Based on the heat absorbed by the calorimeter, the heat of reaction, ΔHrxn is 333.5 kJ/mol
What is the heat evolved by the sample?The heat evolved or given out by the sample is the equal to the amount of heat absorbed by the calorimeter.
The heat absorbed by calorimeter is given as:
Heat = specific heat capacity × temperature differenceHeat = 13.3 × (56.0 - 32.0)
Heat evolved = 319.2 kJ
Moles of sample reacted = 53.8/56.23 = 0.957
ΔHrxn = 319.2 kJ/0.957 moles = 333.5 kJ/mol
Therefore, the heat of reaction, ΔHrxn is 333.5 kJ/mol.
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1. Which type of chemical bonding involves a transfer of electrons?
Answer:
ionic bonding
Explanation:
it's ionic bonding while covalent bonding involves sharing
calculate the mass in grams of the following 0.2moles of iron
35.0 L of an ideal gas at 268 K and 5.16 atm are heated to 343 K with a new pressure of 8.00 atm. What is the new volume (in L)?
The new volume of the ideal gas heated to the given values of temperature and pressure is 28.9 Litres.
What is Combined gas law?Combined gas law put together both Boyle's Law, Charles's Law, and Gay-Lussac's Law. It states that "the ratio of the product of volume and pressure and the absolute temperature of a gas is equal to a constant.
It is expressed as;
P₁V₁/T₁ = P₂V₂/T₂
Given the data in the question;
Initial volume V₁ = 35LInitial pressure P₁ = 5.16atmInitial temperature T₁ = 268KFinal temperature T₂ = 343KFinal pressure P₂ = 8.0atmFinal volume V₂ = ?To calculate the new volume of the gas, we subtsitute our given values into the expression above.
P₁V₁/T₁ = P₂V₂/T₂
P₁V₁T₂ = P₂V₂T₁
V₂ = P₁V₁T₂ / P₂T₁
V₂ = ( 5.16atm × 35L × 343K ) / ( 8.0atm × 268K )
V₂ = 61945.8LatmK / 2144atmK
V₂ = 28.9L
Therefore, the new volume of the ideal gas heated to the given values of temperature and pressure is 28.9 Litres.
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9.81 A steel alloy is known to contain 93.65 wt% Fe,
6.0 wt% Mn, and 0.35 wt% C.
(a) What is the approximate eutectoid temperature of this alloy?
(b) What is the proeutectoid phase when this
alloy is cooled to a temperature just below the
eutectoid?
(c) Compute the relative amounts of the proeutectoid phase and pearlite. Assume that there
are no alterations in the positions of other phase
boundaries with the addition of Mn
The approximate eutectoid temperature of this alloy that has 6.0 wt% Mn is 650°C or 1330°F.
How to calculate the temperature?From the information given, the approximate eutectoid temperature of this alloy that has 6.0 wt% Mn is 650°C. This can be converted to Fahrenheit as:
= (650 × 2) + 30
= 1300 + 30
= 1330F
The proeutectoid phase when this alloy is cooled to a temperature just below the eutectoid will be ferrite. It's a ceramic like material with magnetic properties.
The relative amounts of the proeutectoid phase will be:
= (0.62 - 0.20)/062
= 0.68
Similarly, the relative amount of the pearlite will be:
= 0.20/0.62
= 0.32
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How many moles of gas will occupy a volume of 5.50 L at 6.20 kPa and 45.0 °C?
4. A gas mixture contains the following gases with the mole fractions indicated: N2OA (0.221), CHA (0.10), O2
(0.210), and N2 (0.463). The mixture also contains CO. What is the mole fraction of CO in this mixture?
Answer:
Partial pressure is proportional to the number of moles so: partial pressure = total pressure x mole fraction. Let's calculate total pressure first. We know the volume in liters and the temperature. We can also find the number of moles of each gas by conversion.Mar 25, 2019
An earthquake is 1. (predictable, unpredictable). When an earthquake
occurs, the vibrations spread out in 2. (all, one) direction/s from its center.
The vibrations are most strongly felt at the 3. (epicenter, outer) and gradually
diminish as they spread out. Earthquakes happen when the 4. (oceanic,
tectonic) plates rub against each other, which makes the crust of the Earth
shake. The energy from the 5. (oceanic, seismic) waves is so strong that it
makes the crust of the Earth rumble, creating an earthquake.
