Answer:
Au
Explanation:
For the density of a face-centered cubic:
[tex]Density = \dfrac{4 \times M_w}{N_A \times a^3}[/tex]
where
[tex]M_w[/tex] = molar mass of the compound
[tex]N_A=[/tex] avogadro's constant
[tex]a^3 =[/tex] the volume of a unit cell
Given that:
Density [tex](\rho)[/tex] = 19.30 g/cm³
a = 0.408 nm
a = [tex]0.408 \times 10^{-9} \times 10^{2} \ cm[/tex]
a = [tex]4.08 \times 10^ {-8} \ cm[/tex]
∴
[tex]19.3 = \dfrac{4 \times M_w}{(6.023 \tmes 10^{23})\times (4.08 \times 10^{-8})^3}[/tex]
[tex]M_w= \dfrac{19.3\times (6.023 \times 10^{23})\times (4.08 \times 10^{-8})^3}{4}[/tex]
[tex]M_w=197.37 \ g/mol[/tex]
Thus, the molar mass of 197.37 g/mol element is Gold (Au).
Once the activity of americium in a smoke detector falls below 5 percent of its original activity, it's no longer able to effectively detect smoke and trigger the alarm. If the half-life of americium-241 is approximately 432.2 years, how many years will it take before the americium-241 is unable to detect smoke?
Question 11 options:
A)
10 years
B)
20 years
C)
1,868 years
D)
2 years
Answer:
C 1,868 years
Explanation:
I just took the test - I tried doing the math and was close but couldn't get it exact; so I guessed and I was correct :)
Answer:
1,868 years
Explanation:
write a skeletal equation for the following reaction: An aqueous solution of barium nitrate and an aqueous solution of sodium sulfate are mixed together. Then balance the completed chemical equation.
Answer:
Ba(NO₃)₂(aq) + Na₂SO₄(aq) ⇒ BaSO₄(s) + 2 NaNO₃(aq)
Explanation:
Let's consider the unbalanced double displacement equation for the reaction of an aqueous solution of barium nitrate and an aqueous solution of sodium sulfate.
Ba(NO₃)₂(aq) + Na₂SO₄(aq) ⇒ BaSO₄(s) + NaNO₃(aq)
To get the balanced equation, we will multiply NaNO₃(aq) by 2.
Ba(NO₃)₂(aq) + Na₂SO₄(aq) ⇒ BaSO₄(s) + 2 NaNO₃(aq)
PLZZZ HELP
The cooling of water vapor enough to return to a liquid state
A Evaporation
B Condensation
C Precipitation
D Transpiration
An unknown element is a mixture of isotopes ¹²⁰X and ¹²²X. The average atomic mass of X is 120.81 amu. What is the percent abundance of ¹²²X?
Answer:
40.5% is abundance of X-122
Explanation:
we know there are two naturally occurring isotopes of X, X-120 and X-122.
First of all we will set the fraction for both isotopes
X for the isotopes having mass 122
1-x for isotopes having mass 12 0
The average atomic mass of X is 120.81 amu
we will use the following equation,
122x + 120 (1-x) = 120.81
122x + 120 - 120x = 120.81
122x- 120x = 120.81 -120
2x = 0.81
x= 0.81/2
x= 0.405
0.405 × 100 = 40.5%
40.5% is abundance of X-122 because we solve the fraction x.
now we will calculate the abundance of X-120.
(1-x)
1 - 0.405 = 0.595
0.595 × 100 = 59.5 %
59.5 % for X-120.
Is strontium phosphide a ionic or covalent bond
Answer:
Strontium is a soluble earth metal with the nuclear number 38. Phosphate is a polyatomic particle containing phosphorus and oxygen molecules. Strontium loses electrons to turn out to be emphatically charged, and phosphate is an adversely charged particle.
Explanation:
When strontium phosphide comes into contact with water, it transforms into a solid that emits poisonous and combustible fumes. It is a highly reactive substance utilized in the production of chemically reactive devices as well as a laboratory reagent. Strontium phosphide is ionic.
Two elements combine to form an ionic compound. Sr is the metal while P is the non-metal in the ionic combination. After transferring its two valence electrons to P to create the phosphide ion, which has a net negative charge of -3, strontium becomes a cation.
