Answer:
the molar mass of the element
Select the statement that correctly describes an endothermic process.
a. The enthalpy change for the process is negative.
b. Heat is lost by the system, but work is done on the system.
c. The enthalpy of the products is higher than that of the reactants.
d. The temperature change of the products is greater than that of the reactants.
e. Heat is released by the system, to the surroundings.
Answer:
C. The enthalpy of the products is higher than that of the reactants
Explanation:
An endothermic process is any process with an increase in the enthalpy of the system
The enthalpy of the products is higher than that of the reactants describes an endothermic process. Therefore, option (C) is correct.
What is the endothermic process?An endothermic process can be described as any thermodynamic process with an increase in the enthalpy H of the system. In such a process, a closed system commonly absorbs thermal energy from its surroundings.
An endothermic reaction leads to an increase in the temperature of the system and a decrease temperature of the surroundings. A physical process, such as the melting of ice cubes is an endothermic process.
Whether a process can take place spontaneously depends not only on the enthalpy change but also on the entropy change and absolute temperature.
An endothermic process commonly needs a favorable entropy increase (∆S > 0) in the system. In an endothermic process, the energy of the products is higher than that of the reactants.
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How many molecules of C 2H 5Br will be present if you had 4.52 g of this compound?
11th grade chemistry question will mark brainliest
2.50 g of CO2 gas is confined in a rigid cylinder at a pressure
of 4.65 atm. If 0.42 g of gas is released from the cylinder,
what is the new pressure?
Answer:
3.88 atm
Explanation:
We'll begin by calculating the number of mole of CO₂ in each case. This can be obtained as follow:
For 2.50 g of CO₂:
Mass of CO₂ = 2.5 g
Molar mass of CO₂ = 12 + (2×16) = 44 g/mol
Mole of CO₂ =?
Mole = mass / molar mass
Mole of CO₂ = 2.5 / 44
Mole of CO₂ = 0.06 mole
For 0.42 g of CO₂:
Mass of CO₂ = 2.5 g
Molar mass of CO₂ = 44 g/mol
Mole of CO₂ =?
Mole = mass / molar mass
Mole of CO₂ = 0.42 / 44
Mole of CO₂ = 0.010 mole
Finally, we shall determine the new pressure. This can be obtained as follow:
Initial mole (n₁) = 0.06 mole
Initial pressure (P₁) = 4.65 atm
Final mole (n₂) = 0.06 – 0.010 = 0.05 mole
Final pressure (P₂) =?
NOTE: Temperature and volume is constant.
P₁ / n₁ = P₂ / n₂
4.65 / 0.06 = P₂ / 0.05
Cross multiply
0.06 × P₂ = 4.65 × 0.05
0.06 × P₂ = 0.2325
Divide both side by 0.06
P₂ = 0.2325 / 0.06
P₂ = 3.88 atm
Thus, the new pressure is 3.88 atm.
¿soy guapo?
si dices que si te doy una galletita
Answer:
Hindi ko po ma gets sinasabi nyu pwedeng pakiayus
Suppose you need to prepare 138.1 mL of a 0.190 M aqueous solution of NaCl. What mass, in grams, of NaCl do you need to use to make the solution
Answer:
Explanation:
· 44 g NaCl Explanation: The problem provides you with the molarity and volume of the target
The answer is rounded to two sig figs, the number of sig figs you have for the molarity of the solution.
The mass of a solute needed to prepare a solution with given volume is find by molarity. The mass of NaCl need to make a 138.1 mL solution of 0.190 M is 1.53 grams.
What is molarity ?Molarity of a solution is a term to express its concentration. Mathematically, it is the ratio of no.of moles of solute to the volume of solution in litres.
Given that, the volume of solution is 138.1 mL. One litre solution is 1000 mL. Hence, 138.1 mL is 0.1381 L. The molarity of the solution is 0.190 M. From these data we can calculate the no.of moles of NaCl as below:
no.of moles = molarity × volume of solution in L
= 0.190 M × 0.1381 L
= 0.0262 moles.
This is the no.of moles required to make the solution.
Molecular mass of NaCl = 58.4 g/mol.
Thus mass of 0.0262 moles of NaCl = 0.0262 mol × 58.4 g/mol
= 1.53 g.
