Answer:
Helium and hydrogen......
Why does a red object appear red?
O A. It reflects light of wavelengths other than red.
OB. It absorbs light of red wavelengths.
O C. It absorbs light of wavelengths other than red.
O D. It reflects infrared radiation.
Right answers only for brainly
Answer:
Objects appear different colours because they absorb some colours (wavelengths) and reflected or transmit other colours. ... For example, a red shirt looks red because the dye molecules in the fabric have absorbed the wavelengths of light from the violet/blue end of the spectrum
A red object appear red because it absorbs light of wavelengths other than red. Therefore, option C is correct.
What is wavelength ?The distance between identical points (adjacent crests) in adjacent cycles of a waveform signal propagated in space or along a wire is defined as the wavelength. This length is typically specified in wireless systems in meters (m), centimeters (cm), or millimeters (mm) (mm).
A transverse wave's wavelength is defined as the distance between two adjacent crests. A longitudinal wave's wavelength can be calculated as the distance between two adjacent compressions.
The wavelengths that are reflected or transmitted are what we see as colors. A red shirt, for example, appears red because the dye molecules in the fabric have absorbed light wavelengths from the violet/blue end of the spectrum. The only light reflected from the shirt is red light.
Thus, option C is correct.
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Write a net ionic equation for the reaction that occurs when aqueous solutions of hydrofluoric acid and barium hydroxide are combined. Include solubility states
Answer: The net ionic equation is [tex]2H^+(aq)+2F^-(aq)+Ba^{2+}(aq)+2OH^-(aq)\rightarrow BaF_2(s)+2H_2O(l)[/tex]
Explanation:
The net ionic equation of any reaction does not include any spectator ions.
Spectator ions are defined as ions that do not get involved in a chemical equation. They are found on both the sides of the chemical reaction when it is present in ionic form.
The chemical equation for the reaction of hydrofluoric acid and barium hydroxide follows:
[tex]2HF(aq)+Ba(OH)_2(aq)\rightarrow BaF_2(s)+2H_2O(l)[/tex]
The ionic form of the above equation follows:
[tex]2H^+(aq)+2F^-(aq)+Ba^{2+}(aq)+2OH^-(aq)\rightarrow BaF_2(s)+2H_2O(l)[/tex]
There are no spectator ions in the ionic form.
The net ionic equation for the above reaction follows:
[tex]2H^+(aq)+2F^-(aq)+Ba^{2+}(aq)+2OH^-(aq)\rightarrow BaF_2(s)+2H_2O(l)[/tex]
What do the symbols in the parentheses indicate
Answer:
(C) the physical state of each reactant and product
Explanation:
Hope this helps
what happens when a molecule absorbs infrared radiation
Answer:
When a molecule absorbs infrared radiation,transition s occur from the ground vibrational state to an excited vibrational state. For a molecule to be IR active there must be a change in dipole moment as a result of the vibration that occurs when IR radiation is absorbed.
If 50.0 g of silicon dioxide is heated with an excess of carbon, 27.9 g of silicon carbide is produced. What is the percent yield of the reaction
Answer: The percent yield of the reaction is 83.5 %
Explanation:
The given balanced equation is
[tex]SiO_2+3C\rightarrow SiC+2CO[/tex]
[tex]SiO_2[/tex] is the limiting reagent as it limits the formation of product and [tex]C[/tex] is the excess reagent.
According to stoichiometry :
60.08 g of [tex]SiO_2[/tex] produce = 40.11 of [tex]SiC[/tex]
Thus 50.0 of [tex]SiO_2[/tex] will produce=[tex]\frac{40.11}{60.08}\times 50.0=33.4[/tex] of [tex]SiC[/tex]
Experimental yield of SiC = 27.9 g
Percent yield = [tex]\frac{\text {Experimental yield}}{\text {theoretical yield}}\times 100=\frac{27.9g}{33.4g}\times 100=83.5\%[/tex]
Thus percent yield of the reaction is 83.5 %
The percent yield of 83.5 % of 50.0 g of silicon dioxide is heated with an excess of carbon, and 27.9 g of silicon carbide is produced in the reaction.
What is the chemical balance of the equation?
The chemical equations are balanced when the reactants react to form products. The reactants and products react in proper ratios and if they are not in ratio then we balance them by adding the required quantity in the reactants and the products.
The given balanced equation is
[tex]\rm SiO_2+3C---- > SiC+2CO[/tex]
[tex]SiO_2[/tex] is the limiting reagent as it limits the formation of product and is the excess reagent.