Ions are charged particles that form when an atom (or group of atoms) receives or loses an electron, and ionic compounds are composed of these charged particles.
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URGENT!!!!!! Please help I will give brainliest
. A block of wood has a mass of 150 grams and a volume of 550 cm3. What is its density?
Answer:
mass= 150 g
volume= 550 cm3
density= mass/ volume
= 150/550
= 0.27 g/cm3
What process caused the accumulation of sand that produce the sand dunes?
A. deposition
B. physical weathering
C.
chemical weathering
D.
erosion
Answer:
Anwser A
Explanation:
Sand dunes are created by wind deposition.
The accumulation of sand that produce the sand dunes is called wind deposition. Therefore, option (A) is correct.
What is the process form sand dunes?Sand dunes are formed when wind deposits the sand on top of each other. It stays until a small mound starts to form. As the first mound forms, sand builds up on the windward side more and more until the edge of the dune breaks due to its own weight.
When the angle of the dune becomes too big to support the weight, the collapse of sand dune begins. This is called the angle of repose usually around 30°-34° also depends upon wind speed, grain size, and roundedness of the individual grains.
As these dunes collapse, the sand starts to move in the same direction as the wind. The sand piles up on multiple sides of the dune by changing wind direction and is unable to get the angle of repose such dune never collapses.
Therefore, the sand dunes produce the accumulation of sand through a process called wind deposition.
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How many liters of C4H10 are present in 0.25 moles of C4H10 at STP?
Answer:
V = 5.6 L
Explanation:
Given data:
Number of moles of C₄H₁₀ = 0.25 mol
Temperature = standard = 273.15 K
Pressure = standard = 1 atm
Volume of C₄H₁₀ = ?
Solution:
Formula:
PV = nRT
R = general gas constant = 0.0821 atm.L /mol.K
1 atm × V = 0.25 mol × 0.0821 atm.L /mol.K × 273.15 K
V = 5.6 atm.L/ 1 atm
V = 5.6 L
what would you expect in the melting point data if benzoic acid and acetanilide are mixed in equal amount
Answer:
There will be an increased span of the melting point of acetanilide
Explanation:
if benzoic acid and acetanilide are mixed in equal amounts, there will be an increased span of the melting point of acetanilide than what is known already. This is because the two compounds have mixed together to become a mixture.
What is the mole fraction of ions in solution if the vapor pressure of an aqueous solution of NaCl is 2.02 kPa
Answer:
.133
Explanation:
Dissolution of solute lowers the vapor pressure of solvent .
Relative lowering by non -volatile solute is equal to mole fraction of solute dissolved .
Vapor pressure of pure water is 2.33 k Pa
Lowering of vapor pressure = 2.33 - 2.02 = .31 k Pa .
relative lowering = .31 / 2.33 = .133
relative lowering will be equal to mole fraction of non volatile solute like NaCl
so mole fraction of NaCl dissolved = .133
Pentane (CH3CH2CH2CH2CH3) and neopentane (C(CH3)4 both have the C5H12 formula. Which compound has stronger induced dipole, induced dipole forces
Answer:
n-Pentane
Explanation:
All molecules possess dispersion forces. It is possible in non-polar molecules that a temporary distortion in the electron distribution of one molecule can affect the electron distribution in a neighboring molecule. This is known as induced dipole, induced dipole forces.
However, this induced dipole, induced dipole forces depends on the shape of the molecule. Molecules of n-pentane are capable of better interaction via induced dipole, induced dipole forces since the molecules interact over the entire length of the molecule rather than neopentane which is more compact and nearly spherical.
8.3.2 Test (CST): Chemical Reactions Question 2 of 25 For a certain chemical reaction, the bond energy of the reactants is 68 kJ, and 25 kJ of energy is released. For energy to be conserved, what is the bond energy of the products? O A. 83 kJ O B. 93 kJ C. 43 kJ OD. 33 kJ
Answer:
C. 43 kJ
Explanation:
Bond energy (bond enthalpy (H) or bond strength) is the amount of energy required to break a bond. The bond energy is used to determine the strength of a chemical bond.
