH2 - CH - CH2 - CH = CH2
Which is a way that the model of the atom became more accurate due to new investigations? Select one: A. Experiments showed that the atom is made of smaller particles. B. Neutrons were detected orbiting the nucleus. C. Cathode-ray tube experiments showed that the atom is indivisible. D. Thomson showed that the atom contains alpha particles.
Answer: The correct answer would 100% be A. Experiments showed that the atom is made of smaller particles.
just took the test and got it right
A buret containing NaOH solution has an initial volume reading of 0.14 mL.
25.00 mL of 0.1000 M HCl is titrated to a phenolphthalein end point, which occurs at a final reading of 27.16 mL NaOH. What is the molarity of the NaOH titrant?
Answer:
0.092 M
Explanation:
NaOH(aq) + HCl(aq) ------> NaCl(aq) + H2O(l)
CA= concentration of acid= 0.1000 M
CB= concentration of base= ?????
VA= volume of acid= 25.00 mL
VB= volume of base= 27.16 mL
NA= number of moles of acid= 1
NB= number of moles of base= 1
CAVA/CBVB= nA/nB
CB= CAVAnB/VBnA
CB= 0.1000 M × 25.00 mL ×1/27.16 mL ×1
CB= 0.092 M
How many grams of CuSO4 would be needed to make 150 mL of 0.300 M CuSO4 solution?
[tex]\boxed{{\text{7}}{\text{.182 g}}}[/tex] of [tex]{\text{CuS}}{{\text{O}}_{\text{4}}}[/tex] would be needed to make 150 mL of 0.300 M [tex]{\text{CuS}}{{\text{O}}_4}[/tex] solution.
Further Explanation:
The proportion of substance in the mixture is called concentration. The most commonly used concentration terms are as follows:
1. Molarity (M)
2. Molality (m)
3. Mole fraction (X)
4. Parts per million (ppm)
5. Mass percent ((w/w) %)
6. Volume percent ((v/v) %)
Molarity is a concentration term that is defined as the number of moles of solute dissolved in one litre of the solution. It is denoted by M and its unit is mol/L.
The formula to calculate the molarity of [tex]{\text{CuS}}{{\text{O}}_4}[/tex] solution is as follows:
[tex]{\text{Molarity of CuS}}{{\text{O}}_4}\;{\text{solution}}=\dfrac{{{\text{Moles}}\;{\text{of}}\;{\text{CuS}}{{\text{O}}_4}}}{{{\text{Volume }}\left( {\text{L}}\right){\text{ of}}\;{\text{CuS}}{{\text{O}}_4}\;{\text{solution}}}}[/tex] ......(1)
Rearrange equation (1) to calculate the moles of [tex]{\text{CuS}}{{\text{O}}_4}[/tex].
[tex]{\text{Moles}}\;{\text{of}}\;{\text{CuS}}{{\text{O}}_4}= \left( {{\text{Molarity of HN}}{{\text{O}}_3}\;{\text{solution}}} \right)\left( {{\text{Volume of}}\;{\text{CuS}}{{\text{O}}_4}\;{\text{solution}}} \right)[/tex] ......(2)
The volume of [tex]{\text{CuS}}{{\text{O}}_4}[/tex] solution is to be converted into L. The conversion factor for this is,
[tex]{\text{1 mL}} = {10^{ - 3}}\;{\text{L}}[/tex]
So the volume of [tex]{\text{CuS}}{{\text{O}}_4}[/tex] solution is calculated as follows:
[tex]\begin{aligned}{\text{Volume of CuS}}{{\text{O}}_4}\;{\text{solution}}&= \left( {{\text{150 mL}}}\right)\left({\frac{{{{10}^{ - 3}}\;{\text{L}}}}{{{\text{1 mL}}}}} \right)\\&= 0.15{\text{ L}}\\\end{aligned}[/tex]
The molarity of [tex]{\text{CuS}}{{\text{O}}_4}[/tex] solution is 0.300 M.
The volume of [tex]{\text{CuS}}{{\text{O}}_4}[/tex] solution is 0.15 L.
Substitute these values in equation (2).
