A 1.757-g sample of a / alloy was dissolved in acid and diluted to exactly 250.0 mL in a volumetric flask. A 50.00-mL aliquot of the diluted solution was brought to a pH of 10.0 with an / buffer; the subsequent titration involved both cations and required 28.89 mL of 0.06950 M EDTA. A second 50.00-mL aliquot was brought to a pH of 10.0 with an / buffer, which also served to mask the ; 19.07 mL of the EDTA solution were needed to titrate the . Calculate the percent and in the sample.
Answer:
78.14% Pb²⁺ and 21.86% of Cd²⁺
Explanation:
The first titration involves the reaction of both Pb²⁺ and Cd²⁺
In the second titration, as the buffer is HCN/NaCN, the Cd²⁺ precipitates as Cd(CN)₂ and the only ion that reacts is Pb²⁺
In the first titration:
Moles EDTA = Moles Pb²⁺ and Cd²⁺:
28.89mL = 0.02889L * (0.06950moles / L) = 2.008x10⁻³ moles in the aliquot. In the sample:
2.008x10⁻³ moles * (250.0mL / 50.0mL) =
0.01004 moles = Pb²⁺ + Cd²⁺ (1)
In the second titration:
19.07mL = 0.01907L * (0.06950mol / L) = 1.325x10⁻³ moles Pb²⁺ in the aliquot. In the sample:
1.325x10⁻³ moles Pb²⁺ * (250.0mL / 50.0mL) =
6.626x10⁻³ moles Pb²⁺
That means the moles of Cd²⁺ are:
0.01004 moles = Cd²⁺ + 6.626x10⁻³ moles Cd²⁺
3.413x10⁻³ moles Cd²⁺
The mass of each ion is:
Cd²⁺ -Molar mass: 112.411g/mol-:
3.413x10⁻³ moles Cd²⁺ * (112.411g / mol) =
0.384g of Cd²⁺
Pb²⁺ -Molar mass: 207.2g/mol-:
6.626x10⁻³ moles Pb²⁺ * (207.2g / mol) =
1.373g of Pb²⁺
The percent mass of each ion is:
1.373g Pb²⁺ / 1.757g = 78.14% Pb²⁺
And:
0.384g of Cd²⁺ / 1.757g * 100 = 21.86% of Cd²⁺
Which of the following is TRUE about most gases?
1) They expand to completely fill their container.
2) They cannot be compressed.
3) All of their particles are the same size.
4) They have a fixed volume.
5) Their particles are very close together.
Explanation:
I think it is the first option
Answer:
1) They expand to completely fill their container. :)
Explanation:
What are characteristics of absorption spectra? Check all that apply.
Light is absorbed, which produces characteristic lines.
| Light is emitted, which produces characteristic lines.
Lines are dark on a visible light background.
Lines are brightly colored on a black background.
Lines are produced by electrons being excited.
Lines are produced from electrons returning to a lower energy level.
Answer:
Light is absorbed, which produces characteristic lines.
Lines are dark on a visible light background.
Lines are produced by electrons being excited.
Explanation:
Edg
The characteristics of absorption spectra light is absorbed, which produces characteristic lines, lines are dark on a visible light background and Lines are produced by electrons being excited.
What is absorption spectra?The term "absorption spectroscopy" applies to spectroscopic methods that assess how much radiation interacts with a sample and is absorbed as a proportion of frequency or wavelength. The sample takes in photons, meaning energy, from the emitting field.
What are electrons?The electron would be a subatomic particle with a negative one fundamental charge electric charge. Due to their lack of components or substructure, electrons, which have become part of the lepton particle family's first generation, could be typically regarded to be elementary particles.
The percentage of incoming electromagnetic energy that a material absorbs across a variety of frequencies is displayed in the material's absorption spectrum. In a way, an emission spectrum would be the converse of an absorption spectrum.
To know more about absorption spectrum and electrons
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Is anyone good at chemistry if so can someone help me please ?
(NO LINKS)
Since pH + pOH = 14, given a pOH of 4.53, our pH would be 14 - 4.53 = 9.47. And since the pH is greater than 7, this solution is basic. So, the correct answer choice would be D.
c) If 21.0 g of potassium reacts with 62.5 g of barium nitride, what mass of potassium nitride will be produced?
