Explanation:
Physical change
★ Boiling of water
❤︎ freezing of water
❣︎ washing of clothes
♫︎ mixing black and brown stones
Chemical change
➪ making of dough
㋛︎ burning of wood
❥︎ cooking of the raw food
❁ burning of paper
ꨄ︎ rusting of iron
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A couple coffee changes from a temperature of 75ﾟC to 12ﾟC what is the change in temperature in ﾟC
Explanation:
Answer
Open in answr app
The initial temperature of the coffee T0=100∘C.
The temperature of the room 15∘C.
Let T be the temperature at time t in minutes.
By Newton's law of cooling,
dtdTα(T−15)
∴dtdT=k(T−15)
⇒T−15dT=kdt
⇒∫T−15dT=∫kdt
⇒log(T−15)=kt+logc
⇒log(cT−15)=kt
⇒T−15=cekt
At t=0,T=100
We have 100−15=ce0⇒85=c
Thus we get T−15=85ekt.
When t=5minutes,T=60
⇒60−15=85e5k.
⇒e
example for five electrolyte solutions write down five examples for electrolyte solutions
Answer:
A substance that dissociates into ions in solution acquires the capacity to conduct electricity. Sodium, potassium, chloride, calcium, magnesium, and phosphate are examples of electrolytes.
Answer From Gauth Math
state function and non state function
Answer:
State functions represent quantities or properties of a thermodynamic system, while non-state functions represent a process during which the state functions change. For example, the state function PV is proportional to the internal energy of an ideal gas, but the work W is the amount of energy transferred as the system performs work.
Explanation:
When KCl dissolves in water:
the Cl- ions are attracted to the partially negative oxygen atoms of the water molecule.
the K+ ions are attracted to Cl- ions on the KCl crystal.
the K+ ions are attracted to the partially positive hydrogen atoms of the water molecule.
the K+ ions are attracted to the partially negative oxygen atoms of the water molecule.
the Cl- ions are attracted to dissolved K+ ions.
Please explain!
This dissociation occur because:
O had to bond with H due to the Hydrogen bonding rule, which will form OH~ (Hydroxide).
K is more attracted to Hydroxide than Cl, so it will depart Cl and bond with OH~.
that leaves a H and a Cl, which one has a positive charge and the other has a negative, so they will bond and form Hydrochloric Acid.
Which of the following are examples of single replacement reactions? Select all that apply.
Answer:
Na2S(aq)+Cd(No3)2(aq)=CdS(s)+2NaNo3(aq)
Answer: it’s checkbox 2&3
what surface phenomenon s
The special properties of surface layers, that is, the thin layers of a substance at the boundary of contiguous bodies, mediums, or phases. These properties result from the excess free energy of the surface layer and from the special features of the layer's structure and composition.
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A voltaic cell prepared using zinc andiodine has the following cell notation.
Zn(s) | Zn2+(aq) ||I-(aq) | I2(s) |C(graphite)
Which of the following equations correctly represents the balanced,spontaneous, cell reaction?
a. 2I-(aq) +Zn2+(aq) --->I2(s) + Zn(s)
b. I2(s) + Zn(s)---> 2I-(aq) +Zn2+(aq)
c. 2I-(aq) + Zn(s)---> I2(s) +Zn2+(aq)
d. I2(s) +Zn2+(aq) --->2I-(aq) + Zn(s)
e. None of the above, since graphite must be in the equation.
The following equations correctly represents the balanced,spontaneous, cell reaction is option B. I2(s) + Zn(s)---> 2I-(aq) +Zn2+(aq).
The spontaneous cell reaction in a galvanic cell is led by a reduction reaction at the right electrode and a reduction reaction at the left electrode. Oxidation reaction at the left electrode reduction reaction at the right electrode. According to the second law of thermodynamics, all spontaneous processes must increase the entropy of the universe.
The reaction that produces the current in the galvanic cell is spontaneous. In a full-solution galvanic cell, the standard electrode potential for a redox reaction becomes more positive as the reaction proceeds forward in the galvanic cell. This is known as the spontaneous process of the galvanic cell. Reactions with negative values release free energy and are therefore spontaneous. Reactions with positive are not spontaneous and do not favor products.
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At elevated temperatures, hydrogen iodide may decompose to form hydrogen gas and iodine gas, as follows:
2HI(g) ⇌ H2 (g) + I2 (g)
In a particular experiment, the concentrations at equilibrium were measured to be [HI] = 0.85 mol/L, [I2] = 0.60 mol/L, and [H2] = 0.27 mol/L. What is Kc for the above reaction?
