Answer:
Chemical
Explanation:
Whenever "burns" is being used, most of the time it is a chemical change
Answer:
chemical change
Explanation:
it's a chemical change because when gas burn it produces water and carbon dioxide
Which of these statements gives a correct reason as to why our body needs water?
(1 Point)
1. It provides us with energy.
2. It helps us to eliminate waste.
3. It helps regulate our body temperature.
Answer:
2. It helps us to eliminate waste
3. It helps regulate our body temperature
Explanation:
In addition to the function of bringing nutrients to the cells, water provides the elimination of substances out of the body. This occurs, for example, through urine, which is basically formed by water and toxic or excess substances dissolved.
Water also helps in regulating body temperature. This occurs when the heat becomes exaggerated, sweat is released, which has water in its composition. When in contact with the medium, the sweat evaporates on the surface of the skin, causing the body to cool.
Which of the following aqueous solutions are good buffer systems? . 0.24 M hydrochloric acid + 0.23 M sodium chloride 0.28 M ammonia + 0.35 M ammonium nitrate 0.16 M barium hydroxide + 0.28 M barium bromide 0.15 M nitrous acid + 0.14 M potassium nitrite 0.35 M calcium nitrate + 0.21 M calcium iodide
Answer: 0.28 M ammonia + 0.35 M ammonium nitrate and 0.15 M nitrous acid + 0.14 M potassium nitrite
Explanation:
Buffer solution is the solution which resists the change in the magnitude of the pH when small additions of either acid or base is added.
Acidic Buffer solutions consist of weak acid and its conjugate base usually mixed in relatively equal and large quantities.
Basic Buffer solutions consist of weak base and its conjugate acid usually mixed in relatively equal and large quantities.
Thus 0.28 M ammonia + 0.35 M ammonium nitrate ( weak base + conjugate acid) and 0.15 M nitrous acid + 0.14 M potassium nitrite (weak acid + conjugate base) are good buffer systems
The aqueous solutions that are good buffer systems are:
0.28 M ammonia + 0.35 M ammonium nitrate. 0.15 M nitrous acid + 0.14 M potassium nitrite.We want to determine which of the given solutions would make a good buffer.
What is a buffer?A buffer is a solution used to resist abrupt changes in pH when an acid or a base is added.
What kinds of buffers exist?Acidic buffer: formed by a weak acid and its conjugate base.Basic buffer: formed by a weak base and its conjugate acid.Which of the following aqueous solutions are good buffer systems?
0.24 M hydrochloric acid + 0.23 M sodium chloride. No, since HCl is a strong acid.0.28 M ammonia + 0.35 M ammonium nitrate. Yes, it would be a good basic buffer.0.16 M barium hydroxide + 0.28 M barium bromide. No, since Ba(OH)₂ is a strong base. 0.15 M nitrous acid + 0.14 M potassium nitrite. Yes, it would be a good acidic buffer.0.35 M calcium nitrate + 0.21 M calcium iodide. No, since no acids nor bases are present.The aqueous solutions that are good buffer systems are:
0.28 M ammonia + 0.35 M ammonium nitrate. 0.15 M nitrous acid + 0.14 M potassium nitrite.Learn more about buffers here: brainly.com/question/24188850
A base has a molarity of 1.5 M with respect to the hydroxyl ion (OH-) concentration. If 7.35 cm³ of this base is taken and diluted to 147 cm³, then what is the concentration of the hydroxyl ion. How many moles of hydroxyl ion are there in the 7.35 cm³? In the 147 cm³?
Answer:
0.077M is the concentration of the hydroxyl ion
Explanation:
If 7.35 cm3 of this base is take and diluted to 147 cm3, then what is the concentration of the hydroxyl ion?
Use the dilution equation:
M1V1 = M2V2
M1 * 147cm³ = 1.5 M * 7.35 cm³
M1 = 1.5 M * 7.35 cm³ / 147 cm³
M1 = 0.077 M
0.077M is the concentration of the hydroxyl ionHow many moles of hydroxyl ion are there in the 7.35 cm3?
