a 958 g sample of liquid h2o is placed in the freezer and allowed to completely freeze. determine the amount of heat transferred during the freezing in kj.
Answers
To determine the amount of heat transferred during the freezing of a 958 g sample of liquid H2O, we need to consider the heat of fusion and the specific heat capacity of water.
The freezing process involves the transfer of heat from the water to the surroundings until it reaches the freezing point and turns into solid ice.
The heat transferred can be calculated using the equation Q = m * ΔHf, where Q is the heat transferred, m is the mass of the substance, and ΔHf is the heat of fusion.
In this case, the mass of the water sample is given as 958 g. To determine the heat transferred during freezing, we need to know the heat of fusion for water, which is 334 J/g. However, since the answer should be in kilojoules (kJ), we need to convert the mass to kilograms. Therefore, the mass of the water sample is 0.958 kg.
Using the formula Q = m * ΔHf, we can calculate the heat transferred. Substituting the values, we have Q = 0.958 kg * 334 J/g. Now we need to convert the result from joules to kilojoules by dividing by 1000. The final calculation is Q = (0.958 kg * 334 J/g) / 1000 = 0.320 kJ.
Therefore, the amount of heat transferred during the freezing of the 958 g sample of liquid H2O is approximately 0.320 kJ.
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Related Questions
How many molecules of NaOH are in 10.0 g of NaOH? *
Answers
The number of molecules in 10.0 gram of NaOH is 15 * 10²².
To solve this question, we need to understand some terms of mole concept,
Mole - It is the amount of substance containing same number of molecules or atoms as there are atoms in 12 gram of carbon-12 isotope.
Molecules - It is group of atoms bonded together, representing the smallest fundamental unit of a chemical compound taking part in chemical reaction.
Molecular weight - The sum of atomic masses of all atoms in molecules.
Avogadro number - It is the number of atoms, ions, electrons, molecules in one mole of substance. It is represented as NA.
NA = 6.0 * 10²³ (approx)
To calculate the number of molecules, we apply the formulae,
no. of molecules = moles * NA
moles = weight / molecular weight
moles = 10.0 / 40
= 0.25
Substituting this value to calculate number of molecules,
no. of molecules = 0.25 * 6.0 * 10²³
= 15 * 10²²
Therefore the number of molecules of in 10.0 g of NaOH is 15 * 10²².
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If it takes 1.33 seconds for radio waves (which travel at the speed of light) to reach the moon from Earth, how far away is the moon?
Answers
Speed of light * time = distance
299,792,458 * 1.33 = 398,723,969 meters
398,723.969 km to the moon
If the radio waves from earth reach moon within 1.33 s in a speed of light then, the distance of moon from earth will be 3.9 ×10⁸ m.
What are radio waves?Radio waves are electromagnetic waves with highest wavelength and lesser energy. The speed of these waves will be equal to the light speed that is, 3 ×10⁸ m/s.
Distance is the product of time and velocity. It is given that the time taken by the radio wave to reach moon from earth is 1.33 seconds and the velocity of wave is 3 ×10⁸ m/s thus, distance to moon is calculated as follows:
Distance = Time × velocity
= 1.33 s × 3 ×10⁸ m/s
= 3.9 ×10⁸ m
Hence, moon is 3.9 ×10⁸ m away from earth.
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Can someone help with making a discussion for the reactivity of group 1 and 2 elements
Answers
Group 1 elements will be more reactive than group 2 because group 1 element has one valence electrons.
The kind of elements which posses 1 valence electrons, will be kept in group 1. Due to it has 1 valence electrons, hence it will be more reactive.
In a group, by moving top to down in the periodic table reactivity increases.
Reactivity would be a parameter that expresses how easily a substance reacts chemically. The chemical may react alone or in combination with some other atoms or molecules, and energy is often released as a result of the reaction. The most reactive substances and elements have the potential to spontaneously as well as explosively ignite.
Therefore, group 1 elements will be reactive than group 2 elements.
