Answer:
i = 2.79
Explanation:
The excersise talks about the colligative property, freezing point depression.
Formula to calculate the freezing point of a solution is:
Freezing point of pure solvent - Freezing point of solution = m . Kf . i
Let's replace data given. (i = Van't Hoff factor, numbers of ions dissolved in solution)
48.1°C - 44°C = 0.15 m . 9.78°C/m . i
4.1°C / (0.15 m . 9.78°C/m) = i
i = 2.79
In this case, numbers of ions dissolved can decrease the freezing point of a solution, which is always lower than pure solvent.
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a) The rows on the periodic table are called periods. How many energy levels are in the atoms of each element in period 2 (lithium-neon)
b) What is the group number of the halogens?
c) What do the elements in each group have in common?
please please help me, i will give brainliest
Answer:
A two energy levels K and L
B halogen are present in group 17
C in same group elements have same valence electrons
Explanation:
Explain the differences between an ideal gas and a real gas.
Answer:
Ideal Gas
The ideal gas is extremely small and the mass is almost zero and no volume Ideal gas is also considered as a point mass.
Real Gas
The molecules of real gas occupy space though they are small particles and also have volume.
anation:
The differences between an ideal gas and a real gas are that the ideal gas follows the gas laws perfectly under all conditions. Whereas a real gas deviates from ideal gas behaviors.
The ideal gas law, also known as the general gas equation, is a fundamental principle in thermodynamics and relates the pressure, volume, temperature, and number of moles of an ideal gas.
An ideal gas is a theoretical gas that follows the gas laws perfectly under all conditions of temperature and pressure. It is assumed to have no volume, no intermolecular forces, and elastic collisions between its particles. An ideal gas also obeys the ideal gas law.
On the other hand, a real gas is a gas that does not follow the gas laws perfectly under all conditions of temperature and pressure. Real gases have volume and intermolecular forces that affect their behavior. These forces cause deviations from ideal gas behavior, especially at high pressures and low temperatures.
In summary, while an ideal gas is a theoretical gas that follows the gas laws perfectly under all conditions, a real gas is a gas that deviates from ideal gas behavior due to its volume, intermolecular forces, and non-elastic collisions between its particles.
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Given the equation:
4Al2O3 + 9Fe --> 3Fe3O4 + 8Al
If 27.5 g of Al2O3 reacted with 8.4 g of Fe, how many of Fe 3O4 are formed?
a) Calculate the limiting reactant
b) Calculate the number of grams of Al produced.
c) Calculate the number of grams of Fe3O4 produced.
d) Calculate the percent yield if 10g of Fe O4 were obtained?
Answer: a) [tex]Fe[/tex] is the limiting reagent
b) 3.59 g
c) 11.6g
Explanation:
[tex]4Al_2O_3+9Fe\rightarrow 3Fe_3O_4+8Al[/tex]
To calculate the moles :
[tex]\text{Moles of} Al_2O_3=\frac{27.5g}{102g/mol}=0.27moles[/tex]
[tex]\text{Moles of} Fe=\frac{8.4g}{56g/mol}=0.15moles[/tex]
According to stoichiometry :
a) 9 moles of [tex]Fe[/tex] require= 4 moles of [tex]Al_2O_3[/tex]
Thus 0.15 moles of [tex]Fe[/tex] will require=[tex]\frac{4}{9}\times 0.15=0.067moles[/tex] of [tex]Al[/tex]
Thus [tex]Fe[/tex] is the limiting reagent as it limits the formation of product and [tex]Al[/tex] is the excess reagent.
