Answer:
c = 0.38 j/g.°C
Explanation:
Given data:
Heat absorbed by copper = 10 j
Mass of copper = 30 g
Initial temperature = 18.20°C
Final temperature = 19.07°C
Specific heat capacity of copper = ?
Solution:
Specific heat capacity:
It is the amount of heat required to raise the temperature of one gram of substance by one degree.
Formula:
Q = m.c. ΔT
Q = amount of heat absorbed or released
m = mass of given substance
c = specific heat capacity of substance
ΔT = change in temperature
ΔT = 19.07°C -18.20°C
ΔT = 0.87 °C
10 J = 30 g×c×0.87 °C
10 J = 26.1 g.°C×c
c = 10 J /26.1 g.°C
c = 0.38 j/g.°C
How many moles of NaCl , if mixed with excess Pb2+ ions in solution, would be needed to form 45.5 g of PbCl2 ?
The number of mole of NaCl needed to react with excess Pb²⁺ to produce 45.5 g of PbCl₂ is 0.328 mole
We'll begin by calculating the number of mole in 45.5 g of PbCl₂. This can be obtained as follow:
Mass of PbCl₂ = 45.5 g
Molar mass of PbCl₂ = 207 + (35.5×2) = 278 g/mol
Mole of PbCl₂ =?Mole = mass / molar mass
Mole of PbCl₂ = 45.5 / 278
Mole of PbCl₂ = 0.164 mole Finally, we shall determine the number of mole of NaCl needed to produce 0.164 mole (i.e 45.5 g) of PbCl₂. This can be obtained as follow:2NaCl + Pb²⁺ —> PbCl₂ + 2Na⁺
From the balanced equation above,
2 moles of NaCl reacted to produce 1 mole of PbCl₂
Therefore,
Xmol of NaCl will react to produce 0.164 mole of PbCl₂ i.e
Xmol of NaCl = 2 × 0.164
Xmol of NaCl = 0.328 mole
Thus, the number of mole of NaCl needed for the reaction is 0.328 mole
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Suppose the current flowing from a battery is used to electroplate an object with silver. Calculate the mass of silver that would be deposited by a battery that delivers 1.65 A·hr of charge.
Answer:
m = 0.00659 kg = 6.59 g
Explanation:
From Faraday's Law of Electrolysis, we know that:
m = ZQ
where,
m = mass of silver deposited = ?
Q = charge supplied = (1.65 A-hr)(3600 s/1 hr) = 5940 C
Z = electrochemical equivalent of silver = 1.18 x 10⁻⁶ kg/C
Therefore,
m = (1.11 x 10⁻⁶ kg/C)(5940 C)
m = 0.00659 kg = 6.59 g
The mass of silver that would be deposited by a battery is 6.65 grams
The precipitation of Ag requires the removal of one electron. The reduction process for silver electrode at the cathode is as follows:
[tex]\mathbf{Ag^+ + e^- \to Ag(s)}[/tex]
The current flowing in the battery = 1.65 A = 1.65 C/sThe time at which the current is flowing = 1 hr = 3600sec∴
The charge Q = Current (I) × time (t)Charge Q = 1.65 C/s × 3600 sCharge (Q) = 5940 CIn one mole of an electron, the charge carried = 96500 C
Recall that:
The atomic mass of silver (Ag) = 108 g
∴
The mass of silver that would be deposited in a 5940 C can be computed as:
[tex]\mathbf{=5940\ C \times \dfrac{108 \ g }{96500 \ C}}[/tex]
= 6.65 grams
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An egg sinks in fresh water but it floats on salty water.why?
Explain why atoms in group 2a are likely to form ions with plus two charge explain why why atoms in group 7a are likely to form ions with a minus one charge
Answer:
Atoms in group 2a are likely to form ions with a +2 charge because they have two valence electrons, both of which experience a very weak pull from the nucleus due to electron shielding. This causes the atoms to be easily pulled away from the nucleus, creating the +2 ions we see in nature.
