Answer:
Physical Change
Explanation:
Sublimation is a physical change. When a substance sublimes, it changes from a solid to a gas without going through the liquid phase.
Describe the development of the modern periodic table. Include contributions made by Lavoisier, Newlands, Mendeleev, and Moseley.
Answer: Lavoisier organized a list of the known elements of his day as four categories. Newlands was the first to organize the elements and show that properties repeated in a periodic way. Mendeleev and Meyer proposed periodic tables showing a relationship between atomic mass and elemental properties. Moseley organized the elements by atomic number instead of atomic mass.
Explanation:
T/F___ At the eutectic composition, an alloy can solidify at a constant temperature.___ For effective dispersion strengthening, the dispersed phase should be needle-like, as opposed to round___ Intermetallic compounds are usually hard and brittle.___ For effective dispersion strengthening, the dispersed phase should be continuous.___ Stoichiometric intermetallic compounds exist overa range of compositions.___ Faster solidification results in smaller interlamellar spacing
Answer:
TRUEFALSETRUEFALSEFALSETRUEExplanation:
At the eutectic composition, an alloy can solidify at a constant temperature : TRUE . this is because at eutectic composition the type of reaction that takes place there is invariant reaction in its thermal equilibrium For effective dispersion strengthening, the dispersed phase should be needle-like, as opposed to round : FALSE. because the rounded shape will not cause a crack. Intermetallic compounds are usually hard and brittle : TRUE. because Intermetallic compounds prevents dislocation movements and this makes them brittle and hardFor the effective dispersion and strengthening, the dispersed phase should be continuous : FALSE. this is because the dispersed precipitate must be small and not continuous Stoichiometric intermetallic compounds exist over a range of compositions : FALSEFaster solidification results in smaller interlamellar spacing : TRUEFor each pair of covalently bonded atoms, choose the one expected to have the shortest bond length. (A) C-I (B) H-I ...... (A,B) fill in the blank 1 (C) H-Cl (D) H-I ...... (C,D) fill in the blank 2
Answer:
i) B
ii) D
Explanation:
Bond length is determined by the size of the atoms involved and the bond order
A) C-I
B) H-I
answer : H-I has the shortest bond length because H has an electronegativity value of 2.2 while C has an electronegativity value of 2.5 hence the bond between H-I is greater than C - I due the electronegativity difference between H-I is greater as well.
C) H-Cl
D) H-I
answer : H-Cl has the shortest bond length due the electronegativity difference between H-CI is greater as well.
Write a structural formula for the principal organic product formed in the reaction of methyl bromide with each of the following compounds:
1. Sodium hydroxide
2. Potassium ethoxide
3. Sodium benzoate
4. Lithium azide
Answer:
1. CH3Br + NaOH --------> H3C---OH + Na---Br
Explanation:
What is factor that is covered up by another trait Dominant or recessive
Answer: Recessive
Explanation: The recessive trait is often faded away by the dominant/other
Also looking at the word dominant it means powerful, most important, influential meaning it would most likely overpower
Goodluck :)
calculate the difference in slope of the chemical potential against temperature on either side of the normal freezing point of water and the normal boiling point of water the molar entropy change accompanying fussion is 22.0 and that accompanying evaporation
Answer:
(a) The normal freezing point of water (J·K−1·mol−1) is [tex]-22Jmole^-^1k^-^1[/tex]
(b) The normal boiling point of water (J·K−1·mol−1) is [tex]-109Jmole^-^1K^-^1[/tex]
(c) the chemical potential of water supercooled to −5.0°C exceed that of ice at that temperature is 109J/mole
Explanation:
Lets calculate
(a) - General equation -
[tex](\frac{d\mu(\beta )}{dt})p-(\frac{d\mu(\alpha) }{dt})_p[/tex] = [tex]-5_m(\beta )+5_m(\alpha )[/tex] = [tex]-\frac{\Delta H}{T}[/tex]
[tex]\alpha ,\beta[/tex] → phases
ΔH → enthalpy of transition
T → temperature transition
[tex](\frac{d\mu(l)}{dT})_p -(\frac{d\mu(s)}{dT})_p[/tex] =[tex]= -\frac{\Delta_fH}{T_f}[/tex]
= [tex]\frac{-6.008kJ/mole}{273.15K}[/tex] ( [tex]\Delta_fH[/tex] is the enthalpy of fusion of water)
= [tex]-22Jmole^-^1k^-^1[/tex]
(b) [tex](\frac{d\mu(g)}{dT})_p-(\frac{d\mu(l)}{dT})_p= -\frac{\Delta_v_a_p_o_u_rH}{T_v_a_p_o_u_r}[/tex]
= [tex]\frac{40.656kJ/mole}{373.15K}[/tex] ([tex]\Delta_v_a_p_o_u_rH[/tex] is the enthalpy of vaporization)
= [tex]-109Jmole^-^1K^-^1[/tex]
(c) [tex]\Delta\mu =\Delta\mu(l)-\Delta\mu(s)[/tex] =[tex]-S_m\DeltaT[/tex]
[tex][\mu(l-5[/tex]°[tex]C)-\mu(l,0[/tex]°[tex]C)][/tex] = [tex][\mu(s-5[/tex]°[tex]C)-\mu(s,0[/tex]°[tex]C)][/tex][tex]=-S_m[/tex]ΔT
[tex]\mu(l,-5[/tex]°[tex]C)-\mu(s,-5[/tex]°[tex]C)=-Sm\DeltaT [\mu(l,0[/tex]
[tex]\Delta\mu=(21.995Jmole^-^1K^-^1)\times (-5K)[/tex]
= 109J/mole
What is a special characteristic of Jupiter, Saturn, Neptune and Uranus?
