Answer:
Q = 10118.4 j
Explanation:
Given data:
Mass of ice = 30.0 g
Initial temperature of ice = -20°C
Final temperature = 140°C
Energy required = ?
Solution:
The specific heat of ice is 2.108 J/g*°C
Formula:
Q = m.c. ΔT
Q = amount of heat absorbed or released
m = mass of given substance
c = specific heat capacity of substance
ΔT = change in temperature
ΔT = 140°C - (-20°C)
ΔT = 160°C
Q = 30.0 g× 2.108 J/g°C ×160°C
Q = 10118.4 j
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)
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:
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:
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.
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.
As the puck falls, its potential energy (PE):
increases
decreases
stays the same
not enough information?”
Answer:
stay the same
Explanation:
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.The electronegativity of manganese is 1.6, sulfur is 2.5, oxygen is 3.5, chlorine is 3.0, and bromine is 2.8. With which element will manganese
react to form ionic compounds?
A. sulfur
B. oxygen
C. chlorine
D. bromine
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
3. Unscramble the name of internal organs nesintites
Answer:
intestines?
Explanation:
apparently my answer needs to be 20 words long so I'ma write all this so i can answer
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.
An atom has the electron configuration shown below. How many valence electrons are in this atom?
Captionless Image
2
3
4
6
What charge would you expect on an ion of this fictitious atom?
Captionless Image
+3, cation
+5, cation
-5, anion
-3, anion
Which occurrence explains why noble gases are essentially unreactive?
Dipole Interactions
VSEPR Theory
Dispersion Forces
Octet Rule
A covalent bond occurs when ________ are shared between two atoms.
electrons
protons
neutrons
dipoles.
A substance conducts electricity well and has a boiling point of 1478 °C. Is this likely an ionic or covalent substance?
Not enough information to answer.
ionic
covalent
Select all the compounds listed below that are covalent compounds.
B
C
D
A
Captionless Image
A
B
C
D
Captionless Image
Trihocus Dipocus
Dihocus Tripocus
Hocus (II) Pocus
Hocus (III) Pocus
Two nonmetal Halloween elements react to form the compound TriTrick DiTreat. What is the formula? Trick = X and Treat = Y
C
D
B
A
Write the formula for Candycorn Pumpkinate. Candycorn (Cc) has a charge of +3 and pumpkinate (PkO) a charge of -2.
A
B
C
D
Which statement best describes the atomic structure of metals?
Valence electrons packed in a lattice arrangement around cations.
Valence electrons packed in a lattice arrangement around anions.
Closely packed cations with loosely held valence electrons.
Loosely packed cations with tightly held valence electrons.
Which of the following properties is NOT explained by metallic bonding?
Crystalline structures
Malleabilty
Ductility
Thermal conductivity
What is the ionic charge of element X in the compound XP? Phosphorus is in group 15 on the periodic table.
1+
1-
3+
3-
_____________is not reactive with only 2 electrons in its valence shell.
Krypton
Helium
Neon
Xenon
How many electrons are shared in the double bonds in the structural formula shown below?
Captionless Image
2
4
6
8
Option 5
How many lone PAIRS are shown in the molecule below?
Captionless Image
none
2
4
8
A molecule of XY (2 nonmetals) is polar because
X is a metal so exhibits magnetic properties.
X and Y are both ions.
it is ionic and all ionic bonds are polar.
the X atom is able to attract the shared electrons more strongly than a Y atom.
Answer:
question no 4 answer is electrons
How many gold atoms are present in 4.0 x 10-10 mol of gold?
Answer:
2.408 x 10^14
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.
Easy Points
Given the electron configuration: 1s22s22p63s23p64s23d104p65s24d4
Select the correct element
A. Mo
B.Cr
C. Y
D.Sc
Answer:
A. Mo
Explanation:
The given electron configuration: 1s22s22p63s23p64s23d104p65s24d4 shows 42 electrons and Molybdenum has atomic number 42.
But the correct electronic configuration of molybdenum is [Kr]4d5 5s1, and not [Kr]5s24d4 which is based on the diagonal rule.
The diagonal rule states that a half full 5s subshell and half-full 4d subshell are more stable than a full 5s subshell and 4d filled with four electrons.
Hence, the correct element is "A. Mo".
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
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.
1.
(02.01 LC)
Modern atomic theory states that atoms are neutral. How is this neutrality achieved? (3 points)
Equal number of neutrons and protons
More electrons than protons
Equal number of protons and electrons
More neutrons than electrons
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.
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.
in 3 minutes, one half of an original sample of polonium will decay. What happens to the other half?
Which component is missing from the process of cellular respiration? Glucose + Oxygen → Carbon Dioxide + ________ + Energy (4 points) a Water b Sugar c Oxygen d Carbon
Answer: Oxygen or carbon I’ll say oxygen
Explanation:
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
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
what is equal to a temperature of 20 celsius
Answer:
68 degrees fahrenheit or 293.15 degrees kelvin
Explanation:
Answer:
68°F
Explanation:
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?
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:
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.
A piston is holding 125 mL of gases at a temperature of 300 K and a pressure of 2.39 atm. What is the volume of the gases if the temperature is increased to 500K and the pressure falls to 2.15 atm
Answer:
231.59 mL
Explanation:
From the question given above, the following data were obtained:
Initial volume (V₁) = 125 mL
Initial temperature (T₁) = 300 k
Initial pressure (P₁) = 2.39 atm
Final temperature (T₂) = 500 k
Final pressure (P₂) = 2.15 atm
Final volume (V₂) =..?
The new volume of the gas (V₂) can be obtained by using the combined gas equation as shown below:
P₁V₁ /T₁ = P₂V₂ /T₂
2.39 × 125 /300 = 2.15 × V₂ /500
Cross multiply
300 × 2.15 × V₂ = 2.39 × 125 × 500
645 × V₂ = 149375
Divide both side by 645
V₂ = 149375/645
V₂ = 231.59 mL
Therefore, the new volume of the gas is 231.59 mL
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.
