1. How many joules of heat are necessary to melt 500 g of ice at its freezing point?
Answer: To melt 500 g of ice, 4000 joule of heat is required.
Explanation:
I love the helps
The energy required to melt one gram of ice is 334 J. Then the heat energy required to melt 500 g of ice into water is 1.6 × 10⁵ J.
What is heat of fusion ?The change in energy associated with a phase change or any chemical reaction is called enthalpy change. Then, heat energy required to melt or freeze the substance.
The heat of fusion of ice is 334 J/g. Therefore, the heat energy required to melt the 1 g of ice is 334 J. Now the equation being used to find the energy for m g of ice to melt is:
q = mHf.
Hf = 334J/g
m = 500 g
q = 500 × 334 J/g = 1.6 × 10⁵ J
Therefore, the heat energy needed to melt 500 g of ice to water is 1.6× 10⁵ J.
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When Thomas Edison first sold electricity, he used zinc coulometers to measure charge consumption. (In a coulometer the cathode is weighed before a current is passed through it, and then again after the passage of current. The weight increase is proportional to the amount of current that flows through the cathode.) If the zinc plate in one of Edison's coulometers increased in mass by 7.85 g, how much charge had passed through it
When the zinc plate in one of Edison's coulometers increased in mass by 7.85 g, the amount of charge that had passed through it is 23,173 C.
Ionization of zinc
The zinc metal will ionize as shown below;
Zn²₊ + 2e⁻ → Zn
The molar mass of zinc metal is given as 65.38 g/mol
Amount of charge passed through 65.38 g/molAmount of charge that will deposite the given mass of zinc is calculated as follows;
e⁻ = 96500 C
2e⁻ = 2 x 96500 C = 193,000 C
Amount of charge passed through 7.85 g65.38 g -------> 193,000 C
7.85 g -----------> ?
= (7.85 x 193,000)/(65.38)
= 23,173 C
Thus, when the zinc plate in one of Edison's coulometers increased in mass by 7.85 g, the amount of charge that had passed through it is 23,173 C.
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Between a water molecule and an anion, like Cl-, a _____A_____ occurs between a _____B_____ of the water molecule and the anion.
Between a water molecule and an anion, like Cl-, a hydrogen bon occurs between hydrogen atom of the water molecule and the anion.
What is hydrogen bond?Hydrogen bond is a weak bond between two molecules resulting from an electrostatic attraction between a proton in one molecule and an electronegative atom in the other. Hydrogen atom in water molecule attract anion due to presence of hydrogen bond.
So we can conclude that hydrogen bond occurs between hydrogen atom of the water molecule and the anion.
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Answer:
Explanation:88766
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What is the total number of atoms contained in 3.63 moles of nickel?
Answer:
Explanation:
1 mole of nickel contains 6.02 * 10^23 atoms
3.63 mols of nickel contain x atoms.
What you have is a proportion. A proportion consists of 2 ratios or 4 parts.
Of the 4 parts, you know three of them. The problem is to solve for the 4th.
1/3.63 = 6.02*10^23 / x Cross multiply
x = 3.63 * 6.02* 10^23 Combine the right.
Answer: x = 2.19*10^24 atoms
Consider the structure shown.
A central S atom is bonded to three O atoms, two through a single line and one through two lines. There are six dots around two of the O atoms and 4 dots around the third O atom.
Determine the number of shared and unshared electrons in the structure.
shared (bonding) electrons:
unshared (lone, nonbonding) electrons:
Determine the number of shared and unshared pairs of electrons in the structure.
shared (bonding) pairs of electrons:
unshared (lone, nonbonding) pairs of electrons:
Determine the total number of valence electrons in the structure.
total valence electrons:
There are eight lone pairs and four bond pairs of electrons in the SO3 molecule. The valence electrons are found on the valence shell of the molecule.
Lewis structure of SO3The molecule SO3 is represented by the Lewis structure shown in the image attached to this answer. The central atom in the molecule is sulfur.
There are sixteen non bonding electrons in the molecule and eight bonding electrons in the molecule Hence, we have eight lone pairs and four bond pairs of electrons in the molecule as shown in the Lewis structure.
