Answer:
Heat required = 84.25 Joule
Explanation:
Heat required = mass × specific heat capacity × temperature change
Specific heat capacity of aluminium = 0.90 J/g/K
Heat required = 2.3 × 0.9 × (46.9 -6.2)
= 84.25 Joules
PLEASEEE HELPPP MEEEEE WITH THIS QUESTIONNN!!!!!
I REALLY NEED A GREAT RESPONSE AND ILL MARK YOU BRAINLIEST FOR YOUR EFFORT!!!!!!!
QUESTION: THINK CRITICALLY: Some conifers have female cones on the top half of the tree and male cones on the bottom half. Why would this arrangement of cones on a tree be important?
Answer:
The male cones appear on the trees in the spring time. The male cones are smaller than the female cones that we typically think of when we think of pine cones. These cones are softer and are only on the trees in the spring. After they release their pollen they die away and disappear.
Explanation:
How could weathering by release of pressure affect the amount of weathering by freezing and thawing?
The amount of weathering by the freezing and thawing process of water is the most effective weathering.
What is weathering?Weathering is a process in which breaking or dissolving of rocks and minerals present on the earth surface.
Freezing and thawing weathering is a kind of physical weathering in which water goes down to the pores of rock and gets freeze and expands and causes breaking of rocks.Release of pressure also result in the weathering of the underlying rocks.Weathering by the freezing effect of water causes more effect on the breaking as compare to the pressure release weathering.
Hence Freezing & thawing weathering is most powerful weathering.
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Which of the following atoms is the smallest?
Be
Ne
O
Li
B
Answer:
Li
Explanation:
The element, Neon (Ne), is the smallest among the given elements
From the question,
We are to determine which of the given elements is the smallest.
The given elements are
Be - Beryllium
Ne - Neon
O - Oxygen
Li - Lithium
B - Boron
From the periodic table, we can observe that all of the given elements belong to period 2.
Using the trend of atomic size on the periodic table,
We know that, atomic size decreases across the period.
This means, the atomic sizes of the elements will decrease in the order
Li > Be > B > O > Ne
Hence, the element, Neon (Ne), is the smallest among the given elements
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A gas occupies 10.00L at 100k and exerts a pressure of 1.71atm. What volume, in liters, will the gas occupy if the temp is increased to 290.29K and the pressure is increased to 9.70atm?
Answer:
5.12 L
Explanation:
P1V1/T1 = P2V2/T2
1.71 atm *10.0L /100 K = 9.70 atm *x/290.29 K
x = 1.71 atm *10.0L*290.29K /(100 K * 9.70 atm)= 5.12 L
if 84.9 grams of solid iron reacts with oxygen gas, how many molecules of oxygen will react
Answer:
Molecules of oxygen [tex]= 6.86 * 10^{23}[/tex]
Explanation:
The balanced equation of reaction between iron and oxygen is
4 Fe + 3 O2 → 2 Fe2O3
4 moles of iron react with 3 moles of oxygen.
Mass of one mole of iron is 55.845
number of iron moles in 84.9 grams of solid iron is equal to
[tex]\frac{84.9}{55.845} \\= 1.52[/tex]
Now 1 mole of iron will react with [tex]\frac{3}{4} = 0.75[/tex] mole of oxygen
Thus 1.52 moles of iron will react with [tex]0.75 * 1.52 = 1.14[/tex] moles of oxygen
Number of atoms of oxygen in 1.14 moles
[tex]1.14* 6.02 * 10^{23}\\[/tex]
[tex]= 6.86 * 10^{23}[/tex]
HURRRYYYY
Based on the chemical equation, use the drop-down menu to choose the coefficients that will balance the chemical equation:
()CaSO4 → ()O2 + ()CAS
Answer:
1, 2, 1
Explanation:
Please see the step-by-step solution in the picture attached below.
Hope this answer can help you. Have a nice day!
Answer:
1,2,1
Explanation:
just did the assigment
A _____ is a fracture or break in Earth's surface.
A FAULT is a fracture or break in Earth's surface
In the Bohr model of the hydrogen atom, the electron occupies distinct energy states. One transition between energy states of the hydrogen atom is represented by the picture on the left.
1. In this transition an electron moves from the n = level to the n = level.
2. Energy is_______ in this process.
A. Absorbed
B. Emitted
3. The electron moves ___________ the nucleus.
A. Closer to
B. Further from
Answer:
1. ELECTRON MOVES FROM THE n = 4 to n = 1 LEVEL
2. ENERGY IS EMITTED
3. THE ELECTRON MOVES CLOSER TO THE NUCLEUS
Explanation:
the question is incomplete as the picture is not shown but here is the picture and the solution.
Bohr model of the hydrogen atom shows that electrons would not emit energy but emit or absorb protons as it moves to a lower or higher energy levels respectively. In this question as shown in the picture below, the hydrogen atom moves from energy level 4 to energy level 1 and in such transition, energy is emitted and returns to its ground state after been excited to a higher level o n equals to 4. The energy emitted follows the law of conservation of energy. That is the amount of energy needed to excite the atom to a higher level is emitted upon transition back to the ground state.
The size of the hydrogen atom will also reduce and the electron will move closer to the nucleus. This is because as energy increases, the electron is found at a greater distance away from the nucleus and vice versa. And as the electron moves farther away the electrostatic force between it and the nucleus reduces and it is loosely held by the nucleus and vice versa, As the case of the question, the electron moves closer to the nucleus and it is strongly attached to the nucleus due to increase electrostatic attraction between it and the nucleus.
Answer:
In this transition, energy is emitted
The electron moves closer to the nucleus
Explanation:
In the Bohr's model of the atom, electrons occupy specific energy levels shown by the principal quantum number. An electron that is stationary in its orbit does not radiate energy.
However, an electron may absorb energy and be excited to higher energy levels or emit energy when descending from a higher to a lower energy level. This energy is usually observed as a photon of light of appropriate wavelength and frequency.
In the image, the electron descends from energy level n=4 to energy level n=1. Since it has moved from a higher to a lower energy level, energy is emitted. Recall that energy levels increase outwards from the nucleus. Since n=1 is closest to the nucleus, the electron has moved closer to the nucleus. Hence the answers above.
Would you expect carboxylic acids with general formula CH3(CH2)nCOOH to become more or less water soluble as n increases? Explain.
Answer:
less soluble
Explanation:
As n increases, the non polar hydrocarbon tail increases in length, while there is only one polar carboxylic group at the end. Since only the carboxylic group can form hydrogen bond with water, and the non polar hydrocarbon tail cannot, the long tail will hinder the formation of hydrogen bond between acid and water molecules, hence solubility decreases.
The carboxylic acids with general formula CH3(CH2)nCOOH to become less water soluble as n increases.
What is carboxylic acid ?An organic acid that has a carboxyl group joined to an R-group is said to be carboxylic. A carboxylic acid's general formula is RCOOH or RCO2H, where R stands for an alkyl, alkenyl, aryl, or other group. Carboxylic acids are frequently present.
The carboxylic acids do not produce dimers when introduced to water. Instead, individual acid and water molecules create hydrogen bonds with one another. These interactions allow carboxylic acids to disintegrate in water to create acidic solutions.
Similar to how alcohols, aldehydes, and ketones are soluble in water, carboxylic acids are as well. Acids with fewer than five carbons dissolve in water; those with a higher molecular weight are insoluble because they include a greater proportion of hydrocarbons.
Thus, The carboxylic acids with general formula CH3(CH2)nCOOH to become less water soluble as n increases.
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Among nonmetals,which nonmetal is most likely to form a covalent bond?
Answer:
most common non metal is chlorine
Mr. Auric Goldfinger, criminal mastermind, intends to smuggle several tons of gold across international borders by disguising it as lumps of iron ore. He commands his engineer minions to form the gold into little spheres with a diameter of exactly and paint them black. However, his chief engineer points out that customs officials will surely notice the unusual weight of the "iron ore" if the balls are made of solid gold (density ). He suggests forming the gold into hollow balls instead, so that the fake "iron ore" has the same density as real iron ore. Calculate the required thickness of the walls of each hollow lump of "iron ore."
The given question is not complete, the complete question is:
Solving applied density problems Mr. Auric Goldfinger, criminal mastermind, intends to smuggle several tons of gold across International borders by disguising it as lumps of iron ore. He commands his engineer minions to form the gold into little spheres with a diameter of exactly 6 cm and paint them black However, his chief engineer points out that customs officials will surely notice the unusual weight of the "iron ore" if the balls are made of solid gold (density 19.3 g/cm'). He suggests forming the gold into hollow balls Instead (see sketch at right), so that the fake "Iron ore" has the same density as real iron ore (5.15 g/cm'). One of the balls of fake iron ore," sliced in half Calculate the required thickness of the walls of each hollow lump of iron ore. Be sure your answer has a unit symbol, if necessary, and round it to 2 significant digits.
Answer:
The correct answer is 0.29 cm.
Explanation:
To produce fake iron balls that is, formed of gold there is a need to make sure that the mass of the iron ball should be equivalent to the mass of the fake ball.
To calculate the volume of iron ball with the help of the given diameter, the formula to be used is 4/3πr³. The diameter of the spheres mentioned in the given question is 6 cm, so the radius will be 6/2= 3 cm.
Now, the volume of the iron ball would be = 4/3 × 3.14 × 3³ = 113.04 cm³
To determine the mass of the iron ball, the formula to be used is volume * density. Now putting the values we get,
113.04 × 5.15 g/cm³ = 582.156 grams (The density of the iron ore is 5.15 g/cm³)
Now, the mass of the gold ball should also be equal to 582.156 g. The density of the solid gold is 19.3 g/cm³, therefore, the volume of the gold ball by using the above formula would be,
mass of gold ball = Volume × density
Volume = mass of gold ball / density
Volume = 582.156 g / 19.3 g/cm³
= 30.1635 cm³
Thus, the volume of the hollow sphere would be 30.1635 cm³ with the outer radius as 3 cm, now there is a need to find the inner radius.
Volume of hollow ball = 4/3π [R³ -r³]
30.1635 cm^3 = 4/3 pie [3³ = r³]
30.1635 × 3/4 × 3.14 = 27-r³
7.2046 = 27-r³
r³ = 19.7954
r = 2.7051 cm
Hence, the thickness would be outer radius - inner radius = 3-2.7051 = 0.2949 cm or 0.29 cm.
The number of atoms in exactly 12 grams of carbon-12 is called
The number of atoms which are present exactly in 12 grams of carbon-12 is called Avogadro's number.
What is Avogadro's number?Avogadro's number is the number of atoms which are present in 1 mole of any substance and it is equal to 6.022×10²³.
And moles will be calculated as:
n = W/M, whereW = given massM = molar massMoles of Carbon-12 = 12g / 12g/mol = 1mole
In 1 mole of Carbon-12 = 6.022×10²³ atoms are present.
Hence, the number of atoms in exactly 12 grams of carbon-12 is called Avogadro's number.
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Based on Table I, which compound dissolves in water by an exothermic process? *
NH4NO3
NH4Cl
NaOH
NaCl
The compound whose dissolution is exothermic in the list is NaOH.
What is an exothermic reaction?An exothermic reaction is one in which heat is gven out in the process. In an exothermic reaction, the reaction vessel feels hot after the reaction is complete.
The table is not shown here. However, we know that the dissolution of NaOH in water is an exothermic process hence the answer is option C.
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What is the energy per mole of photons, in kJ/mol, emitted by an argon ion laser which produces a green beam with a frequency of 5.83x1014 Hz?
Answer:
Energy per mole of photons = 2.31 × 10^2 KJ/mol
Explanation:
Energy, E = hf;
Where h is Planck's constant = 6.63 ×10^-34, and f is frequency of the photons.
E = 6.63 × 10^-34 × 5.8 × 10^14
E = 3.84 × 10^-22 KiloJoules
I mole of photons contains Avogadro's number of particles, 6.02 × 10^23
Therefore, the energy per mile of photon is 3.84 × 10^-22 KJ × 6.02 × 10^23
Energy per mile of photon = 2.31 × 10^2 KJ/mol
In the
Preparation of ethene from ethanol and
tetraoxosulphate (vi) acid, state
the concentration of the acid.
Answer:
The acid must be a concentrated acid
Explanation:
Ethene is prepared in the laboratory by heating ethanol with excess concentrated tetraoxosulphate VI acid at 170°C . The reactionoccursc in two stages;
1) when the ethanol and sulphuric acid are mixed in a ratio of 1:2, ethyl hydrogentetraoxosulpate VI is formed
2) The compound formed in the first step is heated in the presence of excess concentrated sulphuric acid to give ethene and sulphuric acid.
The overall reaction can be perceived as the dehydration of ethanol. The gas produced (ethene) is usually passed through sodium hydroxide solution to remove any gaseous impurities present.
concentrated sulphuric acid is used in this process since it is a good dehydrating agent.
What is the molarity of a solution containing 0.05 moles of solute in 0.25L of solution?
Answer:
0.2 M
Explanation:
The molarity is the number of moles per liter:
(0.05 moles)/(0.25 liter) = 0.2 moles/liter = 0.2 M
Which statement best describes displacement? Check all that apply
Answer:
i need help with this and the answer above is wrong
Explanation:
pls
The British gold sovereign coin is an alloy of gold and copper having a total mass of 7.988 g, and is 22-karat gold.
(a) Find the mass of gold in the sovereign in kilograms using the fact that the number of karats = 24× (mass of gold)/ total mass.
(b) Calculate the volumes of gold and copper, respectively, used to manufacture the coin.
(c) Calculate the density of the British sovereign coin.
Answer:
(a) [tex]m_{gold}=7.322g[/tex]
(b)
[tex]V_{gold}=0.379cm^3[/tex]
[tex]V_{copper}=0.122cm^3[/tex]
(c) [tex]\rho _{coin}=15.94g/cm^3[/tex]
Explanation:
Hello,
(a) In this case, with the given formula we easily compute the mass of gold contained in the sovereign as shown below:
[tex]m_{gold}=\frac{m_{tota}*karats}{24}=\frac{7.988g*22}{24}=7.322g[/tex]
(b) Now, by knowing the density of gold and copper, 19.32 and 8.94 g/cm³ respectively, we compute each volume, by also knowing that the rest of the coin contains copper:
[tex]V_{gold}=\frac{m_{gold}}{\rho_{gold}} =\frac{7.322g}{19.32g/cm^3}=0.379cm^3[/tex]
[tex]m_{copper}=7.988g-7.322g=1.09g\\V_{copper}=\frac{m_{copper}}{\rho_{copper}}=\frac{1.09g}{8.94g/cm^3} \\\\V_{copper}=0.122cm^3[/tex]
(c) Finally, the volume is computed by dividing the total mass over the total volume containing both gold and copper:
[tex]\rho _{coin}=\frac{m_{total}}{V_{gold}+V_{copper}}=\frac{7.988 g}{0.379cm^3+0.122cm^3}\\ \\\rho _{coin}=15.94g/cm^3[/tex]
Best regards.
Answer:
a
The mass of gold is [tex]L = 7.322 *10^{-3} \ kg[/tex]
b
The volumes of gold and copper is [tex]V_g = 3.794 *10^{-7} \ m^3[/tex] , [tex]V_c = 7.426 *10^{-8} \ m^3[/tex]
c
The density of the British sovereign coin
[tex]\rho = 17.593*10^{3} \ kg/m^3[/tex]
Explanation:
From the question we are told that
The total mass of the gold is [tex]K = 7.988 \ g = 7.988 * 10^{-3} \ kg[/tex]
The karat of the British gold sovereign is [tex]z = 22[/tex]
Let the mass of gold in the alloy be L
Now we are told that
[tex]z = 24 * \frac{L}{K}[/tex]
substituting value
[tex]22 = 24 * \frac{L}{7.988 * 10^{-3}}[/tex]
So [tex]L = \frac{22}{24} * 7.899*10^{-3}[/tex]
[tex]L = 7.322 *10^{-3} \ kg[/tex]
The volume of the gold coin is mathematically represented as
[tex]V_g = \frac{L}{\rho_g }[/tex]
Where [tex]\rho_g[/tex] is the density of the gold which a constant with value
[tex]\rho_g = 19.3 *10^{3} \ kg /m^3[/tex]
So
[tex]V_g = \frac{7.322 *10^{-3}}{19.3 *10^{3} }[/tex]
[tex]V_g = 3.794 *10^{-7} \ m^3[/tex]
The mass of copper is mathematically evaluated as
[tex]m_c = K - L[/tex]
[tex]m_c = 7.988*10^{-3} - 7.322 *10^{-3}[/tex]
[tex]m_c = 6.657 *10^{-4} \ kg[/tex]
Volume of the copper is
[tex]V_c = \frac{m_c}{\rho_c}[/tex]
Where [tex]\rho_c[/tex] is the density of the copper which a constant with value
[tex]\rho_c = 8.92 * 10^{3} \ kg/m^3[/tex]
So
[tex]V_c = \frac{6.657 *10^{-4}}{8.92 *10^{3}}[/tex]
[tex]V_c = 7.426 *10^{-8} \ m^3[/tex]
The total volume of the British gold sovereign coin is \
[tex]V = V_g + V_c[/tex]
substituting values
[tex]V = 3.7939 *10^{-7} + 7.4626 *10^{-7}[/tex]
[tex]V = 4.54 *10^{-7} \ m^3[/tex]
The density of the British gold sovereign coin is
[tex]\rho = \frac{K}{V}[/tex]
substituting values
[tex]\rho = \frac{7.988 *10^{-3}}{4.54 *10^{-7}}[/tex]
[tex]\rho = 17.593*10^{3} \ kg/m^3[/tex]
Whats is the difference between a strong electrolyte and a weak electrolyte
Answer:
Well, for one thing,I played football for 7 years. Gatorade wouldn't be Gatorade without electrolytes. The electrolytes in that bottle of Gatorade give you energy. Those electrolytes Are what propel you through whatever you are doing at that time. Those are what give you energy.
Explanation:
1. Write the balanced chemical equation for the synthesis of magnesium phosphide from its elements, including the word “energy” as a product.
- Write the Keq expression for the reaction.
Answer:
3Mg(s) +2P(s) -------> Mg3P2(s) + energy
Keq= [Mg3P2]/[Mg]^3 [P]^2
Explanation:
The equation for the formation of magnesium phosphide from its elements is;
3Mg(s) +2P(s) -------> Mg3P2(s) + energy
Hence we can see that three moles of magnesium atoms combines with two moles of phosphorus atoms to yield one mole of magnesium phosphide. The equation written above is the balanced chemical reaction equation for the formation of the magnesium phosphide.
The equilibrium expression for the reaction K(eq) will be given by;
Keq= [Mg3P2]/[Mg]^3 [P]^2
where does the chemical reaction take during photosynthesis
Answer:
in all green plants and most algae
Question 1 When of alanine are dissolved in of a certain mystery liquid , the freezing point of the solution is lower than the freezing point of pure . On the other hand, when of iron(III) chloride are dissolved in the same mass of , the freezing point of the solution is lower than the freezing point of pure . Calculate the van't Hoff factor for iron(III) chloride in . Be sure your answer has a unit symbol, if necessary, and round your answer to significant digits.
Answer:
See explaination
Explanation:
please kindly see attachment for the step by step solution of the given problem
Someone pls help me, I need the answer ASAP!!
Pure A (liq) has vapour pressure at 421 K is 80.1 kPa, and pure B (liq) is 61.2 kPa. The two substance form ideal liquid and gaseous mixtures. If the equilibrium composition of a mixture is established, in which the mole fraction of A in the vapour is 0.410, Calculate:
(a) The total pressure of the vapour.
(b) The composition of the liquid mixture.
Answer:
a) Total vapor pressure = 68.948 Kpa
b) Mole fraction of A = 41%, mole fraction of B = 59%
Explanation:
Find the given attachments.
A 1 liter solution contains 0.247 M nitrous acid and 0.329 M sodium nitrite. Addition of 0.271 moles of calcium hydroxide will: (Assume that the volume does not change upon the addition of calcium hydroxide.)
a. Raise the pH slightly
b. Lower the pH slightly
c. Raise the pH by several units
d. Lower the pH by several units
e. Not change the pH
f. Exceed the buffer capacity
Answer:
a. Raise the pH slightly
Explanation:
We know that
Pka of HNO2/KNO2 =3.39
Moles of HNO2 in the buffer=0.247 mol/L×1L=0.247 moles
Moles of NO2-=0.329mol/L×1L=0.329 moles
If 0.271 moles of Ca(OH)2 is added it will neutralise 0.136 moles of acid ,HNO2,remaining HNO2=0.247-0.136=0.111 moles
Moles of NO2- will increase as 0.0333 moles Ca(NO)2 will be formed =0.0333+0.036=0.0693 moles
pH=pka+log [base]/[acid] {henderson -hasselbach equation}
=3.39+log (0.0693/0.0317)=3.39+0.34=3.73
pH=3.73
Gino made a table to describe parts of the electromagnetic spectrum. A 3-column table with 4 rows. The first column labeled wave has entries ultraviolet, radio waves, infrared, x-rays. The second column labeled frequency has entries high, very low, low, high. The third column labeled Wavelength has entries long, very long, long, short. What mistake did Gino make? X-rays should have a low frequency and a long wavelength. Infrared light should have a high frequency, not a low frequency. Radio waves should have a very high frequency and a very short wavelength. Ultraviolet light should have a short wavelength, not a long wavelength.
Answer:
D. Ultraviolet light should have a short wavelength, not a long wavelength.
Explanation:
just took the quiz on Ed
The mistake Gino made is, ultraviolet light should have a short wavelength, not a long wavelength.
What is electromagnetic spectrum?Electromagnetic spectrum is the arrangement of electromagnetic radiations in the order of increasing frequency or decreasing wavelength.
Examples electromagnetic radiations based on increasing wavelength include;
Gamma rays X raysUltravoilet raysVisible lightInfrared lightMicrowavesRadio wavesThus, the mistake Gino made is, ultraviolet light should have a short wavelength, not a long wavelength.
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A barrel of water weighs 60 pounds. What must you put in it for it to weigh 40 pounds?
Answer:
A hole
Explanation:
put a hole in the barrel and let some water out
The thing you would add to the barrel would be holes which would cause water to fall out of the barrel.
What is a pound?Pound is defined as the basic unit for weight in the Foot Pound Second (F.P.S) system and is equal to 16 ounces.
An example of a pound is a man weighing 186 pounds.
The thing you would add to the barrel would be holes which would cause water to fall out of the barrel.
The amount of holes you would add and where you would add them would depend all on how much the barrel weighs without the water.
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Use the drop-down menus to seled the correct responses to each question about ocean zones
In which zone do you find marshes and mangrove forests?
In vich zone are plan con plentiful, providing plenty of food for the fish that live there?
in which zone would you find very little plant or animal de compared to other zones?
Answer:
Intertidal zone
Neritic zone
Open-ocean zone
Note: the correct questions are found below;
In which zone do you find marshes and mangrove forests?
In which zone are plankton plentiful, providing plenty of food for the fish that live there?
In which zone would you find very little plant or animal life compared to other zones?
Explanation:
The intertidal zone, sometimes called the littoral zone, is the area of the marine shoreline that is exposed to air at low tide, and covered with seawater when the tide is high. Intertidal zonation refers to the tendency of plants and animals to form distinct communities between the high and low tide lines. Some microclimates in the littoral zone are moderated by local features and larger plants such as mangroves.
The neritic zone is the region of shallow water (200 meters depth) above the continental shelf where light penetrates to the sea floor.
Due to the abundant supply of sunlight and nutrients such as plankton in this zone, it is the most productive ocean zone supporting the vast majority of marine life.
The open oceans or pelagic ecosystems are the areas away from the coastal boundaries and above the seabed. It encompasses the entire water column and lies beyond the edge of the continental shelf. It extends from the tropics to the polar regions and from the sea surface to the abyssal depths.
Answer:
Intertidal zone
Neritic zone
Open-ocean zone
Explanation:
1. A 99.8 mL sample of a solution that is 12.0% KI by mass (d: 1.093 g/mL) is added to 96.7 mL of another solution that is 14.0% Pb(NO3)2 by mass (d: 1.134 g/mL). How many grams of PbI2 should form?
Pb(NO3)2(aq) + 2 KI(aq) PbI2(s) + 2 KNO3(aq)
Answer:
The mass of PbI2 will be 18.2 grams
Explanation:
Step 1: Data given
Volume solution = 99.8 mL = 0.0998 L
mass % KI = 12.0 %
Density = 1.093 g/mL
Volume of the other solution = 96.7 mL = 0.967 L
mass % of Pb(NO3)2 = 14.0 %
Density = 1.134 g/mL
Step 2: The balanced equation
Pb(NO3)2(aq) + 2 KI(aq) ⇆ PbI2(s) + 2 KNO3(aq)
Step 3: Calculate mass
Mass = density * volume
Mass KI solution = 1.093 g/mL * 99.8 mL
Mass KI solution = 109.08 grams
Mass KI solution = 109.08 grams *0.12 = 13.09 grams
Mass of Pb(NO3)2 solution = 1.134 g/mL * 96.7 mL
Mass of Pb(NO3)2 solution = 109.66 grams
Mass of Pb(NO3)2 solution = 109.66 grams * 0.14 = 15.35 grams
Step 4: Calculate moles
Moles = mass / molar mass
Moles KI = 13.09 grams / 166.0 g/mol
Moles KI = 0.0789 moles
Moles Pb(NO3)2 = 15.35 grams / 331.2 g/mol
Moles Pb(NO3)2 = 0.0463 moles
Step 5: Calculate the limiting reactant
For 1 mol Pb(NO3)2 we need 2 moles KI to produce 1 mol PbI2 and 2 moles KNO3
Ki is the limiting reactant. It will completely be consumed ( 0.0789 moles). Pb(NO3)2 is in excess. There will react 0.0789/2 = 0.03945 moles. There will remain 0.0463 - 0.03945 = 0.00685 moles
Step 6: Calculate moles PbI2
For 1 mol Pb(NO3)2 we need 2 moles KI to produce 1 mol PbI2 and 2 moles KNO3
For 0.0789 moles KI we'll have 0.0789/2 = 0.03945 moles PbI2
Step 7: Calculate mass of PbI2
Mass PbI2 = moles PbI2 * molar mass PbI2
Mass PbI2 = 0.03945 moles * 461.01 g/mol
Mass PbI2 = 18.2 grams
CHEM EXPERT NEEDED***
A volume of 150.0 mL of H2O is initially at 24.00 °C. A chilled steel rod at 2.50 °C is placed in the water and the final temperature of the system is 21.20 °C.
Specific heat of water = 4.184 J/(g⋅∘C) and the specific heat of steel = 0.452 J/(g⋅∘C)
Write the equation and calculate the mass of the rod.
Answer:
1. m₁C₁ΔT₁ + m₂C₂ΔT₂ = 0
2. 207 g
Explanation:
This is a problem in calorimetry — the measurement of the quantities of heat that flow from one object to another.
It is based on the Law of Conservation of Energy — Energy can be transformed from one type to another, but it cannot be destroyed or created.
If heat flows out of one object, the same amount of heat must flow into another object.
Since there is no change in total energy,
Heat₁ + heat₂ + heat₃+ … = 0
The symbol for the quantity of heat transferred is q, so we can rewrite the word equation as
q₁ + q₂ + q₃ + … = 0
The formula for the heat absorbed or released by an object is
q = mCΔT, where
m = the mass of the sample
C = the specific heat capacity of the sample, and
ΔT = T_f - T_i = the change in temperature
1. Equation
There are two heat flows in this problem,
Heat from steel rod + heat absorbed by water = 0
q₁ + q₂ = 0
m₁C₁ΔT₁ + m₂C₂ΔT₂ = 0
2. Data:
m₁ = ?; C₁ = 0.452 J°C⁻¹g⁻¹;T_f = 21.20 °C; T_i = 2.50 °C
V₂ = 150.0 mL; C₂ = 4.184 J°C⁻¹g⁻¹; T_f = 21.20 °C; T_i = 24.00 °C
3. Calculations
(a) m₂
The density of water is 0.9982 g/mL, so
m₂ = 150.0 mL × 0.9982 g/mL = 149.7 g
(b) Temperature changes
[tex]\Delta T_{1} = T_{\text{f}} - T_{\text{i}} = 21.20 \, ^{\circ}\text{C} - 2.50 \, ^{\circ}\text{C} = 18.70 \, ^{\circ}\text{C}\\\Delta T_{2} = T_{\text{f}} - T_{\text{i}} = 21.20 \, ^{\circ}\text{C} - 24.00 \, ^{\circ}\text{C} = -2.80 \, ^{\circ}\text{C}[/tex]
(c) q₁
q₁ = m₁C₁ΔT₁ = m₁ × 0.452 J°C⁻¹g⁻¹ × 18.70 °C = 8.452m₁ J·g⁻¹
(d) q₂
q₂ = m₂C₂ΔT₂ = 149.7 g × 4.184 J°C⁻¹g⁻¹ × (-2.80 °C) = -1754 J
(e) m₁
[tex]\begin{array}{rcl}q_{1} + q_{2} & = & 0\\8.452m_{1} \, \text{J}\cdot\text{g}^{-1} + (-\text{1754 J}) & = & 0\\8.452m_{1}\,\text{g}^{-1} - 1764 &=& 0\\m_{1} & = & \dfrac{1764}{8.452 \,\text{g}^{-1}}\\\\ & = & \textbf{207 g}\\\end{array}\\\text{ The mass of the steel rod is $\large \boxed{\textbf{207 g}}$}[/tex]
which statement correctly describes the transfer of energy in the food chain in the land
Answer:
The question lacks options, the options are:
A) Energy is transferred to consumers, which convert it to nitrogen and use it to make amino acid
B) Energy from producers is converted into oxygen and transformed to consumers.
C) Energy from the sun is stored by green plants and transferred to consumers.
D) Energy is transferred to consumers, which use it to produce food.
The answer is C
Explanation:
Organisms obtain energy in an ecosystem by feeding on one another in a chain called FOOD CHAIN. Energy is transferred when one organism feeds on another. A food chain always begins with a PRODUCER, which is an autotrophic organism capable of producing its own food via light energy from the sun.
In a terrestrial ecosystem, the energy a plant captures via Its Chlorophyll is used to produce food during photosynthesis. This energy is stored in the plants and transferred when a set of organisms called PRIMARY CONSUMER feeds on the plant. The transfer continues in that order till decomposers.