Therefore, the mass of NaCl required is 1.53 g.
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Qual número atômico do ferro?
Answer:
The answer is Iron.
Explanation:
I hope this helps you out. Have a nice day!
Draw a Lewis structure for thiocyanic acid, HSCN, adding charges and lone electron pairs to the appropriate atoms.
Answer:
See explanation and image attached
Explanation:
Thiocyanic acid is made made up of hydrogen, sulphur, carbon and nitrogen atoms. Carbon is the central atom in the molecule.
The molecule has a total of sixteen valence electrons as shown in the image attached. There are no formal charges in the structure of the molecule as shown.
The molecule is linear in shape.
You are stowing items and come across an aerosol bottle of hairspray. What should you do? Please choose all that apply
Answer:stow the hairspray
Explanation:
The element antimony has two stable isotopes, antimony-121 with a mass of 120.90 amu and antimony-123 with a mass of 122.90 amu. From the atomic weight of Sb = 121.76 one can conclude that: ________
antimony-123 has the highest percent natural abundance
most antimony atoms have a mass of 121.76 amu
antimony-121 has the highest percent natural abundance
both isotopes have the same percent natural abundance
Answer:
antimony-121 has the highest percent natural abundance
Explanation:
percent natural abundance;
121.76 = 120.90 x + 122.90 (1 - x)
121.76 = 120.90 x + 122.90 - 122.90x
121.76 = -2x + 122.90
121.76 - 122.90 = -2x
x= 121.76 - 122.90/ -2
x= 0.57
Where x and 1 - x refers to the relative abundance of each of the isotopes
Percent natural abundance of antimony-121 = 57 %
Percent natural abundance of antimony-123 = (1 - 0.57) = 43%
Let us remember that isotopy refers to a phenomenon in which atoms of the same element have the same atomic number but different mass numbers. This results from differences in the number of neutrons in atoms of the same element.
We can clearly see that antimony-121 has the highest percent natural abundance.
Why ethanol is used in pectin extraction
Explanation:
is responsible for interrupting the interaction between pectins and solvent molecules
if salt and sand is mixed with distilled water, what will be the residue? and, what will be the filtrate?
Answer:
Filtration is a technique used as a remedy to separate mixes
Explanation:
If you have a sodium, then you will explore that salt dissolves but the sand is still the same.
If the salt in the resin water solution scanners, the sand remains the residue and passes through the filter paper.
All you have to do now is pleasant the salty water so that the water can evaporate, leaving the salt behind.
A compound that contains only carbon, hydrogen, and oxygen is 58.8% C and 9.87% H by mass. What is the empirical formula of this substance
Answer: The empirical formula of the compound becomes [tex]C_5H_{10}O_2[/tex]
Explanation:
The empirical formula is the chemical formula of the simplest ratio of the number of atoms of each element present in a compound.
Let the mass of the compound be 100 g
Given values:
% of C = 58.8%
% of H = 9.87%
% of O = [100 - 58.8 - 9.87] = 31.33%
Mass of C = 58.8 g
Mass of H = 9.87 g
Mass of O = 31.33 g
The number of moles is defined as the ratio of the mass of a substance to its molar mass. The equation used is:
[tex]\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}[/tex] ......(1)
To formulate the empirical formula, we need to follow some steps:
Step 1: Converting the given masses into moles.Molar mass of C = 12 g/mol
Molar mass of H = 1 g/mol
Molar mass of O = 16 g/mol
Putting values in equation 1, we get:
[tex]\text{Moles of C}=\frac{58.8g}{12g/mol}=4.9 mol[/tex]
[tex]\text{Moles of H}=\frac{9.87g}{1g/mol}=9.87 mol[/tex]
[tex]\text{Moles of O}=\frac{31.33g}{16g/mol}=1.96mol[/tex]
Step 2: Calculating the mole ratio of the given elements.Calculating the mole fraction of each element by dividing the calculated moles by the least calculated number of moles that is 1.96 moles
[tex]\text{Mole fraction of C}=\frac{4.9}{1.96}=2.5[/tex]
[tex]\text{Mole fraction of H}=\frac{9.87}{1.96}=5.03\approx 5[/tex]
[tex]\text{Mole fraction of O}=\frac{1.96}{1.96}=1[/tex]
Converting the mole fraction into whole numbers by multiplying them with 2.
