Answer:
D. Two scientists may have different underlying assumptions that lead them to different conclusions about the same thing.
Explanation:
It's all about how a person analyzes data. Some do it mathmatically while others do it logically. By doing it different ways, you may still come to the same conclusion, despite working at the problem in a different way.
Which of the following is an alkaline earth metal?
A Carbon
B aluminum
C magnesium
D silicon
Answer:
Magnesium.
Explanation:
Because it is in group II
Consider the following reaction at equilibrium. What effect will decreasing the temperature have on the system? DH=+890kJCO2(g)+2H2O(l)<--> CH4(g)+2O2(g)a) the equilibrium constant will increaseb) the reaction will shift to the left in the direction of the reactantsc) the reaction will shift to the right in the direction of the productsd) no effect will be observed
Answer:
Option B. The reaction will shift to the left in the direction of the reactants.
Explanation:
The equation for the reaction is given below:
CO₂ + 2H₂O <=> CH₄ + O₂
Enthalpy change (ΔH) = +890 KJ
The reaction illustrated by the equation is endothermic reaction since the enthalpy change (ΔH) is positive.
Increasing the temperature of an endothermic reaction will shift the equilibrium position to the right and decrease the temperature will shift the equilibrium position to the left.
Therefore, decreasing the temperature of the system illustrated by the equation above, will shift the reaction to the left in the direction of the reactants.
Thus, option B gives the right answer to the question.
why do the Philippines have generally warm temperature throughout the year?a. it is near the sun b.it has many volcanoes c. it lies near the equator d. it has many islands.what is the correct answer?
Answer:
F. When everyone is together it gets hotter
Explanation:
Answer:
c. it lies near the equator
After standardizing a NaOH solution, you use it to titrate an HCl solution known to have a concentration of 0.203 M. You perform five titrations and obtain the following results: 0.210, 0.204, 0.201, 0.202, and 0.197 M. a) What is the mean
Answer:
0.203 is the mean of the concentration of the HCl solution
Explanation:
You have 5 concentrations. The most appropiate result is the mean of those results. The mean is a statistical defined as the sum of each result divided by the total amount of results. For the results of the problem, the mean is:
0.210 + 0.204 + 0.201 + 0.202 + 0.197 = 1.014 / 5 =
0.203 is the mean of the concentration of the HCl solutionA sample of brass, which has a specific heat capacity of , is put into a calorimeter (see sketch at right) that contains of water. The temperature of the water starts off at . When the temperature of the water stops changing it's . The pressure remains constant at . Calculate the initial temperature of the brass sample. Be sure your answer is rounded to significant digits.
Answer:
The initial temperature of the brass sample is 90.1°C
Note: The question is incomplete. A similar but complete question is given below :
A 52.9g sample of brass, which has a specific heat capacity of 0.375·J·g−1°C−1, is put into a calorimeter (see sketch at right) that contains 100.0g of water. The temperature of the water starts off at 15.0°C. When the temperature of the water stops changing it's 18.4°C. The pressure remains constant at 1 atm. Calculate the initial temperature of the brass sample. Be sure your answer is rounded to 2 significant digits.
Explanation:
Assuming that the calorimeter is an isolated system and that no heat is lost from the calorimeter. The total heat in the system is the sum of the heat content of the brass and that of water
Total heat lost by the brass = heat gained by the water
The quantity of heat lost or gained, Q = mcΔT
Where m = mass of the substance, c = specific heat capacity of substance, ΔT = temperature change
Heat gained by water is positive while heat lost by brass is negative
mass of brass = 52.9 g, specific heat capacity of brass = 0.375·J·g−1°C−1, ΔT = (18.4 - t °C; where t is the initial temperature), mass of water = 100.0 g, specific heat capacity of water = 4.186 J/g°C, ΔT = = 18.4 - 15.0 = 3.4 °C
Heat lost by brass z= - [ 52.9 × 0.375 × (18.4 - t)] = -365.01 + 19.8375t
Heat gained by water = 100 × 4.186 × 3.4 = 1423.24
Equating heat lost by brass to heat gained by water
-365.01 + 19.8375t = 1423.24
19.8375t = 1423.24 + 365.01
19.8375t = 1788.25
t = 90.1° C
Therefore, the initial temperature of the brass sample is 90.1°C
A sample of 10.6 g of KNO3 was dissolved in 251.0 g of water at 25 oC in a calorimeter. The final temperature of the solution was 21.5 oC. What is the molar heat of solution of KNO3
Answer:
36.55kJ/mol
Explanation:
The heat of solution is the change in heat when the KNO3 dissolves in water:
KNO3(aq) → K+(aq) + NO3-(aq)
As the temperature decreases, the reaction is endothermic and the molar heat of solution is positive.
