Answer:
Nhiệt dung riêng của đồng là
380
J
/
k
g
.
K
Explanation:
If a light bulb has a voltage of 1.5 V and has 2.5A of current running through it, what is the resistance of the light bulb?
Answer:
0.6 ohm
Explanation:
voltage = 1.5 V
current = 2.5 A
resistence = ?
V = IR
1.5 = 2.5 * R
1.5 / 2.5 = r
0.6 = R
therefore resistence is 0.6 ohm
Plz help!!!! NO LINKS
Answer:
481.16 cm³
Explanation:
From the question given above, the following data were obtained:
Height (h) = 11.72 cm
Diameter (d) = 7.23 cm
Pi (π) = 3.14159
Volume of cylinder (V) =?
Next, we shall determine the radius. This can be obtained as follow:
Diameter (d) = 7.23 cm
Radius (r) =?
r = d/2
r = 7.23 / 2
r = 3.615 cm
Finally, we shall determine the volume of the cylinder. This can be obtained as shown below:
Height (h) = 11.72 cm
Pi (π) = 3.14159
Radius (r) = 3.615 cm
Volume of cylinder (V) =?
V = πr²h
V = 3.14159 × 3.615² × 11.72
V = 3.14159 × 13.068225 × 11.72
V = 481.16 cm³
Therefore, the volume of the cylinder is 481.16 cm³.
Which of the following reasons explains why if salt water is heated, the water turns into steam while the salt remains?
Water and salt have an equal boiling point.
Water has a lower boiling point than salt.
Salt has a lower boiling point than water.
Salt and water have an equal melting point.
If the salt water is heated, the water turns into steam and the salt remains because the water has a lower boiling point than the salt.
The following points can be considered:
The boiling point is defined as the temperature at which the substance turns into the gaseous state from the liquid state.The boiling point of water is [tex]100^{o} C[/tex].The salt is a substance comprising two entities separated by the opposite charges with ionic interactions.The boiling point of a salt is higher than the boiling point of the water.The process involved when salt water is heated:
The salt water mixture when heated, the water turns into steam at [tex]100^{o} C[/tex]But the salt remains until it reaches its boiling temperature. If the salt is soluble in water and is then heated, then there occurs an elevation in the boiling point of the substance, due to the presence of the salt.Therefore, the answer is water has a lower boiling point than salt.
Learn more about salt:
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A 8.29g sample of calcium sulfide was decomposed into its constituent elements, producing 4.61g of calcium and 3.68g of sulfur. Which of the statements are consistent with the law of constant composition (definite proportions)?
a. Every sample of calcium sulfide will have 44.4% mass of calcium.
b. Every sample of calcium sulfide will have 2.86 g of calcium.
c. The mass ratio of Ca to S in every sample of calcium sulfide is 1.25.
d. The ratio of calcium to sulfur will vary based on how the sample was prepared.
e. The mass percentage of calcium plus the mass percentage of sulfur in every sample of calcium sulfide equals 100%.
Answer:
d,e
Explanation:
why is platinum metal preferred to other metals for the flame test
Answer:
Platinum is especially good for this because it is unreactive, and does not produce a color in the flame which will mask the presence of other metals.
Hope this answer is right!
Answer:
Hey mate, here is your answer
1. Platinum doesn't impart any color to the flame.
2. It is not oxidised under the high temperature of the flame from a bunsen burner.
3. It is almost chemically inert. Even at high temperatures, it remains unattacked by free radicals / acid radicals.
Therefore, platinum wire is crucial for a flame test. Also, a platinum wire should be thoroughly cleaned before using it for a new flame test.
A platinum wire is cleaned by dipping it into concentrated HNO3 and then placing it in the non luminous part of the bunsen flame. Otherwise, the perviously tested radicals will impart color to the flame, which may cause confusion.
Explanation:
Hope it helps you
The strongest base that can exist in a solution in appreciable concentration is the conjugate base of the solvent.
a. True
b. False
Answer:
a. True
Explanation:
From the basic concepts of acids and bases, we know that when a base accepts a hydrogen ion (H⁺), it forms a conjugate acid which can accept again the H⁺ ion:
B⁻ + H₂O ⇆ BH + OH⁻
The stronger the base, the weaker the conjugate base. Thus, as more strength has a base, lesser strength will have the conjugate base (it will not be able to accept again the H⁺ ion). For example, when water (H₂O) loses its H⁺ , it forms the conjugate base OH⁻. So, OH⁻ is the stronger base that can exist in an aqueous solution.
H₂O ⇆ H⁺ + OH⁻
In fact, strong bases are hydroxides, such as NaOH or KOH.