The bond energy is the difference between the energy of the reactants and the energy of the products. The bond energy is given by:
[tex]\Delta H=\Sigma Bond\ energy\ reactants-\Sigma Bond\ energy\ products\\\\Where \ \Delta H=bond\ energy\ or\ energy\ released\\\\Given\ that\ \Delta H=25\ kJ,\Sigma Bond\ energy\ reactants=68\ kJ, Hence:\\\\\Delta H=\Sigma Bond\ energy\ reactants-\Sigma Bond\ energy\ products\\\\Substituting:\\\\25\ kJ=68\ kJ- \Sigma Bond\ energy\ products\\\\ \Sigma Bond\ energy\ products=68\ kJ-25\ kJ\\\\ \Sigma Bond\ energy\ products=43\ kJ\\[/tex]
Answer: is simply C.
Calculate the volume of 7.28 g of a metal that has a density of 6.28 g/cm
Answer:
1.16 cubic centimeters
Explanation:
In the nitrogen cycle, plants use nitrogen compounds to produce *
Answer: Once nitrogen is converted into compounds like ammonium and nitrate, these can be taken up from soils by plants and then the nitrogen can be used to form macromolecules like proteins and nucleic acids (DNA and RNA).
The answer is proteins
What is the pH of a 75.0 mL solution that is 0.045 M in weak base and 0.053 M in the conjugate weak acid
Answer:
7.07
Explanation:
HA = weak acid = 0.053
A+ = conjugate base = 0.045
Ka = 7.2x10^-8
Ka = [H+][A-]/HA
7 2x10^-8 = [H+][0.045]/0.053
[H+] = 7.2x10^-8 x 0.053/0.045
= 8.48x10^-8
PH = -log[H+]
= -log[8.48x10^-8]
PH = -[login.48 + log10^-8]
PH = -0.928 - (-8)log10
= 7.07
As an electron in an atom moves from a higher energy state to a lower energy state, the atom does what?
Answer: absorbs energy
Explanation:
Answer:
releases energy
Explanation:
a solution is 5.00% potassium chloride by mass. how much potassium chloride would you expect to collect by evaporating 150.0 g of the solution
Answer:
When 150.0g of the solution are evaporated, 7.50g of KCl must be collected
Explanation:
A solution 5% of potassium chloride means that there are 5g of KCl per 100g of solution.
When all the solution is evaporated, the solute KCl will be collected as a solid.
In 150g of solution there are:
150g * (5.00gKCl / 100g solution) = 7.50g of KCl are present in 150g of solution.
That means:
When 150.0g of the solution are evaporated, 7.50g of KCl must be collectedanalysis shows the presence of 203 ug of cholesterol. what is the correct set up for conversion of mcg to kg
Answer:
The answer to your question is given below
Explanation:
From the question given above, the following data were obtained:
Mass of cholesterol (in μg) = 203 μg
Mass of cholesterol (in Kg) =?
The following conversion scale can be used to convert micro grams (μg) to kilogram (kg).
1 μg = 1×10¯⁹ Kg
Therefore,
203 μg = 203 μg × 1×10¯⁹ Kg / 1 μg
203 μg = 2.03×10¯⁷ Kg
Thus, 203 μg is equivalent to 2.03×10¯⁷ Kg
Classify each of the following as a Strong acid (sa) or a Weak acid (wa) and indicate how each should be written in aqueous solution. Classify ... In solution this acid should be written as: fill in the blank 1 1. nitric acid fill in the blank 3 2. perchloric acid fill in the blank 5 3. hydrofluoric acid
Answer:
1. nitric acid: sa
2. perchloric acid: sa
3. hydrofluoric acid: wa
Explanation:
A strong acid (sa) is the one that is completely dissociated into ions in water. Conversely, a weak acid (wa) is not completely dissociated in water.
From the options, the strong acids are:
1. nitric acid (HNO₃). It dissociates completely into ions when is dissolved in water, as follows:
HNO₃ → H⁺ + NO₃⁻
2. perchloric acid (HClO₄). It is completely dissociated in water as follows:
HClO₄ → H⁺ + ClO₄⁻
The weak acid is hydrofluoric acid (HF). In water, only a small proportion is dissociated into ions. The proportion of ions formed is given by the equilibrium constant Ka. The dissociation is written by using double arrows:
HF ⇄ H⁺ + F⁻
How many moles of Fluorine (F2) are
needed to completely react 8.0
moles of NF3?
