Compound 1 melts at 40 degrees Celsius. Compound 2 melts at 1310 degrees Celsius. Compound 3 melts at
240 degrees Celsius. Compound 4 melts at -62 degrees Celsius. Which is most likely to be an ionic compound?
Compound 4
Compound 2
Compound 3
Compound 1
Explanation:
We know that,
Ionic compound have high melting point.Here,
Compound 2 has high melting point.
So,
Compound 2 is most likely to be an ionic compound.
The ph of a lime is 1.90. What is the [H3O+]?
Answer:
thts the acidic presence
Explanation:
Identify the nucleic acid DNA
1. Cholesterol
2. Proteins
3. Disacharide
Answer:
DNA
Explanation:
As the puck falls, its potential energy (PE):
increases
decreases
stays the same
not enough information?”
Answer:
stay the same
Explanation:
C. Use Hess's law and the following equations to calculate ΔH for the reaction N2(g) + 2O2(g) N2O4(g). (Show your work.) (8 points)
2NO2(g) N2O4(g) ΔH = –57.0 kJ/mol
N2(g) + O2(g) 2NO(g) ΔH = 180.6 kJ/mol
2NO2(g) 2NO(g) + O2(g) ΔH = 114.4 kJ/mol
PLS HELP I NEED THIS RIGHT NOW!!
THANKS!!
50 points for whoever give me an answer!!
Answer:
ΔH=9.2 KJ
Explanation:
2NO₂→N₂O₄ ΔH=-57 KJ/mol
N₂ + O₂→2NO ΔH=180.6 KJ/mol
2NO + O₂→2NO₂ ΔH= -114.4 (notice this was reversed and sign changed
_____________________________________________
N₂+2O₂→N₂O₄ ΔH= 9.2 KJ
By reversing the third equation, we can get the O₂ on the left side or the (reactant side) so that we can get a total of 2O₂ in the final equation on the bottom. Cross out 2NO₂ on the first equation on the reactant side and 2NO₂ in equation 2 on the product side. You also want to cross out 2NO in the third equation on both the reactant and product side. This leaves the same above the line as below the line.
Since you reverse equation 3, the change in enthalpy will change sign so you input -57, 180.6 and -114.4 to get 9.2 KJ
Hope that helps.
Titanium has an HCP unit cell for which the ratio of the lattice parameters c/a is 1.58. If the radius of the Ti atom is 0.1445 nm, calculate the density of Ti and compare it with the literature value of 4.51 g/cm3 . The atomic mass of titanium is 47.87 g/mol.
Answer:
4.81 g / mol
Explanation:
Given :
Titanium has an HCP unit cell
Radius of titanium, R = 0.1445 nm
Unit cell volume, [tex]$V_c= 6R^2 C\sqrt3$[/tex]
But for Ti, c/a = 1.58
So, c = 1.58 a
And a = 2R or c = 3.16 R
[tex]$V_c = 6R^2 \times 3.16 R \times \sqrt3$[/tex]
[tex]$V_c=6 \times 3.16 \times \sqrt3 \times (1.445 \times 10^{-8})^3 $[/tex]
[tex]$V_c= 9.91 \times 10^{-23}\ cm^3 / unit \ cell $[/tex]
Density of Ti (theoretical), [tex]$\rho=\frac{n. A_{Ti}}{V_C.N_A} $[/tex]
For HCP, n = 6 atoms per unit cell and atomic mass = 47.87 g/mol
[tex]$\rho=\frac{6 \times 47.87}{9.91 \times 10^{-23} \times 6.023 \times 10^{23}} $[/tex]
= 4.81 g/mol
This is the theoretical density of titanium.
The value given in literature is 4.51 g/mol
An atom of argon has a radius of and the average orbital speed of the electrons in it is about . Calculate the least possible uncertainty in a measurement of the speed of an electron in an atom of argon. Write your answer as a percentage of the average speed, and round it to significant digits.
Here is the full question:
An atom of argon has a radius of 71 .pm and the average orbital speed of the electrons in it is about 3.9 × 10⁷ m/s. Calculate the least possible uncertainty in a measurement of the speed of an electron in an atom of argon. Write your answer as a percentage of the average speed, and round it to significant digits.
Answer:
Explanation:
From the above information:
The radius of an atom of argon = 71 .pm = 71 × 10⁻¹² m
The diameter of the atom of argon Δx =142 × 10⁻¹² m
According to Heisenberg's Uncertainty Principle,
[tex]\Delta x. \Delta p_x \geq \dfrac{h}{2}[/tex]
[tex]\Delta x. \Delta V \geq \dfrac{h}{4 \pi m_e}[/tex]
[tex]\Delta V \geq \dfrac{h}{4 \pi m_e \Delta_x}[/tex]
[tex]\Delta V \geq \dfrac{6.634 \times 10^{-34} \ J.s}{4 \pi \times 9.1 \times 10^{-3} \ kg \times 142 \times 10^{-12} \ m}[/tex]
[tex]\Delta V \geq \dfrac{6.634 \times 10^{-34} \ J.s}{1.62382641 \times 10^{-11} \ kg.m}[/tex]
[tex]\Delta V \geq 4.08 \times 10^5 \ m/s[/tex]
where; the average speed [tex]V_{avg}[/tex] = 3.9 10⁷ m/s
∴
The percentage of the average speed is expressed as a fraction of:
[tex]\% = \dfrac{4.08 \times 10^5}{3.9 \times 10^7}\times 100[/tex]
[tex]\% =1.0462[/tex]
[tex]V_{avg } = 1.046 \times 10^0[/tex]
[tex]\mathbf{V_{avg }\simeq 1.0 \%}[/tex]
The world's annual ____
is currently approximately 1.2 percent, at which rate the world's population is projected to double in about 54 years.
Why is it nearly impossible to compress a liquid?
O A. The particles don't have enough energy to move out of their fixed
positions.
B. The particles have so much energy they move independently of
one another.
C. The particles are close together and can only slide past one
another.
D. The particles are spread so far apart that they do not affect one
another.
Complete analysis question 2 from page B-63 in your book. "Was there copper in Cups 1-6? How did you know it was or was not there? Explain using evidence from this activity"
Answer:
I NEED HELP TOO AND ALSO PLEASE DONT 1 STAR 5 STAR FOR THE MEMES
Explanation:
Answer:
cup 2
Explanation:
it has more water in there therefore its more diluted
The density of a gas is 2.49 g/L at 3.00 atm and 25oC. Calculate the molar mass of the gas. Multiple choice question. 2.0 g/mol 20.3 g/mol 18.3 g/mol 24.9 g/mol
Answer:
Molar mass = 20.3 (Approx)
Explanation:
Given:
Density = 2.49 g/l
Pressure = 3 atm
Tempreture = 25 degree celcius = 273 + 25 = 298 k
Find:
Molar mass
Computation:
pm = drt
3(m) = (2.49)(298)(0.0821)
m = 20.3 (Approx)
Molar mass = 20.3 (Approx)
g determine the mass of products formed by the combustion of 7.600 g of a compound with empirical formula c7h12
Answer:
[tex]m_{CO_2}=24.38gCO_2\\m_{H_2O}=8.550gH_2O[/tex]
Explanation:
Hello.
In this case, since the combustion of C7H12 which is probably heptyne (molar mass = 96 g/mol) is:
[tex]C_7H_1_2+10O_2\rightarrow 7CO_2+6H_2O[/tex]
In which the products are carbon dioxide (molar mass = 17 g/mol) and water (18 g/mol) that are in a 7:1 and 6:1 mole ratio with the heptyne, respectively; thus, the yielded mass of both carbon dioxide and water is:
[tex]m_{CO_2}=7.600gC_7H_{12}*\frac{1molC_7H_{12}}{96gC_7H_{12}}*\frac{7molCO_2}{1molC_7H_{12}} *\frac{44gCO_2}{1molCO_2} \\m_{CO_2}=24.38gCO_2\\\\m_{H_2O}=7.600gC_7H_{12}*\frac{1molC_7H_{12}}{96gC_7H_{12}}*\frac{6molH_2O}{1molC_7H_{12}} *\frac{18gH_2O}{1molH_2O} \\m_{H_2O}=8.550gH_2O[/tex]
Best regards.
Which may be true for a substance that absorbs energy?
ОА.
The energy decreases the molecular motion but increases the kinetic energy of the substance.
The energy increases the molecular motion and the kinetic energy of the substance.
OB.
Ос.
The energy decreases the molecular motion and the kinetic energy of the substance.
OD
The energy increases the molecular motion but decreases the kinetic energy of the substance.
Answer:
The energy increases the molecular motion and the kinetic energy of the substance.
Explanation:
A substance that absorbs energy will have their kinetic energy increased and also the molecular motion.
This is in compliance with the kinetic molecular theory of gases.
When a body gains energy, the molecules becomes more energized. They begin to vibrate about a fixed point in a lattice. This also increases the kinetic energy of the substance. Kinetic energy is the energy due to the motion of the particles of a medium.Juan noticed that a door that sticks on hot days does not stick when it cools off at night. This is because the metal contracts as it cools. The reason for this is that, as the metal cools, the atoms:
become smaller and take up less space .
slow down and move closer together.
merge together to form fewer atoms.
speed up and move further apart.
A sample of element Z, which has two isotopes, is made up of 75% Z-12 and 25% Z-13. Calculate the average atomic mass. Round your answer to TWO PLACES after the decimal. Enter your answer as a number (no units)
Answer:
Average atomic mass = 12.25
Explanation:
Percent abundance of Z-12 = 75%
percent abundance of Z-13 = 25%
Average atomic mass = ?
Solution:
Average atomic mass = (abundance of 1st isotope × its atomic mass) +(abundance of 2nd isotope × its atomic mass) / 100
Average atomic mass = (75×12)+(25×13) /100
Average atomic mass = 900 + 325 / 100
Average atomic mass = 1225 / 100
Average atomic mass = 12.25 amu.
A container of N2O3(g) has a pressure of 0.575 atm. When the absolute temperature of the N2O3(g) is tripled, the gas completely decomposes, producing NO2(g) and NO(g). Calculate the final pressure of the gas mixture, assuming that the container volume does not change.
Plants and animals that share a______ often help each other survive. Plants provide food and shelter for animals. In turn, animals help plants reproduce. When bees and other insects gather____they also carry______from flower to flower. This helps to_____the flowers. The______ of each flower then produces seeds and grows into a fruit. Other animals scatter the seeds.
Answer:
biome or habitat, nectar, pollen, pollinate, propagation
Explanation:
Do any of these terms sound familiar?
All of the following complexes will be colored (in the visible) EXCEPT ________. a) [Zn(en)3]2 b) [Fe(CN)6]4- c) [Ni(H2O)6]2 d) [Cr(NH3)6]3 e) [Cu(NH3)4]2
Answer:
a
Explanation:
All of the complexes will be colored except [Zn(en)3]2.
Fe, Ni, Cr, and Cu all form colored complexes because of their partially-filled d-orbitals and are generally referred to as transition elements. The d-orbital can split into higher and lower orbitals and electrons can jump from one level to the other. The jumping of electrons leads to light absorption and this characteristic impacts color to elements with partially-filled d-orbitals.
Zinc does not possess a partially-filled d-orbital and as such, its electrons cannot transition between levels, even though it belongs to the 'd-block' element.
The correct option is a.
The combustion of hexane is given by the following reaction. 2 C 6 H 14 + 19 O 2 → 12 CO 2 + 14 H 2 O The enthalpy of reaction is −4163.0 kJ/mol. How much energy (in joules) will be released if 72.78 grams of hexane is burned. (Molar mass of hexane = 86.20 g/mol).
Answer:
[tex]E=3.5149kJ[/tex]
Explanation:
Hello.
In this case, for such combustion of hexane which release heat, we can compute that amount by taking into account that the reaction releases 4163.0 kJ of energy every 1 mole of hexane, it means that for 72.78 g, which in moles is:
[tex]n_{hexane}=72.78g*\frac{1mol}{86.20g}=0.8443mol[/tex]
Thus the energy released when 0.8443 moles of hexane are released turn out:
[tex]E=n_{hexane}\Delta _cH=0.8443mol*-4163.0\frac{kJ}{mol}*\frac{1000J}{1kJ} \\\\E=3.5149kJ[/tex]
Best regards!
A silver ring has a density of 10.50 g/mL. What is the mass of the ring that has a volume of 10.0 mL?
20.5 g?
105 g?
0.952 g?
Answer:
the answer is 105 g/mL
Explanation:
beacuse mass = density×volume
Explain why the elements Cobalt and Nickel in the fourth period violate the original periodic law as stated by Mendeleev.