The volume of a fixed mass of gas at 2 atm pressure is 20L.What will be its volume if the pressure is increased 4 times without changing the temperature.
Answer:
The correct answer is - 5L.
Explanation:
From the ideal gas equation -
pv=nRT
p = pressure
v =volume
Here nRT is constant so
P would be inversely proportioned to v
So, p1/p2 = v2/v1
Putting values:
2/4(2) = v2/20 (p2 = 4 times of P1)
2/8 = v2/20
V2 = 5
Thus, the correct volume at new pressure would be - 5 L.
What is the major organic product obtained from the sequence of reactions 2-phenyl-4 bomobutane and NaN3?
Answer:
(E)-1-phenylbut-1-ene
Explanation:
2-phenyl-4 bromobutane is an amphetamine that contains a phenyl group. It forms a major stable product with other reacting agents.
The major organic product that is obtained from the sequence of the reactions of the 2-phenyl-4 bomobutane when it reacts with [tex]NaN_3[/tex] is the (E)-1-phenylbut-1-ene.
Thus the answer is 2-phenyl-4 bromobutane is an amphetamine that contains a phenyl group. It forms a major stable product with other reacting agents.
The major organic product that is (E)-1-phenylbut-1-ene.
The molecular formula of water is H, O. What does it express
Answer:
Firstly, the molecular formula of water would be H2O. Secondly, it expresses the amount of different atoms in the water molecule. In this case, H2 would be two Hydrogen atoms, and O would be 1 Oxygen atom.
Explanation:
Hope this helped!
Answer:
It basically means that water contains 2 atoms of Hydrogen and 1 atom of Oxygen.
It also expresses that the valency of Oxygen is 2 and water has more Hydrogen than OxygenJax designs an experiment to determine how the amount of sodium chloride affects the boiling point of water. He adds 1 g, 5 g, and 10 g of sodium chloride to three different beakers, each containing 100 mL of water. There is a fourth beaker that contains 100 mL water without any sodium chloride. He heats each of the samples on a Bunsen burner and measures the boiling point with the same thermometer. Which of the following is/are the control(s) in the experiment? (Choose all that apply)
Answer:
Amount of water
The thermometer
Explanation
In an experiment, there is always a dependent variable and an independent variable. The independent variable is manipulated and its effect on the dependent variable is observed.
The control is that factor in the experiment that must remain constant so that effect of the independent variable on the dependent variable can be observed.
In this case, the independent variable is the amount of sodium chloride while the dependent variable is the temperature at which the solution boils.
The controls must be the amount of water which must be held constant and the same thermometer used to measure the temperature so that the effect of the amount of sodium chloride on the temperature of the solution can be studied.
The following are the controls in the experiment:
The beaker with 100 mL of water without any sodium chloride.
The temperature of the Bunsen burner.
The type of thermometer used.
The control(s) in the experiment are the beaker with 100 mL of water without any sodium chloride. This beaker is used to compare the boiling points of the other beakers, which have different amounts of sodium chloride added.
The control beaker ensures that any differences in boiling point are due to the amount of sodium chloride added, and not to other factors, such as the temperature of the Bunsen burner or the type of thermometer used.
The other factors that could affect the boiling point of water, such as the humidity of the air or the altitude, are kept constant in the experiment.
To learn more about experiment, follow the link:
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Groups on the periodic table also correspond with the number of ?
The question is incomplete, the complete question is;
Groups of the periodic table correspond to elements with a. the same color b. the same atomic number c. similar chemical properties d. similar numbers of neutrons
Answer:
similar chemical properties
Explanation:
In the periodic classification of elements, elements are divided into groups and periods. Elements in the same group of the periodic table have the same number of outermost electrons and share very similar chemical properties.
Elements in the same period have the same number of shells and the same maximum energy level of the outermost electron. Chemical properties carry markedly across a period.
If 7.90 mol of C5H12 reacts with excess O2, how many moles of CO2 will be produced by the following combustion reaction?
C5H12+8O2=6H2O+5CO2
Answer:
moles CO₂ produced from combustion of 7.9 mole of C₅H₁₂ = 39.5 moles CO₂
Explanation:
C₅H₁₂ + 8O₂ => 6H₂O + 5CO₂
Given: 7.9moles excess _____ ? moles
From Equation, 1 mole C₅H₁₂ =============> 5 moles CO₂
Given 7.9 mole C₅H₁₂ =============> X
Solving for 'X' using ratio and proportion ...