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The symbols for units of length in order from largest to smallest are
Answers
Topic: Mass Balance. A company sells fishmeal to be used as a protein supplement in certain foods. The process consists of: a. Extraction of fish oil, stage in which a pasta is obtained that has 20% flour and 80% water. b. Drying of pasta in a rotary drum, which produces fishmeal with 40% humidity. How much pasta must be input to the process to produce 1000 kg ?
Answers
To produce 1000 kg of fishmeal (M = 1000 kg), you would need 3000 kg of pasta. To determine the amount of pasta required to produce 1000 kg of fishmeal, we need to consider the mass balance of the process. Let's break down the steps involved:
A. Extraction of fish oil:
The pasta obtained from the extraction stage contains 20% flour and 80% water. To calculate the amount of pasta, we need to determine the mass of flour and water in the pasta. Let's assume the total mass of the pasta is P kg.
Mass of flour = 20% of P = 0.2P kg
Mass of water = 80% of P = 0.8P kg
b. Drying of pasta:
During the drying stage, the pasta is dried in a rotary drum, resulting in fishmeal with 40% humidity. This means that the final fishmeal will contain 60% dry matter.
Let's assume the mass of the dried fishmeal is M kg.
Mass of dry matter = 60% of M = 0.6M kg
Since the dry matter in the fishmeal comes from the flour in the pasta, we can equate the mass of dry matter to the mass of flour:
0.6M kg = 0.2P kg
To produce 1000 kg of fishmeal, we want to find the corresponding value of P:
0.6M = 0.2P
P = (0.6M) / 0.2
P = 3M
Therefore, to produce 1000 kg of fishmeal (M = 1000 kg), you would need 3000 kg of pasta.
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a push or a pull between an object (many types)
Your answer
Answers
Answer:
your answer would be force
Explanation:
What pillar of sustainability is broken by recycling
electronics in India? Should the US make a law that electronics can
only be recycled in the US?
Answers
The pillar of sustainability broken by recycling electronics in India is environmental sustainability. Implementing a law that restricts electronics recycling to the US would not necessarily be the most effective solution, as it overlooks the complex global dynamics of electronic waste management.
Recycling electronics in India often involves improper disposal methods, such as burning or dismantling without proper safety measures. This leads to environmental pollution, including the release of hazardous substances into the air, soil, and water, thus violating the principle of environmental sustainability.
However, simply mandating that electronics can only be recycled in the US may not be the most optimal solution. Electronic waste is a global issue, and restricting recycling to a single country disregards the fact that electronic products are manufactured and consumed worldwide. A more comprehensive approach to addressing electronic waste would involve international cooperation, strict regulations, and monitoring of recycling practices to ensure they meet environmental standards.
Efforts should focus on improving recycling practices globally, including promoting responsible electronic waste management, developing sustainable recycling infrastructure in multiple countries, and encouraging the adoption of safe and environmentally friendly recycling practices. This approach would foster global sustainability and address the challenges associated with electronic waste disposal more effectively than a geographically limited restriction.
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what are advantage of using alternatives to fossil fuels?
Answers
Answer:
Fossil fuels release greenhouse gases and are non renewable
Based on the thermodynamic functions of enthalpy and entropy, can an unfavorable reaction that has a positive ÎG at RT be made favorable by increasing the reaction temperature?
(a) Yes, regardless of the sign of ÎH, if ÎS is positive, a reaction can be rendered favorable by increasing the temperature.
(b) only if both ÎH and ÎS are negative
(c) No, an unfavorable reaction cannot be rendered favorable.
(d) yes, but only if ÎH is positive and ÎS is negative
Answers
Your answer: (a) Yes, regardless of the sign of ΔH, if ΔS is positive, a reaction can be rendered favorable by increasing the temperature.
A property whose value doesn't depend on the path taken to reach that specific value is known to as state functions or point functions. In contrast, those functions which do depend on the path from two points are known as pathThe fundamental thermodynamic equations follow from five primary thermodynamic definitions and describe internal energy, enthalpy, Helmholtz energy, and Gibbs energy in terms of their natural variables.