[tex]\text{Mole fraction of C}=2.5\times 2=5[/tex]
[tex]\text{Mole fraction of H}=5\times 2=10[/tex]
[tex]\text{Mole fraction of O}=1\times 2=2[/tex]
Step 3: Taking the mole ratio as their subscripts.The ratio of C : H : O = 5 : 10 : 2
Hence, the empirical formula of the compound becomes [tex]C_5H_{10}O_2[/tex]
The empirical formula of the substance is[tex]C_5H_{10}O_2[/tex].
Explanation:
Given:
A compound made up of 58.8% of carbon, 9.87% hydrogen, and oxygen.
To find:
The empirical formula of this substance.
Solution
The percentage of carbon in a given substance by mass = 58.8%
The percentage of hydrogen in a given substance by mass = 9.87%
The percentage of oxygen in a given substance by mass :
[tex]= 100\%-58.8\%- 9.87\%=31.33\%[/tex]
Consider 100 grams of a substance.
In 100 grams of substance:
The mass of carbon =58.8% of 100 g = 58.8 g
The mass of hydrogen = 9.87% of 100 g = 9.87 g
The mass of oxygen = 31.33% of 100 g= 31.33 g
The moles of carbon [tex]=\frac{58.8 g}{12.0107 g/mol}=4.90 mol[/tex]
The moles of hydrogen[tex]=\frac{9.87g}{1.00784g/mol}=9.79 mol[/tex]
The moles of oxygen[tex]=\frac{31.33g}{15.999g/mol}=1.96 mol[/tex]
let the empirical formula of the substance = [tex]C_xH_yO_z[/tex]
The value of subscript x:
[tex]=\frac{4.90 mol}{1.96 mol}=2.5[/tex]
The value of subscript y:
[tex]=\frac{9.79mol}{1.96 mol}=5[/tex]
The value of subscript z:
[tex]=\frac{1.96mol}{1.96 mol}=1[/tex]
The empirical formula of a substance :
[tex]C_{2.5}H_5O_1=C_{\frac{25}{10}}H_5O_1=C_{25}H_{50}O_{10}[/tex]
Reducing to the lowest whole numbers:
[tex]C_{25}H_{50}O_{10}=C_5H_{10}O_2[/tex]
The empirical formula of the substance is [tex]C_5H_{10}O_2[/tex].
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Suppose of potassium acetate is dissolved in of a aqueous solution of ammonium sulfate. Calculate the final molarity of acetate anion in the solution. You can assume the volume of the solution doesn't change when the potassium acetate is dissolved in it. Round your answer to significant digits.
The question is incomplete, the complete question is;
Suppose 0.377g of potassium acetate is dissolved in 250.mL of a 57.0mM aqueous solution of ammonium sulfate.
Calculate the final molarity of acetate anion in the solution. You can assume the volume of the solution doesn't change when the potassium acetate is dissolved in it.
Round your answer to 3 significant digits.
Answer:
0.0152 M
Explanation:
The equation of the reaction is;
2CH3COOK(aq) + (NH4)2SO4(aq)------> K2SO4(aq) + 2CH3COONH4(aq)
Number of moles of potassium acetate = 0.377g/98.15 g/mol = 0.0038 moles
Number of moles of ammonium sulphate = 250/1000L × 57 × 10^-3 = 0.014 moles
2 moles of potassium acetate yields 2 moles of ammonium acetate
Hence;
0.0038 moles of potassium acetate yields 0.0038 moles of ammonium acetate
Also
1 mole of potassium sulphate yields 2 moles of ammonium acetate
0.014 of potassium sulphate yields 0.014 × 2/1 = 0.028 moles of ammonium acetate
So potassium acetate is the limiting reactant.
Since 0.0038 moles of ammonium acetate is produced, the final concentration of potassium acetate is = 0.0038 moles of ammonium acetate/0.25L = 0.0152 M
Hence final concentration of acetate ions =0.0152 M
All --- is a good conductor of heat
Give the name of the molecular compound and the name of the aqueous solution for each of the binary compounds below.
a. HCN
b. HF
c. H2S
Explanation:
A compound containing only two elements is called a binary compound.
(a). The compound HCN contains a hydrogen ion and cyanide ion. Hence, the name of HCN is hydrogen cyanide.