1000 cm³ contains 1.5 mol OH- ions
7.35 cm³ contains : 7.35 cm³ / 1000 cm³ *1.5 mol
= 0.011025 mol
Answer correct to 2 significant digits = 0.011 mol OH- ions.A solution of pentane and ethanol (CH3CH2OH)that is 50.% pentane by mass is boiling at 57.2°C. The vapor is collected and cooled until it condenses to form a new solution.
Calculate the percent by mass of pentane in the new solution. Here's some data you may need:
normal boiling point density vapor pressure at
57.2°C
pentane 36.°C 0.63gmL 1439.torr
ethanol 78.°C 0.79gmL 326.torr
Be sure your answer has 2 significant digits.
dont round during math only for answer!
Note for advanced students: you may assume the solution and vapor above it are ideal.
Answer:
The correct answer is 81.52 percent.
Explanation:
Based on the given information, the boiling point of pentane is 36 degree C and the boiling point of ethanol is 78 degree C. The density of pentane and ethanol is 0.63 g/ml and 0.79 g/ml. The vapor pressure of pentane at 57.2 degree C is 1439 torr and the vapor pressure of ethanol at 57.2 degree C is 326 torr.
In the given case, 50 percent pentane by mass signifies that mass of pentane is 50 grams. Thus, the mass of ethanol will be 100-50 = 50 grams.
The moles or n can be calculated by using the formula,
n = weight/molecular mass
The molecular mass of pentane is 72.15 g per mol and the molar mass of ethanol is 46.07 g/mol.
The moles of pentane is,
= 50 g/72.15 g/mol = 0.6930 mol
The moles of ethanol is,
= 50 g/46.07 g/mol = 1.0853 mol
The mole fraction of pentane is,
= 0.6930 mol / (0.6930 + 1.0853) mol = 0.3897
The mole fraction of ethanol is,
= 1.0853 mol / (0.6930 + 1.0853) mol = 0.6103
Now the vapor pressure of solution will be,
= pressure of pentane * mole fraction of pentane + pressure of ethanol * mole fraction of ethanol
= (1439 * 0.3897) + (326 * 0.6103)
= 759.736 torr
The vapor pressure of pentane within the solution,
= vapor pressure of pentane * mole fraction of pentane
= 1439 torr * 0.3897
= 560.778 torr
The fraction of pentane is,
= 560.778 / 759.736 = 0.738
Let us assume that the total mole is 1, the mole fraction of pentane is 0.738, so the mole fraction of ethanol will become, 1-0.738 = 0.262
The mass of pentane = 0.738 * 72.15 = 53.2467
The mass of ethanol = 0.262 * 46.07 = 12.07034
The percent by mass of pentane in new solution will be,
Mass% = mass of pentane/Total mass * 100%
= 53.2467/(53.2467 + 12.07034) * 100%
= 53.2467/65.31704 * 100 %
= 81.52 %
Use the formation reactions below such that when added together, they match the balanced equation for the combustion of methane.
Cgraphite(s)+ 2H2(g) → CH4(g) ΔH 1=−74.80kJ
Cgraphite(s)+ O2(g) → CO2(g) ΔH2=−393.5k
H2(g)+ 1/2O2(g) → H2O(g) ΔH3=−241.80kJ
Calculate ΔHrxn for the combustion of methane, CH4(g).
CH4(g)+ 2O2(g) → CO2(g)+ 2H2O(g) ΔHrxn =--------------kJ
Answer:
ΔH of the reaction is -802.3kJ.
Explanation:
Using Hess's law, you can know ΔH of reaction by the sum of ΔH's of half-reactions.
Using the reactions:
(1) Cgraphite(s)+ 2H₂(g) → CH₄(g) ΔH₁ = −74.80kJ
(2) Cgraphite(s)+ O₂(g) → CO₂(g) ΔH₂ = −393.5k J
(3) H₂(g) + 1/2 O₂(g) → H₂O(g) ΔH₃ = −241.80kJ
The sum of (2) - (1) produce:
CH₄(g) + O₂(g) → CO₂(g) + 2H₂(g) ΔH' = -393.5kJ - (-74.80kJ) = -318.7kJ
And the sum of this reaction with 2×(3) produce:
CH₄(g) + 2 O₂(g) → CO₂(g) + 2H₂O(g) And ΔH = -318.7kJ + 2×(-241.80kJ) =
-802.3kJ
Hot coffee in a mug cools over time and the mug warms up. Which describes the energy in this system? The average kinetic energy of the particles in the mug decreases. The average kinetic energy of the particles in the coffee increases. Thermal energy from the mug is transferred to the coffee. Thermal energy from the coffee is transferred to the mug.