1mole C₅H₁₂ / 7.9mole C₅H₁₂ = 5mole CO₂ / X
=> X = 5 mole CO₂ x 7.9mole C₅H₁₂ / 1mole C₅H₁₂ = 39.5 moles CO₂
≅ 40 moles CO₂ (2 sig. figs.)
Determine the molality and molarity of a sodium chloride solution prepared by adding 52.80 g of solid NaCl to 150.0 g of water. The density of the saline solution is 1.1972 g mL . Molality
Answer:
6.02 m5.334 MExplanation:
First we convert 52.80 g of NaCl to moles, using its molar mass:
52.80 g ÷ 58.44 g/mol = 0.9035 molTo determine the molality, we convert 150.0 g of water to kg:
150.0 g / 1000 = 0.150 kgmolality = 0.9035 mol / 0.150 kg = 6.02 mAs for the molarity, we determine the total mass of solution:
52.80 g + 150.0 g = 202.8 gAnd calculate the volume, using the density:
202.8 g ÷ 1.1972 g/mL = 169.39 mL169.39 mL / 1000 = 0.16939 LFinally we calculate the molarity:
0.9035 mol / 0.16939 L = 5.334 M4. An exothermic reaction is accompanied by a decrease in entropy. How would this reaction be
classified?
A. spontaneous at all temperatures
B. nonspontaneous only at low temperatures
C. nonspontaneous at all temperatures
D. spontaneous only at low temperatures
Answer:
Spontaneous at only low temperature. I made a chart for my AP Chem class if you want to refer to it.
A student calculates the empirical formula of a compound to be C1.5H3.5. Express this as a correct empirical formula.
Answer:
No, the correct empirical formula is [tex]C_3H_7[/tex].
Explanation:
Hello there!
In this case, according to the given information, it turns out necessary for us to bear to mind the fact that empirical formulas must not be expressed in decimal numbers, for that reason, we need to multiply the given empirical formula by 2 to get the correct one:
[tex]C_3H_7[/tex]
Which is now possible.
Regards!
dfine chemical reaction
Answer:
A process that involves rearrangement of the molecular or ionic structure of a substance, as opposed to a change in physical form or a nuclear reaction.
Explanation:
Pretty much just not a physical reaction or otherwise
what two parts are needed to make a neutral atom of neon
Answer:
it needs two electrons in the first and eight to fill the second.
Explanation:
Because neon has two atomic shells, it needs two electrons in the first and eight to fill the second. Neon has a total of ten electrons which means two filled shells.
The pH of a 0.1 M solution of an unknown weak acid is 3.7. What is the pKa of this acid?
Explanation:
Knowing the pH, you know the concentration of protons:
−log[H+]=pH=3.7
[H+]=10−3.7 M
Now, since the weak (monoprotic) acid dissociates into its conjugate base and a proton, the mols of protons are equimolar with the mols of conjugate base---the protons came FROM the weak acid, so the conjugate base that forms must be equimolar with the protons given out to the solvent.
HA⇌A−+H+
Hence, [A−]=[H+] in the same solution volume. Using the equilibrium constant expression, we get:
Ka=[H+]2eq[HA]eq
Don't forget that the HA form of HA had given away protons, so the mols of protons given away to generate A− is subtracted from the mols of (protons in) HA.
=[H+]2eq[HA]i−[H+]eq
=(10−3.7M)20.02M−10−3.7M
Ka=2.0105×10−6 M
The main consequence of exposure to the chemicals at Love Canal was:
allergies.
hair loss.
birth defects.
upper respiratory disease.
The main consequence of exposure to the chemicals at Love Canal was:
allergies.
hair loss.
birth defects.☑️upper respiratory disease.
Calculate and compare the number of ATP molecules generated between a 24 carbon fatty acid and 4 glucose molecules.
Answer:
Idont no men sorry idont understand
Explanation:
Sorry
Question 3 (2 points)
Using the following equation how many grams of water you would get from 846 g of
glucose:
C6H12O6 + 602 + 6CO2 + 6H20 + energy
Your Answer:
Answer
units g)
Answer: The mass of water produced is 507.6 g
Explanation:
The number of moles is defined as the ratio of the mass of a substance to its molar mass. The equation used is:
[tex]\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}[/tex] ......(1)
Given mass of glucose = 846 g
Molar mass of glucose = 180 g/mol
Plugging values in equation 1:
[tex]\text{Moles of glucose}=\frac{846g}{180g/mol}=4.7 mol[/tex]
The given chemical equation follows:
[tex]C_6H_{12}O_6+6O_2\rightarrow 6CO_2+6H_2O+energy[/tex]
By the stoichiometry of the reaction:
If 1 mole of glucose produces 6 moles of water
So, 4.7 moles of glucose will produce = [tex]\frac{6}{1}\times 4.7=28.2mol[/tex] of water
Molar mass of water = 18 g/mol
Plugging values in equation 1:
[tex]\text{Mass of water}=(28.2mol\times 18g/mol)=507.6g[/tex]
Hence, the mass of water produced is 507.6 g
Classification of igneous, sedimentary and metamorphic rocks is based on
A)Mineral assemblages and composition assemblages and composition
B)Appearance of the rock and texture
C)composition and mineral make-up
D)Texture and rock chemistry
Balancea las siguientes ecuaciones por el método de redox. Determina el
agente oxidante, el agente reductor, la sustancias oxidada y la sustancia
reducida para cada caso.