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*PLEASE HELP**
Which of the following aqueous solutions would have the lowest freezing point?
0.1 M sodium chloride
0.1 M calcium phosphate
0.2 M potassium sulfide
0.3 M aluminum nitrate
0.3 M barium chloride
Answer:
0.1 M Calcium phosphate
Explanation:
Which is also
0.1mCal2
In picture 4, the net force on the car is mostly the result of? A. Gravity. B. Constant velocity. C. Wind. D. Friction.
Answer:
D beacuse I think that's Force
• How do the physical and chemical properties of each packaging type help create new and better product?
Answer:
chemical composition and physical properties of packaging materials determine their ability to fulfill the various functions expected from the package.
How many grams of oxygen gas are required to react completely with 2.8 g of solid sodium
in a synthesis reaction?
Explanation:
0.9 grams of oxygen gas we need.
What does absolute zero physically mean at the particle level?
ASAP!
Answer:
Absolute zero is the lowest limit of the thermodynamic temperature scale, a state at which the enthalpy and entropy of a cooled ideal gas reach their minimum value, taken as zero kelvin.
If 22.00 mL of 2.00 M potassium iodide is needed to reach the equivalence point with 18.00 mL of lead (II) nitrate, determine the molarity of the lead (II) nitrate solution. Note: First write the balance equation between potassium iodide and lead (II) nitrate.
The molarity of the lead(II) nitrate solution if 22.00 mL of 2.00 M potassium iodide is needed to reach the equivalence point with 18.00 mL of lead (II) nitrate is 1.2M.
How to calculate molarity?The molarity of a solution can be calculated using the following formula:
CaVa/CbVb = na/nb
Where;
Ca = concentration of acidCb = concentration of baseVa = volume of acidVb = volume of basena = number of moles of acidnb = number of moles of baseThe balanced equation of the reaction is as follows:
Pb(NO3)2 (aq) + 2KI (aq) → 2KNO3 (aq) + PbI2 (s)
22 × 2/18 × Cb = 2/1
44/18Cb = 2
Cb = 44 ÷ 36
Cb = 1.2M
Therefore, the molarity of the lead(II) nitrate solution if 22.00 mL of 2.00 M potassium iodide is needed to reach the equivalence point with 18.00 mL of lead (II) nitrate is 1.2M.
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When 20.4g of sodium metal are mixed with chlorine gas, are 52.0 g of sodium chloride
produced? Explain (use calculations to prove your answer.
.ves or no
-with amounts shown)
Answer: True
Explanation:
[tex]\mathrm{The\ balanced \ chemical \ equation\ is\ :}\\$2 \mathrm{Na}{(s)}+\mathrm{Cl}_{2}(g) \rightarrow 2 \mathrm{NaCl}(s)[/tex]
For Na
[tex]\\$Given mass $=20.4 \mathrm{~g}$ \ \ Molecular mass $=23 \mathrm{~g}\ \ $Number of moles $=\frac{\text { Given mass }}{\text { Molecular mass }}$$$\begin{aligned}&=\frac{20.4}{23} \\&=0.887 \text { moles }\end{aligned}$$Stoichiometric ratio of $\mathrm{Na}$ is same as that of $\mathrm{NaCl}$ i.e., $1: 1$.$\therefore$ Moles of $\mathrm{NaCl}=0.887$ motes[/tex]
For NaCl
[tex]$$\\\begin{aligned}\text { Molecular mass } &=23+35.5 \\&=58.5 \mathrm{~g}\end{aligned}$$[/tex]
[tex]\begin{aligned}\\& $\therefore$ Mass of $\mathrm{NaCl}$ produced will be=\text { No.of moles } \times \text { Molecular mass } \\&=0.887 \times 58.5 \\&=51.9 \\&\simeq 52 \mathrm{~g} \quad\end{aligned}$$[/tex]
Therefore, it is true that when 20.4g of sodium metal are mixed with chlorine gas, 52.0 g of sodium chloride is produced
Explanation:
The answer: True
I explained the answer to your question in the submitted photo
What do ferns and gymnosperms have in common?They are all vascular plants.
Reproduction depends on birds, bees, and other animals.
They all produce seeds.
They depend on water for fertilization.