Explanation:
21.0 g of potassium reacts with 62.5 g of barium nitride, what mass of potassium nitride will be produced
I NEED HELP WITH THIS CHEMISTRY QUESTION PLS
Answer:
Iron, according to:
[tex]2Al(s)+3Fe(NO_3)_2(aq)\rightarrow 3Fe(s)+2Al(NO_3)_3(aq)[/tex]
Explanation:
Hi there!
In this case, according to the law of conservation of mass, which states that matter cannot be neither created nor destroyed, it is possible for us to figure out the missing element in the reaction by taking into account this is a single displacement reaction in which Al goes with NO3 to produce the Al(NO3)3, and therefore the other element would be iron (Fe) as can be seen on the following chemical reaction:
[tex]2Al(s)+3Fe(NO_3)_2(aq)\rightarrow 3Fe(s)+2Al(NO_3)_3(aq)[/tex]
Best regards!
a sample of 0.0084 mol of HCl is dissolved in water to make a 1500 mL solution. calculate the molar it’s of the HCl solution, The H3O, and the pH
Answer:
pH = 2.25
Explanation:
pH is a measurement in chemistry defined as the -log [H₃O⁺]. Molarity [], is defined as the ratio between moles of solute (HCl) and the liters of solution
To solve this question we must find the molarity of the H₃O⁺ knowing: [HCl] = [H₃O⁺]
[HCl]:
0.0084moles / 1.500L
= 0.0056M = [HCl] = [H₃O⁺]
pH = -log [H₃O⁺] = -log [0.0056M]
pH = 2.25A solution prepared by dissolving 0.0084 moles of HCl in 1500 mL of solution has a molar concentration of HCl of 5.6 × 10⁻³ M, a molar concentration of H₃O⁺ of 5.6 × 10⁻³ M and a pH of 2.3.
A solution is prepared by dissolving 0.0084 moles of HCl in 1500 mL of solution. The molarity of HCl is:
[tex][HCl] = \frac{0.0084mol}{1.5L} = 5.6 \times 10^{-3} M[/tex]
HCl is a strong acid according to the following equation.
HCl(aq) + H₂O(l) ⇒ Cl⁻(aq) + H₃O⁺(aq)
Thus, the concentration of H₃O⁺ will be equal to the initial concentration of HCl, 5.6 × 10⁻³ M.
Finally, we will calculate the pH of the solution using its definition.
[tex]pH = -log [H_3O^{+} ] = -log (5.6 \times 10^{-3} ) = 2.3[/tex]
A solution prepared by dissolving 0.0084 moles of HCl in 1500 mL of solution has a molar concentration of HCl of 5.6 × 10⁻³ M, a molar concentration of H₃O⁺ of 5.6 × 10⁻³ M and a pH of 2.3.
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Please
5.50 L of a 0.190 M CaCl2M CaCl2 solution
How do you find Grams?
Answer:
115.891
Explanation:
Molarity is equal to moles/liters so to get moles we multiply molarity by liters, after this we multiply the moles by the total atomic weight of the compound to get grams
If I contain 2 moles of gas in a container with a volume of 30 liters and at a temperature of 337 K, what is the pressure inside the container?
Answer:
1.84
Explanation: just input the value into the formula pv=nrt
p*30=2*0.08206*337 then divide both sides by 30 and get 1.84
What is the molarity of a solution made by adding :1.565 moles of PbN03 to 500 mL
Answer:
This question is a bit vague. We're not told if 500ml is the volume of the solution and additional info is not given to calculate the volume of pbNo3 being added.
If you solve with 500ml as the volume of solution ... You'll have the answer below.
Molarity=moles of solutes/Volume of solvent(in litres)
moles of solute given=1.565moles
Volume = 500ml. There's 1000ml to a litre. Dividing by 1000ml to convert to Litres... You have 0.5L
Molarity = 1.565/0.5
=3.13M
Which product forms from the synthesis reaction between lithium (Li) and oxygen (O)?
