Answers
Related Questions
Which of the following statements is true?
a. ΔHfus = ΔHsolid
b. ΔHfus = –ΔHsolid
c. Hfus is always negative.
d. ΔHsolid is always positive.
Answers
Answer:
c. Hfus is always negative.
Explanation:
Because energy is released when fusing solids
Given the equation 2Si(s) + 2Cl2(g) --> 2SiCl2(g) + 687 kJ, how much heat is produced when 106 g of Cl2 react?
Answers
Answer:
514 kJ
General Formulas and Concepts:
Atomic Structure
Reading a Periodic TableElementsCompoundsMolesStoichiometry
Analyzing Reactions rxnUsing Dimensional AnalysisExplanation:
Step 1: Define
Identify
[Given] rxn (balanced): 2Si (s) + 2Cl₂ → 2SiCl₂ (g) + 687 kJ
[Given] 106 g Cl₂
[Solve] kJ heat
Step 2: Identify Conversions
[rxn] 2 mol Cl₂ → 687 kJ
[PT] Molar Mass of Cl: 35.45 g/mol
Molar Mass of Cl₂: 2(35.45) = 70.9 g/mol
Step 3: Stoichiometry
[DA] Set up: [tex]\displaystyle 106 \ g \ Cl_2(\frac{1 \ mol \ Cl_2}{70.9 \ g \ Cl_2})(\frac{687 \ kJ}{2 \ mol \ Cl_2})[/tex][DA] Divide/Multiply [Cancel out units]: [tex]\displaystyle 513.554 \ kJ[/tex]Step 4: Check
Follow sig fig rules and round. We are given 3 sig figs.
513.554 kJ ≈ 514 kJ
Topic: AP Chemistry
Unit: Thermochemistry
Given the structural formula: This compound is classified as an
Answers
Answer:
A.) aldehyde is the answer
From the given structural formula, the compound is ethanamide and thus, belongs to the group of amides. Thus, the correct option is B.
Amide is a functional group of organic compounds having an acyl group (R-C=O) linked to amine group (-NR¹R² where R¹ and R² are hydrogen atoms or alkyl groups). The amide functional group is given as -CON= (not double bond with N, but two distinct single bonds).
Amides can be classified into the following types depending on the moiety attached to nitrogen other than the carbonyl carbon:
1. Primary amides - amide in which the nitrogen atoms is attached to two hydrogen atoms
2. Secondary amides - in which the nitrogen atom is attached to one hydrogen and one alkyl group.
3. Tertiary amides - in which the nitrogen atom is attached to two alkyl groups.
Learn more about amides in:
https://brainly.com/question/29595493
#SPJ2
How is the height of grasses in grasslands related to precipitation?
Short and tall grasses prefer very low amounts of precipitation
o Shorter grasses grow in areas that receive more precipitation
o Taller grasses grow in areas that receive more precipitation
o Short and tall grasses prefer the high amounts of precipitation
Answers
Answer:
It just does
Explanation:
Answer:
Tallgrass Praries have more Rainfall
Explanation:
one use for an electromagnet?
Answers
Answer:
It is used in induction of electric current through electromagnetic induction.
A flexible container has 5.00 L of nitrogen gas at 298 K. If the temperature is increased to 333 K, what will be the new volume of that sample of nitrogen?
0.179 L
0.223 L
4.47 L
5.59 L
Answers
Answer:
5.59 L
Points earned on this question: 4
Explanation:
took the test
The new volume of the sample of gas when the temperature is increased from 298 K to 333 K is 5.59 L
Charles' lawCharles' law states as follow:
V₁ / T₁ = V₂ / T₂
Where
V₁ is the initial volume T₁ is the initial temperature V₂ is the new volume T₂ is the new temperature How to determine the new volumeFrom the question given above, the following data were obtained
Initial volume (V₁) = 5 LInitial temperature (T₁) = 298 KNew temperature (T₂) = 333 KNew Volume (V₂) =?V₁ / T₁ = V₂ / T₂
5 / 298 = V₂ / 333
Cross multiply
298 × V₂ = 5 × 333
Divide both side by 298
V₂ = (5 × 333) / 298
V₂ = 5.59 L
Learn more about gas laws:
https://brainly.com/question/6844441
3) list the methods to prevent rusting?