Answer:
The gas and ice giants — Jupiter, Saturn, Uranus and Neptune — are outliers. They are much larger than the terrestrial planets, but their cores are small and icy. Most of their size is formed by a combination of gases that become denser and hotter as you get closer to the core.
sodium combines with chlorine to produce sodium chloride formula equation and balanced
Answer:
[tex]2Na+Cl_2 \rightarrow 2NaCl[/tex]
Explanation:
When sodium combines with chlorine, it will form sodium chloride.
The equation is :
[tex]Na+Cl_2 \rightarrow NaCl[/tex]
The balanced equation is :
[tex]2Na+Cl_2 \rightarrow 2NaCl[/tex]
Hence, the above equation shows the balanced equation when sodium combines with chlorine to form sodium chloride.
state two differences between palmitic acid, oleic acid and linoleic acid in full sentences
Answer:
Linoleic acid is omega-6 fatty acid, Oleic acid is omega-9 fatty acid and Palmitic acid is omega-7 fatty acid
Explanation:
Linoleic acid is omega-6 fatty acid which is not naturally produced by the body while Oleic acid is omega-9 fatty acid which occurs naturally in various animal and vegetable fats and oils.
As compared to oleic acid, Linoleic acid is lightweight and thin.
Palmitic acid is omega-7 monounsaturated fatty acid which occurs naturally and is found in plant and marine sources.
Palmitic acid is lighter than both the oleic acid and Linoleic acid
Use the following Balanced Equation to complete the question: 2 Al + 6 HBr → 2 AlBr3 + 3 H2
If you have 12 moles of HBr how many moles of H2 can be produced?
*Will give Brainly!*
Options:
1. Unsaturated fat or saturated fat
2. Fatty acids, carbohydrates, sterols, or phospholipids
3. Fatty acids, carbohydrates, or triglycerides
Please helppp
Answer:
1. saturated
2. fatty acids
3. fatty acids
Explanation:
Answer:
option 2 is correct
Explanation:
Draw a resonance structure, complete with all formal charges and lone (unshared) electron pairs, that shows the resonance interaction of the acetoxy with the ortho position in phenyl acetate.
Answer:
See explanation
Explanation:
The acetoxy group in ortho position in phenyl acetate does interact with the phenyl moiety in the molecule via resonance.
This detailed interaction of the acetoxy group in ortho position in phenyl acetate with the phenyl moiety in the molecule via resonance is shown in the image attached.
This interaction is made possible because the oxygen atom of the acetoxy group has lone pairs of electrons that are suitably positioned to interact with the ring via resonance.
Which Sl unit would be most appropriate for expressing the mass of this
animal?
Answer: Kilograms
Explanation: Milliliters and Kilometers are the wrong unit of measurement, and Milligrams are too small. Kilograms would be most appropriate to measure the weight of a heavy animal.
Characterize EACH of the three given statements as being TRUE or FALSE and then indicate the collective true-false status of the statements using the choices. (1) Water's boiling point is much higher than expected, based on comparison with other substances, because of hydrogen bonding. (2) In the gaseous state, disruptive forces and cohesive forces are of about the same magnitude. (3) As liquid surface area increases, the rate of evaporation of a liquid increases.