Answer:
They are all vascular plants.
Explanation:
Vascular plants, also known as tracheophytes, are highly advanced plant creatures with leaves, stems, and roots, as well as a vascular system made up of conducting vessels. Ferns are herbaceous, pteridophytic vascular plants that do not produce flowers or seeds. Gymnosperms are vascular plants that produce seeds but do not produce blooms. Because the seeds aren't covered or protected by an ovary, they can be seen on the plant's leaves or other components. Angiosperms are flowering plants containing seeds that develop inside the ovary, which develops and produces fruit.
Answer:
They all produce seeds
Explanation:
How much 1.75 M H3PO4, in mL, would you need to add to 50.00 mL of 3.50 M Ca(OH)2 in order to neutralize the solution
The volume of the 1.75 M H₃PO₄ solution required to neutralize 50 ml of 3.5 M Ca(OH)₂ solution is 66.67 mL
Balanced equation2H₃PO₄ + 3Ca(OH)₂ —> Ca₃(PO₄)₂ + 6H₂O
From the balanced equation above,
The mole ratio of the acid, H₃PO₄ (nA) = 2The mole ratio of the base, Ca(OH)₂ (nB) = 3How to determine the volume of H₃PO₄ Molarity of acid, H₃PO₄ (Ma) = 1.75 MVolume of base, Ca(OH)₂ (Vb) = 50 mLMolarity of base, Ca(OH)₂ (Mb) = 3.5 MVolume of acid, H₃PO₄ (Va) =?MaVa / MbVb = nA / nB
(1.75 × Va) / (3.5 × 50) = 2/3
(1.75 × Va) / 175= 2/3
Cross multiply
1.75 × 3 × Va = 175 × 2
5.25 × Va = 350
Divide both side by 5.25
Va = 350 / 5.25
Va = 66.67 mL
Thus, the volume of the H₃PO₄ solution needed is 66.67 mL
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Calculate the volume in mL of 0.279 M Ca(OH)2 needed to neutralize 24.5 mL of 0.390 M H3PO4 in a titration.
Note: the answer should have 3 significant digits. Do not include the unit mL in the answer.
The volume of the 0.279 M Ca(OH)₂ solution required to neutralize 24.5 mL of 0.390 M H₃PO₄ is 51.4 mL
Balanced equation2H₃PO₄ + 3Ca(OH)₂ —> Ca₃(PO₄)₂ + 6H₂O
From the balanced equation above,
The mole ratio of the acid, H₃PO₄ (nA) = 2The mole ratio of the base, Ca(OH)₂ (nB) = 3How to determine the volume of Ca(OH)₂ Molarity of acid, H₃PO₄ (Ma) = 0.390 MVolume of acid, H₃PO₄ (Va) = 24.5 mLMolarity of base, Ca(OH)₂ (Mb) = 0.279 MVolume of base, Ca(OH)₂ (Vb) =?MaVa / MbVb = nA / nB
(0.39 × 24.5) / (0.279 × Vb) = 2/3
9.555 / (0.279 × Vb) = 2/3
Cross multiply
2 × 0.279 × Vb = 9.555 × 3
0.558 × Vb = 28.665
Divide both side by 0.558
Vb = 28.665 / 0.558
Vb = 51.4 mL
Thus, the volume of the Ca(OH)₂ solution needed is 51.4 mL
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NH4NO3+Zn(OH)2
Balance the equation
Answer:
Balanced equation: Zn (NO 3) 2 + 2 NH 4 OH = 2 NH 4 NO 3 + Zn (OH) 2 Reaction type: double replacement
Explanation:
Amphetamine (C9H13N) is a weak base with a pKb of 4.2.
Calculate the pH of a solution containing an amphetamine concentration of 215 mg/L .
Express your answer to two decimal places.