Explanation:
Since Kc is
[tex]k = \frac{(products)}{(reactants)} [/tex]
You can insert the Hydrogen and Iodine gas on top, and Hydrogen Iodide in the denominator.
Note: you can only include gases and aqueous species in an equilibrium expression, and all the species in this reaction are gaseous so you're good.
Inserting their molarity at equilibrium into their places, and you can solve. Don't forget to make the coefficient of HI turn into a power.
How does the radiation from radioisotopes cause damage to human tissue?
Answers
A.
by ionization knocking electrons away from atoms
B.
by breaking the bonds between atoms in molecules
C.
by causing nuclear chain reactions inside cells
D.
by causing transmutations of atoms within cells
Answer:
Explanation:
B.
by breaking the bonds between atoms in molecules
According to Arrhenius, NH4+ an acid or a base? Write an equation to support
According to Arrhenius definition of acids, [tex]NH4^+[/tex] is an acid.
According to Arrhenius definition of acids and bases, acid is any substance that produces hydrogen ion in solution as its only positive ion.
Following this definition, let us now consider what happens when [tex]NH4^+[/tex] is introduced into a water;
[tex]NH4^+[/tex](aq)-------> NH3(aq) + [tex]H^+[/tex](aq)
Hence, according to Arrhenius definition of acids, [tex]NH4^+[/tex] is an acid.
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The following is what kind of reaction?
2 CH4 +4 02 → 2 CO2 + 4H2O
Answer:
It is a combustion reaction.
a) Define typical polyfunctional acid ?
b) Show the equations of dissociation mechanism of phosphoric acid as an example.
c) Write the equation for calculating the [H3O*].
a) A polyfunctional acid is an acid that has more than one functional group.
b) The equations of dissociation of phosphoric acid are:
H₃PO₄ + H₂O ⇄ H₂PO₄⁻ + H₃O⁺ H₂PO₄⁻ + H₂O ⇄ HPO₄²⁻ + H₃O⁺ HPO₄²⁻ + H₂O ⇄ PO₄³⁻ + H₃O⁺c) The equation for calculating the concentration of H₃O⁺ is [tex] [H_{3}O^{+}] = (\frac{K_{1}K_{2}K_{3}[H_{3}PO_{4}]}{[PO_{4}^{-3}]})^{1/3} [/tex]
a) A polyfunctional acid can be defined as an acid that has more than one functional group. Phosphoric acid (H₃PO₄) is an example of polyfunctional acid since it is composed of three hydroxyl groups joined to a phosphorus atom, which is also joined to an oxygen atom by a double bound. In that structure, the three hydrogen atoms of the hydroxyl groups give the acidic behavior to this compound.
b) Phosphoric acid has three equations of dissociation:
H₃PO₄ + H₂O ⇄ H₂PO₄⁻ + H₃O⁺ (1)H₂PO₄⁻ + H₂O ⇄ HPO₄²⁻ + H₃O⁺ (2)HPO₄²⁻ + H₂O ⇄ PO₄³⁻ + H₃O⁺ (3)The dissociation constants for the three above equations are:
[tex] K_{1} = \frac{[H_{2}PO_{4}^{-}][H_{3}O^{+}]}{[H_{3}PO_{4}]} [/tex] (4)
[tex] K_{2} = \frac{[HPO_{4}^{2-}][H_{3}O^{+}]}{[H_{2}PO_{4}^{-}]} [/tex] (5)
[tex] K_{3} = \frac{[PO_{4}^{3-}][H_{3}O^{+}]}{[HPO_{4}^{2-}]} [/tex] (6)
c) We can calculate the concentration of H₃O⁺ for each equilibrium with the equations (4), (5), and (6).
The general reaction of dissociation of phosphoric acid is given by the sum of equations (1), (2), and (3):
H₃PO₄ + 3H₂O ⇄ PO₄³⁻ + 3H₃O⁺ (7)
The concentration of H₃O⁺ for the total dissociation reaction (eq 7) can be found as follows:
[tex] K_{t} = \frac{[PO_{4}^{-3}][H_{3}O^{+}]^{3}}{[H_{3}PO_{4}]} [/tex] (8)
Where:
[tex] K_{t} = K_{1}*K_{2}*K_{3} [/tex]
Hence, by knowing the dissociation constants K₁, K₂ and K₃, and the concentrations of PO₄³⁻ and H₃PO₄, the [H₃O⁺] is:
[tex][H_{3}O^{+}] = (\frac{K_{1}K_{2}K_{3}[H_{3}PO_{4}]}{[PO_{4}^{-3}]})^{1/3}[/tex]
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Question 1 of 10
What is the correct orientation of the bar magnet, based on the magnetic field
lines shown?