Answer:
d
Explanation:
Answer:
D
Explanation:
Edge 2021
What are extensive properties of Oxygen?
10. How many grams of NH, are present in 6 moles
of NH,?
Answer:
90.08784 grams
Explanation:
idk
An ethylene glycol solution contains 21.4 g of ethylene glycol (C2H6O2) in 97.6 mL of water.
Required:
a. Determine the freezing point of the solution. Express you answer in degrees Celsius. (Assume a density of 1.00 g/mL for water.)
b. Compute the boiling point of the solution. (Assume a density of 1.00 g/mL for water.)
Answer:
a. TFinal = -6.57°C
b. Tfinal = 101.80°C
Explanation:
When a solute is added to a solvent producing an ideal solution, the freezing point of the solution decreases with regard to pure solvent. Also, boiling point increases with regard to pure solvent.
The formulas are:
Freezing point:
ΔT = Kf×m×i
Where Kf is freezeing point depression constant of water (1.86°C/m), m is molality of solution and i is van't Hoff factor (1 for ethylene glycol).
Boiling point:
ΔT = Kb×m×i
Where K is freezeing point depression constant of water (0.51°C/m), m is molality of solution and i is van't Hoff factor (1 for ethylene glycol).
Moles of 21.4g of ethylene glycol (Molar mass: 62.07g/mol) are:
21.4g C₂H₆O₂ ₓ (1mol / 62.07g) = 0.345 moles
And kg of 97.6mL of water = 97.6g are 0.0976kg. Molality of the solution is:
0.345mol / 0.0976kg = 3.5325m
Replacing in the formulas:
a. Freezing point:
ΔT = 1.86C/m×3.5325m×1
ΔT = 6.57°C
0°C - Tfinal = 6.57°C
TFinal = -6.57°Cb. Boiling point:
ΔT = 0.51°C/m×3.5325m×1
ΔT = 1.80°C
Tfinal - 100°C = 1.80°C
Tfinal = 101.80°C
The reaction of hydrogen bromide(g) with chlorine(g) to form hydrogen chloride(g) and bromine(g) proceeds as follows: 2HBr(g) + Cl2(g)2HCl(g) + Br2(g) When 23.9 g HBr(g) reacts with sufficient Cl2(g), 12.0 kJ is evolved. Calculate the value of rH for the chemical equation given.
Answer:
The enthalpy of reaction per mole of HBr for this reaction = ΔrH = -40.62 kJ/mole.
Explanation:
2HBr(g) + Cl2(g) → 2HCl(g) + Br2(g)
When 23.9 g HBr(g) reacts with sufficient Cl2(g), 12.0 kJ of heat is evolved, calculate the value of ΔrH for the chemical reaction.
Note that ΔrH is the enthalpy per mole for the reaction.
Molar mass of HBr (g) = 80.91 g/mol.
Hence, 1 mole of HBr = 80.91 g
23.9 g of HBr led to the reaction giving off 12.0 kJ of heat
80.91 g of HBr will lead to the evolution of (80.91 × 12/23.9) = 40.62 kJ heat is given off.
Hence, 40.62 kJ of heat is given off per 80.91 g of HBr.
This directly translates to that 40.62 kJ of heat is given off per 1 mole of HBr
Hence, the heat given off per mole of HBr for this reaction is 40.62 kJ/mole.
But since the reaction liberates heat, it means the reaction is exothermic and the enthalpy change for the reaction (ΔHrxn) is negative.
Hence, ΔrH = -40.62 kJ/mole.
Hope this Helps!!!
A growing concern in agricultural and food chemistry is the presence of residues in food. We use many forms of organic chemicals in agriculture and food chemistry and there is growing concern as to how safe these materials are. Choose an organic chemical used in agricultural of food chemistry and report on the functional groups contained in your compound, the uses of the compound, and the safety of that compound.
Answer:
Monosodium Glutamate (MSG) is a chemical which is used in agricultural of food chemistry.
Explanation:
Monosodium Glutamate (MSG) is a chemical that is used in types of different food as food additives. The functional group that is present in Glutamate are carboxylic acid and amine. This chemical is used in different types of foods which is responsible for enhancing the taste of the food. Monosodium Glutamate is safe if it is used in moderate dose but adversely affected when it is used in large amount.
If a jet’s cruising altitude is 32,200ft(to three significant figures),the distance in km is :(1 mile=1.61km;1 mile=5280 ft)
Answer:
9.82 km.
Explanation:
Hello,
In this case, given the conversion factors from miles to kilometres and from miles to feet, we can directly compute the jet’s cruising altitude in kilometres as shown below:
[tex]32,200ft\times \frac{1mile}{5280ft}\times \frac{1.61km}{1mile} \\\\=9.82km[/tex]
Best regards.
A vegetable soup recipe requires one teaspoonful of salt. A chef accidentally puts in one tablespoonful. Now the soup is much too salty.
a) What can the chef do to reduce the salty taste of the soup?
b) What effects would your suggestion in a) have on the soup?
Answer:
a. Put a piece of fresh sliced yam with a bore into it into the soup.
Explanation:
b. Osmosis may occur
The chef can put a slice of yam in the soup with a hole in it as it will absorb excess of salt by process of diffusion.
What is diffusion?
Diffusion is defined as the process of movement of molecules which takes place under concentration gradient. It helps in movement of substances in and out from the cell.The molecules move from lower concentration region to a higher concentration region till the concentration becomes equal.
There are 2 main types of diffusion:
1) simple diffusion-process in which substances move through a semi-permeable membrane without the aid of transport proteins.
2) facilitated diffusion- It is a passive movement of molecules across cell membrane from higher concentration region to lower concentration.
There are 2 types of facilitated diffusion one is osmosis and dialysis.
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If a gas occupies 12.60 liters at a pressure of 1.50 atm, what will its pressure at a volume of 2.50 liters?
Answer:
7.56 atm
Explanation:
Boyle's law states that the pressure and volume of a gas are proportional to each other
The formular for Boyle's law is
P1V1=P2V2
According to the question above, the values given are
P1=1.50 atm
P2= ?
V1=12.60 litres
V2= 2.50 litres
Let us make P2 the subject of formular
P2= P1V1/V2
P2= 1.50×12.60/2.50
P2= 18.9/2.50
P2= 7.56 atm
Hence when the volume of a gas is 2.50 litres then it's pressure is 7.56 atm
What is a good title for this chart?
Answer:
pH of the acid
Explanation:
ions always have the same electronic structure as elements in which group of the periodic table?
Answer:
In 0 group of the periodic table
Explanation:
So they will not react with other atoms because they have a full outer shell of electrons and an overall charge of 0.
Hope it helps.
calculate the moles of 25.2 g Na2S2O8
Answer:
To calculate the moles we must first find the molar mass M
M (Na2S2O8) = (23*2) + (32*2) + (16*8)
= 46 + 64 + 168
= 278g/mol
Molar mass = mass/moles
moles =mass / molar mass
= 25.2/278
= 0.0906mol
Hope this helps.
Determine the limiting reactant in a mixture containing 95.7 g of B2O3, 75.7 g of C, and 369 g of Cl2. Calculate the maximum mass (in grams) of boron trichloride, BCl3, that can be produced in the reaction. The limiting reactant is:
Answer:
[tex]B_2O_3[/tex]
Explanation:
First, we have to find the reaction:
[tex]B_2O_3~+~C~+~Cl_2~->~BCl_3~+~CO[/tex]
The next step is to balance the reaction:
[tex]B_2O_3~+~3C~+~3Cl_2~->~2BCl_3~+~3CO[/tex]
Now, we have to calculate the molar mass for each compound, so:
[tex]B_2O_3=~69.62~g/mol[/tex]
[tex]C=~12~g/mol[/tex]
[tex]Cl_2=~70.96~g/mol[/tex]
With these values, we can calculate the moles of each compound:
[tex]95.7~g~B_2O_3\frac{1~mol~B_2O_3}{69.62~g~B_2O_3}=1.37~mol~B_2O_3[/tex]
[tex]75.7~g~C\frac{1~mol~C}{112~g~C}=6.30~mol~C[/tex]
[tex]369~g~Cl_2\frac{1~mol~Cl_2}{70.96~g~C}=5.20~mol~Cl_2[/tex]
Now we can divide by the coefficient of each compound in the balanced equation:
[tex]\frac{1.37~mol~B_2O_3}{1}=~1.37[/tex]
[tex]\frac{6.30~mol~C}{3}=~2.1[/tex]
[tex]\frac{5.20~mol~Cl_2}{3}=~1.73[/tex]
The smallest values are for [tex]B_2O_3[/tex], so this is our limiting reagent.
I hope it heps!
When you turn on the air conditioner during a hot summer day the cooler air will sink to the floor, while warmer air rises to the
ceiling
Which type of heat transfer is this an example of?
(A) conduction
(B) convection
(C) radiation
(D)
kinetic
The boiling point of ethanol is 78.40°C. A student conducts an
experiment and finds a boiling point of 75.70°C. How far off
from the accepted value was the student's result?
Error = °C
Answer:
2.7 °C
Explanation:
78.4-75.7=2.7
The student's result is 2.7° C less than the expected result.
We have a student conducting an experiment to find the boiling point of ethanol.
We have to determine how far off from the accepted value is the student's result.
What is Measurement error ?Measurement Error (also called Observational Error) is the difference between a measured quantity and its true value.
According to the question, we have -
True value of the boiling point of ethanol [T] = 78.40°C.
Measured value of the boiling point of ethanol [M] = 75.70°C.
The Error (E) in the measurement will be -
E = T - M
E = 78.40° - 75.70° = 2.7° C
Hence, the student's result is 2.7° C less than the expected result.
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Use bond energies to calculate ΔHrxn Δ H r x n for the reaction. 2H2(g)+O2(g)→2H2O(g) 2 H 2 ( g ) + O 2 ( g ) → 2 H 2 O ( g )
Answer:
[tex]\large \boxed{\text{-486 kJ}}[/tex]
Explanation:
You calculate the energy required to break all the bonds in the reactants.
Then you subtract the energy needed to break all the bonds in the products.
2H₂ + O₂ ⟶ 2H-O-H
Bonds: 2H-H 1O=O 4H-O
D/kJ·mol⁻¹: 436 498 464
[tex]\begin{array}{rcl}\Delta H & = & \sum{mD_{\text{reactants}}} - \sum{nD_{\text{products}}}\\& = & 2 \times 436 +1 \times 498 - 4 \times 464\\&=& 1370 - 1856\\&=&\textbf{-486 kJ}\\\end{array}\\\text{The enthalpy of reaction is $\large \boxed{\textbf{-486 kJ}}$}.[/tex]
Why don't we discuss the results during the results section of the project?
Answer: The result section of the project contains your findings while carrying out your research or study.
Explanation:
The Results section of a research or study usually contains only the findings of your study or research.The findings which usually include
1. Data presented in tables, charts, graphs, and other figures.
2. A contextual analysis of this data explaining its meanings. Usually in sentences.
Our result gotten is not discussed in result section because every project or research work has a discussion page where every results or findings are discussed. The result section is expected to carry what you found.
2 FONS
How does the electric force between two charged particles change if the
distance between them is increased by a factor of 22
A. It increases by a factor of 4.
B. It increases by a factor of 2.
C. It decreases by a factor of 4
O
D. It decreases by a factor of 2.
SUB
Answer:
C. It decreases by a factor of 4
Explanation:
F1 = kq1*q2/r²
F2 = kq1*q2/(2r)² = kq1*q2/(4r²) = kq1*q2/(r²*4) = F1/4
What allows two or more atoms to be held together?
Answer:
Atoms come together to form molecules because of their electrons. Electrons can join (or bond) atoms together in two main ways. When two atoms share electrons between them, they are locked together (bonded) by that sharing. These are called covalent bonds.
Explanation:
Answer:
Electrons
Explanation:
took the test got 100%
Suppose that while you're in the lab performing a simple distillation you encountered one of the following errors: The components within the mixture, isopropanol and dichloromethane, distilled well below their boiling point. Poor separation between isopropanol and dichloromethane was observed. The initial volume of the distillation mixture has decreased significantly, almost dry, but no distillate was collected.
