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:
clarify the following expression s
a.atomic number
b.mass number
c.nucleus
Answer:
Atomic number of a chemical element is the number of protons found in the nucleus of every atom of that element.
The mass number, also called atomic mass number or nucleon number, is the total number of protons and neutrons in an atomic nucleus.
The atomic nucleus is the small, dense region consisting of protons and neutrons at the center of an atom.
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
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.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.
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what is the chemical name of CCI3
Answer:
Trichloromethyl radical
Explanation:
Answer:
trichloromethanide
Hope this helped
if water is raise up by 50K and it takes 20900J to do it, what is the mass of the water?
Answer:
100g
Explanation:
Tetrachloromethane,CC15,is classified as a
Ou are subliming camphor and you note that pure camphor is condensing nicely on the cold finger. You check on the process several minutes later and you see that the amount of camphor on the cold finger has not changed appreciably since the last time you looked at it. However, there is still plenty of impure camphor left at the bottom of the flask. What do you suppose is the reason and what do you need to do.
Answer:
The reaction is endothermic
Increase temperature of the flask
Explanation:
Sublimation is a phenomenon in which a substance changes directly from solid to gas,without passing through the liquid phase.
Camphor is a sublime substance. The sublimation of camphor is an endothermic reaction. This implies that energy is absorbed in the process.
For an endothermic reaction, the equilibrium position is shifted towards the right hand side by increasing the temperature of the system. Hence, if the flask is heated, more camphor will condense within a shorter time interval.
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.
(True/False) Solid Potassium Chloride, KCl (s), consists of equal numbers of positive Potassium ions (K+), and negative Chloride ions (Cl-) arranged in three dimensional networks called crystals. (6 Pts)
Answer:
true
Explanation:
How many atoms of each element are in one molecule of 2-heptanone?
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:)
_________ 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 most accurately illustrates the electrostatic forces between protons and electrons?
A high concentration of hydrogen ions means a solution is what?
A. very acidic
B. neither acidic or basic
C. neutral
D. very basic
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]
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:
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:
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.
Which materials sink in water? Hint: There is more than one nightanswer. Rubber Wooden Ball Ice Granite Titanium
Answer:
Granite and Titanium will sink
Explanation:
Granite and Titanium will sink in water.Granite and Titanium will sink in water because density of Granite and Titanium is higher then water. Also there raw shape does not help them to float on water.
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!
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
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
Lizzie is pushing Alex on a scooter. Lizzie is pushing with 75 N of force to the left,
and Alex is helping with 20 N to the left. What is the net force on the scooter?*
Answer:
95 N
Explanation:
they are both pushing in the same direction so you simply add
75+20=95
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:
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
can u tell me the steps to measure a straight line.. need answer immediately..
Part B
4.80 x 1022 molecules of propane, C3Hg.
Express your answer with the appropriate units.
Calculate the mass in grams
The cell membrane is found in all cells *
True
False
Answer:
true
Explanation:
all cells will have plasma membranes