Answers
Answer:
paint on surface of object , oiling
If I mix two chemicals in a test tube and notice after a few seconds that there are ice crystals forming on the outside of the test tube, I am witnessing a(n) *
Answers
Answer:
endothermic reaction
Explanation:
It simply means that you are witnessing an endothermic reaction.
An endothermic reaction is one that absorbs heat energy from its surrounding, thereby leaving the reaction vessel with a lower temperature as compared to before the reaction.
It is as opposed to exothermic reactions which are reactions that give off energy in the form of heat to the surrounding, thereby leaving a reaction vessel warmer than before the reaction.
In this case, the formation of ice crystals outside the test tube means that heat energy has been absorbed by the reaction which leaves the vessel a temperature cold enough to activate the formation of ice.
Use mathematics to prove that the 5.50 grams of salicylic acid (C7H6O3) used in this experiment is equal to 0.04 mol.
Answers
Answer:
Please find the answer to the question below
Explanation:
In chemistry, the following mathematical formula is used to calculate the number of moles contained by a substance:
mole = mass of substance (g)/molar mass of substance (g/mol)
Molar mass of salicylic acid (C7H6O3) = 12(7) + 1(6) + 16(3)
= 84 + 6 + 48
= 138g/mol
Mass = 5.50grams
mole = 5.5/138
mole = 0.039
Approximately, the number of moles of 5.5grams of salicylic acid is 0.04moles. This is in accordance with the mole value (0.04) given in this question.
Isaac wants to make s'mores. He holds a marshmallow on a metal skewer over a fire. A few seconds later, the marshmallow is cooked and the skewer feels warm. What most likely happened?
Answers
Answer:
D. Thermal energy in the form of heat moved from the fire to the skewer and marshmallow.
Explanation:
He holds a marshmallow on a metal skewer over a fire. A few seconds late, the marshmallow is cooked and the skewer feels warm.
Answer:
D. Thermal energy in the form of heat moved from the fire to the skewer and marshmallow.
Explanation:
I got it right on edge!
Which question would most likely be studied by a biologist?
A.
How can a drug that treats cancer be synthesized?
B.
How can cancer-causing substances be regulated?
C.
How much ultraviolet radiation passes through the atmosphere?
D.
What causes cancer cells to grow uncontrollably?
Answers
Answer:
The correct answer would be - D. What causes cancer cells to grow uncontrollably?
Explanation:
A Biologist is a person that studies living organisms and the study of living organisms and their process called biology. Biology is a very vast field that involves many branches such as zoology, botany, biochemistry, immunology, biophysics, anatomy, ecology and many more.
So, given all are can be an example of the study biology wanted to do, however, the question most likely studied by a biologist would be What causes cancer cells to grow uncontrollably as it deals with an organism and their biological process.
An example of a product made from a synthetic material is
Question 5 options:
A)
a PET plastic water bottle.
B)
knitted wool socks.
C)
a cotton t-shirt.
D)
a pine 2×4 board.
Answers
Hi there! A simple answer and explanation is below :)
Answer:
A) PET plastic water bottle
Explanation:
Plastic goes through a manufacturing process before being used to make bottles for liquids like milk, soda, motor oil, and shampoo, as well as dry items like pharmaceuticals and nutritional supplements. Plastic is made up of a variety of organic polymers, including polyethylene and ethylene, in its unprocessed condition. In a soft state, plastic can be molded into the desired shape and then cast into a solid stat
7.296 x 10^2 / 9.6 x 10^-9
Answers
Answer:
7.6x10^-8
Explanation:
Please help, only a couple of days left!!!
Answers
Answer:
the heat from the universe during the big bang
a.k.a.
ITS A
Explanation:
the universe is still expanding, so what is gonna be used to create that new matter that's expanding the universe? energy and heat from the beginning of the universe! the universe started off as this point that was probably smaller than a quantum foam and infinite heat and started expanding from there
What causes the reaction rate to decrease as the reaction progresses?
A. The concentration of the reactants decreases.
B. The reaction's activation energy decreases.
C. The rate constant of the reaction decreases.
D. The temperature of the reaction decreases.
Answers
Answer:
a
Explanation:
The concentration of the reactants decreases which causes the reaction rate to decrease as the reaction progresses and the correct option is option A.
What is Rate of a Reaction?
The rate of reaction refers to the speed at which the products are formed from the reactants in a chemical reaction.