Volcanoes are formed when 6. (cold, hot) molten rock or 7. (coal,
magma) deep underground oozes up to the surface of the Earth. They are
also formed as one of the plates is pushed under the other as it is heated to
a point where it begins to 8. (freeze, melt). When 9. (high, low) pressure
develops underground, the magma shoots up or erupts through a weak spot
in the Earth's crust. When the magma reaches the surface of the Earth, it is
called 10. (lahar, lava).
Answer:
1. Unpredictable
2. All
3. Epicenter
4. Tectonic
5. Seismic
6. Hot
7. Magma
8. Melt
9. High
10. Lava
Explanation:
An earthquake is unpredictable. When an earthquake occurs, the vibrations spread out in all directions from its center. The vibrations are most strongly felt at the epicenter and gradually diminish as they spread out. Earthquakes happen when the tectonic plates rub against each other, which makes the crust of the Earth shake. The energy from the seismic waves is so strong that it makes the crust of the Earth rumble, creating an earthquake. Volcanoes are formed when hot molten rock or magma deep underground oozes up to the surface of the Earth. They are also formed as one of the plates is pushed under the other as it is heated to a point where it begins to melt When high pressure
develops underground, the magma shoots up or erupts through a weak spot in the Earth's crust. When the magma reaches the surface of the Earth, it is called lava.
Which statement is true in regards to problem 3
The decrease in pressure resulted in an increase in volume
The increase in temperature resulted in an increase in volume
The increase in temperature resulted in a decrease in volume
How many mL of a 2.50 M K2SO4 solution are required to obtain 1.20 moles of
K2SO4?
The answer is: " 480 mL of [2.50 M K₂SO₄] solution."
____________
Explanation:
Given :
1.20 mol K₂SO₄ ⇒ __? mL __ of 2.50 M K₂SO₄ ;
____________
Note: 2.50 M K₂SO₄ = 2.50 mol/ L ;
____________
1.20 mol = [tex]\frac{1 L}{2.50 mol}[/tex] ;
The units of "mols" cancel; since "mol / mol = 1 ;
and we have: " [tex]\frac{(1.20*1) L}{(2.50)} = [{\frac{1.20}{2.50}}] L = (0.480) L ;[/tex]
→ {Note: we want to keep the appropriate number of "significant figures"; so we write our answer: "0.48 L" ; as: "0.480 L" .
→ Now, we want to solve for the number of "mL ("milliliters").
→Note the exact conversion: "1000 mL = 1 L ;
So: ("0.480 L") * (1000) = " 480 mL of solution." → which is our answer.
____________
Hope this helps!
____________
Do you know how much water could you get if you started with 250.0 grams of hydrogen?
from Hydrogen + oxygen when it yields water?
The amount of water that could we get if you started with 250.0 grams of hydrogen is 2,250 grams.
What is moles - mass realation?Moles (n) and mass of any substance are related to each other according to the given equation as:
n = W/M, where
W = given mass
M = molar mass
Given balanced chemical reaction is:
2H₂ + O₂ → 2H₂O
Moles of 250g of H₂ = 250g / 2g/mol = 125mol
From the stoichiometry of the reaction it is clear that,
2 moles of H₂ = produces 2 moles of H₂O
125 moles of H₂ = produces 125 moles of H₂O
Now mass of water will be calculated as:
Mass = (125mol)(18g/mol) = 2,250g
Hence required mass of water is 2,250 grams.
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Explain how chemical and physical changes affect our lives. (3-4 sentences pls!)
Answer:
Explanation:
Chemical and physical changes occur all around us all the time. These changes are essential parts of our daily lives, for example, digesting food, combustion, osmosis, and phase changes. However, a few of the chemical and physical changes that occur daily are harmful for the environment. This project introduces four physical/chemical changes that are related to the following environmental issues: plastic decomposition, global warming, effects of acid rain, and oil spills.
Consider the titration of 40.0 mL of 0.200 M HClO4 with 0.100 M KOH. How much base is required?
Answer:
1.30
Explanation:
The neutralization reaction involved in the titration is:
HClO₄(aq) + KOH(aq) → KClO₄(aq) + H₂O(l)
According to the chemical equation,
1 mol of HClO₄ reacts with 1 mol of KOH (1 equivalent of acid with 1 equivalent of base). The moles are calculated from the product of the molar concentration (M) and the volume in liters.
