Answer:
w = -531 kJ
1. Work was done by the system.
Explanation:
Step 1: Given data
Heat gained by the system (q): 687 kJ (By convention, when the system absorbs heat, q > 0).Change in the internal energy of the system (ΔU°): 156 kJStep 2: Calculate the work done (w)
We will use the following expression.
ΔU° = q + w
w = ΔU° - q
w = 156 kJ - 687 kJ
w = -531 kJ
By convention, when w < 0, work is done by the system on the surroundings.
There are 20 mice in a 5 m2 field ecosystem. The population density of mice is _____.
20 per m 2
5 per m 2
25 per m 2
4 per m 2
Answer:
4per m 2
20 mice divided by 5 so it will be 4 per m 2
In the reaction __S+3O2→2SO3, what coefficient should be placed in front of the S to balance the reaction?
Question 1 options:
1
2
3
Answer:
2
Explanation:
because on the product side you have 2 sulfurs so you need 2 on the reactant side.
HELP!!
IF YOU DON'T KNOW THE ANSWER DON'T ANSWER!
Answer: increase
Explanation:
ahhhhhhhhhhhhhhh
A 0.98 gram sample of a volatile liquid was heated to 348 k. the gas occupied 265 ml of space at a pressure of 0.95 atm. what is the molecular weight of this gas?
Answer:
The molecular weight is [tex]Z = 111.2 \ g/mol[/tex]
Explanation:
From the question we are told that
The mass of the sample is [tex]m = 0.98 \ g[/tex]
The temperature is [tex]T = 348 K[/tex]
The volume which the gas occupied is [tex]V = 265 \ ml = 265 *10^{-3} L[/tex]
The pressure is [tex]P = 0.95 \ atm[/tex]
Generally from the ideal gas equation we have that
[tex]PV = n RT[/tex]
Here n is the number of moles of the gas while the R is the gas constant with value [tex]R = 0.0821 \ atm \cdot L \cdot mol^{-1} \cdot K^{-1}[/tex]
[tex]n = \frac{PV}{ RT}[/tex]
=> [tex]n = \frac{ 0.95 * 265 *10^{-3} }{ 0.0821 * 348}[/tex]
=> [tex]n = 0.00881 \ mol[/tex]
Generally the molecular weight is mathematically represented as
[tex]Z = \frac{m}{n}[/tex]
=> [tex]Z = \frac{0.98 }{0.00881}[/tex]
=> [tex]Z = 111.2 \ g/mol[/tex]
An atom of which element has the strongest attraction for the electrons in a bond?
a. aluminum
b. carbon
c. chlorine
d. lithium
Answer:
chlorine
Explanation:
This is because the electronegativity increases from left to right and decreases from top to bottom of the periodic table.
Adaleigh is learning about renewable and non-renewable resources in her science class. She decides to take
a nature walk and makes notes of all the renewable resources that she sees. Which of the following is an
observation that Adaleigh could have made on her walk?
A. The seeds on the ground are going to grow into new trees.
B. The tallest trees had the most seeds around their bases.
C. When trees decay, they could eventually turn into coal.
D. Pine trees are older than oak trees.
Answer:
A. The seeds on the ground are going to grow into new trees.
Explanation:
Trees are renewable resources.
Calculate the amount of heat, in Joules, needed to raise 34.0g of water from 55.0°C to 76.0*C. The specific heat of water is 4.18 J/gºC.
Answer:
2984.52J
Explanation:
Using the formula: Q = m × c × ∆T
Where;
Q = amount of heat (in Joules)
m = mass (in grams)
c = specific heat capacity (J/g°C)
∆T = change in temperature (°C)
Based on the information provided in the question;
m = 34.0g
c = 4.18 J/gºC.
Initial temperature = 55.0°C
Final temperature = 76.0°C
Hence, Q = m × c × ∆T
Q = 34 × 4.18 × (76 - 55)
Q = 142.12 × 21
Q = 2984.52J
Therefore, 2984.52J is the amount of heat, in Joules, needed to raise 34.0g of the water.
