Answer:
Explanation:
So we know q = mc[tex]\Delta[/tex]T.
q = 55.7 J
c = 0.129j/g°C
and [tex]\Delta[/tex]T = 314-274 = 40°C.
and m is mass which can solve since we got every other variable. We will get m = 10.8g.
The most common experimental technique to perform elemental analysis is combustion analysis, where a sample is burned in a large excess of oxygen and the combustion products are trapped in a variety of ways. A 99.99% pure, 0.4808 g sample containing only carbon, hydrogen, and nitrogen is subjected to combustion analysis, resulting in the formation of 0.6859 g CO2, 0.6973 g H2O, and 0.4646 g NO. What is the empirical formula of the sample
Answer:
C₂H₅N₂
Explanation:
In the combustion analysis, all NO comes from the nitrogen of the sample, that means:
Moles NO = Moles N in the sample
In the same way:
Moles CO2 = Moles C in the sample
Moles H2O = 1/2 moles H in the sample
To solve this problem we must convert the mass of each gas to moles in order to find the moles of each atom. The empirical formula is the simplest whole number ratio of atoms presents in the molecule:
Moles NO = N -Molar mass: 30g/mol
0.4646g * (1mol / 30g) = 0.01549 moles N
Moles CO2 = C -Molar mass: 44.01g/mol-
0.6859g * (1mol / 44.01g) = 0.01559 moles C
Moles H2O = 1/2moles H -Molar mass: 18.02g/mol-
0.6973g * (1mol / 18.02g) = 0.03870 moles H
The ratio of atoms is -Dividing in the low number of moles = moles N-:
C = 0.01559 / 0.01549 = 1
N = 0.01549 / 0.01549 = 1
H = 0.03870 / 0.01549 = 2.5
Twice this ratio of atoms -Because empirical formula must be given only with whole numbers:
C = 2
N = 2
H = 5
The empirical formula is:
C₂H₅N₂What was the purpose of letting the transformed cells sit in LB for a few minutes before spreading them onto the plates?
A. This allows time for the cells to express the antibiotic resistance gene
B. This allows the cells to take up the plasmid after the heat shock procedure
C. This allows time for the cells to warm up before plating
D. This allows cells time to start glowing green
Answer: D
Explanation:
lave
Use the drop-down menus to identify the parts of a
wave.
A
B:
C
D
Answer:
Use the drop-down menus to make your selections.
What is the difference between wave A and wave B?
✔ Wave A has higher amplitude than wave B.
What is the difference between wave C and wave D?
✔ Wave C has a lower frequency than wave D.
Explanation:
Match each definition to the appropriate term.
Sum of the internal energy plus the product of the pressure and volume for a reaction
The extent of randomness in a system
The condition that a reaction takes place without outside help
Difference of the enthalpy (of a system) minus the product of the entropy and absolute temperature
Solution in which no more solute can be dissolved in the solvent
Answer:
Enthalpy, Entropy, Spontaneity, Gibbs free energy, saturated solution
Explanation:
Enthalpy is defined as the heat released or the heat absorbed during the process at a constant pressure which is equal to the Enthalpy shift. Enthalpy is also called as heat content and it is the sum total of internal energy and the product of the volume and pressure of a system.
Entropy is defined as the measure of randomness of a system or the disorder of the system.
Spontaneity is defined as the condition of being spontaneous. It is the condition where a reaction takes place without any help from outside.
Gibbs free energy is defined as the energy that is used to quantify the maximum work done in a thermodynamic system at constant temperature and pressure. It is the also known as the Gibbs energy or function.
Saturated solution is defined as the solution where the maximum amount of the dissolved solute is present in the solvent. In case of a saturated solution, the extra solute does not dissolve. In order words, it is a solution where no more solute can dissolved in solvent.
The sum of the internal energy plus the product of the pressure and volume for a reaction represents Enthalpy , Entropy is the extent of randomness in a system, Spontaneity is that condition that a reaction takes place without outside help, Gibb's free energy is the difference of the enthalpy (of a system) minus the product of the entropy and absolute temperature and Saturated solution in which no more solute can be dissolved in the solvent.