We have the following moles of acid (HClO₄):
40.0 mL x 1 L/1000 mL = 0.04 L 0.200 mol/L x 0.04 L = 8 x 10⁻³ moles HClO₄
Since HClO₄ is a strong acid (completely dissociated into H⁺ and ClO₄⁻ ions), the moles of HClO₄ are equal to the moles of H⁺.
Then, we can calculate the initial pH:[H⁺] = 0.200 M → pH = -log [H⁺] = -log (0.200) = 0.70
Now, we calculate the pH after the addition of KOH. Since KOH is a strong base, the concentration of KOH is equal to the concentration of OH⁻ ions.
a) 0.0 mLNo KOH is added, so the pH is the initial pH:
0.70
b) 80.0 mL KOH80.0 mL x 1 L/1000 mL = 0.08 L0.100 mol/L x 0.08 L = 8 x 10⁻³ moles KOH = 8 x 10⁻³ moles OH⁻
After neutralization we have: 8 x 10⁻³ moles H⁺ - 8 x 10⁻³ moles OH⁻ = 0The neutralization reaction is complete and there is no remaining H⁺ from the acid.
The concentration of H⁺ is equal to the concentration of H⁺ of water:
[H⁺] = 1 x 10⁻⁷ M → pH = -log [H⁺] = -log (1 x 10⁻⁷) = 7.0
c) 10.0 mL KOH10.0 mL x 1 L/1000 mL = 0.01 L0.100 mol/L x 0.01 L = 1 x 10⁻³ moles KOH = 1 x 10⁻³ moles OH⁻
After neutralization we have: 8 x 10⁻³ moles H⁺ - 1 x 10⁻³ moles OH⁻ = 7 x 10⁻³ moles H⁺
The total volume is:
V = 40.0 mL + 10.0 mL = 50 mL = 0.05 L[H⁺] = 7 x 10⁻³ moles/0.05 L = 0.14 → pH = -log [H⁺] = -log (0.14) = 0.85
d) 100.0 mL KOH100.0 mL x 1 L/1000 mL = 0.1 L0.100 mol/L x 0.1 L = 0.01 moles KOH = 1 x 10⁻² moles OH⁻
After neutralization we have:
1 x 10⁻² moles OH⁻ - 8 x 10⁻³ moles H⁺ = 2 x 10⁻³ moles OH⁻
The total volume is:
V = 40.0 mL + 100.0 mL = 140 mL = 0.14 L[OH⁻] = 2 x 10⁻³ moles/0.14 L = 0.014 → pOH = -log [OH⁻] = -log (0.014) = 1.84pH + pOH = 14 → pH = 14 - pOH = 14 - 1.84 = 12.15
e) 40.0 mL KOH40.0 mL x 1 L/1000 mL = 0.04 L0.100 mol/L x 0.04 L = 4 x 10⁻³ moles KOH = 4 x 10⁻³ moles OH⁻
After neutralization we have: 8 x 10⁻³ moles H⁺ - 4 x 10⁻³ moles OH⁻ = 4 x 10⁻³ moles H⁺
The total volume is:
V = 40.0 mL + 40.0 mL = 80.0 mL = 0.08 L[OH⁻] = 4 x 10⁻³ moles/0.08 L = 0.05 M → pH = -log [H⁺] = -log (0.05)
= 1.30
What do these two changes have in common?
sewing an apron
bleaching clothes
Give the systematic name for the following coordination compound or complex ion:
The accurate systematic name of the coordination compound is diaminodicyano platinum II.
What is a coordination compound?A coordination compound is which contains a central metal atom or ion along with ligands in its coordination sphere. Some times, counterions may alaso be present to balance the charges.
The accurate systematic name of the coordination compound is diaminodicyano platinum II.
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A geology student describes a rock sample she is studying in class. The rock sample is igneous rock, but the student wonders if the material that it formed from was part of a sedimentary rock formation millions of years ago. Could this be correct? Could the material for igneous rock come from sedimentary rock?
Answer:
The study of rocks is called petrology.
The correct answer is B.
Explanation:
All the rocks present in the earth is present during ancient times during the formation of the earth's atmosphere.
Due to the presence in the upper surface of the earth, the color of the rocks is changed.