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As a lead-acid battery is discharged (as the overall reaction progresses to form more products), what happens to the pH of the solution in the battery and what happens to the voltage of the cell? O A The pH of the solution increases and the voltage increases. O B The pH of the solution increases and the voltage decreases. O C The pH of the solution increases and the voltage remains the same O D The pH of the solution decreases and the voltage decreases O E The pH of the solution decreases and the voltage increases. OF The pH of the solution decreases and the voltage remains the same.
Answers
As a lead-acid battery is discharged, the overall reaction progresses, and the lead sulfate (PbSO4) and water (H2O) are produced.
As a lead-acid battery is discharged, the overall reaction produces more products and therefore consumes more acid. This leads to a decrease in the pH of the solution in the battery. Additionally, as the battery discharges, the voltage of the cell decreases due to the reduction in the concentration of reactants available for the reaction to occur. Therefore, the answer is option B: the pH of the solution increases and the voltage decreases.
Your answer: D. The pH of the solution decreases and the voltage decreases.
The sulfuric acid (H2SO4) concentration in the electrolyte decreases, which leads to a decrease in the pH of the solution. At the same time, as the battery discharges, the voltage of the cell also decreases due to the reduction of the available reactants.
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The dose of ampicillin for the treatment of an ear infection is 105 mg ampicillin per kilogram of body weight (105 mg/kg). what is the daily dose for a 42-lb child?
Answers
The daily dose for a 42-lb child should be equal to 2002.14 mg.
What is ampicillin?
Ampicillin is an antibiotic used to prevent and treat a variety of bacterial illnesses or infections.
The daily dose of ampicillin for treatment of an Ear Infection is 105mg,
The weight of child 42-lb (1 lb =454g)
The weight of child in kg
42 lb × 454 g/1 lb × 10^-3/1 g
= 19.068 kg
Now daily dose of ampicillin for the treatment of an Ear infection for the child is
= 105 mg/1kg × 19.068 kg
=2002.14 mg
Therefore, The daily dose for a 42-lb child should be equal to 2002.14 mg.
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What trend does the atomic radius follow along a period on the periodic
table?
O A. The atomic radius gets smaller the farther right it appears on the
periodic table.
O B. The atomic radius stays constant across the periodic table.
O C. The atomic radius increases as the number of protons increases
across the table.
O D. The atomic radius gets larger the farther right it appears on the
periodic table.
Answers
What is natural selection help plz help
Answers
Answer:
Natural selection is the differential survival and reproduction of individuals due to differences in phenotype. It is a key mechanism of evolution, the change in the heritable traits characteristic of a population over generations.
Explanation:
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Answer:
Natural selection is the process whereby organisms better adapted to their environment tend to survive and produce more offspring.
Explanation:
Which choice is a biotic factor of an ecosystem?
A. sun
B. ants
C. air
D. soil
Answers
A gas mixture contains 1.52 atm of Ne, 766 mmHg of He and Ar. What is the partial pressure, in atmospheres, of At if the gas mixture has a total pressure of 3.27atm
Answers
Answer:
0.74 atm.
Explanation:
From the question given above, the following data were obtained:
Pressure of Ne (Pₙₑ) = 1.52 atm
Pressure of He (Pₕₑ) = 766 mmHg
Total pressure (Pₜ) = 3.27 atm
Pressure of Ar (Pₐᵣ) =?
Next, we shall convert the pressure of He from mmHg to atm. This can be obtained as follow:
760 mmHg = 1 atm
Therefore,
766 mmHg = 766 mmHg × 1 atm / 760 mmHg
766 mmHg = 1.01 atm
Finally, we shall determine the partial pressure of Ar. This can be obtained as follow:
Pressure of Ne (Pₙₑ) = 1.52 atm
Pressure of He (Pₕₑ) = 1.01 atm
Total pressure (Pₜ) = 3.27 atm
Pressure of Ar (Pₐᵣ) =?