Which properties will define chemical reaction?Thermodynamically chemical reactions will be define by considering the properties like entropy, enthalpy, free energy, internal energy, temperature and many more.
Enthalpy of the reaction tells about the total amount of heat released or absorbed during a chemical reaction, and it is calculated as sum of the internal energy plus the product of the pressure and volume for a reaction.Entropy of any reaction tells about the randomness and uncertainty present within the molecule or atoms.Spontaneity of any chemical reaction tells about the ease of completion of that reaction. Gibb's free energy is the total energy involved in that reaction and represented as difference of the enthalpy (of a system) minus the product of the entropy and absolute temperature.Saturated solutions are those solutions in which all solute get completely dissolved, no solute will remain undissolved.Hence correct answers are Enthalpy , Entropy ,Spontaneity, Gibb's free energy and Saturated solutions.
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12. How many moles of atoms are present in 154 g of Na2O?
A) 2.48 mol
B) 7.45 mol
C) 51.3 mol
D) 0.827 mol
Answer:
[tex]\boxed {\boxed {\sf A. \ 2.48 \ mol \ Na_2O}}[/tex]
Explanation:
We are asked to convert an amount in grams to moles. To do this, we use the molar mass. This is the number of grams in one mole of a substance. It is the same value numerically as the atomic mass on the Periodic Table, however the units are grams per mole, not atomic mass units.
Look up the molar masses for the individual elements.
Sodium (Na): 22.9897693 g/mol Oxygen (O): 15.999 g/molLook back at the formula: Na₂O. Notice there is a subscript of 2 after sodium. This means there are 2 atoms of sodium in every molecule, so we have to multiply sodium's molar mass by 2 before adding oxygen's.
Na₂O: 2(22.9897693 g/mol)+ 15.999 g/mol = 61.9785386 g/molSet up a ratio using the molar mass.
[tex]\frac {61.9785386 \ g \ Na_2O}{1 \ mol \ Na_2O}[/tex]
Multiply by the given number of grams.
[tex]154 \ g \ Na_2O*\frac {61.9785386 \ g \ Na_2O}{1 \ mol \ Na_2O}[/tex]
Flip the ratio so the grams of sodium oxide can cancel each other out.
[tex]154 \ g \ Na_2O*\frac {1 \ mol \ Na_2O}{61.9785386 \ g \ Na_2O}[/tex]
[tex]154 *\frac {1 \ mol \ Na_2O}{61.9785386 }[/tex]
[tex]\frac {154}{61.9785386 } \ mol \ Na_2O[/tex]
[tex]2.48473106141 \ mol \ Na_2O[/tex]
The original measurement of grams given has 3 significant figures, so our answer must have the same. For the number we calculated, that is the hundredth place.
2.48473106141The 4 in the thousandth place tells us to leave the 8.
[tex]2.48 \ mol \ Na_2O[/tex]
There are 2.48 moles of sodium oxide in 154 grams, so choice A is correct.
How long did it take to get the Hubble Telescope into space?
If 4.50 moles of C2H6 undergoes combustion, how many moles of oxygen would it combust with?
Answer:
First balance the equation
C2H6 + 7/2O2 2CO2 +3H2O
for one mole of C2H6 there are 7/2 mole of O2 required. so for4.50 moles you require 4.50 x 7/2 = 15.75 moles of O2.
Explanation:
Why are diamonds unevenly distributed on Earth?
Soil forms only in places where rock particles are deposited.
Soil forms only in places where larger rocks are broken into smaller rocks.
Soil forms only within the Earth under heavy pressure.
Soil forms in the air and is then deposited mainly in places that get a lot of rain.
Answer:
Why aren't diamonds found evenly distributed on Earth? Diamonds are only formed under specific conditions that involve geological processes, such as volcanic activities and plate movements. Since these conditions and processes only take place in certain areas, you can only find diamonds in these special places.
Explanation:
Chrysanthemic acid occurs as a mixture of esters in flowers of the chrysanthemum (pyrethrum) family.
a. True
b. False
Answer:
A: True
Explanation:
Statement is true because chrysanthemic acid is formed naturally as a result of production of two molecules of dimethylallyl diphosphate which forms pyrophosphate ester.