A. Li2O
B. LiO
C. LiO2
D. Li2O2
Answer:
A Li2O
Explanation:
Li has a 1+ charge and O has a 2- charge so to balance the charges there needs to be 2 Li for every 1 O
The product forms from the synthesis reaction between lithium (Li)and oxygen (O) is Li₂O. The correct option is A.
What is synthesis reaction?
Synthesis reaction is the reaction when two or more products combine to form a single product.
An example of a synthesis reaction is the combination of sodium (Na) and chlorine (Cl) to produce sodium chloride (NaCl).
Thus, the correct option is A. Li2O.
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5
How many J of energy are needed to raise the temperature of 18.3 g of
water from 11.88°C to 49.32°C?*
2540 J
1740 J
2870 J
3570 J
Q = mcΔT, where Q is the heat energy, m is the mass, c is the specific heat, and ΔT is the change in temperature (T₂-T₁). The specific heat of water is 4.184 J/g °C. We are given the mass of water (m = 18.3 g), the final temperature (T₂ = 49.32 °C), and the initial temperature (T₁ = 11.88 °C). The change in temperature, ΔT, equals 49.32 °C - 11.88 °C = 37.44 °C. With all these values at hand, we can solve for the amount of energy needed, Q:
Q = (18.3 g)(4.184 J/g °C)(37.44 °C) = 2866.7 J ≈ 2870 J (three sig figs).
What can be different between products and reactants in a balanced equation?
a) The total mass of products and reactants
b) The total moles of each element present in the reactants and in the products.
c) The number of molecules in the reactants and in the products
Answer:
b) The total moles of each element present in the reactants and in the products.
Explanation:
Hello there!
In this case, since the law of conservation of mass is used to realize that the mass, atoms and molecules of all the species involved in a chemical reaction must be the same at both reactants and products, we can see that a and c stand for those that must be equal; thus, we infer that the moles can be different as they stand for the amount of substance which is related to the mass via molar masses. Therefore, the answer would be b) The total moles of each element present in the reactants and in the products.
Regards!
Graphite, an allotrope of carbon, is converted into cubic diamond through a process that may take a billion years or longer. As illustrated above, scientists can make synthetic diamonds using a certain process in about one week. However, these synthetic diamonds have carbon atoms in a hexagonal lattice. Diamonds with a carbon atoms in a cubic lattice are not produced even though they are thermodynamically more stable than hexagonal diamond. Which of the following best justifies why the synthetic process produces hexagonal diamond and not the more thermodynamically stable cubic diamond?
a. The amount of energy required to create new bonds between carbon atoms in cubic diamond is much greater than the amount of energy required to create hexagonal diamond.
b. The amount of energy required to create new bonds between carbon atoms in cubic diamond is much smaller than the amount of energy required to create hexagonal diamond.
c. The activation energy needed to form cubic diamond is much less than the activation energy needed to form hexagonal diamond.
d. The activation energy needed to form cubic diamond is much greater than the activation energy needed to form hexagonal diamond.
Answer:
The activation energy needed to form cubic diamond is much greater than the activation energy needed to form hexagonal diamond.
Explanation:
The activation energy refers to the minimum energy that reacting species must possess before they can undergo a particular chemical reaction.
This implies that if species do not possess the activation energy, they hardly undergo a given reaction. The activation energy is the barrier between reactants and products.
Hence, a reaction that has a very high activation energy occurs slowly or may not even occur. The activation energy needed to form cubic diamond is much greater than the activation energy needed to form hexagonal diamond hence the synthetic process produces hexagonal diamond and not the more thermodynamically stable cubic diamond.
PLSSS HELP ASAP!!!!!!!!
Answer:
i-dk but A seems most logical to me
Explanation:
(d) Other
sugar molecules become
_____ and are carried away from the crystal.
the force of attraction is
Answer:
liquid
Explanation:
defiantly
There are about 26 deuterium atoms for every million hydrogen atoms across the universe, but it is six times as prevalent in the water on Earth and in other solar system bodies. Deuterium has one more ———— than hydrogen.