Answer:
The correct answer is - 1 and 3 are true.
Explanation:
Hydrogen bonds require a lot of energy to be broken as these bonds are relatively strong intermolecular forces which makes the boiling point of liquid like water very high, as it requires a lot of heat to break the intermolecular bonds holding the water molecules together.
An increase in the surface area of the liquid also increases the rate of evaporation as it takes place among the molecules of the liquid on the surface.
Suppose that scientists want to study a feature of the galaxy that is very far away. They decide to use a telescope that observes high-energy gamma rays. Explain why this would be a good choice.
Answer & Explanation:
Gamma rays are the most energetic form of electromagnetic radiation. By observing the distant galaxy at gamma-rays, scientists can search for new physics, test theories, and perform experiments that are not possible in earth-bound laboratories.
Help it’s about Binary compounds and transition metals
Answer:
Cr 6+ & SO4 2-
Explanation:
Sulfate is a polyatomic ion that has a charge of 2-. There are three of them in the chemical formula so it equates to a 6- total charge. Thus, chromium must have a 6+ charge to give the compound a neutral charge.
Use the periodic table to answer this question.
How many moles of He are in 16 g of the element?
A 4.0 mol
B 1.0 mol
C 8.0 mol
D 16 mol
Answer:
A. 4.0 mol
Explanation:
Divide 16 g by the molar mass of He, which is 4.0 g/mol.
16 g / 4.0 g/mol = 4.0 mol
A voltaic cell is constructed in which the anode is a Fe|Fe2 half cell and the cathode is a Cd|Cd2 half cell. The half-cell compartments are connected by a salt bridge. (Use the lowest possible coefficients. Be sure to specify states such as (aq) or (s). If a box is not needed, leave it blank.) The anode reaction is:
Answer: The Anode reaction is [tex]Fe(s)\rightarrow Fe^{2+}(aq)+2e^-[/tex]
Explanation:
Oxidation-reduction reaction or redox reaction is defined as the reaction in which oxidation and reduction reactions occur simultaneously.
Oxidation reaction is defined as the reaction in which a substance looses its electrons.Oxidation occurs at anode.
Anode : [tex]Fe(s)\rightarrow Fe^{2+}(aq)+2e^-[/tex]
Reduction reaction is defined as the reaction in which a substance gains electrons. Reduction occurs at cathode.
Cathode : [tex]Cd^{2+}(aq)+2e^-\rightarrow Cd(s)[/tex]
What do the symbols in the parentheses indicate
Answer:
(C) the physical state of each reactant and product
Explanation:
Hope this helps
2. Gas A has twice as much mass as Gas B. Compared to one mole of gas A, one mole of
gas B contains:
a) one-half as many particles
b) the same number of particles
c) twice as many particles
d) 22.4 times as many particles
daily routine care of farm animal husbandry
What is the mechanism by which Ozone is formed in the presence of sunshine?
Suppose you have a 1:1:1 by weight mixture of three solid compounds, salicylic acid 4-nitroaniline naphthalene. You dissolve 1 gram of this mixture in diethyl ether, and place a tiny drop of the ether solution on a TLC plate. After developing the TLC plate, you see three spots. Which compound would would you expect to have the largest Rf value
Answer:
The correct answer is - 4-nitroaniline.
Explanation:
It is given that all three solid compounds salicylic acid + 4-nitroaniline + naphthalene are equal in the ratio in the mixture and then 1 gram of this mixture is dissolved in the diethyl ether and run a drop of the solution on TLC plate. This plate shows three spots.
The salicylic acid and naphthalene would stay dissolved in the diethyl ether solution due to the 4-nitroaniline could be extracted by adding aqueous acid and involve in the aqueous layer and thus spot of 4-nitroaniline would be with largest Rf value.
Good Morning I have a question I need help and can not find the answer o it maybe someone help me? The question is _______ Most Of the Energy that drives water cycle comes from__________? (this is from Science)
Answer:
hydro, water
Explanation:
Help it’s due right now I will give you 15 points or more
Answer:
1. Temperature, the average kinetic energy of particles, indicates how warm something is. Thermal energy, or the overall kinetic energy of the particles, indicates how a substance or material will transmit heat or chill something else.
2. A thermal expansion is a matter to change in volume in response to a change in temperature.
3. Heat is the form of energy that is transferred between systems or objects with different temperatures.
4. Air temperature near or over bodies of water is much different from that over land due to differences in the way water and land heat and cool. Properties that affect water temperature are transparency, ability to circulate, and specific heat.