A. North pole on the left end and south pole on the right end
B. South pole on the top edge and north pole on the bottom edge.
C. South pole on the left end and north pole on the right end
D. North pole on the top edge and south pole on the bottom edge
Answer:
d. north pole on the top edge and south pole on the bottom edge
Explanation:
Why does the temperature stop rising while ice melts into water?
A. The temperature does not stop rising.
B. The electrons are increasing in energy levels.
C. Because no more heat is being added to the system.
D. The energy is being absorbed to separate the particles.
Answer:
When you heat ice, its temperature rises, but as soon as the ice starts to melt, the temperature stays constant until all the ice has melted. This happens because all the heat energy goes into breaking the bonds of the ice's crystal lattice structure.
Explanation:
The temperature stop rising while ice melts into water because, the energy is being absorbed to separate the particles. This is because of latent heat of fusion.
What is latent heat of fusion?The amount of energy needed to convert the solid substance into a liquid substance by modifying its physical effects. It exists also named enthalpy of fusion. When heat exists supplied to ice, it begins melting and heat is used to increase temperature initially. But after the occasional temperature of ice does not vary and the extra heat exists utilized to melt the ice by cracking bonds between crystal lattice of ice.
The temperature stops increasing while the ice melts into the water because the energy exists being absorbed to divide the particles. This exists because of the latent heat of fusion.
Therefore, (D) option is the correct answer.
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Two methods by which we can conserve water and water the plants.
Answer:
Two methods which help us to conserve water are:
Sprinkler irrigation system: this irrigation has an arrangement of vertical pipes with rotating nozzles on the top. It is more useful in the uneven and sandy land where sufficient water is not available.
Drip irrigation system: this irrigation system has an arrangement of pipes or tubes with very small holes in them to water plants drop by drop just at the base of the root. It is very efficient as water is not wasted at all.
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Which of the following compares the rainforest and the tundra environments correctly?
A. A rainforest is hotter than the tundra because it is closer to the equator.
B. A rainforest is less humid than the tundra because of its higher elevation.
C. A tundra has higher temperatures than the rainforest because it receives more
sunshine.
D. A tundra has higher humidity than the rainforest because of its proximity to water bodies.
For Science BTW!
Answer:
A
Explanation:
A rain forest is hotter than the tundra because it is closer to the equator
PLEASE HELP!!!!!!! The boiling point of water is 100ºC. The boiling point of acetone is 56ºC. Which statement about distilling a mixture of acetone and water is correct?\
A. Water will vaporize from the mixture before acetone.
B. Water is collected as it leaves the mixture.
C. Acetone remains in the original container.
D. Acetone is captured and cooled.
Answer:
D. Acetone is captured and cooled.
The correct answer is option D: Acetone is captured and cooled.
Distillation is a method of separation based on the difference in boiling point of two liquids.
The liquid that has a lower boiling point is first separated from the mixture. It vaporizes, cooled and collected before the liquid that has a higher boiling point.
In this case, acetone is captured and cooled before water since it has a boiling point of 56ºC and water has a boiling point of 100ºC.
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Determine
the
number
of grams of C4H10
that
are
required
to
completely
react
to
produce 8.70 mol of CO2
according
to
the
following
combustion
reaction:
2 C₄H₁₀(g)
+
13 O₂(g)
→
8 CO₂(g)
+
10 H₂O(g)
Answer:
8 CO₂(g)
Explanation:
just took the exam
1. Draw the condensed structural formula of sodium benzoate showing all charges, atoms including any lone pairs in the side chain functional group, and all sigma and pi bonds.
2. Draw the condensed structural formula of benzoic acid showing all atoms including any lone pairs in the side chain functional group, and all sigma and pi bonds. Indicate the acidic hydrogen.
3. Draw the condensed structural formula of tetrahydrofuran (THF) showing all heteroatoms plus their lone pairs and all sigma and pi bonds.
The structures are shown in the image attached.
A structural formula is the representation of the molecule in which all atoms and bonds in the molecule are shown.
Since the question requires that all the lone pairs, formal charges and sigma and pi bonds should be shown, then the simple condensed structural formula becomes insufficient in this case.
I have attached images of the structural formula of sodium benzoate (image 1), benzoic acid (image 2) and tetrahydrofuran (image 3).
All the formal charges, lone pairs as well as sigma and pi bonds are fully shown.
