Answer:
answer is true
Answer:
True
Explanation:
choose the letter that best describes the behavior of a substance during a phase change:
/A/ neither absorbs or releases energy
/B/ always absorbs energy
/C/ always releases energy
/D/ either absorbs or releases energy
Answer:
/D/ either absorbs or releases energy
Explanation:
During a phase change energy is either absorbed or released.
A phase change is a reversible process which occurs when a substance changes is its state from one form to another.
Phase changes are used to delineate physical changes.
A phase diagram provides a graphic representation of the change. The diagram can be 2 dimensional or 3 dimensional.Select each process that shows a physical change. Select all that apply. Several logs chopped into pieces. Chopping Wood Logs burning as in a campfire. Burning Wood A pot of water on a grate over a burning fire. Heating Water A marshmallow on a stick held above a fire. Roasting Food
Answer:
Chopping wood logsA pot of water o a grate over a burning fireExplanation:
Physical change is easily reversible. Burning/combustion is a chemical process where substances react rapidly with oxygen: this is usually irreversible.
The marshmallow, roasted food and burned wood all undergo combustion and hence are tagged chemical changes.
I hope this helps.
Answer:
Chopping Wood
Heating Water
Explanation:
Write the balanced symbol equation for the electrolysis of aluminium oxide to produce aluminium, and the reduction of iron oxide with carbon to produce iron.
Then use that to calculate the atom economy for each.
Answer:
Electrolysis of Al₂O₃: 4Al³⁺ (s) + 6O²⁺ (g) → 4Al (s) + 3O₂ (g)
Reduction of Elemental Fe: 2Fe₂O₃ (s) + 3C (s) → 4Fe (s) + 3CO₂ (g)
Atom Economy for Electrolysis of Al₂O₃: 52.9227%
Atom Economy for Reduction of Fe₂O₃: 62.8534%
Explanation:
Step 1: Define Compounds
Aluminum Oxide - Al₂O₃
Iron Oxide - Fe₂O₃
Step 2: RxN
Al₂O₃ (s) → Al (s) + O₂ (g)
Fe₂O₃ (s) + C (s) → Fe (s) + CO₂ (g)
Step 3: Balance RxN
2Al₂O₃ (s) → 4Al (s) + 3O₂ (g)
We need the same number of O on both sides (6 is the LCM)We will also need to balance the number of Al on both sides due to the change of O (4 reactant/product)This is ONLY the decomposition reaction for Aluminum oxide, NOT the electrolysis.
2Fe₂O₃ (s) + 3C (s) → 4Fe (s) + 3CO₂ (g)
We need the same number of O on both sides (6 is the LCM)We will also need to balance the number of Fe on both sides due to the change of O (4 reactant/product)We will also need to balance the number of C on both sides due to the change of O (3 reactant/product)This is the final single-replacement reaction for the reduction of Iron Oxide to Iron.
Step 4: Electrolysis of Al₂O₃
We will have to use oxidation-reduction reactions (half-reactions). Let's break up the reaction into it's elements.
Al³⁺ + ? → Al
To make the ion Al³⁺ turn into its neutral atom, we will need to add 3e⁻ to balance the half reactionAl³⁺ + 3e⁻ → Al
O²⁻ → O₂ + ?
Oxygen is a diatomic element, and in it's natural state is bonded to itself. We need to balance the half reaction2O²⁻ → O₂ + ?
We need to figure out how much electrons the ion O²⁻ loses to turn into its neutral atom. We see that we will need to lose 4e⁻2O²⁻ → O₂ + 4e⁻
Our half reactions:
Al³⁺ + 3e⁻ → Al
2O²⁻ → O₂ + 4e⁻
We now need balance the entire half reaction. Our LCM is 124 (Al³⁺ + 3e⁻ → Al) = 4Al³⁺ + 12e⁻ → 4Al
3 (2O²⁻ → O₂ + 4e⁻) = 6O²⁻ → 3O₂ + 12e⁻
Add the 2 half reactions4Al³⁺ + 12e⁻ + 6O²⁺ → 4Al + 3O₂ + 12e⁻
Cancel out spectator ions/e⁻ to get our final half reaction4Al³⁺ (s) + 6O²⁺ (g) → 4Al (s) + 3O₂ (g)
Step 5: Atom Economy
According to GCSE and my own deciphering, your equation for Atom Economy is essentially calculating for something similar to percent yield (but not quite).