A. Ionic pair
B. Hydrogen bond
C. Proton
D. Electron
E. Neutron
Answer:
Option E
Deuterium has one more neutron than hydrogen
Explanation:
Deuterium is an isotope of Hydrogen and hence there will variation in the number of neutron
Hydrogen has 0 neutron
Deuterium has 1 neutron and
Tritium has 2 neutron
Thus option E is correct
In the universe, there are approximately 26 deuterium atoms for every million hydrogen atoms. Deuterium has one more neutron than hydrogen.
The correct option is E.
What is deuterium?Deuterium is a stable isotope of hydrogen, whose atomic weight is 2.014.
It is also called heavy hydrogen, and it contains one neutron and one proton.
In nuclear fusion reactors, deuterium is employed as a tracer, while in heavy water moderated fission reactors, it is utilized to slow down neutrons.
Thus, the correct option is E.
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How much energy is required to raise the temperature of 10.6 grams of gaseous neon from
20.0 °C to 37.9 °C ?
Answer:
Approximately [tex]1.95 \times 10^{2}\; \rm J[/tex].
Explanation:
Look up the specific heat of gaseous neon:
[tex]c = 1.03 \; \rm J \cdot g^{-1} \cdot K^{-1}[/tex].
Calculate the required temperature change:
[tex]\Delta T = (37.9 - 20.0)\; \rm K = 17.9\; \rm K[/tex].
Let [tex]m[/tex] denote the mass of a sample of specific heat [tex]C[/tex]. Energy required to raise the temperature of this sample by [tex]\Delta T[/tex]:
[tex]Q = c \cdot m \cdot \Delta T[/tex].
For the neon gas in this question:
[tex]c = 1.03\; \rm J \cdot g^{-1}\cdot K^{-1}[/tex].[tex]m = 10.6\; \rm g[/tex].[tex]\Delta T = (37.9 - 20.0)\; \rm K = 17.9\; \rm K[/tex].Calculate the energy associated with this temperature change:
[tex]\begin{aligned}Q &= c \cdot m \cdot \Delta T \\ &= 1.03\; \rm J \cdot g^{-1}\cdot K^{-1} \times 10.6\; \rm g \times 17.9\; \rm K \\ &\approx 1.95 \times 10^{2}\; \rm J\end{aligned}[/tex].
The phenomenon that causes air masses and water to bend or curve is the ______________.
PLZ I NEED HELP ILL GIVE BRAINLIEST
Answer:
The Coriolis effect
Explanation:
The Coriolis effect is the effect that makes tornados, water spouts, and are often seen in storms. They make water curve and rotate as well as the wind And current.
number of atoms per unit cell in face centred cube is
Answer: 4 atoms is the answer. I hope it helped you.
Explanation:
Please disregard this
well i need points
Explanation:
thanks
During the reaction of 2,4-dinitrofluorobenzene with methoxide in methanol it was observed that it occurs at a significantly higher rate than the same reaction of 3,4-dinitrofluorobenzene. Explain the observation with a detailed mechanism and convincing structural arguments.
Answer:
Explanation:
your not so smart
15 The Following statement describes which body system? It also produces blood cells, and stores calcium. It regulates endocrine as well. This specific system uses all bones & joints in your body. A. The Lymphatic System B.The Muscular System C.The Reproductive System D.The Skeletal System
Please help!!!!!!!!!!!!!!
Answer:
my guy we need to read lesson cuz int know what any of that mean
Explanation:
explain the importance of changing states of matter
As a result, when a substance absorbs enough energy then its atoms or molecules move around. And, when increase in this energy takes place then atoms tend to collide frequently with each other. Hence, it causes change in state of a substance. Therefore, changes in matter are important for the conservation of energy
mark brainliest if right
Large cities in the U.S. often formed near the ocean.
What benefit does the ocean provide for people in nearby large cities?
Answer:
a means of work
Explanation:
since its near oceans they are closer to the fish
Please help
I need to turn in in 5 min
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A solution has a pH of 9.5. Is the solution an acid or a base?
Answer:
The solution is Basic
Deep water currents are formed partly due to the amount of _________________ in the water.
Answer:
Density differences
Explanation:
The water transports cool masses of air and hot air, the transports is driven by the amount of changes of Temperature and Salinity (ThermoHaline)