a) C + H2SO4
CO2 + SO2 + H2O
I
b) sh + HNO3
Sb2O5 +NO + H2O
c) Bi(OH)3 +K SnO2
Bi + K Sn03
+ H2O
d) H2S + (Cr2O7)2- + H1+
H2O + S + Cr3+
Answer:
Traduzca al ingles para que pueda responder a su pregunta. Te dare la reapuesta en los comentarios
characteristics of crystal
Answer:
Crystalline solids, or crystals, have distinctive internal structures that in turn lead to distinctive flat surfaces, or faces. The faces intersect at angles that are characteristic of the substance. When exposed to x-rays, each structure also produces a distinctive pattern that can be used to identify the material.
Explanation:
Question 1
Consider the following reaction:
Cl2(g) + 3 F2(g) —> 2 CIF3 (8)
How many moles of product will form if 0.115 moles of fluorine gas react?
Answer:
0.077 mole of ClF₃.
Explanation:
The balanced equation for the reaction is given below:
Cl₂ + 3F₂ —> 2ClF₃
From the balanced equation above,
3 moles of F₂ reacted to produce 2 moles of ClF₃.
Finally, we shall determine the number of mole of ClF₃ produced by the reaction of 0.115 mole of F₂. This can be obtained as follow:
From the balanced equation above,
3 moles of F₂ reacted to produce 2 moles of ClF₃.
Therefore, 0.115 mole of F₂ will react to to produce = (0.115 × 2)/3 = 0.077 mole of ClF₃.
Thus, 0.077 mole of ClF₃ was obtained from the reaction.
A steel with a critical fracture toughness of 150 MPa.m1/2 has a yield strength of 1500 MPa. If fracture were to take place at the yield stress, answer the following questions.
Surface crack size at yielding leading to failure is:_____________.
a. 0.497 cm
b. 0.994 cm
c. 0.32 cm
Answer:
c.
Explanation:
From the given information:
Critical fracture toughness [tex]K_{IC}[/tex] = 150 MPa.[tex]m ^{1/2}[/tex]
yield strength [tex]\sigma[/tex] = 1500 MPa
surface crack size [tex]a_c[/tex] = ???
The formula for the fracture toughness is can be expressed as:
[tex]K_{IC}= \sigma \sqrt{\pi a_c}[/tex]
replacing our values to solve for the surface crack size, we have:
[tex]150= 1500 \sqrt{\pi a_c}[/tex]
[tex]\dfrac{150}{ 1500} = \sqrt{\pi a_c}[/tex]
[tex]\dfrac{0.1}{1.77} = \sqrt{ a_c}[/tex]
[tex]a_c[/tex] = 0.0564²
[tex]a_c[/tex] = 0.0032 m
[tex]a_c[/tex] = 0.32 cm
Compound A has a partition coefficient (K) of 7 when comparing its solubility in CH2Cl2 to water ( K=11, [solubility of A in g/ml in CH2Cl2] divided by [solubility of A in g/ml in H2O]). If we take 17.0 g of A and partition it thoroughly between 150 ml of CH2Cl2 and 100 ml of water, what is the equation which will tell us how much of A (which is represented by x) is in the water layer after this partitioning ?
Answer:
The equation which will tell us how much of A that is mis inmthe water layer after partitioning is: 7 = (17 - x) g / 150 mL ÷ x g /100 mL
Explanation:
A partition coefficient is the ratio of the concentration of a substance in one solvent phase to the concentration in a second solvent phase when the two concentrations are at equilibrium. Usually the two phases are an organic phase and an aqueous phase. Thus, the partition coefficient K, of a compound is the ratio of the compound's concentration in the organic layer compared to the aqueous layer.