b) As 9 moles of [tex]Fe[/tex] give = 8 moles of [tex]Al[/tex]
Thus 0.15 moles of [tex]Fe[/tex] give =[tex]\frac{8}{9}\times 0.15=0.133moles[/tex] of [tex]Al[/tex]
Mass of [tex]Al=moles\times {\text {Molar mass}}=0.133moles\times 27g/mol=3.59g[/tex]
c) As 9 moles of [tex]Fe[/tex] give = 3 moles of [tex]Fe_3O_4[/tex]
Thus 0.15 moles of [tex]Fe[/tex] give =[tex]\frac{3}{9}\times 0.15=0.05moles[/tex] of [tex]Fe_3O_4[/tex]
Mass of [tex]Fe_3O_4=moles\times {\text {Molar mass}}=0..05moles\times 231.5g/mol=11.6g[/tex]
When H2(g) reacts with F2(g) to form HF(g) , 542 kJ of energy are evolved for each mole of H2(g) that reacts. Write a balanced thermochemical equation for the reaction with an energy term in kJ as part of the equation. Note that the answer box for the energy term is case sensitive. Use the SMALLEST INTEGER coefficients possible and put the energy term (including the units) in the last box on the appropriate side of the equation. If a box is not needed, leave it blank.
Answer:
[tex]H_2+F_2\rightarrow 2HF+542 kJ[/tex]
Explanation:
Hello!
In this case, since exothermic reactions evolve or release energy when undergone, we infer that the energy is part of the products as it is a result of the reaction; thus, for the described reaction we should set it up as follows:
[tex]H_2+F_2\rightarrow 2HF+542 kJ[/tex]
However, if the reaction absorbs energy, the energy associated to the reaction is put at the reactants side, keeping in mind that it would be an endothermic reaction.
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A 250 grams sample of an unknown substance was heated from 35 degree Celsius to 50 degree Celsius. The substance absorbed 7,454 J of energy. What is the specific heat of the substance? Identify if the reaction is exothermic or endothermic
Answer:
Specific heat capacity, c = 1.99J/g°C. The reaction is endothermic because heat is being absorbed.
Explanation:
Given the following data;
Mass = 250g
Original temperature, T1 = 35°C
New temperature, T2 = 50°C
Quantity of heat = 7454J
To find the specific heat capacity;
Heat capacity is given by the formula;
[tex] Q = mcdt[/tex]
Where;
Q represents the heat capacity or quantity of heat.
m represents the mass of an object. c represents the specific heat capacity of water. dt represents the change in temperature.dt = T2 - T1
dt = 50 - 35
dt = 15°C
Making "c" the subject of formula, we have;
[tex] c = \frac {Q}{mdt} [/tex]
Substituting the values into the equation, we have;
[tex] c = \frac {7454}{250*15} [/tex]
[tex] c = \frac {7454}{3750} [/tex]
Specific heat capacity, c = 1.99J/g°C.
Therefore, the reaction is endothermic because heat is being absorbed (initial temperature is lower than the final temperature).
Calculate how much heat is absorbed by a sample that weighs 12 kilograms, has a specific heat of 0.231 kg/CJ, and is heated from 45 K to 80 K.
PLEASE ANSWER 20 POINTS
Answer:
97 J
Explanation:
Step 1: Given data
Mass of the sample (m): 12 kgSpecific heat capacity (c): 0.231 J/kg.°C (this can also be expressed as 0.231 J/kg.K)Initial temperature: 45 KFinal temperature: 80 KStep 2: Calculate the temperature change
ΔT = 80 K - 45 K = 35 K
Step 3: Calculate the heat required (Q)
We will use the following expression.
Q = c × m × ΔT
Q = 0.231 J/kg.K × 12 kg × 35 K = 97 J
Which of the following statements does not describe the structure of an atom?
A) The electron cloud is a small and compacted space around the nucleus.
B) Inside the nucleus of an atom are protons and neutrons.
C) Protons are positively charged sub-atomic particles.
D) Electrons are negatively charged sub-atomic particles.
g Aqueous hydrobromic acid will react with solid sodium hydroxide to produce aqueous sodium bromide and liquid water . Suppose 57.4 g of hydrobromic acid is mixed with 41. g of sodium hydroxide. Calculate the minimum mass of hydrobromic acid that could be left over by the chemical reaction. Be sure your answer has the correct number of significant digits.
Answer:
Zero
Explanation:
The complete reaction for this is as follows -
HBr + NaOH = NaBr + H2O
1 mole of NaOH reacts with 1 mole of HBr
m(HBr) = 57.4g and M(HBr) = 80.9g/mol
m(NaOH) = 16g and M(NaOH) = 40g/mol
Number of moles = m/M
Substituting the given values we get -
n(HBr) = 57.4 g/80.9 g/mol = 0.709
n(NaOH) = 16 g/40 g/mol = 0.4
n(H2O) = n(NaOH) = 0.40 mol
According to balanced equation
40 gram of NaOH reacts with 81 grams of HBr
41 gram of NaOH will react with 81/40 * 41 = 83.025 gram of HBr
We have only 57.4 g of HBr only hence, 0 HBr will be left.