[tex]Atom \hspace{3} Economy \hspace{3} = \hspace{3} \frac{Molar \hspace{3} Mass \hspace{3} of \hspace{3} Product}{Molar \hspace{3} Mass \hspace{3} of \hspace{3} All \hspace{3} Reactants} \cdot 100 \%[/tex]
4Al³⁺ (s) + 6O²⁺ (g) → 4Al (s) + 3O₂ (g)Molar Mass of Al - 26.98 g/mol
Molar Mass of O - 16.00 g/mol
Reactants: 4(26.98 g/mol) + 6(16.00 g/mol) = 203.92 g/mol
Products (Al as end product): 4(26.98 g/mol) = 107.92 g/mol
[tex]Atom \hspace{3} Economy \hspace{3} = \hspace{3} \frac{107.92 \hspace{3} g/mol}{203.92 \hspace{3} g/mol} \cdot 100 \%=52.9227 \%[/tex]
2Fe₂O₃ (s) + 3C (s) → 4Fe (s) + 3CO₂ (g)Molar Mass of Fe - 55.85 g/mol
Molar Mass of O - 16.00 g/mol
Molar Mass of C - 12.01 g/mol
Reactants: 4(55.85 g/mol) + 6(16.00 g/mol) + 3(12.01 g/mol) = 355.43 g/mol
Products (Fe as end product): 4(55.85 g/mol) = 223.4 g/mol
[tex]Atom \hspace{3} Economy \hspace{3} = \hspace{3} \frac{223.4 \hspace{3} g/mol}{355.43 \hspace{3} g/mol} \cdot 100 \%=62.8534\%[/tex]
Step 6: Check for significant figures
Since we are not given any values, we don't really need to change any numbers to fit sig fig rules.
_________ are elements of the same element that have a different _______________ due to a different number of _____________.
Answer: Isotopes
Explanation:
The atoms of a chemical element can exist in different types. These are called isotopes. They have the same number of protons (and electrons), but different numbers of neutrons. Different isotopes of the same element have different masses.
Hope this helps!
what is the chemical name of CCI3
Answer:
Trichloromethyl radical
Explanation:
Answer:
trichloromethanide
Hope this helped
23. For the reaction shown, calculate how many moles of each
product form when the given amount of each reactant com-
pletely reacts. Assume there is more than enough of the
other reactant.
2PbS(s) + 302(g) → 2PbO(s) + 2S02(8)
(a) 2.4 mol PbS
(b) 2.4 mol O2
(c) 5.3 mol PbS
(d) 5.3 mol O2
The reaction equation is the chemical formula of reagents and product substances
A reaction coefficient is a number in the chemical formula of a substance involved in the reaction equation. The reaction coefficient is useful for equalizing reagents and products
Mol ratio :
Pbs : O₂ : PbO : SO₂ = 2 : 3 : 2 : 2
(a) 2.4 mol PbSmol PbO
[tex]\tt \dfrac{2}{2}\times 2.4=2.4[/tex]
mol SO₂
[tex]\tt \dfrac{2}{2}\times 2.4=2.4[/tex]
(b) 2.4 mol O₂mol PbO
[tex]\tt \dfrac{2}{3}\times 2.4=1.6[/tex]
mol SO₂
[tex]\tt \dfrac{2}{3}\times 2.4=1.6[/tex]
(c) 5.3 mol PbS
mol PbO
[tex]\tt \dfrac{2}{2}\times 5.3=5.3[/tex]
mol SO₂
[tex]\tt \dfrac{2}{2}\times 5.3=5.3[/tex]
d) 5.3 mol O₂mol PbO
[tex]\tt \dfrac{2}{3}\times 5.3=3.53[/tex]
mol SO₂
[tex]\tt \dfrac{2}{3}\times 5.3=3.53[/tex]
Which of the following elements has the lowest ionization energy?
A. chlorine (CI)
B. potassium (K)
C. magnesium (Mg)
D.neon (Ne)
Answer:
B. Potassium
Explanation:
Potassium
he descriptions below explain two ways that water is used by plants on a sunny day.
I. In a process called transpiration, some liquid water in leaves changes to water vapor. The water vapor is released into the air through tiny pores in the leaves. This allows more liquid water from the soil to be pulled up the roots and stem to replace water lost from the leaves.
II. Plants use some of this water in leaves in a process called photosynthesis. During photosynthesis, water and carbon dioxide break apart and recombine to form two new substances, oxygen and glucose.
Based on the above description of transpiration and photosynthesis, which type of change happens to water during each process?
In transpiration, because some of its properties change, water undergoes a physical change but keeps its identity. In photosynthesis, because its identity changes, water undergoes a chemical change.
In transpiration, because some of its properties change, water undergoes a chemical change but keeps its identity. In photosynthesis, because its identity changes, water undergoes a physical change.
In transpiration, because its physical properties change, water undergoes a physical change and loses its identity. In photosynthesis, because it keeps its identity, water undergoes a chemical change.