[tex]\begin{aligned}{\text{Moles}}\;{\text{of}}\;{\text{CuS}}{{\text{O}}_4}&=\left( {{\text{0}}{\text{.300 M}}} \right)\left( {0.15{\text{ L}}}\right)\\&= 0.04{\text{5 mol}}\\\end{aligned}[/tex]
The formula to calculate the mass of [tex]{\text{CuS}}{{\text{O}}_4}[/tex] is as follows:
[tex]{\text{Mass of CuS}}{{\text{O}}_{\text{4}}}=\left( {{\text{Moles of CuS}}{{\text{O}}_{\text{4}}}} \right)\left( {{\text{Molar mass of CuS}}{{\text{O}}_{\text{4}}}} \right)[/tex] ......(3)
Substitute 0.045 mol for the moles of [tex]{\text{CuS}}{{\text{O}}_4}[/tex] and 159.609 g/mol for the molar mass of [tex]{\text{CuS}}{{\text{O}}_4}[/tex] in equation (3).
[tex]\begin{aligned}{\text{Mass of CuS}}{{\text{O}}_{\text{4}}}&= \left({{\text{0}}{\text{.045 mol}}} \right)\left( {\frac{{{\text{159}}{\text{.609 g}}}}{{{\text{1 mol}}}}}\right)\\&= 7.1824{\text{05 g}}\\&\approx {\text{7}}{\text{.182 g}}\\\end{aligned}[/tex]
Therefore the mass of [tex]{\mathbf{CuS}}{{\mathbf{O}}_{\mathbf{4}}}[/tex] is 7.182 g.
Learn more:
1. Calculation of volume of gas: https://brainly.com/question/3636135
2. Determine the moles of water produced: https://brainly.com/question/1405182
Answer details:
Grade: Senior School
Subject: Chemistry
Chapter: Concentration terms
Keywords: molarity, CuSO4, dilution, moles of CuSO4, volume, solution, 0.045 mol, 150 mL, 0.300 M, 7.182 g, 159.609 g/mol, 0.15 L.
]Aluminum ions form an ionic bond with chromate ions, and the resultant formula is Al2(CrO4)3. What is the ion charge for the chromate ion?
In the compound Al2(CrO4)3, the aluminum ion (Al) has a 3+ charge. To balance the electrical neutrality, each chromate ion (CrO4) must have a 2- charge since three of them are needed to balance the 6+ charge from two aluminum ions.
Explanation:Chromate ion has a charge of 2-. When forming an ionic bond with aluminum ions which have a 3+ charge, the formula becomes Al2(CrO4)3.
To determine the ion charge for the chromate ion in the compound Al2(CrO4)3, we must first understand the charges of the ions involved. Aluminum (Al) forms a cation with a 3+ charge, as indicated by the formula. Since the formula of the compound is electrically neutral and contains two aluminum ions, the total positive charge contributed by aluminum is 6+ (2 ions * 3+).
The compound then must have an equivalent total negative charge to balance this, contributed by three chromate (CrO4) ions. For the charges to balance out, each chromate ion must carry a 2- charge (6+ from Al3+ is balanced by 6- from three 2- ions), making the formula for the ionic compound Al2(CrO4)3 electrically neutral. Therefore, the chromate ion has a 2- charge in this compound.
complete the tables of value for four aqueous solutions at 25 celcius
The table of values for four aqueous solutions at is as shown in Table 1.
Further Explanation:
The negative logarithm of hydrogen ion concentration is termed as pH while that of hydroxide ion concentration is pOH. Higher the pH of solution, more will be the alkalinity and vice-versa. Similarly, higher value of pOH indicates solution is acidic in nature .
The expression for pH is mentioned below.
[tex]\text{pH}=-\text{log}\left[\text{H}^+\right][/tex] ...... (1)
Where [tex]\left[\text{H}^+\right][/tex] is the concentration of hydrogen ion.
The expression for pOH is mentioned below.
[tex]\text{pOH}=-\text{log}\left[\text{OH}^-\right][/tex] ...... (2)
Where [tex]\left[\text{OH}^-\right][/tex] is the concentration of hydroxide ion.
pH and pOH are related to each other by following expression:
pH + pOH = 14 …… (3)
Solution A:
Substitute [tex]6.4\times10^{-13}\text{ M}[/tex] for [tex]\left[\text{H}^+\right][/tex] in equation (1).
[tex]\begin{aligned}\text{pH}=&-\text{log}\left[6.4\times10^{-13}\text{ M}\right]\\=&12.2\end{aligned}[/tex]
Rearrange equation (3) for pOH.
pOH = 14 – pH …… (4)
Substitute 12.2 for pH in equation (4).
[tex]\begin{aligned}\text{pOH}=&14-12.2\\=&1.8\end{aligned}[/tex]
Rearrange equation (2) for [tex]\left[\text{OH}^-\right][/tex] .
[tex]\left[\text{OH}^-\right]=10^{-\text{pOH}}[/tex] …… (5)
Substitute 1.8 for pOH in equation (5).
[tex]\begin{aligned}\left[\text{OH}^-\right]=&10^{-\text{1.8}}\\=&0.016\text{ M}\end{aligned}[/tex]
Solution B:
Substitute [tex]2.7\times10^{-10}\text{ M}[/tex] for [tex]\left[\text{OH}^-\right][/tex] in equation (2).
[tex]\begin{aligned}\text{pOH}=&-\text{log}\left[2.7\times10^{-10}\text{ M}\right]\\=&\ 9.6\end{aligned}[/tex]
Rearrange equation (3) for pH.
pH = 14 – pOH …… (6)
Substitute 9.6 for pOH in equation (6).
[tex]\begin{aligned}\text{pH}=&14-9.6\\=&4.4\end{aligned}[/tex]
Rearrange equation (1) for [tex]\left[\text{H}^+\right][/tex] .
[tex]\left[\text{H}^+\right]=10^\text{-pH}[/tex] …… (7)
Substitute 4.4 for pH in equation (7).
[tex]\begin{aligned}\left[\text{H}^+\right]=&10^\text{-4.4}\\=&0.0000398\text{ M}\end{aligned}[/tex]
Solution C:
Substitute 8.11 for pH in equation (7).
[tex]\begin{aligned}\left[\text{H}^+\right]=&10^\text{-8.11}\\=&0.0000000078\text{ M}\end{aligned}[/tex]
Substitute 8.11 for pH in equation (4).
[tex]\begin{aligned}\text{pOH}=&14-8.11\\=&5.89\end{aligned}[/tex]
Substitute 5.89 for pOH in equation (5).
[tex]\begin{aligned}\left[\text{OH}^-\right]=&10^{-\text{5.89}}\\=&0.000001288\text{ M}\end{aligned}[/tex]
Solution D:
Substitute 4.73 for pOH in equation (5).
[tex]\begin{aligned}\left[\text{OH}^-\right]=&10^{-\text{4.73}}\\=&0.00001862\text{ M}\end{aligned}[/tex]
Substitute 4.73 for pOH in equation (6).
[tex]\begin{aligned}\text{pH}=&14-4.73\\=&9.27\end{aligned}[/tex]
Substitute 9.27 for pH in equation (7).
[tex]\begin{aligned}\left[\text{H}^+\right]=&10^\text{-9.27}\\=&0.0000000005\text{ M}\end{aligned}[/tex]
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Answer details:
Grade: High School
Chapter: Acids, base and salts
Subject: Chemistry
Keywords: pH, pOH, H+, OH-, solution A, solution B, solution C, solution D, hydrogen ion, hydroxide ion, negative logarithm.
what are the advantages of using a computer over a graphing calculator
is MgCO3 an base or acid
What is the frequency of a 6.14 x 10^4 m wave
The observations and results of Thomson’s cathode ray experiment led to what change to the atomic model?
"the addition of negatively charged electrons" is the answer.
helium is the lightest monatomic element is this a chemical property
How is scientific use of the term digital different from the common use?
We commonly know refer to something 'digital' has to something electronic that can be visibly seen such as a watch, clock, camera, screen, etc. It really refers to stored energy or electricity that's not natural. But the word 'digital' in science refers to the depiction of data or information in figures (such as in a table) in contrast to as a chart, graph, drawing, or other pictorial form.
Explanation:
The scientific use of the term digital is much changed from the current use because the term digital in science is a way of representing a discontinuous phenomenon or something this is just finite and faulty. It also describes a data in figures with the use of this term. While “digital” generally refers to electronics in general, the scientific explanation of digital is much different
. How many moles of ammonia gas, NH3, are required to fill a volume of 50 liters at STP?
Answer:2.23 moles
Explanation:
According to avogadro's law, 1 mole of every substance weighs equal to its molecular mass , occupies 22.4 Liters at STP and contains avogadro's number [tex]6.023\times 10^{23}[/tex] of particles.
To calculate the number of moles, we use the equation:
[tex]\text{Number of moles}=\frac{\text{Given volume}}{\text{Molar volume}}=\frac{50}{22.4}=2.23moles[/tex]
Thus 2.23 moles of ammonia gas are required to fill a volume of 50 liters at STP.