Please help with this question..thank you
When [H+] = 4.0 × 10–9 M in water at 25°C, then
Kw =1.0×10–14.
b. pOH = 7.
c. [H3O+] = [OH–].
d. pH= 7
e. A-D are all correct
Answer:
a. Kw = 1.0 × 10⁻¹⁴
Explanation:
a. Let's consider the self-ionization of water.
2 H₂O(l) ⇄ H₃O⁺(aq) + OH⁻
The ion-product of water (Kw) at 25 °C is:
Kw = [H₃O⁺][OH⁻] = 1.0 × 10⁻¹⁴
c. Considering [H⁺] = [H₃O⁺] = 4.0 × 10⁻⁹ M, the concentration of OH⁻ is:
[OH⁻] = 1.0 × 10⁻¹⁴/[H₃O⁺] = 2.5 × 10⁻⁶ M
b. We can calculate the pOH using the following expression.
pOH = -log [OH⁻] = -log 2.5 × 10⁻⁶ = 5.6
d. We can calculate the pH using the following expression.
pH = -log [H⁺] = -log 4.0 × 10⁻⁹ = 8.4
When [H+] = 4.0 × 10–9 M in water at 25°C, then the [tex]Kw =1.0\times 10^-^1^4.[/tex]
What is dissociation constant?
Kw is the dissociation constant or ionization constant of water.
The self-ionization of water will be
[tex]\rm 2 H_2O(l) = H_3O^+(aq) + OH^-[/tex]
The dissociation constant of the water at 25°C will be
[tex]\rm Kw = [H_3O^+][OH^-] = 1.0 \times 10^-^1^4[/tex]
Thus, the correct option is a. [tex]Kw =1.0\times 10^-^1^4.[/tex]
Learn more about dissociation constant
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Use scientific notation to express the number 355000 to:
1) one significant figure
2) two significant figures
3) three significant figures
4) four significant figures
5) six significant figures
Answer:
1) 4*10^5
2) 3.6*10^5
3) 3.55*10^5
4) 3.550*10^5
5) 3.55000*10^5
Explanation:
1) 4 x [tex]10^5[/tex]
2) 3.6 x [tex]10^5[/tex]
3) 3.55 x [tex]10^5[/tex]
4) 3.550 x [tex]10^5[/tex]
5) 3.55000 x [tex]10^5[/tex]
What is scientific notation?A number is written in scientific notation when there is a number greater than or equal to 1 1 11 but less than 10 10 1010 multiplied by a power of 10 10.
Significant figures are the number of digits in a value, often a measurement, that contributes to the degree of accuracy of the value.
1) 4 x [tex]10^5[/tex]
2) 3.6 x [tex]10^5[/tex]
3) 3.55 x [tex]10^5[/tex]
4) 3.550 x [tex]10^5[/tex]
5) 3.55000 x [tex]10^5[/tex]
Learn more about scientific notation here:
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Your aunt is sipping on iced tea and fanning herself during a hot South Carolina summer day. You tell her that there is enough energy in one drop of her iced tea to run the air conditioner for the rest of her life if the energy could be extracted with 100% efficiency. Your aunt asks you to explain. Use the concepts you learned in this unit to explain the relationship between forces, energy, and matter.
Answer:
Isn't this like having enough energy to supply the world for centuries with just 1% of the sea's force?
Explanation:
I guess it's because the amount of energy in it can supply energy.
A current of 5.29 A is passed through a Sn(NO3)2 solution for 1.30 h . How much tin is plated out of the solution?
Answer:
15.26 g of tin
Explanation:
Given that the equation of the process is;
Sn^2+(aq) + 2e ------> Sn(s)
Since 1e = 1F= 96500 C
but q =It
t is in hours so it must be converted to seconds, the SI unit of time
Hence;
119g of tin is deposited by 2 * 96500 C
xg of tin is deposited by 5.29 * 1.30 * 60 * 60
x = 119 * 5.29 * 1.30 * 60 * 60/ 2 * 96500
x = 2946106.8/193000
x= 15.26 g of tin
A current of 5.29 A is passed through a Sn(NO₃)₂ solution for 1.30 hour, the amount of tin plated is 15.26 grams.