An aqueous solution of hydrogen cyanide is known as hydrogen cyanide solution.
(b). The compound HF contains a hydrogen ion and a fluorine ion. The suffix -ide will be added to its name. So, the name of this compound is hydrogen fluoride.
An aqueous solution of HF is known as hydrogen fluoride.
(c). The compound [tex]H_{2}S[/tex] contains two hydrogen atoms and one sulfur atom. The suffix -ide will be added to its name. So, the name of this compound is hydrogen sulfide.
An aqueous solution of this compound is known as hydrogen sulfide solution.
when (S)-3-bromo-2,3-dimethylpentane is treated with sodium chloride with water as the solvent, the products formed are ___________. *Select all that apply
Answer:
(S)-3-chloro-2,3-dimethylpentane
Explanation:
When sodium chloride is treated with bromo dimethylpentane in presence of water, then chloro dimethylpentane is formed. This chemical reaction is stable reaction in water because of its solvency.
Green plants use light from the Sun to drive photosynthesis, a chemical reaction in which liquid water and carbon dioxide gas form aqueous glucose (CH1206) and oxygen (O2) gas. Calculate the moles of glucose produced by the reaction of 2.40 mol of carbon dioxide. Be sure your answer has a unit symbol, if necessary, and round it to 3 significant digits.
Answer:
.
Explanation:
g Calculate the percent yield when you start with 0.50 grams of salicylic acidand end with 0.33 grams of aspirin. The molecular weight of salicylic acid is 138.12 g/mol, and the molecular weight of aspirin is 180.157 g/mol.
Explanation:
hope the picture above helps you to understand:)
The radius of a platinum atom is 139 pm. How many platinum atoms would have to be laid side by side to span a distance of 1.39 mm?
Answer:
5x10⁶ atoms of platium have to be laid side by side
Explanation:
1 atom of platium has a radius of 139pm = 139x10⁻¹²m. The distance that occupies 1 atom of platinum is 2 times its ratio:
139x10⁻¹²m*2 = 2.78x10⁻¹⁰m
Assuming there is no distance between to atoms of platinum, just its ratio. The amount of atoms necessary to occupy 1.39mm = 1.39x10⁻³m is:
1.39x10⁻³m / 2.78x10⁻¹⁰m =
5x10⁶ atoms of platium have to be laid side by sideMethanoic acid is the simplest carboxylic acid molecule. It has one carbon atom. Draw the structural model for methanoic acid (using C and H).
ANSWER IS ABOVE
THE METHANOIC ACID
When 2.50 moles of oxygen reacts with excess hydrogen gas how many grams of water is
produced?
2 H2 + O2--> 2 H20
Answer:
90grams
Explanation:
The reaction given in this question is as follows:
2H2 + O2 → 2H20
Based on this equation, 1 mole of oxygen gas (O2) produces 2 moles of water (H2O)
Hence, 2.50moles of oxygen gas will react with excess hydrogen gas to produce (2.5 × 2) = 5.0moles of water.
Using mole = mass/molar mass
Molar mass of water (H2O) = 1(2) + 16
= 18g/mol
5 = mass/18
mass = 18 × 5
mass of H2O = 90grams
Draw the major product that is obtained when (2S,3S)-2-Bromo-3-phenylbutane is treated with sodium ethoxide.
Answer:
Explanation:
The mechanism of the reaction is shown in the diagram below. From the reaction, when (2S,3S)-2-Bromo-3-phenylbutane undergoes a reaction with sodium ethoxide (ETONa), the E2 elimination reaction is put into place. Here, the H and the leaving group are antiperiplanar to one another and the reaction mechanism proceeds to form an isomeric (E)-2-phenyl-2butane as the major product.
Is the following sets of quantum numbers valid? Give suitable reason. n=3,l=2,m=3,s=+1/2
Answer:
The set of quantum numbers is not valid
Explanation:
There are four sets of quantum numbers;
1) Principal quantum number (n) which takes on integer values from n = 1,2,3 .......
2) Azimuthal quantum number (l) which takes on values 1, 2, ....(n - 1)
3) Magnetic quantum numbers (ml) which takes on values from (-l) to (+l)
4) spin quantum number (ms) which takes on values of ±1/2.