Pₜ = Pₙₑ + Pₕₑ + Pₐᵣ
3.27 = 1.52 + 1.01 + Pₐᵣ
3.27 = 2.53 + Pₐᵣ
Collect like terms
3.27 – 2.53 = Pₐᵣ
Pₐᵣ = 0.74 atm
Thus the partial pressure of Ar is 0.74 atm.
Question 4(5 points)
(01.07 MC)
A student compares the boiling point of substances having different intermolecular forces. Which independent variable did the student most
likely use? (5 points)
Ob
Various compounds made of different forces between molecules
Type of source used to heat up the substances
Type of container used for the substances
Boiling points of various substances
Od
Answers
Answer:
Various compounds made of different forces between molecules
Explanation:
In an experiment, the independent variable is the variable that is changed or manipulated by the experimenter in order to effect a measurable response.
According to this question, a student compares the boiling point of substances having different intermolecular forces. This means that the student uses different substances with different intermolecular forces and measures the boiling point of each, which depends on the intermolecular forced in them. Hence, the independent variable in this experiment is the VARIOUS COMPOUNDS MADE OF DIFFERENT FORCES BETWEEN MOLECULES.
Decomposers in the rainforest ___________ break down materials.
A:A. slowly
B:B. do not
C:C. quickly
D:D. rarely
Answers
Answer:
Quickly
Explanation:
Energy in vs Energy out = Energy balance. Explain this concept, give examples and provide support for your explanation.
Answers
The concept of energy balance refers to the equilibrium between the energy input into a system and the energy output from that system. It is based on the principle of conservation of energy, which states that energy cannot be created or destroyed but can only be transferred or transformed from one form to another.
In terms of human energy balance, it involves the energy intake from food and beverages (energy in) and the energy expenditure through basal metabolic rate, physical activity, and other bodily processes (energy out). When the energy intake matches the energy expenditure, there is an energy balance. However, when there is an imbalance, either an excess or deficit of energy, it can lead to weight gain or weight loss, respectively.
For example, if a person consumes 2000 calories (energy in) through their diet and expends 2000 calories (energy out) through their daily activities and bodily functions, they maintain an energy balance. This means that the energy intake is equal to the energy expenditure, and their weight remains stable.
On the other hand, if a person consumes 2500 calories (energy in) but only expends 2000 calories (energy out), there is a positive energy balance. The excess energy is stored in the body as fat, leading to weight gain over time.
Conversely, if a person consumes 1500 calories (energy in) but expends 2000 calories (energy out), there is a negative energy balance. The body needs to compensate for the energy deficit by utilizing stored energy reserves, such as fat, resulting in weight loss.
Support for the concept of energy balance comes from scientific studies on weight management and obesity. It has been shown that maintaining an energy balance is crucial for weight maintenance, while sustained positive or negative energy balances can lead to weight changes. Additionally, energy balance plays a role in various physiological processes, including metabolism, hormone regulation, and overall health.
By understanding and managing energy balance, individuals can make informed decisions regarding their diet, physical activity, and lifestyle to achieve and maintain a healthy weight and overall well-being.
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HELP!! ASAP! GIVING 10 POINTS AND BRAINLIEST!!
What is one reason why transpiration is important in plants?
Question 17 options:
It produces food from the sugar in the plant cells.
It enables the flow of water out of the plant.
It produces carbon dioxide in the leaves of the plant.
Answers
Answer:
The Answer Is B.
Explanation:
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If a solvent more polar than ethanol were used would you expect the SN1 reaction rate to increase or decrease? decrease O increase What is the nucleophile in the SN2 reaction? 1-bromobutane O acetone O sodium O iodide
Answers
Using a solvent more polar than ethanol would increase the rate of the SN1 reaction. The increased polarity of the solvent enhances the stabilization of the carbocation intermediate, promoting the ionization step and accelerating the reaction rate.
Determine what is the nucleophile in the SN2 reaction?In the SN1 (Substitution Nucleophilic Unimolecular) reaction, the rate-determining step involves the ionization of the substrate to form a carbocation intermediate.