Answer:
Explanation:
Dmitri Mendeleev was a Russian scientist that proposed the first periodic table of elements. Elements in his periodic table were arranged according to there relative atomic mass; however cobalt (Co) with an atomic mass of 58.93 was placed before nickel (Ni) with an atomic mass of 58.69 which was an anomaly as according to his law, nickel should come before cobalt since nickel has a lesser mass compared to cobalt.
what is equal to a temperature of 20 celsius
Answer:
68 degrees fahrenheit or 293.15 degrees kelvin
Explanation:
Answer:
68°F
Explanation:
1 Sound waves, water waves, and light waves are all alike in that they all ____________.
Answer:
They all produce a type of energy
Explanation:not sure but in wat i remenber that wat i learned in 5th grade
A lab group was calculating the speed of a radio car. They measured the distance traveled to be 6 meters and the time to be 3.5 seconds. Then they divided the distance by the time to find the speed. The actual speed was 2.2 m/s. What was their percent error?
Answer:456
Explanation:
I have an oxidation number of -3 and I have 5 energy levels. What element am I?
A. Yttrium
B. Phosphorus
C. Antimony
D. Bismuth
Antimony I think but I am not sure
how do you Pangea and plate tectonic differ?
which outcome occurs as a multicellular organism develops
Answer:
A multicellular organism develops from a single cell (the zygote) into a collection of many different cell types, organized into tissues and organs. Development involves cell division, body axis formation, tissue and organ development, and cell differentiation (gaining a final cell type identity).
Explanation:
A student tries to balance the equation by changing the subscript 2 on Cl to a 3. Explain why this is not correct. What is the correct balanced equation
The question is incomplete, the complete question is;
“Consider the unbalanced chemical equation. Al(s) + Cl2(g) ------> AlCl3(s) A student tries to balance the equation by changing the subscript 2 on Cl to a 3. Explain why this is not correct. What is the correct balanced equation?”
Answer:
2Al(s) + 3Cl2(g) ------> 2AlCl3(s)
Explanation:
If the student changes the subscript of Cl from 2 to 3, he/she has written a symbol for a molecule that does not exist. Halogens exist as diatomic and not triatomic gases.
The balanced equation is; 2Al(s) + 3Cl2(g) ------> 2AlCl3(s).
Notice that the basic principles of valency are not violated in any of the species in the equation above. Cl3 violates the octet rule but Cl2 obeys the octet rule.
A 0.25g sample of Lead-210 has a half life of 20.4 years. Will all of the Lead undergo radioactive decay in 150 years? Explain.
(I really need help on this this the last question for my assignment but i’m completely lost since i don’t think she covered how we’re supposed to solve this and explain it)
Answer:
Using the equation A(t) = 400e-.032t
a) replace t with 4 so A(4) = 400e((-.032)(4))
The hardest part about this is making sure to use order of operations. Be certain it works like this:
A(4) = 400e-.128
A(4) = 400(.8799)
A(4) = 351.9 grams
b) A(8) = 400e((-.032)(8)) = 309.7 grams
c) A(20) = 400e((-.032)(20)) = 210.9 grams
Note here that even after 20 years, not quite half of the original amount is gone. So, we can anticipate that in finding the half life, that our answer should be slightly greater than 20 years.
d) 200 = 400e(-.032t)
Divide both sides of the equation by 400.
.5 = e(-.032t)
Change this to logarithmic form.
Ln .5 = -.032t
-.6931≈ -.032t
t ≈ 21.7 years
Explanation:
calculate the ph at 25 c of a .33 m solution of sodium benzoate. note that benzoic acid is a weak acid with a pka of 4.2
Answer:
The pH at 25°C of 0.33M solution is 5.36.
Explanation:
Let us calculate -:
[tex]NaC_6H_5CO_2$\rightarrow$ salt of weak acid + sodium benzoate[/tex]
pH of salt of weak acid and sodium benzoate is given by-
pH =[tex]7+\frac{1}{2}pk_a+\frac{1}{2}log (concentration of salt)[/tex]
concentration of salt = 0.33M
[tex]pK_a=4.2[/tex]
[tex]pH = 7 +\frac{4.2}{2} +\frac{1}{2}log (0.33)[/tex]
[tex]pH=7 +\frac{4.2}{2} + \frac{(-0.4815)}{2}[/tex]
pH = 5.36
Hence , the answer is 5.36