Hence, the correct answer is B Yes, if the sedimentary rock is moved below Earth’s outer layer and exposed to energy from Earth’s interior, can melt into liquid rock and form igneous rock.
what is the volume of 1.34 mol SO2 at STP
Answer: 30.0 L S02
Explanation: It was right on mine
During nuclear decay, if the atomic number of the daughter atom decreases by one, but the mass number is unchanged, the radiation emitted is
a
a gamma ray
b
a beta-plus particle
c
an alpha particle
d
a beta-minus particle
Answer:
A beta-particle (plus or minus)
The laboratory test of a patient shows blood potassium level of 4.5mEq/L. How many moles of K+ are on 750 mL of the patient's blood
The number of moles of K+ that are on 750 mL of the patient's blood is = 3.375moles.
How to calculate blood potassium levelsSince mmol is one-thousandth of a mole also a mEq is one-thousandth of an equivalent. Therefore both can be used interchangeably.
That is 4.5mEq/L of potassium = 4.5mmol/L
If 4.5 moles = 1000ml ( 1 liter =1000ml)
x mole = 750 ml
Make x the subject of formula,
x mole = 750 × 4.5 / 1000
= 3,375/1000
= 3.375moles
Therefore, the number of moles of K+ that are on 750 mL of the patient's blood is = 3.375moles.
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Which type of heat island is
present in the air layer from
Ground LEVEL to the tops of trees
or buildings?
A. a sub-surface heat island
B. a canopy heat island
C. a fast-moving heat island
D. a rural heat island
Answer:
a fast moving heat island
Explanation:
cause there is a high amount of heating molecule produced.
Answer:
The correct answer is C. a canopy heat island
Which technique can be used to remove air bubbles from a syringe? a) Hold the syringe downward, shake vigorously for 10 seconds, and expel the bubbles through the needle using the syringe plunger. Hold the syringe upright, provide a firm tap or flick to the b) barrel, and expel the bubbles through the needle using the syringe plunger. Hold the syringe upright, shake vigorously for 10 seconds, c) and expel the bubbles through the needle using the syringe plunger. Hold the syringe downward, provide a firm tap or flick to the d) barrel, and expel the bubbles through the needle using the syringe plunger.
hold the syringe downward,shake vigorously for sometime,and expel the bubbles through the needle using the syringe plunger. hold the syringe upright, provide a firm tap or flick to the barrel
How might the hydrosphere affect the biosphere?
A; a river floods animal burrows
B; soil from erosion fills up a pond
C; a thunderstorm causes a landslide
D; plant roots break down large rocks
THE ANSWER IS OPTION B.
B;SOIL FROM EROSION FILLS UP A POND
HOPE THIS HELP
[tex] \small \color{gold}{ \underline{ \tt \bold \pink{ \: by:MissS3xy}}}[/tex]
What type of migration factor is lack of freedom?
A. Economic pull factor
B. Environmental push factor
C. Political push factor
D. Environmental pull factor
Answer:
The answer is C. Political push factor.
Explanation:
Unlike plants, humans cannot make their own food. Where do most humans get energy to live, breathe, and grow? (2 points)
and brain lst
Group of answer choices
Humans eat plants.
Humans are carnivores.
Humans are herbivores.
Humans eat plants and animals.
Answer:
humans are omnivores they eat plants and animals exept for that vegan teacher
Explanation:
The pressure of a 1.7379 mol sample of Ne in a 92.202 L container is measured to be 1.4948 atm. What is the temperature of this gas in kelvins?
The temperature of a 1.7379 mole of a gas with a pressure of 1.4948 atm and volume of 92.202 L is 965.69K .
How to calculate temperature?The temperature of a given gas can be calculated using the ideal gas law equation:
PV = nRT
Where;
P = pressure = 1.4948atmV = volume = 92.202LR = gas law constant = 0.0821 Latm/molKn = number of moles = 1.7379molT = temperature1.4948 × 92.202 = 1.7379 × 0.0821 × T
137.82 = 0.142T
T = 137.82 ÷ 0.142
T = 965.69K
Therefore, the temperature of a 1.7379 mole of a gas with a pressure of 1.4948 atm and volume of 92.202 L is 965.69K.
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What happens to the energy added during a phase change?
OA. It is used for the phase change.
B. It is converted to kinetic energy.
OC. It decreases the temperature.
OD. It increases the temperature.