Weak base: [OH⁻] = √Kb.C
pKb = 4.2
[tex]\tt Kb=10^{-4.2}[/tex]
c = concentration
MM Amphetamine (C9H13N) = 135.21 g/mol
c = 215 mg/L = (0.215 g : 135,21 g/mol) / L = 0.00159 mol/L = 1.59 x 10⁻³ mol/L
[tex]\tt [OH^-]=\sqrt{10^{-4.2}\times 1.59\times 10^{-3}}=3.17\times 10^{-4}[/tex]
pOH = 4 - log 3.17
pH = 14 - (4 - log 3.17)
pH = 10 + log 3.17 = 10.50
What is the first principle energy level called
Answer:
S orbital
Explanation:
no explanation, just a name you memorize
What are the processes that lead to the formation of sedimentary rocks? I WILL GIVE BRAINLIEST
A.weathering and erosion followed by dispersion.
B.volcanic eruptions followed by dispersion,
C. volcanic eruptions followed by compaction
D.weathering and erosion followed by compaction
Answer:
erosion, weathering, dissolution, precipitation, and lithification So,D.weathering and erosion followed by compaction
Explanation:
mark me brainliest!!
According to the given equation, how many moles of O, are required to react with 4.71 moles of C4H10?
2C4H10 + 1302 —8CO2 + 10 H
According to the given equation, 2C4H10 + 1302 — 8CO2 + 10H, 2 moles of O are required to react with 4.71 moles of C4H10.
How to calculate number of moles?The number of moles of a compound can be calculated stoichiometrically as follows:
The balanced chemical equation is given as follows:
2C4H10 + 1302 — 8CO2 + 10H
Based on the above equation, 2 moles of C4H10 reacts with 13 moles of O
Therefore; 4.71 moles of C4H10 will react with 4.71 × 6.5 = 30.62 moles of O
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Answer: 30.6
Explanation:
what is safe storage of produced materials exlain long
Answer:
Stacking storage sacks/ bags by interlocking, and placing heavier object on lower shelves.
Explanation:
Not sure what you meant exactly, but this is my best guess.
Which of the following are characteristics of stratovolcanoes? Select all that apply.
More common near convergent boundaries
More common at hotspots
Effusive eruptions
Explosive eruptions
High viscosity magma
Low viscosity magma
Answer:
More common near convergent boundaries
Explosive Eruptions
Low Viscosity Magma
Explanation:
Hot spots like hawaii are better known for shield volcanoes. The magma is high viscosity which causes them to build pressure before erupting, leading to explosive eruptions.
Suppose that a car's starter motor draws 221 A of current for 6.20 s to start the car. What mass of Pb is oxidized in the lead–acid battery to supply this much electricity?
1.47 grams
Actually, I figured it out., here is the answer in case anyone is wondering:
It has two electrons in the process and Q is 1370.2 (Q= I*T= 221*6.2=1370.2) this gets to 1370.2/192736 (the number on the denominator is due to that fact that there are two electrons involved) That equals 0.007 Mols, and then using the grams per mol from the periodic table for lead, we get that value is equal to 1.47 grams.
The lead acid battery produces energy by oxidation of lead. The amount of lead oxidized in this case is 1.47 g.
What is lead acid battery?The lead acid battery is the common accumulator that we have in use. It is made up of a cell that contains lead electrodes in an acid.
The oxidation of lead occurs according to thr equation;
Pb(s) ----> Pb^2+(aq) + 2e
If 207 g of Pb is oxidized by 2(96500)C
x g of lead is oxidized by (221 * 6.20) C
x = 207 g * (221 * 6.20) C/2(96500)C
x = 1.47 g
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At 4.5 atm of pressure, the solubility of a gas is 9.5 g/L.
How much gas, in grams, will dissolve in 1 L if the pres.
sure is reduced by 3.5 atm?
For a gas at 4.5 atm of pressure, the solubility of a gas is 9.5 g/L.
How much gas, in grams, is mathematically given as
s2=8.3782grams
What is the amount of gas in grams?Generally, the equation for the is mathematically given as
Si /S2 √P1/√P2
Therefore
[tex]s2=9.5*\sqrt{3.5}/\sqrt{4.5}[/tex]
s2=8.3782g
In conclusion. The solubility is
s2=8.3782g
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Nitrogen (iv) oxide is passed through the combustion tube before copper is heated.Give a reason for this?
to generate steam which act on copper
(a)Determine the number of KNO3 molecules in 0.750 mol KNO3.
(b) What is the mass (in milligrams) of 2.39 x 1020 molecules of Ag2SO4.