5. Radiation is the transfer of heat energy through space by electromagnetic radiation.
6. Radiation is natural and found everywhere, it comes from outer space, the air we breathe, and the earth we tread.
7. When a fluid, such as air or a liquid, is heated and then travels away from the source, it carries the thermal energy along. The fluid above a hot surface expands, becomes less dense, and rises.
8. Convection currents in the Earth occur in the mantle
9. The fire's heat causes molecules in the pan to vibrate faster, making it hotter. These vibrating molecules collide with their neighboring molecules, making them also vibrate faster.
10. Since air is a poor conductor, most energy transfer by conduction occurs right near Earth's surface. Conduction directly affects air temperature only a few centimeters into the atmosphere.
- Hope this helps!
Identify the most and the least basic compound in each of the following sets. Leave the remaining answer in each set blank. a) Sodium acetate: _______ Ammonia: _______ Sodium ethoxide: _______ b) Sodium acetate: _______ Sodium chloroacetate: _______ Sodium fluoroacetate: _______ c) Sodium acetate: _______ Sodium methoxide: _______ Sodium phenoxide:
Answer:
The correct answer is -
a) Sodium acetate: least Ammonia: _______ Sodium ethoxide: most
b) Sodium acetate: most Sodium chloroacetate: _______ Sodium fluoroacetate: least
c) Sodium acetate: least Sodium methoxide: most Sodium phenoxide:
Explanation:
A) In this case the basicity can be found by the stability of the base, Sodium acetate is the most stable base due to resonance stabilization of acetate anion. Sodium acetate is the least basic as the lone pair of electrons involved in the resonance here. An ethoxide ion has more electrons to donate an electron pair easily.
Thus, the correct answer is - Sodium acetate is the least basic while sodium ethoxide is the most basic.
B) Fluroacetate gives a very strong acid and the acetate gives the least strong acid among all three as described in case of a), thus, the most basic is acetate and the least is fluoroacetate.
]C) comparing the acidity of the acids formed by the addition of a proton to the anions is an easy and correct way to find the basicity of compounds.
Acetate ion adds a proton ⇒ acetic acid
methoxide adds a proton ⇒ methanol
phenoxide ion adds proton ⇒ phenol
As it is known that the stronger the acid, the weaker is the conjugate base formed by the loss of the proton.
acetic acid is the strongest acid because it can easily give up its proton to form acetate. Methanol is the weakest among all three and hence methoxide anion is the strongest base.
Thus, the correct answer is - sodium acetate is the least basic while sodium methoxide is the most basic.
A student investigated whether the number of bees he saw was related to the temperature outside. His results are on the graph below. Explain the relationship between temperature and the number of bees he saw. Use evidence from the graph to support your answer
Answer:
OOH a lot of points! too bad you scammed me :) its what you get i gueess
Explanation:
Answer:
The number of bees increased as the heat increased.
Explanation:
The line is on a steady increase.
Compare the number of moles calculated in parts a) 0.03 and b). 0.064. Which of the three possible reactions discussed is consistent with these results?
Answer:don’t click link ur gonna get ur info taken
Explanation:
Class A foam can be used
Class A foam is a specialized firefighting foam that is primarily used for extinguishing fires involving ordinary combustible materials, such as wood, paper, fabric, and plastics.
It is designed to enhance the effectiveness of water by reducing surface tension and increasing its ability to penetrate and wet these materials.
Class A foam can be used in various firefighting scenarios, including structural fires, wildland fires, and vehicle fires. It is particularly effective in situations where water alone may not be sufficient to control or extinguish the fire.
The use of Class A foam can improve firefighting operations by increasing the efficiency of water application, reducing water usage, and enhancing fire suppression capabilities. It helps to cool down the fire, minimize heat transfer, and reduce the generation of smoke and hazardous gases.
Overall, Class A foam is a valuable tool in the firefighting arsenal and can greatly aid in the extinguishment of fires involving ordinary combustible materials. Its application should be done in accordance with proper firefighting protocols and guidelines.
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How many molecules of CO2 are there in 3.55 g of CO2?
Answer:
4.9∗1022 molecules of CO2 in a 3.6 gram sample.
Explanation:
The gram molecular weight of co2 is 44 gms.
So the number of molecules in 44 gms of co2 is 6.023×10^23 .
Then the number of molecules in 3.6 gms of co2 is (6.023×10^23×3.6)÷44 = 4.92×10^22