The rate or speed of reaction can be defined as the change in the concentration of any one of the reactants or products per unit time.
Rate of reaction is affected by a change in concentration.
The chemical reaction rate increases with the increase in concentration and decreases with the decrease in the concentration of reactants.
Therefore, The concentration of the reactants decreases which causes the reaction rate to decrease as the reaction progresses and the correct option is option A.
Learn more about Rate of reaction, here:
https://brainly.com/question/30546888
#SPJ3
When a scientist sorts a draw containing different colour socks what skill is she using?
Answers
Answer:
sorting/classifying
Explanation:
.
What is the delta H when 72.0 grams H2O condenses at 100.00C?
Here are some constants that you MAY need.
specific heats heat of fusion heat of vaporization
H2O(s) = 2.1 J/g0C 6.01 kJ/mole 40.7 kJ/mole
H2O(L) = 4.18 J/g0C
H2O(g) = 1.7 J/g0C
2930 kJ
163 kJ
-163 kJ
-2930 kJ
Answers
Answer: The value of [tex]\Delta H[/tex] is -163 kJZ
Explanation:
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)
We are given:
Given mass of water = 72.0 g
Molar mass of water = 18 g/mol
Putting values in equation 1, we get:
[tex]\text{Moles of water}=\frac{72.0g}{18g/mol}\\\\\text{Moles of water}=4mol[/tex]
Calculating the heat released for the condensation process:
[tex]\Delta H=n\times \Delta H_{(vap)}[/tex] ......(2)
where,
[tex]\Delta H[/tex] = amount of heat released
n = number of moles of water = 4 moles
[tex]\Delta H_{(vap)}[/tex] = specific heat of vaporization = -40.7 kJ/mol
Negative sign represents the amount of heat released.
Putting values in equation 2:
[tex]\Delta H=4mol\times (-40.7kJ/mol)=-163kJ[/tex]
Hence, the value of [tex]\Delta H[/tex] is -163 kJ
Uma máquina térmica ideal opera recebe 450 J de uma fonte de calor e liberta 300J no ambiente. Uma segunda máquina térmica ideal opera recebendo 600J e libertando 450J. Se dividirmos o rendimento da segunda máquina pelo rendimento da primeira máquina, obteremos:
Answers
Answer:
Yield of second machine / Yield of first machine = 0.75
Explanation:
Given:
Input of first machine = 450 J
Output of first machine = 300 J
Input of second machine = 600 J
Output of second machine = 450 J
Find:
Yield of second machine / Yield of first machine
Computation:
Yield of first machine = [Q1 - Q2] / Q1
Yield of first machine = [450 - 300] / 450
Yield of first machine = 1 / 3
Yield of second machine = [Q1 - Q2] / Q1
Yield of second machine = [600 - 450] / 600
Yield of second machine = 1 / 4
Yield of second machine / Yield of first machine = [1/4]/[1/3]
Yield of second machine / Yield of first machine = 3/4
Yield of second machine / Yield of first machine = 0.75
Many factors influence the amount of a solute which will dissolve in a solvent.
True
False
Answers
Answer:
true
Explanation:
the answer is true
Explain why solids and liquids are difficult to compress
whereas gases can easily be compressed.
Answers
Answer:
Because they take up a certain amount of volume because there is no space in-between the particles, a gases can be compressed because there is alot of space in-between each particle
Explanation:
how many atoms are in 3 CaSO4
Answers
Answer:
Calcium = 1 atom, Sulfur = 4 atoms, Oxygen = 4 atoms.
For which value of k is the equation below true? 4,522,800,000 = 4.5228 × 10k? A. 5 B. 8 C. 9 D. 10
Answers
Answer:
The value of k is equal to 9.
Explanation:
The given number is 4,522,800,000
We need to write it n the form of a×10ᵇ.
We will count the numbers after 4 in the given number. There are 9 number after 4. So,
[tex]4,522,800,000 =4.5\times 10^9[/tex]
So, we can say that the value of k is equal to 9.
Besides Mars, what other bodies in our solar system are considered the most likely places for the discovery of some form of life? Explain
Answers
Answer:
Europa
Explanation:
it is though that to have a subsurface liquid of water
Answer:
Europa, Venus, And Proxima B.