(c) Estimate the number of NaHCO2 molecules in 3.429 g of NaHCO2.
A. The number of molecules in 0.750 mole of KNO₃ is 4.515×10²³ molecules
B. The mass (in milligrams) of 2.39×10²⁰ molecules of Ag₂SO₄ is 124 mg
C. The number of molecules in 3.429 g of NaHCO₂ is 3.04×10²² molecules
Avogadro's hypothesis
1 mole of substance = 6.02×10²³ molecules
A. How to determine the number of molecules1 mole of KNO₃ = 6.02×10²³ molecules
Therefore,
0.750 mole of KNO₃ = 0.75 × 6.02×10²³
0.750 mole of KNO₃ = 4.515×10²³ molecules
B. How to determine the mass of Ag₂SO₄6.02×10²³ molecules = 312 g of Ag₂SO₄
Therefore,
2.39×10²⁰ molecules = (2.39×10²⁰ × 312) / 6.02×10²³
2.39×10²⁰ molecules = 0.124 g
Multiply by 1000 to express in mg
2.39×10²⁰ molecules = 0.124 g × 1000
2.39×10²⁰ molecules = 124 mg of Ag₂SO₄
C. How to determine the number of molecules68 g of NaHCO₂ = 6.02×10²³ molecules
Therefore,
3.429 g of NaHCO₂ = (3.429 × 6.02×10²³) / 68
3.429 g of NaHCO₂ = 3.04×10²² molecules
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What volume of .15M NaOH could be produced with only 5 grams of NaOH and water?
The volume of 0.15M NaOH that could be produced with only 5 grams of NaOH and water is 0.83L.
How to calculate volume?The volume of a substance can be calculated using the following expression:
Molarity = number of moles ÷ volume
The number of moles of NaOH can be calculated by dividing the mass of NaOH by its molar mass.
Molar mass of NaOH = 40g/mol
n = 5/40
n = 0.125moles
Volume of NaOH = 0.125mol ÷ 0.15M
Volume = 0.83L
Therefore, the volume of 0.15M NaOH that could be produced with only 5 grams of NaOH and water is 0.83L.
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A sample of excited atoms lie 3.314×10−19 J above the ground state. Determine the emission wavelength of these atoms.
The emission wavelength of the atoms excited above the ground state is 599.8 nm.
Emission wavelength of the atomsThe emission wavelength of the atom is determined by using the following formulas as shown below;
E = hf
E = hc/λ
where;
E is the energy of the atomh is Planck's constantc is speed of lightλ is the emission wavelengthλ = hc/E
λ = (6.626 x 10⁻³⁴ x 3 x 10⁸) / (3.314 x 10⁻¹⁹)
λ = 5.998 x 10⁻⁷ m
λ = 599.8 x 10⁻⁹ m
λ = 599.8 nm
Thus, the emission wavelength of the atoms is 599.8 nm.
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Which of the compounds below will dissociate in water? Check all that apply.
Ba(NO3)2
CaSO4
CO2
H2CO3
Mg3(PO4)2
those numbers are subscripts
An ionic compound does dissociate to a large extent in water. The compound that will completely dissociate in water here is Ba(NO3)2.
What is a soluble compound?A soluble compound is a compound that can dissociate to a large extent in water. Not all compounds are soluble in water. Only ionic compounds are soluble in water.
The compound that would dissolve in water among the list of compounds here is Ba(NO3)2.
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Answer:
A) Ba(NO3)2
B) CaSO4
C) CO2
D) H2CO3
E) Mg3(PO4)2
Explanation:
Wish I could give a good explanation, but I am still learning myself. Try searching up a video explaining this concept!
A patient who is scheduled for an x-ray expresses concerns about being exposed to radiation because he witnessed the effects of radiation on his father, who died of cancer. How should the dental assistant respond to this patient’s concerns?
The dental assistant should respond to this patient’s concerns by telling him that the amount of x-ray is very minimal and can't cause any negative effect.
What is X-ray?This is a penetrating form of electromagnetic radiation which produces images of the structures inside your body.
Exposure to large amounts of radiation could increase risk of cancer which is why minimal amounts which is safe is adopted.
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