To solve the molar heat we need to find the moles of KNO3 dissolved and the change in heat as follows:
Moles KNO3 -Molar mass: 101.1032g/mol-
10.6g * (1mol/101.1032g) = 0.1048 moles KNO3
Change in heat:
q = m*S*ΔT
Where q is heat in J,
m is the mass of the solution: 10.6g + 251.0g = 261.6g
S is specififc heat of solution: 4.184J/g°C -Assuming is the same than pure water-
And ΔT is change in temperature: 25°C - 21.5°C = 3.5°C
q = 261.6g*4.184J/g°C*3.5°C
q = 3830.87J
Molar heat of solution:
3830.87J/0.1048 moles KNO3 =
36554J/mol =
36.55kJ/mol
A calorimeter has been filled with 75 mL of water. The density of water at 25 °C is
0.998 g/mL. How many grams of water do you have at 25°C?
Answer:
isn't it 0.998
Explanation:
cause 0.998 is in the same grams / mole. I don't get
A calorimeter has been filled with 75 mL of water. The number of grams of water is 74.85 grams.
What is a calorimeter?A calorimeter is an instrument that is used to measure calorimetry. It is used to measure the heat of chemical reactions and physical and chemical changes.
Mass is the quantity of matter in a physical body. Volume is the space occupied by a three-dimensional object. Mass is the quantity of matter in a physical body. The product of the compound's molar mass and the substance's moles are defined as mass.
Given, that the volume of the water is 75 mL
The temperature of the water is 25 °C
The density of water is 0.998 g/mL
To calculate the mass, the volume is multiplied by density.
Mass = volume x density
putting the values in the formula
75 x 0.998 = 74.85 grams
Thus, the grams of water that have at 25°C is 74.85 grams.
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True/False: Chemical reactions can NOT proceed in the reverse direction
Water has a density of 1.00 g/mL. If you put an object that has a density of 0.79 g/mL into water, it will sink to the
bottom.
ANSWER:
True
False
Answer:
False
Explanation:
An object with a density greater than 1.00g/mL (greater than the density of water) will sink. An object with a density less than the density of water, will float.
If the water has a density of 1.00 g/mL. If you put an object that has a density of 0.79 g/mL into water, it will sink to the bottom, this statement is false.
What is density?The density of an actual content is its mass per unit volume. The most common symbol for density is d, but the Latin letter D can also be used.
Three of an object's most fundamental properties are mass, volume, and density. Mass describes how heavy something is, volume describes its size, and density is defined as mass divided by volume.
The density of something is a measure of how heavy it is in relation to its size. When an artifact is more dense than water, it plunges; when an object is less dense than water, it floats.
Density is a property of a substance that is independent of the amount of substance.
As in the given scenario, water is having density 1 g/mL and object in having density less then it so it will float on water.
Thus, the given statement is false as the material will not sink, rather it will float on water.
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In the context of small molecules with similar molar masses, arrange the intermolecular forces by strength.
a. London dispersion forces
b. hydrogen bonding
c. dipole-dipole interactions
Answer:
Hydrogen bonding - London dispersion forces - dipole-dipole interactions
Strongest ----> Weakest
Na2CO3 reacts with dil.HCl to produce NaCl, H2O and CO2. If 21.2 g of pure Na2CO3 are added in a solution containing 21.9g HCl , a. Find the limiting reagent. (2) b. Calculate the number of moles of excess reagent left over.(2) c. Calculate the number of molecules of H2O formed.(1) d. Calculate volume of CO2 gas produced at 270C and 760mm Hg pressure.(2) e. Write significance of limiting reagent
Answer:
See explanation
Explanation:
Equation of the reaction;
Na2CO3(aq) + 2HCl(aq) -------> 2NaCl(aq) + H2O(l) + CO2(g)
Number of moles of Na2CO3 = 21.2g/106g/mol = 0.2 moles Na2CO3
Number of moles of HCl = 21.9g/36.5g/mol = 0.6 moles of HCl
1 mole of Na2CO3 reacts with 2 moles of HCl
0.2 moles of Na2CO3 reacts with 0.2 × 2/1 = 0.4 moles of HCl
Hence Na2CO3 is the limiting reactant
Since there is 0.6 moles of HCl present, the number of moles of excess reagent=
0.6 moles - 0.4 moles = 0.2 moles of HCl
1 mole of Na2CO3 forms 1 mole of water
0.2 moles of Na2CO3 forms 0.2 moles of water
Number of molecules of water formed = 0.2 moles × 6.02 × 10^23 = 1.2 × 10^23 molecules of water
1 mole of Na2CO3 yields 1 mole of CO2
0.2 moles of Na2CO3 yields 0.2 moles of CO2
1 mole of CO2 occupies 22.4 L
0.2 moles of CO2 occupies 0.2 × 22.4 = 4.48 L at STP
Hence;
V1=4.48 L
T1 = 273 K
P1= 760 mmHg
T2 = 27°C + 273 = 300 K
P2 = 760 mmHg
V2 =
P1V1/T1 = P2V2/T2
P1V1T2 = P2V2T1
V2 = P1V1T2/P2T1
V2 = 760 × 4.48 × 300/760 × 273
V2= 4.9 L
The limiting reactant is the reactant that determines the amount of product formed in a reaction. When the limiting reactant is exhausted, the reaction stops.
Arrange aluminum, boron, nitrogen, and phosphorous in order of increasing electronegativity.
a. Al < N < P < B
b. Al < B < P < N
c. N < P < B < Al
d. B < Al < N < P
Answer:
Option b.
Al < B < P < N
Explanation:
Electronegativity is the capacity of an atom to attract electrons.
Usually, if we look at the periodic table, the elements in the left are the ones with the least electronegativity, and as we go to the right, the electronegativity increases (this is not really exact)
There are a lot of tables of electronegativity that can be used here, we can find that:
element: electronegativity:
N 3.04
B 2.04
P 2.19
Al 1.61
So, the order from least to greatest is:
Al, B, P, N
Then the correct option is:
b: Al < B < P < N
What is the law of multiple proportions?
A. The proportion of elements to compounds is constant.
B. All elements are found in equal proportions in nature.
C. Different compounds may contain the same elements but may have different ratios of those elements.
D. All compounds contain the same elements in the same proportions.
Answer:
a. the proportion of elements to compounds is constant.
What is the first step in the curved arrow mechanism for the chlorination of benzene in the presence of FeCl3
Answer:
See explanation
Explanation:
The chlorination of benzene occurs in the presence of a Lewis acid. A Lewis acid is a compound that can accept a lone pair of electrons.
The first step in the chlorination of benzene is the formation of the ion Cl^+ which attacks the benzene ring.
This ion is formed when the Cl2 molecule undergoes heterolytic fission assisted by FeCl3 to yield FeCl4^- and Cl^+.
The Cl^+ electrophile now attacks the benzene ring to yield chlorobenzene.
A reaction produces 3.0 mol of gas, which occupies 1.46 L. What is the volume of the product when 4.1 mol are produced at constant temperature and pressure?
Answer:
1.99 L
Explanation:
Given that,
A reaction produces 3.0 mol of gas, which occupies 1.46 L.
We need to find the volume of the product when 4.1 mol are produced at constant temperature and pressure.
We know that,
PV = nRT
i.e.
[tex]V\propto n\\\\\dfrac{V_1}{V_2}=\dfrac{n_1}{n_2}\\\\V_2=\dfrac{V_1n_2}{n_1}\\\\V_2=\dfrac{1.46\times 4.1}{3}\\\\V_2=1.99\ L[/tex]
So, the new volume is 1.99 L.
4. What is the percent yield of a reaction that produces 12.5 g CF2Cl2 from 32.9 g of CCl4 and excess HF
Answer:
Percent yield = 48.3%
Explanation:
The reaction is:
CCl₄ + 2HF → CF₂Cl₂ + 2HCl
1 mol of CCl₄ reacts with 2 moles of hydrofluoric acid in order to produce 1 mol of CF₂Cl₂ and 2 moles of hydrogen chloride.
HF is in excess, so the limiting reagent is the CCl₄.
We convert mass to moles:
32.9 g . 1mol / 153.8g = 0.214 moles
Ratio is 1:1. In conclussion: 0.0813 moles of CCl₄ can produce 0.0813 moles of CF₂Cl₂. We convert moles to mass, to determine the theoretical yield:
0.214 mol . 120.91g /mol = 25.8 g
Percent yield = (Yield produced /Theoretical yield) . 100
Percent yield = (12.5 g/ 25.8g) . 100 = 48.3%
What is the mass of 2.30x10^22 formula units of NaOH (molar mass =40.0g/mol)
Answer:
643(%=:(¥75 )(:7$"8"),"7$"()9_/"¥?:
Identify the options below that are results of adding a catalyst to a chemical system.
