The results are shown in the following table:
Test Tube Number of moles of zinc Heat absorbed by water (J) Change in internal energy of copper(II) sulfate (J) Reaction enthalpy (J/mol)
3 0.00765 1046 -1046 -13,600
4 0.00385 2093 -2093 -54,100
How to explain the informationHere are the calculations for test tubes 3 and 4:
Test Tube
Number of moles of zinc:
mass of zinc / molar mass of zinc = 0.500 g / 65.38 g/mol = 0.00765 mol
Heat absorbed by the water:
Q = mCΔT = 10.0 g * 4.186 J/g°C * 25°C = 1046 J
Change in internal energy of the copper(II) sulfate:
ΔU = -Q = -1046 J
Reaction enthalpy, in joules/mole:
ΔH = -ΔU / n = -1046 J / 0.00765 mol = -13,600 J/mol
Test Tube 4
Number of moles of zinc:
mass of zinc / molar mass of zinc = 0.250 g / 65.38 g/mol = 0.00385 mol
Heat absorbed by the water:
Q = mCΔT = 10.0 g * 4.186 J/g°C * 50°C = 2093 J
Change in internal energy of the copper(II) sulfate:
ΔU = -Q = -2093 J
Reaction enthalpy, in joules/mole:
ΔH = -ΔU / n = -2093 J / 0.00385 mol = -54,100 J/mol
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true or false: the more matter a star contains,the longer it is able to shine.
Pls help fast
Explanation:
true ..........................
This image shows a...
Answer:
I think is the last one!!!! punnet square ⬜
Which organism is a producer? A:owl B:mouse C:grass D:snake please somebody help me
Answer:
I think it's C. Grass. :)
Someone help me please!!!
A. 6 moles
B. 9 moles
C. 3 moles
D. 20 moles
I think please check me, in case I am wrong
Hi pls help with these questions. Will give brainliest for correct answer :)
Answer:
4
Explanation:
because those to elements link together creating amazing fractions
How many carbon atoms are there in a 12.5 kg sample of carbon?
step by step solution
Answer:
6.27 X 10^26 atoms
Explanation:
Write down the formula:
number of moles = mass/Ar (Ar is atomic mass)
Ar of carbon = 12
mass = 12.5kg or 12500g
Substitue these values into the formula:
number of moles = 12,500g / 12 = 3125/3 or 1041.6
Convert this to atoms:
1 mole = 6.022 X 10^23 atoms
So, 1041.6 moles = 6.27 X 10^26 atoms
the seven continents used to be one huge supercontinent called Ppaonderosa, Panhandle, Pangaea, Panthalassa
Answer:
Pangaea
Explanation:
Answer:
Pangea
Explanation:
Pangaea or Pangea was a supercontinent that existed during the late Paleozoic and early Mesozoic eras. It assembled from earlier continental units approximately 335 million years ago, and it began to break apart about 175 million years ago
9
Which statement best describes the Bohr model of the atom?
Electrons can move freely between intermediate energy levels.
B
Electrons move around the nucleus in circular orbits:
С
Electrons emit and absorb energy at continuous wavelengths.
D Electrons are accommodated in lower energy levels.
Answer:
B.electrons move around the nucleus in circular orbits.
define satt and give an example?
Answer:
Heyy..Here is your answer..Satt is the German word for full and it most likely comes from the same Latin word that saturated.Hope it helps..!!BRAINLIEST Give examples of at least three critical questions of society that science can help answer.
Answer:
1. How did life begin?
2. Are we alone in the universe?
3. What makes us human?
If an element is very reactive, is it more likely to be found in elemental state or in a compound?
Answer:
Compound state
Explanation:
Because reactive elements mostly react immediately with other elements
Which of the following is true about daughter cells?
A
They are genetically identical.
B
They each have their own nucleus.
C
They will most likely undergo mitosis.
D
all of the above
d. all of the above
AnswerD:
Explanation:
How many eggs are in 1 mole of eggs?
Answer:
I believe it is Avogadro's number: 6.022 × 10²³
Explanation:
One mole of a substance is equal to 6.022 × 10²³ units of that substance
What is the approximate volume of 280 g of chlorine gas (Cl2) at STP
78 L Cl₂
General Formulas and Concepts:Math
Pre-Algebra
Order of Operations: BPEMDAS
BracketsParenthesisExponentsMultiplicationDivisionAdditionSubtractionLeft to RightChemistry
Atomic Structure
Reading a Periodic TableSTP (Standard Conditions for Temperature and Pressure) = 22.4 L per mole at 1 atm, 273 KStoichiometry
Using Dimensional AnalysisExplanation:Step 1: Define
280 g Cl₂
Step 2: Identify Conversions
[PT] Molar Mass of Cl - 35.45 g/mol
Molar Mass of Cl₂ - 2(35.45) = 70.90 g/mol
[STP] 1 mol = 22.4 L
Step 3: Convert
[DA] Set up: [tex]\displaystyle 280 \ g \ Cl_2(\frac{1 \ mol \ Cl_2}{79.90 \ g \ Cl_2})(\frac{22.4 \ L \ Cl_2}{1 \ mol \ Cl_2})[/tex][DA] Multiply/Divide [Cancel out units]: [tex]\displaystyle 78.4981 \ L \ Cl_2[/tex]Step 4: Check
Follow sig fig rules and round. We are given 2 sig figs.
78.4981 L Cl₂ ≈ 78 L Cl₂
Which type of organism is responsible for performing the majority of nitrogen fixation?
Answer:
B. bacteria
Explanation:
they are responsible for the fixation of nitrogen
Answer:
the answer is B bacteria
Which energy transformation describes what occurs in a circuit? (select
the BEST answer)
chemical --> electrical --> light
thermal --> chemical --> light
electrical --> thermal --> light
Olight --> thermal --> chemical
Answer:
electrical --> thermal --> light
Explanation:
Answer:
electrical--> thermal--> light
How many moles of Na2SO4 can be made with 7.28 mol of H2SO4?
Answer:
7.28 mol Na2SO4
Explanation:
Since it is already in moles, all we have to do is use a molar ratio
A molar ratio is the proportions of reactants and products using the balanced equation. When writing a mole ratio, the given information must cross out with the right thing.
7.28 mol H2SO4 * 1 mol Na2SO4/1 H2SO4 = 7.28 mol Na2SO4
*notice how the H2SO4 crosses out
Look at the image below:
Mid ocean ridge
Sea towe
Marie Sedie
Osta 7m
WORM
PC
hohe materieur
Tron
Orope
thenosphere
perduta
What type of plate boundary is shown here?
convergent
divergent
transform
Answer:
Divergent
20 words
Answer:
divergent...........................
Why is 1/t used as a measure of rate of reaction?
1/t denotes that the reaction order is of the first order. That is, the rate of reaction is directly proportional to the concentration of the reactant. Because scientists use standard units, 1/t equals one divided by one second.
What do you mean by first order reaction ?The term first order reaction is defined as a chemical reaction in which the reaction rate is linearly dependent on the concentration of only one reactant.
In other words, a first-order reaction is a chemical reaction in which the rate varies as the concentration of only one of the reactants changes.
Because a reaction that takes longer to complete is obviously a slower reaction. A fast reaction is one that takes less time to complete. 1/t simply provides a quantitative value for comparing reaction rates.
Thus, 1/t denotes that the reaction order is of the first order.
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i need ur help guys please. 50 pts
Answer:
Sodium Chloride - Food flavoring, preservation and desiccation, fermentation processes, wood pulp bleaching in paper industry, buna and neoprene production in plastic industry.
Sodium Hydroxide - Bar soap and detergent production, drain cleaning, paper manufacturing, purification of bauxite ore prior aluminium production, artificial fibers production, oil refining.
Sodium Carbonate - Glass manufacturing, water softening, food additive, soap manufacturing, antiacid production.
Sodium Sulphate - Drugs for therapeutical use, wood pulp production in paper industry, soap and detergent production.
Potassium Nitrate - Fertilizer production, rocket propellant and gunpower production, wastewater treatment.
Potassium Chlorate - Oxygen-supply systems in aerospace applications.
Potassium Permanganate (VII) - Treatments of fungi and bacterial infections, wasterwater treatment and gastric irrigation.
Potassium Chloride - Hypoalkemia treatment, flavor enhancing in food.
Explanation:
Sodium Chloride - Food flavoring, preservation and desiccation, fermentation processes, wood pulp bleaching in paper industry, buna and neoprene production in plastic industry.
Sodium Hydroxide - Bar soap and detergent production, drain cleaning, paper manufacturing, purification of bauxite ore prior aluminium production, artificial fibers production, oil refining.
Sodium Carbonate - Glass manufacturing, water softening, food additive, soap manufacturing, antiacid production.
Sodium Sulphate - Drugs for therapeutical use, wood pulp production in paper industry, soap and detergent production.
Potassium Nitrate - Fertilizer production, rocket propellant and gunpower production, wastewater treatment.
Potassium Chlorate - Oxygen-supply systems in aerospace applications.
Potassium Permanganate (VII) - Treatments of fungi and bacterial infections, wasterwater treatment and gastric irrigation.
Potassium Chloride - Hypoalkemia treatment, flavor enhancing in food.
explain why a nanowire can be longer than 3000nm but still be considered a metallic nanomaterial
Answer:
A nanowire is a nanostructure, with the diameter of the order of a nanometre (10−9 meters). It can also be defined as the ratio of the length to width being greater than 1000. Alternatively, nanowires can be defined as structures that have a thickness or diameter constrained to tens of nanometers or less and an unconstrained length. At these scales, quantum mechanical effects are important—which coined the term "quantum wires". Many different types of nanowires exist, including superconducting (e.g. YBCO[1]), metallic (e.g. Ni, Pt, Au, Ag), semiconducting (e.g. silicon nanowires (SiNWs), InP, GaN) and insulating (e.g. SiO2, TiO2). Molecular nanowires are composed of repeating molecular units either organic (e.g. DNA) or inorganic (e.g. Mo6S9−xIx).
Explanation:
Hope it helps
Which is one of the Lewis structures for ozone?
000
:0:00
C:6
Answer:
D
Explanation:
Option D is the correct Lewis structure of ozone.
Ozone is known to be an allotrope of oxygen which has three atoms of oxygen.
In the Lewis structure of ozone, one pair of oxygen is actually double-bonded while the other is single-bonded. In this structure, two oxygen atoms carry charges. In the drawing the Lewis structure of ozone, we discover that one oxygen atom of the ozone has a -1 charge and while another oxygen atom of the ozone has a +1 charge.
HELP ASAP PLEASE WILL GIVE 12 points
A. Which of the following reaction mixtures will produce
hydrogen more quickly at room temperature:
(i) zinc granules + dilute nitric acid?
(ii) zinc powder + dilute nitric acid?
B. Give an explanation of your answer to a.
C. Suggest two other methods by which the speed of
this reaction can be altered.
Answer:
zinc powder + dilute nitric acid
Decrease the temperature in Exothermic reactions (Reactions that release energy, or become hot) Add a catalyst (A substance that reduces activation energy, speeding up the reaction) Increase the concentration of reactants. Increase the concentration of catalysts
Explanation:
Brainliest?
What is evolution?
1. Quick change in an organism to eat better
2. A change in the environment
3. Gradual change in the environment due to global warming
4. Gradual change of a species to be better suited for the environment
Answer:
The correct answer is option 4.
Answer:
4 Gradual change of a species to be better suited for the environment
Explanation:
The bouncing of a wave off an object is called a what
Answer:
Reflection-energy waves bouncing off the surface of an object
Explanation:
true or false: Gravity plays an important role in the formation of stars.
Pls help fast???!!!!
Answer:
the the answer iss ( true )
The Statue of Liberty changing from Copper to Green is an example of...
Group of answer choices
A: Temperature Change
B: Gas Formation
C: Color Change
D: Precipitate
Answer:
answering this for points! Sorry! but its probably A OR C
Explanation:
Match each term to its description. Match Term Definition Excess reactant A) Amount of product predicted to be produced by the given reactants Limiting reactant B) Reactant that can produce more of the product Theoretical yield C) Reactant that can produce a lesser amount of the product
Answer:
Excess reactant - Reactant that can produce more of the product
Limiting reactant - Reactant that can produce a lesser amount of the product
Theoretical yield - Amount of product predicted to be produced by the given reactants
Explanation:
In every chemical reaction, there is a limiting reactant and there is an excess reactant.
The limiting reactant determines the amount of product obtained. It is the reactant that produces a lesser amount of the product.
The excess reactant is known to be the reactant that produces a greater amount of the product.
The theoretical yield is calculated using the limiting reactant and is the amount of product predicted to be produced by the given reactants.
BRAINLIST!!
Which of the following describes a process of weathering?
A.
Rocks along the coast are broken up by waves crashing into the shore.
B.
Glaciers carry boulders from mountaintops to low-lying plains.
C.
Mud, silt, sand, and pebbles are carried across the region by running water.
D.
The wind lays down sediment to form small hills called dunes.
Answer:
D or C.
Explanation:
Sorry if its wrong
Answer:
A. Rocks along the coast are broken up by waves crashing into the shore.
Explanation:
A cation with a +4 charge has 26 neutrons and 18 electrons. What is the identity of the element?
mag aral wag puro brainly