2. The heat from an acetylene torch is produced by burning acetylene (C2H2) in oxygen.
2C2H2 + 502 --> 4CO2 + 2H20
When 2.40mol C2H2 reacts with 7.40mol O2,
a. Which reactant is the limiting reactant?
b. How many grams of water can be produced by the reaction?
c. How many moles of the excess reactant remains?
I NEED THIS ANSWER QUICKLY IF YOU CAN ONLY DO B THATS FINE THANK YOU
Answer: a. C₂H₂
b. 43.2 g
c. 1.4 moles
Explanation: In a chemical reaction, when a reagent is completely consumed and limits the product formed is called Limiting Reagent. The reactant that is left is the Excess Reactant.
For the burning of acetylene:
[tex]2C_{2}H_{2}+5O_{2} \rightarrow 4CO_{2}+2H_{2}O[/tex]
a. An easy way to determine which reactant is limiting, is to divide the number of moles of each reactant by the coefficient in the balanced reaction. The component that gives the smallest number is the limiting reagent.
The ratio for acetylene is
[tex]\frac{2.4}{2}[/tex] = 1.2
For oxygen:
[tex]\frac{7.4}{5}=[/tex] 1.48
So, the limiting reactant is acetylene.
b. From the balanced reaction, for each 2 moles of acetylene is consumed, 2 moles of water is produced. Then, for 2.4 moles, it will be produced 2.4 moles of water.
Mol is mass in grams divided by molar mass of the component.
[tex]n=\frac{m}{M}[/tex]
Molar mass of water is M = 18 g/mol.
Then, mass of water produced:
m = n.M
m = 2.4(18)
m = 43.2 g
With 2.4 moles of acetylene, it will be produced 43.2 grams of water.
c. For each 2 moles of acetylene consumed, 5 moles of oxygen is also consumed. So, for 2.4 moles:
2 moles = 5 moles
2.4 moles = n
[tex]n=\frac{2.4*5}{2}[/tex]
n = 6 moles
For 2.4 moles of acetylene, it is consumed 6 moles of oxygen. Then, the excess is
7.4 - 6 = 1.4
The excess reactant remaining is 1.4 moles of oxygen.
Joaquin tells his science class that galaxies consist of gas, dust, and many planets. What is the most important component of galaxios Joaquin is missing in his description?
astero de
comets
constellations
Stars
Answer:
the answer is asteroids!
Explanation:
Answer:
astroid
Explanation:
becaus
Which of the following choices is not evidence supporting the theory of plate tectonics?
Answer:
B
Explanation:
Ivy has a mixture salt and sand . She wants to separate the two substances by pouring the mixture into a jar of water . How could ivy speed up the separation of the two substance? Shake the jar , put the jar into the freezer, add a third substance such as soil to the jar , remove some of the water from the jar before adding the mixture
Answer:
Remove some water from the jar before adding the mixture.
Explanation:
She will speed it up when removing some water it will stay dry and not be sticky to separate the two ingredients
Answer: Remove a bit of water from the jar
Explanation:
A 0.0250L solution of HCl is neutralized by 0.0780L of an unknown Mg(OH)2 solution. Also 0.050L of this Mg(OH)2 solution is neutralized by 0.0300L of a 0.20 M H3(PO3) solution. What is the concentration of the HCl solution
Answer:
[tex]M_{HCl} = 1.12M[/tex]
Explanation:
Hello!