In transpiration, because its chemical properties change, water undergoes a chemical change and loses its identity. In photosynthesis, because it keeps its identity, water undergoes a physical change.
Mark this and return
Answer:number 2
Explanation: because thats how it works
Explanation:
If an object increases in speed, it must be as a result of
o increasing friction.
o unbalanced forces.
O gravitational attraction.
O air resistance.
please hurry i’m taking a test
Answer:
a; increasing fraction
Explanation:
Using triangulation which point is the earthquakes epicenter?
Answer:
free points aye
Explanation:
Answer: 3
Three is where the earthquakes epicenter is.
Plz mark brainliest:)
1. Collect data: Create two water cycles using the Gizmo. Each cycle should have at least four steps and should begin and end at the same location. Choose any starting point from the list on the right. When the cycle is complete, choose the PATH tab and write the steps below.
Answer:
Cycle 1: Lake,atmosphere, clouds,rain,lake
Cycle 2: Atmosphere, clouds, rain, ocean
If a building is anchored into the ground, it
A. was constructed on that particular spot many years ago
B. has water and electrical resources available
C. is built on a solid foundation and unlikely to shift
D. is likely to be damaged due to land subsidence
Please select the best answer from the choices provided
O A
c
B
U
a
D
Answer: C. Is built on a solid foundation and unlikely to shift
Explanation: If a building is anchored into the ground, it is built on a solid foundation and unlikely to shift .
Answer:
C. Is built on a solid foundation and unlikely to shift
Explanation:
How can changes in temperature cause movement of air and other fluids on Earth? , “information I found on the Internet”
Answer:
Winds are a result of the tendency of warm air to rise and, conversely, cool air to sink. ... Because the atmosphere constantly flows, like a fluid in a container, air rushes into such low pressure areas from cooler, high-pressure ones, and the movement of the air creates wind.
Regina conducted an investigation to determine whether earthworms add nutrients to soil. She used two pots of soil. She added three earthworms to the first pot. She did not add any earthworms to the second pot, which was the control. Regina tested the nutrient levels of the soil in both pots after two weeks. What type of investigation is Regina conducting?
The question is incomplete, the complete question is:
Regina conducted an investigation to determine whether earthworms add nutrients to soil. She used two pots of soil. She added three earthworms to the first pot. She did not add any earthworms to the second pot, which was the control. Regina tested the nutrient levels of the soil in both pots after two weeks.
What type of investigation is Regina conducting?
descriptive
comparative
experimental
procedural
Answer:
experimental
Explanation:
In an experimental study, there is an independent variable, a dependent variable and a set up meant for control.
The control is set up to establish the validity of the study.
Experiments are designed to establish cause and effect relationship. In this case, the experiment was designed to establish weather earthworms add nutrient to the soil.
Answer:
experimental
Explanation:
experimental
How does the work needed to lift an object and the gravitational potential energy of the object compare? OThey are equal. OThe work is greater. OThe work is less. OThe comparison dependş on the height.
○ they are equal
○ the work is greater
○ the work is less
○ the comparison depends on the height
Answer:
They are equal
Explanation:
took the test
Answer:
ITS A JUST FINISHED
Explanation:
how did music change during medieval, renaissance and baroque eras
Answer:
usage of trills and vibrato
Explanation:
earlier music used trills while later styles would use vibrato.
A high concentration of hydrogen ions means a solution is what?
A. very acidic
B. neither acidic or basic
C. neutral
D. very basic
Tetrachloromethane,CC15,is classified as a
express the answer to each of the following calculations in scientific notation with the correct number of significant figures: 45.0 x 270
Answer: 1.215 × 10^4 i think
Explanation:
A) saturated
B)desaturated
C)unsaturated
D)supersaturated
Answer:
No Its B Unsaturated becuase the line is slanted
Explanation:
Part B
4.80 x 1022 molecules of propane, C3Hg.
Express your answer with the appropriate units.
Calculate the mass in grams
Where exactly is an orbital? I understand they are a volume where we expect to find electrons 90% of the time but I don't understand where their shapes are and fit on an atom, and the different forms of orbitals confuse me a little. Can someone explain me where they are with the help of an image? Pardon me if my question isn't very clear
Answer:
95% of the time (or any other percentage you choose), the electron will be found within a fairly easily defined region of space quite close to the nucleus. Such a region of space is called an orbital. You can think of an orbital as being the region of space in which the electron lives
How many atoms are present in 7.50 mol of chlorine atoms? _
Answer:
4.52 x 10²⁴ atoms Cl
Explanation:
A mole is a name that means a certain number like a dozen means 12. 1 mole of chlorine atoms is 6.022 x 10²³ chlorine atoms. The unit conversion is 6.022 x 10²³/mol.
[tex]7.50molCl*\frac{6.022 x 10^{23} atomsCl}{1molCl} = 4.5165*10^{24} atomsCl[/tex]
Round to 4.52 x 10²⁴ atoms Cl for the correct number significant figures.
A piece of metal with a volume of 2.45 mL has a density of 4.255g/mL. What is the mass of the metal?
Answer:
The answer is 10.42 gExplanation:
The mass of a substance when given the density and volume can be found by using the formula
mass = Density × volumeFrom the question
volume = 2.45 mL
density = 4.255g/mL
We have
mass = 2.45 × 4.255 = 10.42475
We have the final answer as
10.42 gHope this helps you
The charged particles in the beams that Thomson studied came from atoms. As these particles moved away from their original atoms, they formed a visible beam. The current model of the atom includes protons, neutrons, and electrons. What is the best use of an atomic model to explain the charge of the particles in Thomson's beams? An atom's negative particles are surrounded by positive matter, so the positive particles are easier to remove. An atom's positive particles are surrounded by negative matter, so the negative particles are easier to remove. An atom's smaller negative particles are at a distance from the central positive particles, so the negative particles are easier to remove. An atom's larger positive particles are at a distance from the central negative particles, so the positive particles are easier to remove.
Answer:An atom's positive particles are surrounded by negative matter, so the negative particles are easier to remove.
Explanation:
From our knowledge of the atom, we know that the nucleus lies at the center of the atom. The nucleus is positively charged because it contains the positive particles in the atom
The negative matter (electrons) surround the positive matter (protons) hence it is easier to remove the negative particles compared to the positive particles.
Answer:
C
Explanation:
How many atoms of each element are in one molecule of 2-heptanone?
if water is raise up by 50K and it takes 20900J to do it, what is the mass of the water?
Answer:
100g
Explanation:
5. A guava with a mass of 0.200 kg has a weight of
A. 0.200 N
B. 1.96 N
C. 4.50 N
D. 10.0 N
A guava with a mass of 0.200 kg has a weight of 1.96N
HOW TO CALCULATE WEIGHT:
The weight of an object is its mass with respect to gravity. That is, the weight of an object, which is a force measured in Newton (N) can be calculated as follows:F = mass (m) × acceleration due to gravity (a)
The mass of the guava in this question is given as 0.200kg, hence, the weight is calculated as follows:F = 0.200g × 9.8m/s²
F = 1.96N
Hence, a guava with a mass of 0.200 kg has a weight of 1.96N.
Learn more: https://brainly.com/question/23312072?referrer=searchResults
A 1.00-L flask is filled with 1.00 moles of H2 and 2.00 moles of I2. The value of the equilibrium constant for the reaction of hydrogen and iodine reacting to form hydrogen iodide is 50.5 under the given conditions. What are the equilibrium concentrations of H2 , I2 , and HI in moles/L? H2 (g) + I2 (g) ⇌ 2HI(g)
Answer:
[tex] C_{H_{2}} = 0.07 M [/tex]
[tex] C_{I_{2}} = 1.07 M [/tex]
[tex] C_{HI} = 1.86 M [/tex]
Explanation:
The reaction is:
H₂(g) + I₂(g) ⇄ 2HI(g)
Initially, we have the following concentrations of H₂ and I₂:
[tex] C_{H_{2}} = \frac{n}{V} = \frac{1 mol}{1.00 L} = 1 mol/L [/tex]
[tex] C_{I_{2}} = \frac{n}{V} = \frac{2 mol}{1.00 L} = 2 mol/L [/tex]
Then, in the equilibrium we have:
H₂(g) + I₂(g) ⇄ 2HI(g)
1-x 2-x 2x
[tex] Kc = \frac{[HI]^{2}}{[H_{2}][I_{2}]} = \frac{(2x)^{2}}{(1-x)(2-x)} [/tex]
[tex] 50.5*(1-x)(2-x) - (2x)^{2} = 0 [/tex]
By solving the above equation for x we have:
x₁ = 2.32 and x₂= 0.93
Hence, the concentrations of H₂, I₂ and HI are:
[tex] C_{H_{2}} = 1-x = 1 - 0.93 M = 0.07 M [/tex]
[tex] C_{I_{2}} = 2-x = 2 - 0.93 M = 1.07 M [/tex]
[tex] C_{HI} = 2*x = 2*0.93 M = 1.86 M [/tex]
I hope it helps you!
the boiling point of ethanol is 78.40 C. A student conducts an experiment and finds a boiling point of 75.70 C. What is the student's
percent error ?
Answer:
3.40% corrected to 1dp
Explanation:
78.4-75.7=2.7
percentage error = error/original value× 100
= 2.7/78.40×100
= 3.44387755102040
= 3.40% corrected to 1dp