How do we calculate mass?Mass of any deposited susbatnce that is obtained by the passing of current will be calculated by using the Faraday's Law as:
W = ECT/F, where
W = required mass of deposited tin
C = current = 5.29 A
T = time period = 1.30hr = 4,680sec
F = faradays constant = 96500C
E = equivalent mass
Equivalent mass will be calculated as:
E = molar mass/charge on atom = 119/2 = 59.5 g/equ
On putting all these values in the above equation, we get
W = (59.5)(5.29)(4680) / 96500
W = 15.26 g
Hence mass of tin is 15.26 g.
To know more about Faraday's Law, visit the below link:
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A 25 cm sample of dilute sulfuric acid contains 0.025 moles of the acid.
What is the hydrogen ion concentration in the solution?
A. 0.2 mol/dm3
B. 0.05 mol/dm3
C. 1.00 mol/dm3
D. 2.00 mol/dm3
Answer:B. 0.05 mol/dm3
Explanation:
The hydrogen ion concentration in the solution is 2 mol/dm³
The correct answer to the question is Option D. 2 mol/dm³
We'll begin by calculating the molarity of the solution.
Volume = 25 cm³ = 25 / 1000 = 0.025 dm3
Mole of H₂SO₄ = 0.025 mol
Molarity of H₂SO₄ =?Molarity = mole / Volume
Molarity of H₂SO₄ = 0.025 / 0.025
Molarity of H₂SO₄ = 1 mol/dm³Finally, we shall determine the concentration of Hydrogen ion in the solution.H₂SO₄(aq) —> 2H⁺(aq) + SO₄²¯(aq)
From the balanced equation above,
1 mole of H₂SO₄ contains 2 moles of H⁺.
Therefore,
1 mol/dm³ H₂SO₄ will also contain 2 mol/dm³ H⁺.
Thus, the concentration of Hydrogen ion in the solution is 2 mol/dm³
The correct answer to the question is Option D. 2 mol/dm³
Learn more: https://brainly.com/question/3655413
consider the reaction between acetylene C2H2 and oxygen in a welding torch 2C2H2 + 5O2 = 4CO2 + 2H2O of 5.4 moles of acetylene react with sufficient oxygen how many grams of CO2 should form
Answer:
C. 4.8*10² g.
Explanation:
Andesitic rock is an igneous rock with a composition in between that of basaltic and granitic igneous rock.
true or false
Help pleaseeeeeeeee with this question
Answer:
(C) Vacuum
Explanation:
What is an nucleus ?
Nucleus is present at the centre of atom. It contains protons and neutrons. It is very small as compared to the atom.
Answer:
It is a part of a cell which controls all the activities in the cells and contains the genetic information of the cell that is to be passed down to the next cell when it reproduces.
Explanation:
It is a part of a cell which controls all the activities in the cells and contains the genetic information of the cell that is to be passed down to the next cell when it reproduces.
which formula represents a nonpolar molecule containing polar covelant bond
Answer: H2O and NH3 are polar molecules. H2 is a nonpolar molecule but the H-H bond is also nonpolar.
Therefore, the best choice is CCl4. Although the C-Cl bond is polar due to electronegativity differences, the molecule itself is nonpolar because the net dipole moments cancel out, given its tetrahedral molecular structure.
Explanation:
Name the alkyne please help!!
Answer:
4-ethylhex-2-yne
Explanation:
Based on periodic trends which atom has a larger ionization energy then calcium Ca?
Answer:
Gallium, Germanium, Arsenic, Selenium, Bromine and Krypton
Explanation:
Based on periodic trends, the atom that has a larger ionization energy than calcium are Gallium, Germanium, Arsenic, Selenium, Bromine and Krypton.
Across the period, the ionization energy increases from left to right.
Ionization energy is the energy required to remove the most loosely held electron within an atom. As you go from left to right, the ionization energy increases rapidly.The elements to the right of Ca will have a higher ionization energy compared to Ca.What is the mass of 1.00 mol of oxygen (O2)?
Answer:
Mass = 32 g
Explanation:
Given data:
Number of moles of oxygen = 1.0 mol
Mass of oxygen = ?
Solution:
Formula:
Number of moles = mass/molar mass
Molar mass of oxygen (O₂) is 32 g/mol
by putting values,
1.0 mol = mass/ 32 g/mol
Mass = 1.0 mol ×32 g/mol
Mass = 32 g
what are 4 sources of electrical energy?