According to stoichiometry
60.08 g [tex]SiO_2[/tex] of produce = 40.11 of [tex]SiC[/tex]
Thus 50.0 of [tex]SiO_2[/tex] will produce= [tex]\dfrac{40.11}{60.08} \times 50=33.4\ SiC[/tex]
The experimental yield of SiC = 27.9 g
The percentage yield will be calculated as
[tex]\rm Percentage \ Yield = \frac{Experimental\ yield}{Theoretical \ yield }\times 100[/tex]
[tex]\rm Percentage \ yield =\dfrac{27.9}{33.49} \times 100=83.5[/tex]
Thus the percent yield of 83.5 % of 50.0 g of silicon dioxide is heated with an excess of carbon, and 27.9 g of silicon carbide is produced in the reaction.
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Iron has a density of 7.87 g/cm^3. What is the mass of 55.2 cm^3 of iron?
Answer: Formula: Mass = (Volume)(Density)
Iron Density = 7.87 g/cm^3
Volume of Iron = 55.2 cm^3
Mass=(V)(D)
Mass= (55.2 cm^3) x (7.87 g/cm^3)
Mass= 434,42 g
Explanation:
Iron has a density of 7.87 g/cm³. 434,42 g is the mass of 55.2 cm³ of iron.
What do you mean by density ?The term density is defined as the measurement of how closely a material is packed together.
It is also defined as the mass per unit volume. Density Symbol is D or ρ Density Formula is ρ = m/V, where ρ is the density, m is the mass of the object and V is the volume of the object.
Density is an important because it allows us to find out what substances will float and what substances will sink when placed in a liquid.
Formula:
Mass = (Volume)(Density)
Given:
Iron Density = 7.87 g/cm³
Volume of Iron = 55.2 cm³
Mass=(V)(D)
Mass= (55.2 cm³) x (7.87 g/cm³)
Mass= 434,42 g
Thus, Iron has a density of 7.87 g/cm³. 434,42 g is the mass of 55.2 cm³ of iron.
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Which sublevels hold valence electrons?
Answer:
The Periodic Table can be divided into s, d, p, and f sublevel blocks. For elements in the s sublevel block, all valence electrons are found in s orbitals. For elements in the p sublevel block, the highest energy valence electrons are found in p orbitals.
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!
The pressure can be increased by doing what?
A)increasing the force and decreasing the area
B)increasing the force and increasing the area
C)decreasing the force and increasing the area
D)none of the above
Please help ASAP
Identify the atom with the ground-state electron configuration shown for its valence shell.
3s^2 3p^1
What material would make the most efficient hot pack?
●Lithium Chloride
●Sodium Chloride
●Sodium Hydroxide
●Potassium Chloride
Answer:
Lithium Chloride would be the best one
Sodium Hydroxide would be the second best
Explanation:
1. What volume of a 2.50M Kl(aq) is needed to make 200 ml of a 1.OOM KI)aq)?
Answer:
80 ml
Explanation:
From the question,
Applying Dilution formular
MV = mv................... Equation 1
Where M = Molarity of Kl before dilution, V = Volume of Kl before dilution, m = molarity of Kl after dilution, v = volume of Kl after dilution.
make V the subject of the equation
V = mv/M............. Equation 2
Given: m = 1.00 M, v = 200 ml, M = 2.50 M
Substitute these values into equation 2
V = (1.00×200)/2.50
V = 80 ml
Show the equation you will use to calculate the volume of 1 M Cu(NO3)2 (aq) needed to prepare a set of solutions that have concentrations in the range of 1 M to 1x10-4 M in a 10-mL volumetric flask. Write the reduction half-cell reaction for the copper(II) ion. What is the standard potential for an electrochemical cell that is prepared from a copper half-cell and a zinc half-cell
Answer:
Explanation:
The equation we use to calculate the volume needed to prepare other [tex](C_1,V_1)[/tex] the solution that has a concentration [tex]C_2[/tex] and volume [tex]V_2[/tex] is:
[tex]C_1V_1 =C_2V_2[/tex]
[tex]V_1=\dfrac{C_2V_2}{C_1}[/tex]
where;
[tex]C_1[/tex]= concentration of the first solution
[tex]V_1[/tex] = volume of the first solution
[tex]C_2[/tex] = concentration of the second solution
[tex]V_2[/tex] = volume of the second solution
2) Reduction half cell reaction for the copper (II) ion is:
[tex]Cu^{2+} + 2e^- \to Cu[/tex]
3) [tex]Cu^{+2} + 2e^- \to Cu \text{ \ \ \ E = 0.3370}[/tex]
[tex]Zn^{+2} + 2 e^- \to Zn \ \ \ \ \ \ E = -0.763[/tex]
[tex]Zn \to Zn^{+2} + 2 e^- \ \ \ \ \ \ E = +0.763[/tex]
Since the reduction potential of Cu is more; it means copper will go into reduction and zinc will undergo oxidation.
Standard Potential =[tex]E^0_{left} - E^0_{right}[/tex]
[tex]= -0.763 -0.337[/tex] ( since both are reduction potential)
[tex]\mathbf{E^0_{cell} = -1.100 volt}[/tex]
arrange the following group of atoms in order of increasing atomic size:B,Al,Ga
Answer:
Al,Ga,B
Explanation:
Now since i helped you can you help me with this plz
Matteo took 5 math quizzes. The mean of the 5 quizzes was 8.2. Here are four of his quiz scores 7, 7, 8, 10. What is the 5th quiz score? Show work.
Boron ( B )
Aluminium ( Al )
Gallium ( Ga )
The solubility of a solid in a liquid generally increases with increase temperature.
True
Or
False
Answer:
False, Solubility increases with temperature for most solids.
Explanation:
The reason for using 1-propanol as the solvent of choice for recrystallization is that triphenylphosphine oxide is more soluble in 1-propanol than the alkene product because triphenylphosphine oxide can use its oxygen to hydrogen-bond to 1-propanol, whereas the alkene has no hydrogen-bonding capability. Triphenylphosphine oxide, therefore, is removed based on its polarity and H-bonding ability.
a. True
b. False
Answer:
True
Explanation:
Hydrogen bonding is a bond that exists between hydrogen and a highly electronegative element such as oxygen, nitrogen, fluorine etc.
The greater solubility of the triphenylphosphine oxide owes to the hydrogen bonded interaction between it and the 1-propanol.
The alkene lacks such hydrogen bonded interaction because it does not have a highly electronegative atom in its structure.
Hence, triphenylphosphine oxide is removed based on its polarity and hydrogen bonding ability.
What is the entropy of this collection of training examples with respect to the positive class B. What are the information gains of A1 and A2 relative to the training dataset For A3, which is a continuous attribute, compute the information gain for every possible split. C. What is the best split (among A1,A2, and A3) according to the information gain
The data set is missing in the question. The data set is given in the attachment.
Solution :
a). In the table, there are four positive examples and give number of negative examples.
Therefore,
[tex]$P(+) = \frac{4}{9}$[/tex] and
[tex]$P(-) = \frac{5}{9}$[/tex]
The entropy of the training examples is given by :
[tex]$ -\frac{4}{9}\log_2\left(\frac{4}{9}\right)-\frac{5}{9}\log_2\left(\frac{5}{9}\right)$[/tex]
= 0.9911
b). For the attribute all the associating increments and the probability are :
[tex]$a_1$[/tex] + -
T 3 1
F 1 4
Th entropy for [tex]$a_1$[/tex] is given by :
[tex]$\frac{4}{9}[ -\frac{3}{4}\log\left(\frac{3}{4}\right)-\frac{1}{4}\log\left(\frac{1}{4}\right)]+\frac{5}{9}[ -\frac{1}{5}\log\left(\frac{1}{5}\right)-\frac{4}{5}\log\left(\frac{4}{5}\right)]$[/tex]
= 0.7616
Therefore, the information gain for [tex]$a_1$[/tex] is
0.9911 - 0.7616 = 0.2294
Similarly for the attribute [tex]$a_2$[/tex] the associating counts and the probabilities are :
[tex]$a_2$[/tex] + -
T 2 3
F 2 2
Th entropy for [tex]$a_2$[/tex] is given by :
[tex]$\frac{5}{9}[ -\frac{2}{5}\log\left(\frac{2}{5}\right)-\frac{3}{5}\log\left(\frac{3}{5}\right)]+\frac{4}{9}[ -\frac{2}{4}\log\left(\frac{2}{4}\right)-\frac{2}{4}\log\left(\frac{2}{4}\right)]$[/tex]
= 0.9839
Therefore, the information gain for [tex]$a_2$[/tex] is
0.9911 - 0.9839 = 0.0072
[tex]$a_3$[/tex] Class label split point entropy Info gain
1.0 + 2.0 0.8484 0.1427
3.0 - 3.5 0.9885 0.0026
4.0 + 4.5 0.9183 0.0728
5.0 -
5.0 - 5.5 0.9839 0.0072
6.0 + 6.5 0.9728 0.0183
7.0 +
7.0 - 7.5 0.8889 0.1022
The best split for [tex]$a_3$[/tex] observed at split point which is equal to 2.
c). From the table mention in part (b) of the information gain, we can say that [tex]$a_1$[/tex] produces the best split.