Explanation:
Europa is a moon which is known to have a subsurface liquid of water. Venus can also be inhabited due to it being almost the same size as Earth, and having many common features with earth. Such as; Metal core in the interior of the planet, along with a rocky mantle. Its atmosphere is mainly made up of nitrogen and carbon dioxide. Although humans can't breathe in carbon dioxide, it is a similarity the planets have and I'm sure scientists can make an invention making carbon dioxide into oxygen. Proxima B can also be inhabited in. It is a newly discovered planet and has many of the same features as Earth. It has water, leafy plants, and is close to a star so the temperature is not extremely hot; neither cold.Convert 50 gr of water into moles and into molecules of H2O.
Answers
Tenisha solved the equation below by graphing a system of equations. help!!!!!
Answers
Answer:
(1.0, 1.4)
Explanation:
Graph the two equations [tex]\log_3 5x[/tex] and [tex]\log_5 (2x+8)[/tex]. The point of intersection is the solution to the system of equations.
Graph on Desmos:
[tex]\log_3 5x\implies \text{Red},\\\log_5 (2x+8)\implies \text{Blue}[/tex]
an engineer chooses to use bamboo as a building material because it grows quickly and needs little space to grow. This is an example of?
Answers
Answer: This is an example of Green Design
Green design can be described as a method in which any building project is made by minimizing the harmful effects of construction on humans and environment. Green design is a sustainable design which is better for the economy too. In a green design, eco- friendly materials are used for construction works.
In the scenario discussed in the question, an engineer is using bamboo as a building material due to its eco- friendly features. Hence, it is an example of green design.
Answer:
A) This is an example of Green Design
Explanation:
Which sequence of steps describes the life cycle of a lake?
A. Runoff fills a depression - sediments build up - water becomes
increasingly shallow
B. Runoff fills a depression - sediments are eroded - water becomes deeper
C. Runoff fills a depression - sediments build up
- water rises continuously
D. Runoff fills a depression - sediments are eroded - water spreads over a wider area
Answers
Answer:
The actual sequence of steps which describe the life cycle of a lake is given below:
C. Runoff fills a depression - sediments build up
- water rises continuously
Explanation:
This is because, the water which builds up as a result of the runoff water accumulating on the depression helps towards building up. When it must have accumulated greatly, it ends up forming a lake.
Which of the following statements is correct about electrical insulators?
A. They do not contain any atoms.
B. Their protons are not allowed to move about freely.
C. The electrons are not able to move about freely.
D. They are good at conducting heat only.
Answers
Answer:
the answer is C in my opinion.. hope this might be helpful
Joelle is a manager at a construction company, and she is interested in the chemistry behind the materials they use. She has begun studying the materials used to fill walls. She knows that to keep the temperature inside a room steady the material must be a thermal insulator, and she predicts that materials should not be acidic or else they would dissolve too easily in water.
Which of these is a molecular ingredient that could be used in a wall-filling material ?
C27H36N2O10
Na6Ba6
NeNa
HCl
Answers
Answer:
a
Explanation:
A molecular ingredient that could be used in a wall-filling material is C₂₇H₃₆N₂O₁₀, is not a good thermal insulator, hence option A is correct.
The big molecule C₂₇H₃₆N₂O₁₀ is a poor thermal insulator. Since NeNa is a relatively reactive chemical, it would probably dissolve in water far too quickly. The acidic molecule HCl would dissolve far too quickly in water.
Not a good thermal insulator is C₂₇H₃₆N₂O₁₀. It is a big molecule composed of a lot of hydrogen atoms. Since hydrogen atoms are excellent heat conductors, they would be ineffective in stopping heat from passing through a material used to fill a wall.
Thus, the option (A) C₂₇H₃₆N₂O₁₀ is correct.
Learn more about thermal insulator, here:
https://brainly.com/question/23134662
#SPJ6
if five elements have atomic numbers 2,3,6,9 which two numbers are the most reactive??
Answers
Explanation:
[tex]element \: with \: 2 \: atomic \: number \\ \\ is \: stable \: because \: it \: has \: already \: \\ \\ completed \: its \: orbit \: \\ \\ but \: atomic \: number \: with \: 3 \: and \: 9 \\ \\ will \: have \: to \: become \: stable \: \\ \\ after \: giving \: one \: electron \\ \\ so \: \: element \: with \: 3 \: and \: 9 \: atomic \: number \\ \\ is \: most \: reactive[/tex]