Answer:
Clean Energy. Learn more about energy from solar, wind, water, geothermal, biomass and nuclear. Fossil. Learn more about our fossil energy sources: coal, oil and natural gas.Electric Power. Learn more about how we use electricity as an energy source. Energy Storage. Hydrogen & Fuel Cells.Explanation:
I hope this helps xD
Answer:
Electrical energy is used to power up a light bulb. The current moves from the outlet to the light bulb through the wire.
Lightning is another example of electrical energy. The negatively charged particles are separated from the positively...
Batteries are also sources of electrical energy. In car batteries, the moving charges Explanation:
fI gave u 3 think of the 4th one
When circumstances are right, most materials undergo a process called thermal expansion. Which statement best describes the cause and effect of thermal expansion? Group of answer choices Matter is heated, and its particles spread out more. Matter is heated, and its particles move closer together. Matter is cooled, and its particles move closer together. Matter is cooled, and its particles spread out more.
Answer: Matter is heated, and its particles spread out more
Explanation:
Thermal expansion occurs when there's an expansion of an object or material or when an object becomes bigger because of a rise in its temperature. This brings about the faster movement of the heated molecules and the atoms spreading out.
Therefore, the cause and effect of thermal expansion will be that when matter is heated, and its particles spread out more.
What pH scale number represents a neutral.
What pH scale number represents a neutral.
The answer is 7
what is meant by the term quantitative?
A) number measurement
B) words & explanation
Answer:
a) number measurement
Explanation:
relating to, measuring, or measured by the quantity of something rather than its quality.
Answer:
number and measurement
Explanation:
Quantitative is an adjective that simply means something that can be measured. For example, we can count the number of sheep on a farm or measure the gallons of milk produced by a cow.
Which is a component of John Dalton’s atomic theory?
The ratio of atoms in a compound is fixed.
The atoms of different elements are the same.
An atom is a small particle of matter that can be broken down.
A reaction can create or destroy atoms as well as rearrange them.
Answer:
i think the answer is b
Explanation:
NEED HELP ASAP!!
(04.04 LC)
Which statement is true about the products of cellular respiration?
They contain oxygen.
They contain glucose.
They become the products of photosynthesis.
They become the reactants of photosynthesis.
Answer:
They contain oxygen
hope it helps
Select the correct answer.
Which equation correctly relates kinetic energy, mass, and velocity?
OA. KE=3m22
OB. KE = mv2
Oc. KE=mu
OD. KE = mv3
Answer:
Ke1/2mv2
Explanation:
Hope this helps
Answer:
KE 1/2 MV2
ExplanationExplanationExplanationExplanation: hope this helps
Four students rolled a ball down a slide on the play ground which ball has the greatest applied force
The phase change between white tin and gray tin is difficult to observe directly. Both substances can be burned, however. From these equations, calculate AHⓇ for the conversion of gray tin into white tin:
Sn(s, white) + O2(g) + SnO2(g) AH = -580.69 kJ
Sn(s, gray) + O2(g) + SnO2(g) AH° = -582.78 kJ
AH = _________ kJ
Answer: Thus [tex]\Delta H[/tex] for the conversion of gray tin to white tin is -20.9 kJ
Explanation:
According to Hess’s law of constant heat summation, the heat absorbed or evolved in a given chemical equation is the same whether the process occurs in one step or several steps.
According to this law, enthalpy change of the overall reaction is the sum of the enthalpy changes of the intermediate reactions.
The final reaction is
[tex]Sn(s, gray)\rightarrow Sn(s, white)[/tex] [tex]\Delta H=?[/tex]
The intermediate balanced chemical reaction will be,
[tex]Sn(s, gray)+O_2(g)\rightarrow SnO_2(g)[/tex] [tex]\Delta H^0=-582.78kJ[/tex] (1)
[tex]Sn(s, white)+O_2(g)\rightarrow SnO_2(g)[/tex] [tex]\Delta H^0=-580.69kJ[/tex] (2)
substarcting (2) form (1) we get
[tex]\Delta H=\Delta H_1-\Delta H_2[/tex]
[tex]\Delta H=-582.78-(-580.69kJ)[/tex]
[tex]\Delta H=-20.9kJ[/tex]