The speed of an electron is 1.68*10^8m/s what is the wavelength
Answer:
[tex]\lambda =4.33x10^{-12}m=4.33pm[/tex]
Explanation:
Hello there!
In this case, since the speed, wavelength and mass of an electron are related via the the Broglie wavelength:
[tex]\lambda =\frac{h}{m*v}[/tex]
Thus, by plugging in the mass of the electron and the Planck's constant, we obtain the following wavelength:
[tex]\lambda =\frac{6.626x10^{-34}J*s}{9.11x10^{-31}kg*1.68x10^{8}m/s}\\\\\lambda =4.33x10^{-12}m=4.33pm[/tex]
Best regards!
a Technical
How to write
report
What are the products for
Answer:
[tex]ZnCO_3(s)+2KNO_3(aq)[/tex]
Explanation:
Hello there!
In this case, for the referred reactants side, we can evidence that this is a double displacement reaction whereby Zn gets bonded with CO3 and therefore K gets bonded with NO3 to yield:
[tex]Zn(NO_3)_2+K_2CO_3\rightarrow ZnCO_3+2KNO_3[/tex]
Whereas the KNO3 product is aqueous and the ZnCO3 is solid due to the corresponding solubility rules. Thereby, the answer is the third one.
Regards!
most sedimentary rock forms in the ocean.This is because oceans-
Answer:
Explanation:
are where most bits of broken rock are deposited.
This is because oceans are where most bits of broken rock are deposited.
A gas occupies a volume of 2.4 L at 0.14 ATM. What volume will the gas occupy at 0.84 ATM?
Answer:
0.4 L
Explanation:
Calculate by using Boyle's Law P₁V₁=P₂V₂
(0.14atm)(2.4L) = (0.84atm)(V₂)
0.336 atmL = (0.84atm)(V₂)
V₂ = 0.336 atmL/0.84atm
V₂ = 0.4 L
Do nitrates always form precipitates?
Answer:
Nitrates compared to sulphates are much more soluble therefore won't form precipitates easily.
How many moles of NaOH are contained in 56.0 mL of a 2.40 M solution of 1 point
NaOH in water? (**Use only numerical answers with 3 significant figures.
The units are given in the question.)
Your answer
Answer:
1.34 mol
Explanation:
Molarity, which is the molar concentration of a solution, can be calculated by dividing the number of moles (n) by the volume (V).
That is;
Molarity (M) = n/V
According to the information provided in this question;
M = 2.40M
V = 56.0 mL = 56/1000 = 0.056 L
Since molarity = n/V
number of moles = M × V
n = 0.056 × 24
n = 1.34 mol
Nitric oxide (NO) reacts with oxygen gas to produce nitrogen dioxide. A gaseous mixture contains 0.66 g of nitric oxide and 0.58 g of oxygen gas. After the reaction is complete, what mass of nitrogen dioxide is formed? Which reactant is in excess? How do you know? Suppose you actually recovered 0.91 g of nitrogen dioxide. What is your percent yield?
Answer:
NO is the limiting reagent.
In this reaction 0.886 mole of NO2 is produced
Explanation:
The chemical equation for this reaction is
2NO(g) + O2(g) → 2NO2(g)
In this limiting reagent reaction, 2 moles of NO reacts with one mole of O2 to produce 2 mole of 2NO2
0.886 mole of NO * (2 mole of NO2/2 mole of NO) = 0.886 mole of NO2
0.503 mole of O2 * (1 mole of NO2/1 mole of O2) = 1.01 mole of NO2
Hence, NO is the limiting reagent.
In this reaction 0.886 mole of NO2 is produced
What is the chemical formula for an acid?
Which metals will switch in this single replacement reaction Zn + MgO -->
a. Mg and Zn
b. Zn and O
c. Mg and O
d. This is not a single replacement reaction
Answer:
D
Explanation:
Magnesium is more reactive than zinc so no reaction will take place
If an equilibrium mixture of the three gases at 600K contains 2.92*10^-2 M COCH(g) and 1.76*10^2 M CO, what is the equilibrium
concentration of Cl2?
Answer:
C
Explanation:
Can tell the answer pls
Explanation: where the article????
What is the speed of sound in dry air at 20°C?