SUBE
Answer:
A: It is used for the phase change.
Explanation:
During a phase change, the heat added or realeased, the temperature remains constant and is used to be stored as potential energy.
Side Note: I hope this helps, feel free to let me know if you have any other questions :)
Answer:
What happens to the Energy added during a phase change my anwar would be B
#3 of thermo terms
If the heat of reaction, that is the enthalpy change AH, for a certain process is -19 kJ, that process
Select one:
Answer:
C
Explanation:
If the enthalpy change (i.e. ΔH) of a reaction is negative, then the reaction releases heat and is hence exothermic.
Hence, our answer is C.
Conversely, if ΔH is positive, the reaction absorbs heat and is endothermic.
ΔH tells us nothing about the speed of the reaction.
While ΔH influences free-energy change (ΔG = ΔH - TΔS), we cannot predict the sign of ΔG given only ΔH (recall that a reaction is spontaneous if ΔG < 0).
Epidemiological studies looks into:
A. Trends in exercise
B. Trends in genetics
C. Trends in drug effectiveness
D. Trends in statistics
Answer:
It is used in medical research.
Explanation:
So its answer is trends in drug effectiveness
In the given question, epidemiological studies look into trends in statistics. The correct answer is option D.
Epidemiology is the study of how diseases spread and how to prevent them.
Epidemiologists use statistics to understand how diseases spread and how to prevent them from spreading further. They look at trends in:
The number of cases of a diseaseThe age and sex of people who get the disease, and Other factors that may affect the spread of the disease.Therefore, Option D. "Trends in statistics" is the correct answer.
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What are some individual needs that need to be taken into consideration when planning an exercise program?
A. Current level of health, goals and diet
B. Age, goals, and diet
C. Goals, forms of exercise they enjoy and availability
D. Age, current level of health, current level of fitness
Answer:
c
Explanation:
The current level of health, goals, and diet need to be taken into consideration while planning an exercise program.
What is the planning of an exercise program?Exercise programs should include some specific exercises to improve cardiovascular health, such as swimming, jogging, rowing, elliptical exercises, and biking.
To assess your current fitness level use or make an appointment with an exercise professional for a fitness assessment. Consulting an exercise professional when designing a fitness program can help you reduce injury and customize a program to your needs. The adult pre-exercise screening tool consists of exercise guidelines.
Consider your goals and think about likes and dislikes. Plan a logical progression of activity and build activity into a daily routine. If you begin to lose motivation then set new goals or try a new physical activity.
Give time for recovery after exercising and make sure to have an adequate healthy diet and assemble exercise clothing.
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how long does it take for light to travel 6.0ft
Explanation:
Well,
Light travels approximately 1 foot per nanosecond or 186 miles per millisecond or 300,000 kilometers per second.
Hope this helps!
6. How many grams of KNO3 are produced from 134g of Ca(NO3)2 ?
K3PO4 +Ca(NO3)2 → KNO3 + Ca3(PO4)2
Tribasic Potassium Phosphate + Calcium Nitrate = Tuite + Potassium Nitrate
2 moles of aqueous Tribasic Potassium Phosphate react with 3 moles of aqueous Calcium Nitrate to form 1 mole of solid Tuite and 6 moles of aqueous Potassium Nitrate
Reaction Type
Double Displacement (Metathesis)
Net Ionic Equation
2K3PO4 + 3Ca(NO3)2 = Ca3(PO4)2 + 6KNO3 might be an ionic equation. Calculate the net ionic equation for 2K3PO4(aq) + 3Ca(NO3)2(aq) = Ca3(PO4)2(s) + 6KNO3(aq).
Redox (Oxidation-Reduction) Reaction
K3PO4 + Ca(NO3)2 = Ca3(PO4)2 + KNO3 might be a redox reaction.
Reactants
Tribasic Potassium Phosphate - K3PO4
E340Iii E340(Iii) Potassium Phosphate Tripotassium Phosphate K3PO4 Molar Mass K3PO4 Oxidation Number
Calcium Nitrate - Ca(NO3)2
Saltpeter Lime Nitrate Lime Saltpeter Norge Saltpeter Norway Saltpeter Calcium Saltpeter Norwegian Saltpeter Anhydrous Calcium Nitrate Ca(NO3)2 Molar Mass Ca(NO3)2 Oxidation Number