Answer:
Isopropanol and dichloromethane, distilled well below their boiling point.
Explanation:
The best way to separate isopropanol and dichloromethane is the method of fractional distillation. In this method, different compounds separate from each other due to difference in boiling. The boiling point of dichloromethane is 39.6 degree Celsius which is lower than the boiling point of isopropanol which is 82.5 degree Celsius. So dichloromethane will be evaporated when the temperature reaches to 40 degree Celsius and separated from isopropanol before reaching its boiling point.
Solids in which the atoms have no particular order or pattern are called what solids
Answer:
Amorphous solids .
Explanation:
They have no particular order or pattern.Each particle is in a particular spot, but the particles are in no organized pattern.
4.The reaction of 0.25 g magnesium with 100.0 mL of 2 M hydrochloric acid (density d = 1.039 g/ml) raises the temperature of the solution from 20.0 °C to 35.0 °C. The specific heat for HCl is 3.98 J/(g.C). Mg(s) + 2HCl(aq) —> MgCl2(aq) + H2(g) Calculate the heat of the reaction. (Use the equation Q = s . m .ΔT where s is the specific heat, m is the mass of solution and ΔT is the change in temperature)
Answer:
[tex]Q=450.14J[/tex]
Explanation:
Hello,
In this case, for the given equation to compute the heat, we should compute the mass of the solution of hydrochloric acid, thus, the first step is to compute its reacting mass:
[tex]m_{HCl}^{reacting}=2\frac{mol}{L}*0.1000L *\frac{36.45g}{1mol}=7.29g[/tex]
Then, we obtain the total mass of the formed solution:
[tex]m=0.25g+7.29g=7.54g[/tex]
In such a way, we can infer that the specific heat of the solution is mainly the specific heat of hydrochloric acid, therefore the heat turns out:
[tex]Q=3.98\frac{J}{g\°C} *7.54g*(35.0\°C-20.0\°C)\\\\Q=450.14J[/tex]
Regards.
Classify the following unbalanced chemical reaction Na3PO4(aq) + FecCl2(aq) = Fe3(PO4)2(s) + NaCl(aq)
1. Acid-Base Reaction
2. Precipitation Reaction
3. Oxidation-Reduction Reaction
4. Combustion Reaction
Answer:
2. Precipitation Reaction
Explanation:
Na3PO4(aq) + FecCl2(aq) = Fe3(PO4)2(s) + NaCl(aq)
Fe3(PO4)2(s) - solid, it means it will precipitate.
It is a precipitation reaction.
What is precipitate give example?A precipitate is a solid that forms out of a solution. A common example is that of the mixing of two clear solutions: (1) silver nitrate (AgNO3) and (2) sodium chloride (NaCl): The reaction is. The precipitate forms because the solid (AgCl) is insoluble in water.
What is precipitate formation?A precipitate is a solid formed in a chemical reaction that is different from either of the reactants. This can occur when solutions containing ionic compounds are mixed and an insoluble product is formed. The identity of the precipitate can often be determined by examining solubility rules.
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Which is true regarding a water molecule?
Answer:
Has many answers, but one is that it consists of small polar v shaped molecules with a molecular formula H20.
Explanation:
Water molecules consists of 2 hydrogen atoms bonded with on oxygen atom. Each molecule is electrically neutral but polar, with the center of positive and negative charges located in different places.
Each hydrogen atom has a nucleus consisting of a single positively-charged proton surrounded by a 'cloud' of a single negatively-charged electron and the oxygen atom has a nucleus consisting of eight positively-charged protons and eight uncharged neutrons surrounded by a 'cloud' of eight negatively-charged electrons.
Hoped this helped!
if 196L of air at 1 atm is compressed to 2600mL,what is the new temperature?
Answer:
Around 3.62 degrees kelvin
Explanation:
Assuming this is at STP:
The first step is to convert 2600mL to liters. There are 1000 milliliters in a liter, meaning that this is equal to 2.6L.
Now:
[tex]\dfrac{P_1V_1}{T_1}=\dfrac{P_2V_2}{T_2}\\\\\\\dfrac{196(1)}{273}=\dfrac{2.6(1)}{T_2} \\\\\\T_2\approx 3.62K[/tex]
Hope this helps!