From the above, we can see that m can not have a value of 3 when l =2 because m has values between (-l) to (+l). Thus, the sets of quantum numbers is not valid.
A molecule with the formula AX 4 uses ________ to form its bonds. sp2 hybrid orbitals sp3d hybrid orbitals sp3 hybrid orbitals sp3d2 hybrid orbitals sp hybrid orbitals
Answer:
sp3 hybrid orbitals
Explanation:
The formula of a molecule gives us an idea of its structure and the nature of hybrid orbitals that are involved in the formation of the molecule.
AX4 corresponds to tetrahedral geometry. If a molecule is in tetrahedral geometry, it is most likely sp3 hybridized as usual.
Hence, a molecule with the formula AX 4 uses sp3 hybrid orbitals to form its bonds
What is the mass of 2.30x10^22 formula units of NaOH (molar mass =40.0g/mol)
Answer:
643(%=:(¥75 )(:7$"8"),"7$"()9_/"¥?:
Match the following terms to their correct definitions.
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A cell that requires energy to bring about a nonspontaneous redox reaction.
An ion-containing conducting medium used to physically and chemically connect the two half-cells in an electrochemical cell.
A cell that requires energy to bring about a nonspontaneous redox reaction.
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faraday
salt bridge
anode
cathode
voltaic cell
electrolytic cell
Answer:
Electrolytic cell. Salt bridge.
Explanation:
Match the following terms to their correct definitions.
A cell that requires energy to bring about a nonspontaneous redox reaction. Electrolytic cell. In an electrolytic cell, energy is provided from an outer source, such as a battery. An ion-containing conducting medium used to physically and chemically connect the two half-cells in an electrochemical cell. Salt bridge. The salt bridge contains a salt (strong electrolyte) and it is fundamental in a voltaic cell.What were the advantages for Mendel in using pea plants for his breeding experiments?
Answer:
He chose pea plants because they were easy to grow, could be bred rapidly, and had several observable characteristics, like petal color and pea color.
Explanation:
Which probing question lies within the scope of physics?
O A.
Are fish in the open ocean
attracted by underwater sounds?
O B.
Does increasing the saltiness of
ocean water affect the speed
of sound in the water?
O C.
What effect does the release of industrial wastewater have on
the acidity of oceans?
D. What is the effect of rising sea temperatures on
ocean currents?
Answer:
answer number C is the correct answer for this
What effect does hybridization have on chemical bond
Trial 1: Heat 30.0 grams of water at 0 °C to a final temperature of 40.0 °C.
Trial 2: Heat 40.0 grams of water at 10.0 °C to a final temperature of 40.0 °C.
Which statement is true about the experiments? (5 points)
The same amount of heat is absorbed in both the experiments because the product of mass, specific heat capacity, and change in temperature are equal for both.
The same amount of heat is absorbed in both the experiments because the heat absorbed depends only on the final temperature.
The heat absorbed in Trial 2 is about 3,674 J greater than the heat absorbed in Trial 1.
The heat absorbed in Trial 2 is about 5,021 J greater than the heat absorbed in Trial 1.
Answer:
Explanation:
Using the formula below to calculate the heat absorbed in each trial:
Q = m × c × ∆T
Where;
Q = amount of heat absorbed (J)
m = mass of substance (g)
c = specific heat of water (4.184J/g°C)
∆T = change in temperature (°C)
Trial 1: Heat 30.0 grams of water at 0 °C to a final temperature of 40.0 °C.
Q = 30 × 4.184 × (40 - 0)
Q = 30 × 4.184 × 40
Q = 5,020.8J
Trial 2: Heat 40.0 grams of water at 10.0 °C to a final temperature of 40.0 °C.
Answer:
The same amount of heat is absorbed in both the experiments because the product of mass, specific heat capacity, and change in temperature are equal for both.
Explanation:
Explanation:
Using the formula below to calculate the heat absorbed in each trial:
Q = m × c × ∆T
Trial 1: Heat 30.0 grams of water at 0 °C to a final temperature of 40.0 °C.
Q = 30 × 4.184 × (40 - 0)
Q = 30 × 4.184 × 40
Q = 5,020.8J
Trial 2: Heat 40.0 grams of water at 10.0 °C to a final temperature of 40.0 °C.
Q=40*4.184*30
Q=5020.8J