Atoms in group 7a are likely to form ions with a -1 charge because they are one electron away from completing their outermost shell. The large number of protons in the middle of these atoms also causes the valence electrons to experience a stronger net force. This force also pulls strongly on the valence electrons of other atoms, causing the -1 ions we see in nature.
Scientists who are investigating what has happened over the years to the people who were exposed to radiation during the 1986 Chernobyl nuclear disaster are conducting what type of study
Answer:
Observational study
Explanation:
An investigation of what happened over the years to the people who were exposed to radiation during the 1986 Chernobyl nuclear disaster would be termed an observational study because it will require observing subjects and finding out if there is a kind of correlating factor in the subjects that could indicate the level of exposure to the nuclear radiation.
There are basically two types of research studies:
1. Observational studies
2. Experimental studies
Observational studies involve just the observation of subjects and trying to find out some correlation factors. This kind of study could be prospective when it deals with what could happen in the future based on certain factors or retrospective when it considers what has already happened. An observational study can be cross-sectional, case-only, case-control, or cohort study.
Experimental studies are also referred to as randomized or controlled trial studies. Here, subjects are grouped and each group receives a different treatment in order to isolate the effect of a particular factor or variable relating to the treatment.
How much water must be added to 424 mL of 0.189 M HCl to produce a 0.140 M solution?
Answer:
Volume of water added = 148.4 mL
Explanation:
Given data:
Initial volume = 424 mL
Initial molarity = 0.189 M
Final molarity = 0.140 M
Volume of water added = ?
Solution:
Formula:
M₁V₁ = M₂V₂
0.189 M×424 mL = 0.140 M×V₂
V₂ = 0.189 M×424 mL /0.140 M
V₂ = 80.136 M.mL / 0.140 M
V₂ = 572.4 mL
Final volume of solution is 572.4 mL.
Volume of water added = Final volume - initial volume
Volume of water added = 572.4 mL - 424 mL
Volume of water added = 148.4 mL
What are things animals might do to survive?
Answer:
Animals need food, water, shelter, and space to survive. Herbivores can live only where plant food is available. Carnivores can live only where they can catch their food. Omnivores can live in many places because they eat both plants and animals.
how many moles of ethanol C2H6O, are in a 10.0g sample
Answer: 0.217 mol
Explanation:
To find the amount of moles in a 10 g sample, we need the molar mass of ethanol.
Molar Mass: 46.07 g/mol
Now that we have the molar mass, we can find moles.
[tex]10.0 g*\frac{1mol}{46.07g}=0.217 mol[/tex]
We know that there are 0.217 mol in a 10.0 gram sample.
A mixture of neon and xenon gases, at a total pressure of 739 mm Hg, contains 0.919 grams of neon and 19.1 grams of xenon. What is the partial pressure of each gas in the mixture?_______g Xe
Answer:
Partial pressure of neon = 175 mmHg
Partial pressure of xenon = 564 mmHg
Explanation:
The partial pressure of a gas in a mixture can be calculated as the product of the mole fraction of the gas (Xi) and the total pressure (Pt), as follows:
Pi = Xi Pt
The total pressure is 739 mmHg ⇒ Pt = 739 mmHg
In order to calculate the mole fraction of each gas, we have to first calculate the number of moles of each gas (n) by dividing the mass of the gas into the molar mass (MM):
For neon gas (Ne):
MM(Ne) = 20.18 g/mol
n(Ne)= mass/MM = 0.919 g x 1 mol/20.18 g = 0.045 mol Ne
For xenon gas (Xe):
MM(Xe) = 131.3 g/mol
n(Xe)= mass/MM = 19.1 g x 1 mol/131.3 g = 0.145 mol Xe
Now, we calculate the mole fraction (X) by dividing the number of moles of the gas into the total number of moles (nt):
nt= moles Ne + moles Xe = 0.045 mol + 0.145 mol = 0.190 mol
X(Ne) = moles Ne/nt = 0.045 mol/0.190 mol = 0.237
X(Xe) = moles Xe/nt = 0.145/0.190 mol = 0.763
Finally, we calculate the partial pressures of Ne and Xe as follows:
P(Ne) = X(Ne) x Pt = 0.237 x 739 mmHg = 175 mmHg
P(Xe) = X(Xe) x Pt = 0.763 x 739 mmHg = 564 mmHg
Which of the following grouping contains only representative elements?
A. Na, Co, S
B. Ni, Ga, Zn
c. AI, Mg, LÍ
D. CI, O, Cd
Answer:
C
Explanation:
Al=Aluminum
Mg=Magnesium
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Question 10 of 12- POS
GR8 Sci U03 USA FY21 Question: 1-10
Hannah added a silvery white metal to a beaker of cold water and noticed that gas bubbles were given off and a different substance formed. When she repeated the activity with hot water she noticed the gas bubbles were
released much more rapidly. Which statement best explains why the reaction occurred faster in hot water?
M
The correct answer is Hot water increases the collision rate of molecules, causing the reaction to occur faster.
Explanation:
Temperature is directly related to the kinetic energy or movement of molecules in a substance. In this context, a higher temperature leads to more kinetic energy or more collision between molecules. At the same time, a chemical reaction involves molecules of two or more substances colliding and creating bonds to form new substances. This implies an increase in temperature means molecules colliding faster, new substances forming in a shorter time, and therefore a faster chemical reaction. According to this, the first answer is correct.
Calculate ΔHrxn for the following reaction:CH4(g)+4Cl2(g)→CCl4(g)+4HCl(g)Use the following reactions and given ΔH′s.C(s)+2H2(g)→CH4(g)ΔH=−74.6kJC(s)+2Cl2(g)→CCl4(g)ΔH=−95.7kJH2(g)+Cl2(g)→2HCl(g)ΔH=−184.6kJ
Answer:
ΔH= -390.3kJ
Explanation:
Using Hess's law, we can obtain ΔHrxn from the sum of related reactions.
Using:
(1) C(s) + 2H2(g) → CH4(g) ΔH=−74.6kJ
(2) C(s) + 2Cl2(g) → CCl4(g) ΔH=−95.7kJ
(3) H2(g) + Cl2(g) → 2HCl(g) ΔH=−184.6kJ
(2) - (1):
CH4(g) + C(s) + 2Cl2(g) → CCl4(g) + C(s) + 2H2(g)
CH4(g) + 2Cl2(g) → CCl4(g) + 2H2(g)
ΔH= -95.7kJ - (-74.6kJ) = -21.1kJ
This reaction + 2*(3):
2H2(g) + 2Cl2(g) + CH4(g) + 2Cl2(g) → CCl4(g) + 2H2(g) +4HCl(g)
CH4(g) + 4Cl2(g) → CCl4(g) + 4HCl(g)
ΔH= -21.1kJ + 2*-184.6kJ
ΔH= -390.3kJAt the Sparta Fault in Greece, the hanging wall is below the footwall. This type of fault is called a .
Answer:
1 a
Explanation:
1. How many Chromium atoms are found in 25.8 milligrams of Chromium?
Answer: 51.9961 g/mol, don't know if it helps :)
Explanation:
Answer:
Chromium is a steel-gray, lustrous, hard metal that takes a high polish, is fusible with difficulty, and is resistant to corrosion and tarnishing.
The most common oxidation states of chromium are +2, +3, and +6, with +3 being the most stable. +4 and +5 are relatively rare. Chromium compounds of oxidation state 6 are powerful oxidants.ion:
A 2kg metal cylinder is supplied with 1600J of energy to heat it from 5*C to 13*C. What is the SHC of the metal?
Answer:
100Jkg/°C
Explanation:
Given parameters:
Mass of metal = 2kg
Amount of heat energy = 1600J
Initial temperature = 5°C
Final temperature = 13°C
Unknown:
Specific heat capacity of the metal = ?
Solution:
Specific heat capacity of a body is the amount of heat needed to raise the temperature of unit mass of a body by 1°C.
H = m x C x (T₂ - T₁ )
H is the amount of heat
m is the mass
C is the unknown specific heat capacity
T is the temperature
Insert the parameters and solve;
1600 = 2 x C x (13 - 5)
1600 = 16C
C = 100Jkg/°C
What are the starting substances (molecules) in a chemical equation called?
Answer:
A chemical reaction is the process in which atoms present in the starting substances rearrange to give new chemical combinations present in the substances formed by the reaction. These starting substances of a chemical reaction are called the reactants, and the new substances that result are called the products.
How does the density and distribution of your “stars” change as the balloon expands?
Answer:
The Universe is constantly expanding and as it expands the stars and objects in space move farther apart, just like the points on the balloon when air is blown into it. Density and distribution of "stars" as the balloon expands because when volume increases the density will increase.
Hope this Helps
who established the two important laws of chemical combination combination state them
Answer:
Antoine Lavoisier
1) Law of Conservation of Mass
French chemist, Antoine Lavoisier in 1789, studied this law. This law states that “In all physical and chemical changes, the total mass of the reactants is equal to that of the products” or “Mass can neither be created nor destroyed.”
Calculate the mass percent composition of iron for the third one of these iron ores.
Iron is mined from the earth as iron ore. Common ores include Fe2O3 (hematite), Fe3O4 (magnetite), and FeCO3 (siderite).
Answer:
[tex]\% Fe=48.2\%[/tex]
Explanation:
Hello!
In this case, since the percent composition of an element in a compound is given by:
[tex]\% i =\frac{z_i*m_i}{MM}*100\%[/tex]
Whereas i represent the element in the compound for which we want compute the mass percent. As required for siderite, FeCO3 whose molar mass is 115.854 g/mol, and knowing there is one iron atom there with an atomic mass od 55.85 g/mol, the mass percent of iron there is:
[tex]\% Fe=\frac{1*55.85}{115.854}*100\%\\\\\% Fe=48.2\%[/tex]
Best regards!
Identify at least 5 pure substance found in nature,in the supermarket, grocery storeand even at your home.use the table below to explain your answer based on appearance, separating technique, boiling and melting point.
Answer:
Explanation:
1) Pure substance: Water (found at home)
Appearance: It is homogeneous since it is a single substance that appears as liquid. Homogeneous is when the components of a substance are in a single phase
Separating technique: It's component cannot be separated by physical means
Boiling point: Water boils at 100 °C
Melting point: Water melts/freezes at 0°C
2) Pure substance: Table salt (found at home)
Appearance: It is also homogeneous as it is a single substance that is solid. Separating technique: It's component cannot be separated by physical means
Boiling point: Water boils at 1,465 °C
Melting point: Water melts/freezes at 801 °C
3) Pure substance: Butter (found at home and grocery store)
Appearance: It is homogeneous even though it contains different components
Separating technique: It's component can be separated by physical means since butter is an emulsion of fat in water. The 15% water content can be evaporated/distilled out at 100 °C
Boiling point: Butter starts boiling at about 110-120 °C
Melting point: It melts at about 37 °C
4) Pure substance: Candle (wax) (found at home and grocery store)
Appearance: It is homogeneous
Separating technique: It's component cannot be separated by physical means
Boiling point: It starts boiling around 370 °C
Melting point: It melts at about 37 °C
5) Pure substance: table sugar/sucrose (found at home, grocery stores and in supermarkets)
Appearance: It is homogeneous
Separating technique: It's component cannot be separated by physical means
Boiling point: It starts boiling around 697 °C
Melting point: It melts at about 186 °C
A pure substance is an homogeneous material, having a composition, and
properties that are consistent through out the material.
The chemical properties of a pure substance are defined, such as the
products of its reaction can be predictable.
A chemical is pure when it consist of a single type of particle such as an
element, a molecule or a compound.
The five pure substances are presented as follows;
[tex]\displaystyle\begin{tabular}{|l|l|l|l|l|}\underline{Pure \ Substances}&\underline{Appearance}&\underline{Separaing Tech}&\underline{Boiling \ Point}&\underline{Melting \ point}\\1. Diamond&Translucent \ solid&Inseparable&3550^{\circ}&4830^{\circ}\\2. Table \ salt&White\ crystals&Insepble&801^{\circ}&1413^{\circ}\\3. Water&Tran parent \ liquid&Insepble&0^{\circ}&100^{\circ}\\4. Sugar&Whilte \ crystals&Heating&Decomposes&186^{\circ}\\5. Gold&Yellowish \ metal&Inseparable& 2700^{\circ}&1064^{\circ}\end{array}[/tex]
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The pressure of a compressed gas is 1.45 atm. What is this pressure in kPa
Answer:
1.45 Atmospheres = 146.92125 Kilopascals, or about 146.9 Kilopascals
Explanation:
1 Atmosphere = 101.325 Kilopascals, so 101.325 Kilopascals x 1.45 Atmospheres = 146.92125 Kilopascals.
Using the conversion table, the pressure of the compressed gas at 1.45 atm when converted to kilopascal becomes 146.92 kPa.
How to convert from atm to kPa?
Atm is the standard atmosphere which is a unit of pressure.
From conversion table
1 atm atmospheric pressure is equivalent to 101.325 kPa ( kilopascal ).
Now, the pressure of the compressed gas at 1.45 atm will be;
P = 1.45 × 101.325 kPa
P = 146.92 kPa
Therefore, the pressure of the compressed gas at 1.45 atm when converted to kilopascal using the conversion table becomes 146.92 kPa.
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BaO2 is a peroxide. Why?
Answer:
jajjsjsjddjdjdjdjdjjdjeieiririitofodoslwnridooskemridisoskswkwjj jwjwiwiwiwkiwiw
A graduated cylinder initially has 32.5 mL of water in it. After a 75.0 g piece of lead (Pb) is added to the graduated cylinder, the water level rises to the 39.1 mL mark. What is the the volume of the piece of lead.
Answer:
39.1-32.5 and you will find your answer it always like that, you subtract your starting point from your ending point
Explanation:
The volume of the piece of lead is 6.6 mL
From the question given above, the following data were obtained:
Volume of water = 32.5 mLMass of lead (Pb) = 75 gVolume of water + Lead = 39.1 mLVolume of lead =?The volume of the lead can be obtained as follow:
Volume of lead = (Volume of water + Lead) – (Volume of water)
Volume of lead = 39.1 – 32.5
Volume of lead = 6.6 mL
Therefore the volume of the lead is 6.6 mL
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Calculate the number of S atoms in 0.670 mole of S.
Answer:
4.03 × 10²³ atomsExplanation:
The number of S atoms can be found by using the formula
N = n × Lwhere n is the number of moles
N is the number of entities
L is the Avogadro's constant which is
6.02 × 10²³ entities
From the question we have
N = 0.67 × 6.02 × 10²³
We have the final answer as
4.03 × 10²³ atomsHope this helps you
2. Enumerate four Reactive Oxygen Species (ROS)
Answer:
Examples of ROS include peroxides, superoxide, hydroxyl radical, singlet oxygen, and alpha-oxygen.
2. Molecular solutions do not conduct electricity because they contain: *
(1 Point)
The ions are able to move freely from one place to another. So that they conduct electricity. But the molecular solutions does not electricity.
What is a molecular solution?The molecular solution is composed of molecules and consists of non - metallic atoms. These atoms are held together by the covalent bonds. The flow of charged particles is responsible for the conduction of electricity. If there is no flow of electrons or ions then there will be no electricity.
In the molecular solutions, the molecules present are not dissociated into respective ions. Since the molecules are not converted into the charged particles no electricity is produced.
A molecular solution is regarded as a non-electrolyte which does not contain ions. But electrolytes are dissociated into ions and thereby conducts electricity. So all electrolytes are good conductors of electricity.
Thus molecular solution does not contain ions.
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Sweat is made up of all EXCEPT what?
*
A.Sugar
B.Salt
C.Urea
D.Urine
Please help me it due today at 11:00am please help me will mark the brainiest please
Determine the density of CO2 gas at STP
Answer:
the density of CO2 gas at STP is 1.96 g/l.
What are five minerals found on space rocks
Answer:
oxygen, silicon, iron, calcium, sodium
Explanation:
these are all found in space rocks known as meteorites. hope this helps :)