In this case, for the first reaction we need to focus on, the neutralization of magnesium hydroxide by phosphoric acid, we can write up the following equation:
[tex]3Mg(OH)_2+2H_3PO_4\rightarrow Mg_3(PO_4)_2+6H_2O[/tex]
Whereas the acid and base react in a 3:2 mole ratio; thus, we can write:
[tex]2M_{Mg(OH)_2}V_{Mg(OH)_2}=3M_{H_3PO_4}V_{H_3PO_4}[/tex]
Now, solving for the concentration of the magnesium hydroxide solution we get:
[tex]M_{Mg(OH)_2}=\frac{3M_{H_3PO_4}V_{H_3PO_4}}{2V_{Mg(OH)_2}} \\\\M_{Mg(OH)_2}=\frac{3*0.20M*0.0300L}{2*0.050L}=0.18M[/tex]
Now, for the reaction between hydrochloric acid and magnesium hydroxide we have:
[tex]Mg(OH)_2+2HCl\rightarrow MgCl_2+2H_2O[/tex]
[tex]2M_{Mg(OH)_2}V_{Mg(OH)_2}=M_{HCl}V_{HCl}[/tex]
Therefore, solving for the concentration of the hydrochloric acid solution we get:
[tex]M_{HCl}=\frac{2M_{Mg(OH)_2}V_{Mg(OH)_2}}{V_{HCl}} \\\\M_{HCl}=\frac{2*0.18M*0.078L}{0.025L}\\\\M_{HCl} = 1.12M[/tex]
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What is aspartame? EXPLAIN
Answer:
it's an artificial non-saccharide sweetener 200 times sweeter than sucrose, and is commonly used as a sugar substitute in foods and beverages. it's a methyl ester of the aspartic acid/phenylalanine dipeptide with the trade names NutraSweet, Equal, and Canderel
Explanation:
Answer:
Aspartame is some type of very sweet substance that is used as an artificial sweetener, and chiefly in low-calorie products. It is a derivative of aspartic acid and phenylalanine.
Explanation:
As a part of a clinical study, a pharmacist is asked to prepare a modification of a standard 22g package of a 2% mupirocin ointment by adding the needed quantity of mupirocin powder to prepare a 3% w/w mupirocin ointment. How many mg of mupirocin powder are required?
Answer:
226.8 mg of mupirocin powder are required
Explanation:
Given that;
weight of standard pack = 22 g
mupirocin by weight = 2%
so weight of mupirocin = 2% × 22 = 2/100 × 22 = 0.44 g
so by adding the needed quantity of mupirocin powder to prepare a 3% w/w mupirocin ointment
mg of mupirocin powder are required = ?, lets rep this with x
Total weight of ointment = 22 + x g
Amount of mupirocin = 0.44 + x g
percentage of mupirocin in ointment is 3?
so
3/100 = 0.44 + x g / 22 + x g
3( 22 + x g ) = 100( 0.44 + x g )
66 + 3x g = 44 + 100x g
66 - 44 = 100x g - 3x g
97 x g = 22
x g = 22 / 97
x g = 0.2268 g
we know that; 1 gram = 1000 Milligram
so 0.2268 g = x mg
x mg = 0.2268 × 1000
x mg = 226.8 mg
Therefore, 226.8 mg of mupirocin powder are required
We have that for the Question "How many mg of mupirocin powder are required? "
It can be said that
[tex]0.2268g[/tex] of mupirocin powder is required
From the question we are told
a pharmacist is asked to prepare a modification of a standard 22g package of a 2% mupirocin ointment by adding the needed quantity of mupirocin powder to prepare a 3% w/w mupirocin ointment
Weight of standard package = 22g
mupirocin = 2%
Therefore,
Weight of mupirocin = [tex]\frac{2}{100}*22[/tex]
[tex]=0.44g[/tex]
Let amount of mupirocin to be added to prepare 3% w/w mupirocin ointment = X
Therefore,
Total weight of ointment = [tex](22 + X)g[/tex]
amount of mupirocin = [tex](0.44+X)g[/tex]
% of mupirocin in ointment = [tex]3\%[/tex]
therefore,
[tex]\frac{3}{100} = \frac{0.44+X}{22+X}\\\\66+3X = 44+100X\\\\X = 0.2268g[/tex]
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Uranus has a force of Gravity of 8.87 m/s^2. Sam has a MASS of 85 kg. What is his weight in Uranus? *
Answer:
Explanation:
Weight = mass x gravity
mass given = 85 kg
gravity = 8.87 m /s²
Weight = 85 x 8.87 = 753.95 N .