The solvent plays a crucial role in stabilizing the charged species formed during the reaction. A more polar solvent provides better solvation and stabilization for the charged species.
Ethanol is a polar solvent but has lower polarity compared to some other solvents. If a solvent more polar than ethanol is used, it will increase the polarity of the reaction medium. The increased polarity will enhance the stabilization of the carbocation intermediate, promoting the ionization step and resulting in an increased reaction rate for the SN1 reaction.
Therefore, using a more polar solvent than ethanol would lead to an increase in the SN1 reaction rate.
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Pls help me I don’t know how to do this
Answers
Explanation:
We have a 63.9 g sample of calcium hydroxide. First we have to convert those grams into moles. To do that we have to use the molar mass of calcium hydroxide.
Calcium hydroxide = Ca(OH)₂
molar mass of Ca = 40.08 g/mol
molar mass of O = 16.00 g/mol
molar mass of H = 1.01 g/mol
molar mass of Ca(OH)₂ = 1 * 40.08 g/mol + 2 * 16.00 g/mol + 2 * 1.01 g/mol
molar mass of Ca(OH)₂ = 74.10 g/mol
mass of Ca(OH)₂ = 63.9 g
moles of Ca(OH)₂ = 63.9 g /(74.10 g/mol)
moles of Ca(OH)₂ = 0.862 moles
In 1 molecule of Ca we have 2 atoms of O. So in 1 mol of Ca(OH)₂ we will have 2 moles of O atoms.
1 mol of Ca(OH)₂ = 2 moles of O atoms
moles of O atoms = 0.862 moles of Ca(OH)₂ * 2 moles of O /1 mol of Ca(OH)₂
moles of O atoms = 1.724 moles
One mol is similar to a dozen. When we say that we need a dozen eggs we know that we need 12 eggs. If we want a mol of eggs, we want 6.022*10^23 eggs. So one mol of something is 6.022 * 10^23 of that.
1 mol of O atoms = 6.022 * 10^23 atoms
n° of O atoms = 1.724 moles * 6.022 * 10^23 atoms/1 mol
n° of O atoms = 1.04 * 10^24 atoms
Answer: In a 63.9 g sample of Ca(OH)₂ we have 1.04 *10^24 atoms of oxygen.
what is the main difference between chemical and physical properties
Answers
Answer:
Explanation:
A physical property is a characteristic of a substance that can be observed or measured without changing the identity of the substance. Physical properties include color, density, hardness, and melting and boiling points. A chemical property describes the ability of a substance to undergo a specific chemical change.
n‑methyl‑2‑pyrrolidone is an aprotic solvent used in many industrial processes. draw the structure of the product formed when it is heated with aqueous acid.
Answers
The structure of n‑methyl‑2‑pyrrolidone when it is heated with aqueous acid. product is given below
What is aprotic solvent?A polar solvent without an acidic proton is known as a polar aprotic solvent. These solvents don't include hydroxyl or amine groups. These solvents can act as proton acceptors, but unlike protic solvents, they do not act as proton donors in hydrogen bonding.
After being exposed to a strong aqueous acidic media and being heated, N-methyl-2-pyrrolidone opens up, forming a molecule with a carboxylic group at one end and a protonated nitrogen atom with a methyl group connected to it at the other.
Alcohol, water, hydrogen fluoride, formic acid, acetic acid, ammonia, methanol, ethanol, and other well-known substances are a few examples of polar protic solvents. Polar aprotic solvents, on the other hand, lack acidic protons and do not function as donors during hydrogen bonding.
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Which one of the following compounds is most likely to be ionic? select one:
a. hnf2
b. h2co
c. n2h4
d. cacl2
e. icl
Answers
CaCl2 is the compound which is more likely to be ionic .
Ionic compounds: what makes them?Ions, charged particles that develop when an atom (or group of atoms) gets or loses electrons, are the building blocks of ionic compounds. An anion is a negatively charged ion, whereas cations are positively charged ions. When two elements create molecules by a covalent link and share electrons, this results in covalent or molecular compounds.