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Which processes occur during the second stage of technological design? Check all that apply.
designing a solution
studying relevant information
rebuilding and retesting
reporting a solution
defining criteria of success
identifying a problem
building a prototype
A mixture of gases includes helium, neon, argon and krypton. The partial pressures are as follows:
Partial pressure, mm Hg
He 152
Ne 164
Ar 126
Kr 169
What is the total pressure of the mixture after removing the argon component? Report your answer rounded
to the nearest mm Hg but without units
Answer:
the answer to your question is ar 126
How is the mass percent of elements in a compound different for a 1.0-g sample versus a 100.-g sample versus a 1-mole sample of the compound?
Answer:
since mass percent is based on the proportions of elements in a compound, the mass of a sample does not matter
The mass percent or percentage by mass of a chemical compound is a constant.
What is mass percent?Mass percent can be defined as percentage by mass and it is the concentration of a given amount (quantity) of element in a chemical compound or a component of a mixture.
The mass percent or percentage by mass of a chemical compound is a constant, regardless of the amount of substance that is present. Thus, all chemical compound always have a constant composition because mass percent is typically based on the proportions of the elements contained in a chemical compound.
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What is the molarity of an HCl solution if 25.0 mL of this solution required 17.80 mL of 0.108 M NaOH to reach the end point in a titration?
Answer:
[tex]\boxed {\boxed {\sf 0.0769 \ M}}[/tex]
Explanation:
We are asked to find the molarity of an acid given the details of a titration experiment. The formula for titration is as follows:
[tex]M_AV_A= M_B V_B[/tex]
In this formula, M is the molarity of the acid or base and V is the volume of the acid or base. The molarity of the hydrochloric acid (HCl) is unknown and the volume is 25.0 milliliters.
[tex]M_A * 25.0 \ mL = M_BV_B[/tex]
The molarity of the sodium hydroxide (NaOH) is 0.108 molar and the volume is 17.80 milliliters.
[tex]M_A * 25.0 \ mL = 0.108 \ M * 17.80 \ mL[/tex]
We are solving for the molarity of the acid and we must isolate the variable [tex]M_A[/tex]. It is being multiplied by 25.0 milliliters. The inverse operation of multiplication is division, so we divide both sides of the equation by 25.0 mL.
[tex]\frac {M_A * 25.0 \ mL }{25.0 \ mL}= \frac{0.108 \ M * 17.80 \ mL }{25.0 \ mL}[/tex]
[tex]M_A= \frac{0.108 \ M * 17.80 \ mL }{25.0 \ mL}[/tex]
The units of milliliters cancel.
[tex]M_A= \frac{0.108 \ M * 17.80 }{25.0 }[/tex]
[tex]M_A= \frac{1.9224}{25.0 } \ M[/tex]
[tex]M_A= 0.076896 \ M[/tex]
The original measurements have 3 and 4 significant figures. We must round our answer to the least number of sig figs, which is 3. For the number we calculated, that is the ten-thousandth place. The 9 to the right of this place tells us to round the 8 up to a 9.
[tex]M_A \approx 0.0769 \ M[/tex]
The molarity of the hydrochloric acid is 0.0769 Molar.
The turbines in a hydroelectric plant are fed by water falling from a 50 m height. Assuming 91% efficiency for conversion of potential to electrical endrgy, and 8% loss of the resulting power in transmission, what is the mass flow rate of water required to power a 200 W light bulb?
From the information given;
the height of the water stream = 50 mthe efficiency of conversion from potential energy to electrical energy is 91%loss of power transmission = 8%To determine the mass flow rate, let's start by understanding some concepts and parameters.