The reaction rates are increased.
The reaction quotient is unaffected.
The reaction quotient decreases.
The equilibrium constant is unaffected.
Answer:
The correct options are a, b and d
Explanation:
A catalyst is a substance that increases the rate of a chemical reaction by reducing the activation energy. Le Catelier's principle explains how a substance or an "action" can affect a reaction in equilibrium.
The principle states that when a change is made to the conditions of a reacting system at equilibrium, the position of the equilibrium moves to counteract the change made. These changes are change in temperature, pressure, volume and/or concentration. These changes will either cause the equilibrium to shift forward or backward.
However, the presence of a catalyst DOES NOT affect a chemical equilibrium/equilibrium constant nor does it affect the reaction quotient because the same amount of reactants and products are available just as in uncatalyzed reaction except that the reaction proceeds faster (which does not affect equilibrium).
The rate of reaction is given as the time required by the reactant to convert into the product. The addition of catalyst increases the rate of reaction, while the reaction quotient and the equilibrium remain unaffected.
What is a catalyst?A catalyst is a chemical or compound that adds to the reaction and lowers the activation energy by providing an alternative path to the reaction.
The catalyst takes part in the reaction but did not consume in the chemical reaction.
The equilibrium and the reaction quotient are dependent on the conversion of the reactant to the product. The catalyst is not used in the reaction and thus did not affect the reaction quotient or the equilibrium.
Hence, options A, B, and D are correct for the use of catalysts in the chemical reaction.
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Consider the balanced chemical equation below.
3 A ⟶ C + 4 D
How many moles of C would be produced if 7 moles of A were used?
Answer:
2.33 mol C
Explanation:
Step 1: Write the balanced generic chemical equation
3 A ⟶ C + 4 D
Step 2: Establish the appropriate molar ratio
According to the balanced equation, the molar ratio of A to C is 3:1.
Step 3: Calculate the number of moles of C produced from 7 moles of A
We will use the previously established molar ratio.
7 mol A × 1 mol C/3 mol A = 2.33 mol C
Ice and water constitute a system:
A Chemically heterogeneous and physically heterogeneous
B Chemically homogeneous and physically heterogeneous
C Chemically homogeneous and physically homogeneous
D Chemically heterogeneous and physically homogeneous
E None of the above
Answer:
B
Explanation:
It's the same substance but in different states.
HETEROGENEOUS mixtures contain substances that are
not uniform in composition. The parts in the mixture can be separated by physical means.
A 3.0-liter sample of an ideal gas is at a pressure of 2.5 atm at 15oC. (i) How many moles of gas are in the sample? (ii) If the volume does not change, what is the pressure of the gas when the temperature is 50oC?
Explanation:
here are the answers. Note that because the pressure is constant, you can use Gay Lussac's formula
The N H 2 group makes the molecule an amine. Like alcohols, amines can participate in hydrogen bonding. If the drawn molecule encounters water molecules, there will be (select all that apply): a hydrogen bond between the hydrogen of water and the carbon of the amine. a hydrogen bond between the hydrogen of water and the nitrogen of the amine. a hydrogen bond between the oxygen of water and a hydrogen from the -NH2 group. a hydrogen bond between the oxygen of water and a hydrogen from the -CH3 group. no hydrogen bonds.
Answer:
a hydrogen bond between the hydrogen of water and the nitrogen of the amine
a hydrogen bond between the oxygen of water and a hydrogen from the -NH2 group
Explanation:
A hydrogen bond is formed between molecules in which hydrogen is bonded to a highly electronegative element.
In amines, hydrogen is bonded to nitrogen while in water, hydrogen is bonded to oxygen. Both are highly electronegative elements hence hydrogen bonding is possible between amines and water.
This hydrogen bond may involve;
The hydrogen of water and the nitrogen of the amine
Or
The oxygen of water and a hydrogen from the -NH2 group
How long must a 40.0 amp current flow through a solution of iron(III) chloride in order to produce 5.00 moles of iron?
Answer:
10.1 h
Explanation:
Let's consider the reduction half-reaction of iron from an aqueous solution of iron (III) chloride.
Fe³⁺(aq) + 3 e⁻ ⇒ Fe(s)
We can calculate the time required to produce 5.00 moles of Fe using the following relationships.
1 mole of Fe is produced when 3 moles of electrons circulate.1 mole of electrons has a charge of 96486 C (Faraday's constant).1 A = 1 C/s.1 h = 3600 s.[tex]5.00molFe \times \frac{3 mole^{-} }{1molFe} \times\frac{96486C}{1mole^{-} } \times \frac{1s}{40.0C} \times \frac{1h}{3600s} = 10.1 h[/tex]
Complete and balance the equations for the given single displacement reactions. Write the reaction in molecular form. Phases are optional. If you need to clear your work and reset the equation, click the CLR button.Li(s) + H2O---------- Ca(s) + H2O ---------------
Answer:
Li(s) + H2O(l) -----> LiOH(aq) + H2(g)
Ca(s) + 2H2O(l) ---------------> Ca(OH)2(aq) + H2(g)
Explanation:
Metals react with water to yield the metal hydroxide and hydrogen gas as shown in the answer above.
The reaction equations were balanced, the number of atoms of each element on both side of the reaction equation is exactly the same.
This is the way to write a balanced reaction equation for the species shown in the question.
The largest population that an environment can support is called _____.
A) birth capacity
B) death factor
C)limiting factor
D) carrying capacity
Answer:
D) caring capacity
Explanation:
The largest population that an environment can support is called its carrying capacity.hope it helps.stay safe healthy and happy.Answer:
D)
Explanation:
The largest population that an environment can support is by definition a carrying capacity
a sample of copper was heated at 275.1 C and placed into 272 g of water at 21.0 C. The temperature of the water rose at 29.7 C. How many grams of copper were in the sample
Answer:
104.8 g
Explanation:
From the question given above, the following data were obtained:
Initial temperature of copper (T꜀) = 275.1 °C
Mass of water (Mᵥᵥ) = 272 g
Initial temperature of water (Tᵥᵥ) = 21 °C
Equilibrium temperature (Tₑ) = 29.7 °C
Mass of copper (M꜀) =?
NOTE:
Specific heat capacity of copper (C꜀) = 0.385 J/gºC
Specific heat capacity of water (Cᵥᵥ) = 4.184 J/gºC
Finally, we shall determine the mass of the copper in the sample. This can be obtained as follow:
Heat loss by copper = Heat gained by water
M꜀C꜀(T꜀ – Tₑ) = MᵥᵥCᵥᵥ(Tₑ – Tᵥᵥ)
M꜀ × 0.385 (275.1 – 29.7) = 272 × 4.184(29.7 – 21)
M꜀ × 0.385 × 245.4 = 1138.048 × 8.7
M꜀ × 94.479 = 9901.0176
Divide both side by 94.479
M꜀ = 9901.0176 / 94.479
M꜀ = 104.8 g
Thus, the mass of the copper in the sample is 104.8 g
22. Glycerol, C3H8O3, is a substance used extensively in the manufacture of cosmetics, foodstuffs, antifreeze, and plastics. Glycerol is a water-soluble liquid with a density of 1.2656 g/mL at 15 0C. Calculate the molarity of a solution of glycerol made by dissolving 50.000 mL glycerol at 15 0C in enough water to make 250.00 mL of solution. Show work.
Answer:
2.75M
Explanation:
Density = mass/volume
Density of glycerol (C3H8O3) at 15°C is given as 1.2656 g/mL.
Volume of glycerol at this same temperature before dissolving in water = 50mL
Hence, using Density = mass/volume
1.2656 = mass/50
mass = 1.2656g/mL × 50mL
mass = 63.28g
Molarity of solution = number of moles (n) ÷ volume (V)
Volume of glycerol dissolved in water = 250mL = 0.250L
number of moles = mass/molar mass
Molar mass of C3H8O3 = 12(3) + 1(8) + 16(3)
= 36 + 8 + 48
= 44 + 48
= 92g/mol
n = 63.28g ÷ 92g/mol
n = 0.688mol
* Molarity = n/V
Molarity = 0.688/0.250
Molarity = 2.75M
Identify the most oxidized compound. Group of answer choices CH3CH2CHO CH3CH2CH3 CH3CH2CH2OH CH3CH2OCH3 CH3CH2COOH
Answer:
Huh!?
Explanation:
explain me please
Which group has one valence electron
Answer:
Alkaline earth metals or akali metals
Which of the following statements is correct concerning the reaction 2 A + B → 2 C + 2 D?
1. The reaction is second-order overall
2. The reaction is third order overall
3. The rate is equal to k[A]²[B]
4. The rate is equal to k[A][B]
5. It cannot be determined given this information
Answer:
2.The reaction is third order overall
Explanation:
THIS ANSWER IS CORRECT
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