Thus, it belongs to the pyrethrum family
What is the vapor pressure of an aqueous solution that has a solute mole fraction of 0.1000? The vapor pressure of water is 25.756 mmHg at 25 °C.
Answer:
χsolvent = 1.0000 - 0.1000 = 0.9000
Use Raoult's Law:
Psolution = (χsolvent) (P°solvent)
x = (0.900) (25.756)
x = 23.18 mmHg (to four sig figs)
The vapor pressure of an aqueous solution is x = 23.18 mmHg (to four sig figs)
χsolvent = 1.0000 - 0.1000 = 0.9000
Use Raoult's Law:
P solution = (χsolvent) (P°solvent)
x = (0.900) (25.756)
x = 23.18 mmHg (to four sig figs)
What is an aqueous solution?An aqueous answer is one in which the solvent is liquid water. that is, solute (dissolved) ions and molecules are surrounded by water molecules and integrated into the network of bonds within the water. The dissolved species then spread in the course of the water.
A solution wherein water is the solvent is called an aqueous solution. although water is an exceptional solvent, now not the whole thing dissolves comfortably in the water.
Aqueous' in a chemical equation suggests that the cloth dispersed in water (an answer in water). As an example, when we pour sodium hydroxide answer into dilute hydrochloric acid, we get an aqueous solution of sodium chloride. The liquid is used to signify the formation of liquid materials in response.
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Identify the term that matches each electrochemistry definition.
a. The electrode where reduction occurs ___________
b. An electrochemical cell powered by a spontaneous redox reaction ___________
c. The electrode where oxidation occurs__________
d. An electrochemical cell that takes in energy to carry out a nonspontaneous redox reaction ____________
e. A chemical equation showing either oxidation or reduction ___________
Answer: a. Cathode
b. Galvanic cell
c. Anode
d. Electrolytic cell
e. half reaction
Explanation:
Galvanic cell or Electrochemical cell is defined as a device which is used for the conversion of the chemical energy produced in a spontaneous redox reaction into the electrical energy.
Electrolytic cell is a device where electrical energy is used to drive a non spontaneous chemical reaction.
In the electrochemical cell, the oxidation occurs at an anode which is a negative electrode and the reduction occurs at the cathode which is a positive electrode. Thus the electrons are produced at anode and travel towards cathode.
The balanced two-half reactions will be:
Oxidation half reaction : [tex]M\rightarrow M^{n+}+ne^-[/tex]
Reduction half reaction : [tex]N^{n+}+ne^-\rightarrow N[/tex]
Thus the overall reaction will be: [tex]M+N^{n+}\rghtarrow M^{n+}+N[/tex]
How many atoms are in 57.5 liters of xenon gas at STP
Answer:
1.55 × 10²⁴ atoms Xe
General Formulas and Concepts:
Atomic Structure
Reading a Periodic TableMolesSTP (Standard Conditions for Temperature and Pressure) = 22.4 L per mole at 1 atm, 273 K Avogadro's Number - 6.022 × 10²³ atoms, molecules, formula units, etc.Stoichiometry
Using Dimensional AnalysisExplanation:
Step 1: Define
[Given] 57.5 L Xe at STP
[Solve] atoms Xe
Step 2: Identify Conversions
[STP] 22.4 L = 1 mol
Avogadro's Number
Step 3: Convert
[DA] Set up: [tex]\displaystyle 57.5 \ L \ Xe(\frac{1 \ mol \ Xe}{22.4 \ L \ Xe})(\frac{6.022 \cdot 10^{23} \ atoms \ Xe}{1 \ mol \ Xe})[/tex][DA] Divide/Multiply [Cancel out units]: [tex]\displaystyle 1.54583 \cdot 10^{24} \ atoms \ Xe[/tex]Step 4: Check
Follow sig fig rules and round. We are given 3 sig figs.
1.54583 × 10²⁴ atoms Xe ≈ 1.55 × 10²⁴ atoms Xe
Only animals and not plants can adapt to their environment true or false
Answer:
true
Explanation:
np have a good day brainliest?
Which of the following is a primary source for scientific information? O A. Doctoral theses OB. A handbook of scientific facts O C. Reviews of scientific studies D. Public opinion about a scientific issue