The power is known to be the energy per unit of time. Mathematically, it can be written as:
[tex]\mathbf{Power = \dfrac{Energy}{Time}}[/tex]
[tex]\mathbf{P =\dfrac{E_p}{time}}[/tex]
[tex]\mathbf{P =\dfrac{m\times g\times z}{time}}[/tex]
where;
[tex]\mathbf{E_p}[/tex] is the potential energy of the streamm = mass flow rateg = acceleration under gravityz = heightThus;
[tex]\mathbf{E_p}[/tex] = m × 9.81 m/s² × 50 m
[tex]\mathbf{E_p}[/tex] = m × 490.5 (m²/s²)
Recall that:
The power P = 200 W, and;the conversion of the P.E = 91% = 0.91∴
[tex]\mathbf{E_p}[/tex] = 0.91 × 490.5m (m²/s²)
[tex]\mathbf{E_p}[/tex] = 446.355m (m²/s²)
Since the resulting power transmission is said to be 8%
Then;
the loss in the power transmission (P) = 100% - 8% × 446.355m (m²/s²)
the loss in the power transmission (P) = 92% × 446.355m (m²/s²)
the loss in the power transmission (P) = 0.92 × 446.355m (m²/s²)
the loss in the power transmission (P) = 410.65m (m²/s²)
Finally;
P = 410.65m (m²/s²)
[tex]\mathbf{P = 410.65 \times m (\dfrac{m^2}{s^2})}[/tex]
replacing the values, we have:
[tex]\mathbf{200 = 410.65 \times m (\dfrac{m^2}{s^2})}[/tex]
[tex]\mathbf{m = \dfrac{200 watt}{410.65\times (\dfrac{m^2}{s^2})}}[/tex]
[tex]\mathbf{m = \dfrac{200 \dfrac{J}{s}}{410.65\times (\dfrac{m^2}{s^2})}}[/tex]
since 1 J/s = 1 kgm²/s²)
Then:
[tex]\mathbf{m = \dfrac{200 \dfrac{\dfrac{kg\times m^2}{s^2}}{s}}{410.65\times (\dfrac{m^2}{s^2})}}[/tex]
[tex]\mathbf{m = \dfrac{200 \ {kg}}{410.65 \ s}}[/tex]
mass flow rate of the water (m) = 0.487 kg/s
Therefore, we can conclude that the mass flow rate of the water required to power a 200 W bulb light is 0.487 kg/s
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Methylamine is a base because it can bond to H+. Draw Lewis structures to show how methylamine reacts with water to form a hydroxide ion.
Attached are the lewis structures,
The proton released by water bonds to the nitrogen, because it can hold charges relatively better than carbon because of it's bigger size
CaCl2 has which bond?
Answer:
CaCl2 has ionic bond because here calcium gives its electron to the chlorine atom and becomes positivetly charged ion.
What does the third quantum number (m) describe?
A. Which energy level the electron is in
B. What type of orbital the electron is in
C. What direction the electron is spinning
D. The specific orbital within a sublevel
The third quantum number (m) describes the specific orbital within a sublevel. The correct answer is option D.
Quantum numbers are a set of four numbers that describe the properties of an electron in an atom. They specify the energy, position, and orientation of an electron in an atom.
The third quantum number (m) is also called the magnetic quantum number. It describes the orientation of the orbital in space. Each orbital within a sublevel has a different orientation in space, and the magnetic quantum number tells us which orbital we are talking about.
The value of m can range from -l to +l, where l is the second quantum number (the angular momentum quantum number). The value of l determines the number of orbitals in a sublevel, and the value of m determines the specific orbital within that sublevel.
In conclusion, the third quantum number (m) describes the specific orbital within a sublevel. It tells us how the orbital is oriented in space, and it can have values ranging from[tex]\rm -l \ to +l[/tex], where l is the second quantum number.
Option D is the correct answer.
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Which is the best interpretation of the two flat portions of the graph?
In those portions, the heat supplied to the substance by the heater does not lead to a temperature rise as intermolecular forces are broken.
When a substance is heated, we normally expect that its temperature will rise as a consequence.
However, heat may be supplied to a substance but its temperature does not rise owing to the fact that the heat energy supplied is used to break intermolecular bonds.
This occurs during fusion and boiling. The heat supplied at these point does not result in temperature rise since it is used to break intermolecular bonds. The temperature remains steady during these processes as shown by the two flat portions on the graph in the image attached to the question. This heat supplied is known as the latent heat.
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Answer:
The answer for me was "These show where changes of state are occuring"
Explanation:
I got it right
Find the number of ibuprofen molecules in a tablet containing 210.0 mg of ibuprofen (C13H18O2).
Answer:
the answer is 5.83x1020 molecules
Explanation:
I'd really appreciate a brainleast
sodium bisulfite is an ionic compound that is used as a mild bleaching agent and a food preservative. It contains the bisulfate ion, an amphiprotic ion with the chemical formula HSO₃-.
a. Write the chemical equation for the reaction of HSO₃- with OH-. Is the bisulfite ion functioning as an acid or a base in this reaction?
b. Write the chemical equation for the reaction of HSO₃- with H₃O+. Is the bisulfite ion functioning as an acid or a base in this reaction?
a)
HSO₃⁻ + OH⁻ → H₂SO₄⁽²⁻⁾
In this reaction, we know that OH will act as a base. which means that the bisulfite ion will act as an acid
also because SO₃⁽²⁻⁾ will be relative more stable than O⁽²⁻⁾ because of larger valence shell. so HSO₃ will protonate. making it the acid
b)
HSO₃⁻ + H₃O⁺ → H₂SO₃
Here, the hydronium ion will be the one to protonate because that will help it form water, which is a much stabler compound
so the hydronium ion will protonate, making it the acid and the bisulfite will take that proton, making it the base