K = C₁/C₂ at equilibrium
In the compound A given, CH₂Cl₂ is the organic phase while water is the aqueous phase
Amount of A that is partitioned in between dichloromethane, CH₂Cl₂ and water, H₂O is 17.0 g
Let the amount of A that is dissolved in water be x g
Solubility of A in water given in g/mL = (x / 100) g/ml
Amount of A dissolved in dichloromethane, CH₂Cl₂ = (17 - x) g
Solubility of A in dichloromethane, CH₂Cl₂ given in g/mL = (17 - x/150) g/mL
Since the partition coefficient, K of compound A when comparing its solubility in CH₂Cl₂ to water is 7, that is;
K = [solubility of A in g/ml in CH₂Cl₂] / [solubility of A in g/ml in H2O] = 7
The equation for the amount of A in the water layer is given as follows:
7 = (17 - x) g / 150 mL ÷ x g /100 mL
Solving for x
7 = (17 -x) × 100 / 150x
7 × 150x = (17 - x) × 100
1050x = 1700 - 100x
1150x = 1700
x = 1700/1150
x = 1.48 g
an element E forms a hydride EH3, which contains 90% of E by mass. what is the relative atomic mass ?
Answer:
27 g/mol of E
Explanation:
Note that percentage by mass= mass of each element present. So, since there is 90% of E, there is 90g of E present. By implication, there are 10g of H corresponding to 10%H. Note that there is 100g of EH3
1 moles of E corresponds to 90 g of E
Mole ratio of E: H= 1:3
Thus
Number of moles of H = 10g/ 1g/ mol = 10 moles of H
Since E contains 1/3 the number of moles of H
Number of moles of E = 1/3 × 10 = 3.33 moles of E
Molar mass of E= mass of E/ number of moles of E
Since mass of E = 90 g
Molar mass of E = 90g/3.33 moles
Molar mass of E = 27 g/mol
Determine the mass in grams of 3.27 × 10²¹ atoms of arsenic. (The mass of one mole of arsenic is 74.92 g.)
Explanation:
74.92 g.
(The mass of one mole of arsenic is 74.92 g.
Please help me name these organic compounds
Answer:
Aldehydes and Ketones
Both aldehydes and ketones contain a carbonyl group, a functional group with a carbon-oxygen double bond. The names for aldehyde and ketone compounds are derived using similar nomenclature rules as for alkanes and alcohols, and include the class-identifying suffixes -al and -one, respectively:

In an aldehyde, the carbonyl group is bonded to at least one hydrogen atom. In a ketone, the carbonyl group is bonded to two carbon atoms:


As text, an aldehyde group is represented as –CHO; a ketone is represented as –C(O)– or –CO–.
In both aldehydes and ketones, the geometry around the carbon atom in the carbonyl group is trigonal planar; the carbon atom exhibits sp2 hybridization. Two of the sp2 orbitals on the carbon atom in the carbonyl group are used to form σ bonds to the other carbon or hydrogen atoms in a molecule. The remaining sp2 hybrid orbital forms a σ bond to the oxygen atom. The unhybridized p orbital on the carbon atom in the carbonyl group overlaps a p orbital on the oxygen atom to form the π bond in the double bond.
Like the C=OC=O bond in carbon dioxide, the C=OC=O bond of a carbonyl group is polar (recall that oxygen is significantly more electronegative than carbon, and the shared electrons are pulled toward the oxygen atom and away from the carbon atom). Many of the reactions of aldehydes and ketones start with the reaction between a Lewis base and the carbon atom at the positive end of the polar C=OC=O bond to yield an unstable intermediate that subsequently undergoes one or more structural rearrangements to form the final product (Figure 1).
Figure 1. The carbonyl group is polar, and the geometry of the bonds around the central carbon is trigonal planar.
The importance of molecular structure in the reactivity of organic compounds is illustrated by the reactions that produce aldehydes and ketones. We can prepare a carbonyl group by oxidation of an alcohol—for organic molecules, oxidation of a carbon atom is said to occur when a carbon-hydrogen bond is replaced by a carbon-oxygen bond. The reverse reaction—replacing a carbon-oxygen bond by a carbon-hydrogen bond—is a reduction of that carbon atom. Recall that oxygen is generally assigned a –2 oxidation number unless it is elemental or attached to a fluorine. Hydrogen is generally assigned an oxidation number of +1 unless it is attached to a metal. Since carbon does not have a specific rule, its oxidation number is determined algebraically by factoring the atoms it is attached to and the overall charge of the molecule or ion. In general, a carbon atom attached to an oxygen atom will have a more positive oxidation number and a carbon atom attached to a hydrogen atom will have a more negative oxidation number. This should fit nicely with your understanding of the polarity of C–O and C–H bonds. The other reagents and possible products of these reactions are beyond the scope of this chapter, so we will focus only on the changes to the carbon atoms: