Answer:
Number of moles of photons required = 5.04 × 10⁴ moles
Explanation:
The energy of a photon can be calculated from Planck's equation E = hc/λ
Where h = 6.63 × 10-³⁴ Js and c, the velocity of light = 3.0 × 10⁸ m/s
Energy of one mole of photons = N₀ × hc/λ
wavelength of photon, λ = 520 nm = 5.20 × 10-⁷ m
Energy of one mole of photons = 6.02 × 10²³ × 6.63 × 10−³⁴ × 3 × 10⁸/5.20 × 10-⁷
Energy of one mole of photons = 2.30 × 10⁵ J/mol
Energy required to raise the temperature of a given mass of a substance, E = mcΔT
Where m is mass of substance, c is specific heat capacity, ΔT is temperature difference
Mass ofnwternin the pool = volume × density
Volume of water = Volume of swimming pool
Volume of water = 16 × 34 × 6 ft³ = 3264 ft³
1 ft³ = 28316.8 cm³; 3264 ft³ = 28316.8 × 3264 = 92426035.2 cm³
Density of water = 1 g/cm³
Mass of water = 92426035.2 cm³ × 1 g/cm³ = 92426035.2g
ΔT = 80°C - 50°C = 30°C, c = 4.18 J/g/K
Energy required to raise 92426035.2 g water by 30° C = 92426035.2 × 4.18 × 30
Energy required = 1.16 × 10¹⁰ J
Hence, number of moles of photons required = 1.16 × 10¹⁰ J/2.30 × 10⁵ J/mol
Number of moles of photons required = 5.04 × 10⁴ moles
100.0 g of water was placed in a simple, constant-pressure calorimeter. The temperature of the water was recorded as 295.0 K. A 20.0 g copper block was heated to 353.0 K and then dropped into the water in the calorimeter. What was the final temperature of the water if the specific heat capacities of copper is 0.385 J/g K
Answer:
[tex]296.05\ \text{K}[/tex]
Explanation:
[tex]m_w[/tex] = Mass of water = 100 g
[tex]c_w[/tex] = Specific heat of water = [tex]4.184\ \text{J/g K}[/tex]
[tex]m_c[/tex] = Mass of copper = 20 g
[tex]c_c[/tex] = Specific heat of copper = [tex]0.385\ \text{J/g K}[/tex]
[tex]\Delta T_w[/tex] = Temperature change in water = [tex](T-295)[/tex]
[tex]\Delta T_c[/tex] = Temperature change in cooper = [tex](353-T)[/tex]
T = Final temperature of the system
The heat balance of the system is given by
[tex]m_wc_w\Delta T_w=m_cc_c\Delta T_c\\\Rightarrow 100\times 4.184\times (T-295)=20\times 0.385\times (353-T)\\\Rightarrow 418400\left(T-295\right)=7700\left(353-T\right)\\\Rightarrow 418400T-123428000=2718100-7700T\\\Rightarrow T=\frac{1261461}{4261}\\\Rightarrow T=296.05\ \text{K}[/tex]
The final temperature of the water is [tex]296.05\ \text{K}[/tex].
The final temperature of the water when placed in a calorimeter is 296.05K
HOW TO CALCULATE FINAL TEMPERATURE:
The final temperature of water placed in a calorimeter can be calculated using the following expression:Q(water) = - Q(copper)(m × c × ∆T) water = - {m × c × ∆T} copperWhere;
Mass of water = 100 gSpecific heat of water = 4.184 J/g KMass of copper = 20 gSpecific heat of copper = 0.385 J/g KTemperature change in water = T - 295KTemperature change in copper = T - 353K100 × 4.184 × (T - 295) = - {20 × 0.385 × (T - 353)}418.4T - 123428 = - (7.7T - 2718.1)418.4T - 123428 = -7.7T + 2718.1418.4T + 7.7T = 123428 + 2718.1426.1T = 126146.1T = 126146.1 ÷ 426.1T = 296.05KTherefore, the final temperature of the water when placed in a calorimeter is 296.05K.Learn more at: https://brainly.com/question/10987564?referrer=searchResults
A 25.0 mL NaOH solution of unknown concentration was titrated with a 0.189 M HCl solution. 19.6 mL HCl was required to reach the equivalence point. In a separate titration, a 10.0 mL H3PO4 solution was titrated with the same NaOH solution. This time, 34.9 mL NaOH was required to reach the equivalence point. What is the concentration of the H3PO4 solution
Answer:
0.172 M
Explanation:
The reaction for the first titration is:
HCl + NaOH → NaCl + H₂OFirst we calculate how many HCl moles reacted, using the given concentration and volume:
19.6 mL * 0.189 M = 3.704 mmol HClAs one HCl mol reacts with one NaOH mol, there are 3.704 NaOH mmoles in 25.0 mL of solution. With that in mind we determine the NaOH solution concentration:
3.704 mmol / 25.0 mL = 0.148 MAs for the second titration:
H₃PO₄ + 3NaOH → Na₃PO₄ + 3H₂OWe determine how many NaOH moles reacted:
34.9 mL * 0.148 M = 5.165 mmol NaOHThen we convert NaOH moles into H₃PO₄ moles, using the stoichiometric coefficients:
5.165 mmol NaOH * [tex]\frac{1mmolH_3PO_4}{3mmolNaOH}[/tex] = 1.722 mmol H₃PO₄Finally we determine the H₃PO₄ solution concentration:
1.722 mmol / 10.0 mL = 0.172 MWhat is the empirical formula for a compound if a 2.50g sample contains 0.900g of calcium and 1.60g
of chlorine? (3pts]
Answer:
CaCl₂
Explanation:
First we convert the given masses of elements into moles, using their respective molar masses:
0.900 g Ca ÷ 40 g/mol = 0.0225 mol Ca1.60 g Cl ÷ 35.45 g/mol = 0.045 mol ClNow we divide those numbers of moles by the lowest value among them:
0.0225 mol Ca / 0.0225 mol = 10.045 mol Cl / 0.0225 mol = 2Meaning the empirical formula for the compound is CaCl₂.
Why is it important to make sure that the endpoint is noted accurately in titration?
Calculate the mass of 0.900 mol of lithium thiocyanate.
Answer:
58.6 g.
Explanation:
Hello there!
In this case, since the molecular formula of lithium thiocyanate is LiCNS and therefore its molar mass is 65.1 g/mol, it possible to perform the calculation of the mass of 0.900 moles of this substance by recalling the following equivalence statement:
1 mol = 65.1 g.
Thereby, we can calculate the required mass as shown below:
[tex]0.900mol*\frac{ 65.1g}{1mol}\\\\58.6 g[/tex]
Best regards!
what happens to gas molecules as the pressure is increased while the temperature and volume of the container remain constant according to the kinetic molecular theory
Answer:
According to the kinetic molecular theory of gases, the average speed and kinetic energy of gas molecules would INCREASE.
Explanation:
In the kinetic molecular theory of gases, assumptions were made based on macroscopic properties of gas (pressure, volume and temperature) which are as a result of the microscopic properties like the position and the speed of the gas molecules. The kinetic molecular theory explains the behaviour of gases through the following 5 assumptions made about an ideal gas;
--> Molecules of a gas are in constant and rapid motion in straight lines until they collide with one another and with the walls of their containers.
--> The actual volume occupied by the had is negligible compared with the volume of the container.
--> Forces of attraction or repulsion between the molecules of a gas are negligible
--> The collision between the molecules is perfectly elastic.
--> The average kinetic energy of the gas molecules is proportional to the temperature of the gas.
Because gas molecules are in constant motion, it has kinetic energy which can be altered when there is increase in pressure. An increase in pressure will cause gas molecules to collide more frequently with one another. This in turn leads to increase in average speed and the kinetic energy of the individual molecules.
The more energy that particles have, the ___ they move.
The more energy that particles have, the more they move.
Given that the nucleophilic substitution reaction used 5.0 mL of t-pentyl alcohol and 12.0 mL of conc. hydrochloric acid to produce t-pentyl chloride, what is the theoretical yield of t-pentyl chloride, in grams
Answer:
4.90 g
Explanation:
Given that:
volume of t-pentyl alcohol = 5 mL
the standard density of t-pentyl alcohol = 0.805 g/mL
Recall that:
density = mass(in wt) /volume
mass = density × volume
mass = 0.805 g/mL × 5 mL
mass = 4.03 g
Volume of HCl used = 12 mL
The reaction for this equation is shown in the image attached below.
From the reaction,
88.15 g of t-pentyl alcohol reacts with concentrated HCl to yield 106.59 g pf t-pentyl chloride.
4.03 g of t-pentyl alcohol forms,
[tex]= \dfrac{106.59 \ g \times 4.03 \ g}{88.15 \ g}[/tex] of t-pentyl chloride.
Therefore,
Theoretical yield of t-pentyl chloride = 4.90 g
Carbon-11 decays by position emission.The nuclide formed product is
Answer:
They demonstrated that carbon-11 decays by positron emission to the stable nuclide 11B [Eq. (1)].
WHAT IS A ROCK?
Please put the answer below
DO ITTT NOWWWWWWWWWWWWWW
|
\/
Cuo
+ H2 → → Cu + + H20
colorless
water
black
powder
reddish
solid
gas
vapor
Explanation:
because there is 2 hydrogen atoms in the reactions side of the equation (you can tell because the H has a 2 in the subscript) you have to have 2 hydrogen atoms in the reactants side to help balance out the equation. and since the copper and oxygen atoms are already balanced there is no coefficient needed.
Help me please jus tell me 1 2 3 etc for the answers thank you!
Answer:
1. lakes and rivers 2. groundwater 3. watershed 4. pollution
Explanation:
But Are Punnett square percentages always correct?
Answer:
yes
Explanation:
cuz is a square and if all angles are equal of a square then it is correct
Answer the above pic
i bet no one can solve this correctly with steps
Answer:
solution given:
log k=4-[tex] \frac{200}{t} [/tex]
so,
On comparison
∆S°/R = 4
∆ S° = 4R
mousam brother is correct
hope it helps you have a good day
Final volume of a .50 M H3PO4 solution prepared from 50 mL of a 6 M H3PO4 solution
Answer:
600 mL
Explanation:
From the question given above, the following data were obtained:
Initial concentration (C₁) = 6 M
Initial volume (V₁) = 50 mL
Final concentration (C₂) = 0.5 M
Final volume (V₂) =?
Using the dilution formula (i.e C₁V₁ = C₂V₂) we can obtain the final volume as illustrated below:
C₁V₁ = C₂V₂
6 × 50 = 0.5 × V₂
300 = 0.5 × V₂
Divide both side by 0.5
V₂ = 300 / 0.5
V₂ = 600 mL
Thus, the final volume is 600 mL
A 3mL sample of a 200 Molar solution is left open on a lab
counter for two weeks, after which the concentration of the solution is 6 M. What is the new volume of the solution?
Answer: New volume of the solution is 100 mL.
Explanation:
Given: [tex]V_{1}[/tex] = 3 mL, [tex]M_{1}[/tex] = 200 M
[tex]M_{2}[/tex] = 6 M, [tex]V_2[/tex] = ?
Formula used to calculate the new volume of solution is as follows.
[tex]M_{1}V_{1} = M_{2}V_{2}[/tex]
Substitute the values into above formula as follows.
[tex]M_{1}V_{1} = M_{2}V_{2}\\200 M \times 3 mL = 6 M \times V_{2}\\V_{2} = \frac{200 M \times 3 mL}{6 M}\\= 100 mL[/tex]
Thus, we can conclude that new volume of the solution is 100 mL.
Terry, a student, performs a titration. He completes these steps as part of his titration procedure: 1. He cleans and rinses a burette with standardized base. 2. He fills the burette with standardized base solution. 3. He reads and records the initial burette volume. 4. He adds a base from the burette to an acid. 5. He observes a color change in the Erlenmeyer flask. 6. He stops the addition of base from the burette. 7. He reads and records the final burette volume. Which steps will provide information needed to calculate the volume of base needed to reach the equivalence point? A. 1 and 6 B. 3 and 7 C. 3, 4, and 6 D. 1, 2, and 7
Answer:
D
Explanation:
D is the answer because 2 is needed to know
Answer:
B) 3 and 7
Explanation:
i just took the test
A sample of polonium-210 has an initial mass of 390 milligrams (mg). If the half-life of polonium-210 is 36 days, how many mg of the sample remains after 72 days?
A.
392 mg
B.
195 mg
C.
97.5 mg
D.
48.75 mg
Answer:
C
Explanation:
I got this question right on my test.
describe two sources of energy and explain how they work
please help me (50points)
Solar energy:-
In this way the energy generated through sun light with the help of solar panels and to be used in many works.
Wind energy:-
This is generated by moving turbines with windmills .It is used to create electric energy
Based on the molar masses. how can you tell that an equation is balanced
I need to know what the question is asking please help
Answer: What events create the heaviest elements?
I would Select:
Neutron Star Collissions
Supernova
how real gases differ from ideal gases?
An ideal gas is one that follows the gas laws at all conditions of temperature and pressure. To do so, the gas would need to completely abide by the kinetic-molecular theory. On the other hand, a real gas is a gas that does not behave according to the assumptions of the kinetic-molecular theory.
Furthermore, the particles of an ideal gas are extremely small and have a mass equivalent to practically zero. Ideal gas particles also have no volume.
An example of a real gas is helium, oxygen, and nitrogen.
A chemistry student heated 2.255 g of oxygen gas in the presence of 5.145
Answer:
a
Explanation:
Which statement describes the best way to determine how different levels of light affect the growth of seedling plants?
Choose three different light levels, and place four identical plants under each light level to observe the light’s effect on multiple plants.
Choose five different light levels, and place one identical plant under each of the light levels for exactly one week.
Choose four different light levels, and place eight different plant types under the light levels, two under each one, and observe them every day.
Choose one type of light and one type of plant, and then observe the plant for at least four weeks, measuring it each day.
Answer:
Choose three different light levels, and place four identical plants under each light level to observe the light’s effect on multiple plants.
Explanation:
What dosage in grams per kilogram of body weight does a 134 lb woman receive if she takes two 275 mg tablets of penicillin?
How many 150. mg tablets should a 31 lb child take to receive the same dosage?
Answer:
The dosage is 0.0906 g/kgThe child should take 8.5 tablets to receive the same dosageExplanation:
First we convert 134 lb into kg:
1 lb = 0.453 kg134 lb * [tex]\frac{0.453kg}{1lb}[/tex] = 60.702 kgThen we convert 275 mg into g:
1000 mg = 1 g275 mg * [tex]\frac{1g}{1000mg}[/tex] = 0.275 gNow we can calculate the dosage in grams per kilogram of body weight, keeping in mind that two tablets are consumed:
(0.275 g) * 2 / 60.702 kg = 0.0906 g/kgAs for the second part, first we convert 31 lb into kg:
31 lb * [tex]\frac{0.453 kg}{1lb}[/tex] = 14.043 kgNow we calculate how many penicillin grams should be consumed:
14.043 kg * 0.0906 g/kg = 1.27 gWe convert 1.27 g of penicilin into mg:
1.27 g * 1000 = 1270 mgFinally we calculate how many 150 mg tables should be taken:
1270 mg / 150 mg = 8.5 tabletsIf 1.00 g of KCl is completely dissolved in 24.5 g of water, what is the percent composition (by mass) of the solution that is formed?
Answer:
3.92%
Explanation:
The solution that is formed is of KCl in water. This means that the percent composition by mass is given by the formula:
Mass of KCl / Mass of Solution * 100%We now calculate the mass of solution:
Mass of Solution = Mass of KCl + Mass of Water = 1.00 g + 24.5 gMass of Solution = 25.5 gFinally we calculate the percent composition:
1.00 g / 25.5 g * 100% = 3.92%Mechanical digestion begins in the_____ and involves physical processes, such as chewing.
Answer:
begins in the mouth
The pressure on 200 milliliters of a gas at constant
temperature is changed from 380 torr to 760 torr. The new
volume of the gas is
answerA) 100 mL
Explanation:
At constant temperature and number of moles, Using Boyle's law
Given ,
V₁ = 200 mL
V₂ = ?
P₁ = 60 kPa
P₂ = 120 kPa
The new volume of the gas is 100mL
Boyle's law is use to calculate the volume of a gas in relation with its pressure. The Boyle's law equation is as follows:
P1V1 = P2V2
Where;
P1 = initial pressure of the gas (torr)
P2 = final pressure of the gas (torr)
V1 = initial volume of the gas (mL)
V2 = final volume of the gas (mL)
According to the information of this question, the pressure on 200mL of a gas changed from 380 torr to 760 torr. Hence;
V1 = 200mL
V2 = ?
P1 = 380torr
P2 = 760torr
Using P1V1 = P2V2
V2 = P1V1/P2
V2 = (380 × 200) ÷ 760
V2 = 76000 ÷ 760
V2 = 100mL
Hence, the new volume of the gas is 100mL
Learn more: https://brainly.com/question/22467228
करताह!
गर्मियों में घड़े का जल ठंडा क्यों होता है?
Answer:
I don't understand the question
Explanation:
what is your name
How many liters would you need to make a 0.8 M solution with 20 grams of lithium chloride?
Answer:
0.5875L
Explanation:
concentration = mole/ volume
n(LiCl) = 20 / (7 + 35.5) = 0.47 mol
volume = mole / conc.
volume = 0.47 /0.8
= 0.5875 dm³ = 0.5875L