When Cacl2 dissolve in aqueous solution it gives Ca+² and cl- ions.
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Ms. Raymond writes about the benefits of producing crops which are resistant to weed-killers. Many agricultural crops have been documented to cross-pollinate with wild plants. What could be a danger to the environment of crops which are resistant to weed-killers?
Answers
Answer:
Negative effects of weed-killer-resistant crops can include decreased diversity and abundance of wild plants, problems with grain contamination, segregation and introgression of herbicide-resistant traits, and marketplace acceptance, resulting in an increased reliance on herbicides for weed control.
Explanation:
I hope this helps!
The complete combustion of ethanol, to form CO2(g) and H2O(g) at constant pressure releases 726.7 kJ of heat per mole of (a) Write a balanced thermochemical equation for this reaction. a) Draw an enthalpy diagram for the reaction.
Answers
(a) First, we need to write the combustion reaction for ethanol (CH3CH2OH)
CH3CH2OH + O2 → CO2 + H2O
Then, we need to balance this equation. To do that, remember to start with C, then move on to H and finally balanced the amount of O:
CH3CH2OH + 3 O2 → 2 CO2 + 3 H2O
(b) Since this is a reaction that realeases heat (726.7 kJ /mol of ethanol), we know that is an exothermic reaction and the general scope of an enthalpy diagram would be like this:
Where, for the combustion of ethanol, the reactants would be CH3CH2OH + O2, the products would be CO2 + H2O, and ΔH would be -726.7 kJ/mol
The penny coin was removed from circulation in Canada
In February of 2014. The United States may soon do the
same. The major reason for this move was the rising value
of copper metal. When copper’s value increased, pennies
were produced as a zinc slug with a thin layer of copper
plated over top. Zinc reacts readily with hydrochloric acid,
while copper does not. A triangular file is used to nick the
edge of a penny to expose the zinc slug below the layer
of copper. The zinc reacts with the acid releasing bubbles
from the nicked area until nothing remains but a thin shell
of copper. If 0.948 L of hydrogen gas is collected over water
at 20.0°C and a total pressure of 752 mm Hg, determine the
percentage by mass of the copper in the 2.586 g penny.
Answers
As a result, the dry gas volume at STP is 45.58 cm 3.
Water vapor is present in the gas. Since H2 is created during the reaction and water vapor is irrelevant when determining the equivalent weight, we only need the dry gas. As a result, the volume of H2 gas can be calculated using the ideal gas law.
P 1 = 750 mm Hg, 14 mm Hg, 736 mm Hg V = 50 cm 3 T = 17 0 C = 290 K
P = 760mmHg, V =?cm3, T = 0 0 and C = 273K.
The Gas equation follows.
P 1V 1/ T1 = P 2V 2/ T2
290/73650 = 273/760V 2
= 290760V 2
= 7365027V 2 = 45.58 cm
As a result, the dry gas volume at STP is 45.58 cm 3.
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How many moles are in 4.50g of Zn
Answers
To find the number of moles in 4.50g of Zn, we need to use the molar mass of Zn which is 65.38 g/mol.
First, we can calculate the number of moles using the formula:
moles = mass / molar mass
Substituting the given values, we get:
moles = 4.50 g / 65.38 g/mol
moles = 0.0689 mol
Therefore, there are 0.0689 moles in 4.50g of Zn.
11. A chemical reaction happens when chemicals combine to form a new _______
Answers
Answer:
substances
Explanation:
A chemical reaction happens when substances break apart or combine to form one or more new substances.
^Hope it helps, Hazel^
A sample of NH3, gas occupies 75.0 liters at STP. How many molecules is this?
Answers
Answer:
2.016E24 same as 2.016 × 10^24
Explanation:
we have to use 2 conversion facts
22.4 and 6.02E23
1. Convert to moles of NH3 from liters of NH3
75.0 ÷ 22.4 = 3.348 moles of NH3
2. Convert to molecules of NH3 from moles of NH3
3.348 × 6.02E23 = 2.016E24 molecules of NH3
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