Weight on Uranus = 753.95 N .
How many grams are in 3.21 x 1024 molecules of potassium hydroxide?
Answer:
3287.04 grams
Explanation:
The mass of 3.21 × 10²⁴ molecules of potassium hydroxide is equal to 298.5 g.
What is Avogadro's number?Avogadro’s constant can be explained as the proportionality factor that can be used to count the number of particles such as molecules, atoms, or ions in a given sample with a definite amount of substance.
Avogadro's number can be described as the approximate number of nucleons in 1 gram of substance. The value of the Avogadro constant can be expressed as the mass of one mole of a compound, in grams.
The value of Avogadro’s number is found about 6.022×10²³ mol⁻¹.
Given, the number of molecules of the KOH = 3.21 × 10²⁴
The mass of the one mole of KOH = 56 g/mol
The 6.022 × 10²³ molecules of KOH has mass = 56 g
The mass of 3.21 × 10²⁴ molecules of KOH = 56×(3.21× 10²⁴/6.022 × 10²³)
= 298.5 g
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The number of atoms in 10. grams of calcium is equal to 6.0 x 1023 multiplied by which number?
Answer:
1.51×10²³ atoms.
Explanation:
From the question given above, the following data were obtained:
Mass of Calcium (Ca = 10 g
Number of atom of Calcium (Ca) =?
The number of atoms present in 10 g of Ca be obtained as follow:
From Avogadro's hypothesis, we understood that 1 mole of any substance contains 6.02×10²³ atoms. This implies that 1 mole Ca contains 6.02×10²³ atoms.
1 mole of Ca = 40 g.
Now, if 40 g of Ca contains 6.02×10²³ atoms.
Therefore, 10 g of Ca will contain = (10 × 6.02×10²³) / 40 = 1.51×10²³ atoms.
Thus, 10 g of calcium contains 1.51×10²³ atoms.
A chemist has a block of copper metal (density is 8.96). They drop the metal into a graduated cylinder containing water, and find the volume change is 2.90 mL. What is the mass of the block , in grams?
Answer:
26g
Explanation:
Given parameters:
Density = 8.96g/cm³
Volume of metal = 2.9mL
Since 1mL = 1cm³;
Volume = 2.9cm³
Unknown:
Mass of the blocks in grams = ?
Solution:
Density is the mass per unit volume of a substance;
Mass = density x volume = 8.96 x 2.9 = 26g
4. Which employees should be aware of how to turn off power to a shop in an emergency?
Answer:
All employees should know how to work the system
1 Define Soft water and Hard water.
Answer
software is a set of instruction given to a computer to perform specific function. MS office etc.
the tangible parts of a computer are known as hardware.
Explanation:
software pprforms the function while hardwares are the structural parts of a computer.
What determines the change of an ion formed by an atom
Answer:
Ions are formed when the number of protons in an atom does not equal the number of electrons. If more protons are present, the ion is positive and is known as a cation; if more electrons are present, the ion is negative and referred to as an anion. Ions are highly reactive species.
Explanation:
Answer:
An atom becomes charged when the number of protons does not equal the number of electrons. For example, if an element has six protons but only five electrons, the net charge of the element is +1. Conversely, if an element has six protons but seven electrons, then the net charge of the element is -1.
Explanation:
6. 7. A hyperbaric chamber has a volume of 200. L. (a) How many moles of oxygen are needed to fill the chamber at room temperature (23°C) and 3.00 atm pressure? b) How many grams of oxygen are needed? (Hint: Since moles have been asked, which equation has the moles listed in the equation. Use that to solve this problem. Also don’t forget to use the equation 1 mole = Formula weight or Molecular weight to calculate the grams of O2).
Answer:
a) 24.7 mol
b) 790 g
Explanation:
Step 1: Given data
Volume of the chamber (V): 200. LRoom temperature (T): 23 °CPressure of the gas (P): 3.00 atmStep 2: Convert "T" to Kelvin
We will use the following expression.
K = °C + 273.15
K = 23°C + 273.15 = 296 K
Step 3: Calculate the moles (n) of oxygen
We will use the ideal gas equation.
P × V = n × R × T
n = P × V/R × T
n = 3.00 atm × 200. L/(0.0821 atm.L/mol.K) × 296 K = 24.7 mol
Step 4: Calculate the mass (m) corresponding to 24.7 moles of oxygen
The molar mass (M) of oxygen ga sis 32.00 g/mol. We will calculate the mass of oxygen using the following expression.
m = n × M
m = 24.7 mol × 32.00 g/mol = 790 g
The diagram below represents the organizational levels of living things.
organisms
organ systems
?
tissues
cells
Which of the following examples represents the missing organizational level?
A blood
B heart
C plasma
D vein
Answer: its vein
Explanation:
Answer: It’s blood
Explanation:
I did the quiz
identified the nucleus that is found in an item that has a stable valance electron configuration
Answer:
Nucleus 3 i believe
Write a description of how you know a chemical reaction is occurring.
ANSWER FAST FIRST PERSON GETS BRAINLIEST
Answer:
See explanation
Explanation:
Chemical reactions are also referred to as chemical change. A chemical change often leads to the formation of new substances and is not easily reversible.
A chemical reaction may be accompanied by the emission of heat and light, formation of a precipitate, evolution of gas, or a color change.
These observable physical effects may tell us weather a chemical reaction has taken place or not so we have to observe the system closely for any of these effects stated above.
helppp nowwww please!!!!
Answer:
The sun will appear to rise and set more slowly
have a nice day! (^o^)
How many moles of phosphoric acid would be needed to produce 15 grams of water?
Moles of phosphoric acid would be needed : 0.833
Further explanationGiven
15 grams of water
Required
moles of phosphoric acid
Solution
Reaction(decomposition) :
H3PO4 -> H2O + HPO3
mol water (H2O :
= mass : MW
= 15 g : 18 g/mol
= 0.833
From the equation, mol ratio H3PO4 = mol H2O = 1 : 1, so mol H3PO4 = 0.833
In the Energy and Specific Heat lab, what temperature should be recorded as the final temperature of the water when measuring the food sample?
A. The temperature of the water when the food sample is first lit
B. The temperature of the water when the food sample has finished burning completely.
C. The highest temperature the water reaches as the sample burns
D. The temperature of the water after the food sample ash has been removed
Answer:
B. The temperature of the water when the food sample has finished burning completely.
Explanation:
Heat or thermal energy is a form of energy that transfers from one object to another due to a temperature difference between the objects. The units for heat are joules or calories.
Calorimetry is the measurement of heat energy released or absorbed in a chemical reaction. A calorimeter is used in calorimetry. The calorimeter operates on the Law of Conservation of Energy which states that energy is never created or destroyed but is transformed from one form to another or between objects.
In food calorimetry, the energy released when food is burned is measured by recording the rise in temperature of water in a calorimeter when a given mass of a food sample is burned completely.
Energy can be calculated using the formula: Q = mc ∆T
where Q = the energy in joules or calories, m = the mass in grams, c = specific heat and ∆T = the change in temperature (final temperature - initial temperature).
The temperature of the water when the food sample has finished burning completely is taken as the final temperature of the water. The sample is allowed to smolder for sometime before recording the final water temperature. This is because the water temperature will continue to rise after the flame has gone out.
What best describes how the processes of scientific
investigation and technological design are involved in
this situation?
O The clothing company conducted a scientific
investigation to communicate results to researchers,
who then used the knowledge in a technological
design.
O The clothing company conducted a scientific
investigation to produce a product that researchers
could then test while designing new technology.
O The clothing company used technological design to
create a product that helped aid researchers
conducting a scientific investigation.
O The clothing company designed a new technology
that provided information researchers needed in order
to continue with their scientific investigation.
Answer:
O The clothing company conducted a scientific investigation to communicate results to researchers, who then used the knowledge in a technological
design.
Explanation:
The products of scientific investigation are converted into technology for use engineers.
Engineering is the application of science to solve life problems. Science in itself is an inquiry into nature.
Science uses a series of methodical approaches to conduct investigations and researches. The product of the research is taken up by an engineer. The engineer deploys this into the right and applicable technology available. In the clothing company, the product of the investigation are relayed to the engineers who uses technological innovations to design a new tool for use.