Answer:
12 moles of F₂
Explanation:
We'll begin by writing the balanced equation for the reaction. This is illustrated below:
N₂ + 3F₂ —> 2NF₃
From the balanced equation above,
3 moles of F₂ reacted to produce 2 moles of NF₃.
Finally, we shall determine the number of mole of F₂ needed to produce 8 moles of NF₃. This can be obtained as illustrated below:
From the balanced equation above,
3 moles of F₂ reacted to produce 2 moles of NF₃.
Therefore, Xmol of F₂ will react to produce 8 moles of NF₃ i.e
Xmol of F₂ = (3 × 8)/2
Xmol of F₂ = 12 moles
Thus, 12 moles of F₂ is needed for the reaction.
Helppppp
Question 19
The active ingredient in many spices has the empirical formula CsH.O. It's molecular formula could be
Link to Periodic Table of the Elements
o Only C10H1202
Neither C5H.0 nor C10H 1202
Only CsHO
Either C5H.0 or C10H1202
Answer: Either [tex]C_5H_6O[/tex] or [tex]C_{10}H_{12}O_2[/tex]
Explanation:
Molecular formula is the chemical formula which depicts the actual number of atoms of each element present in the compound.
Empirical formula is the simplest chemical formula which depicts the whole number of atoms of each element present in the compound.
The empirical formula is [tex]C_5H_6O[/tex]
Now we have to calculate the molecular formula:
[tex]n=\frac{\text{Molecular weight }}{\text{Equivalent weight}}[/tex]
n is a whole number
The molecular formula could be=[tex]1\times C_5H_6O=C_5H_6O[/tex]
Thus molecular formula could be = [tex]2\times C_5H_6O=C_{10}H_{12}O_2[/tex]
What are in the energy levels that surround the nucleus of an atom?
What is the wavelength of a 2.99 s -1 wave? (provide work plz)
Answer:
Explanation:
λ = [tex]10^8[/tex] meters
Explanation:
f : frequency
c : velocity of light
λ : wavelength
f = c/λ
λ = c /f
c = 2.99 ⋅ [tex]10^8[/tex] m/ s
λ = [tex]\frac{2.99 * 10^8}{2.99 s^-^1}[/tex]λ = [tex]10^8[/tex] meters
A student dissolves of styrene in of a solvent with a density of . The student notices that the volume of the solvent does not change when the styrene dissolves in it. Calculate the molarity and molality of the student's solution. Be sure each of your answer entries has the correct number of significant digits.
Answer:
0.576M and 0.655m
Explanation:
...Dissolves 15.0g of styrene (C₈H₈) in 250.mL of a solvent with a density of 0.88g/mL...
Molarity is defined as moles of solute (Styrene in this case) per liter of solution whereas molality is the moles of solute per kg of solvent. Thus, we need to find the moles of styrene, the volume in liters of the solution and the mass in kg of the solvent as follows:
Moles styrene:
Molar mass C₈H₈:
8C = 12.01g/mol*8 = 96.08g/mol
8H = 1.005g/mol* 8 = 8.04g/mol
96.08g/mol + 8.04g/mol = 104.12g/mol
Moles of 15.0g of styrene are:
15.0g * (1mol / 104.12g) = 0.144 moles of styrene
Liters solution:
250mL * (1L / 1000mL) = 0.250L
kg solvent:
250mL * (0.88g/mL) * (1kg / 1000g) = 0.220kg
Molarity is:
0.144 moles / 0.250L =
0.576MMolality is:
0.144 moles / 0.220kg =
0.655mWater only gets evaporated from the ocean. True or false?
Answer:
×
Explanation:
FALSE BECAUSE NOT OCEAN IT IS ALL
A 20.0 ml sample of glycerol has a mass of 25.2 grams. What is the mass of 63 ml sample of glycerol?
The mass of 63 ml sample : 79.38 g
Further explanationGiven
20 ml and 25.2 g of glycerol
Required
The mass of 63 ml sample
Solution
Density is the ratio of mass per unit volume
Density formula:
[tex]\large{\boxed {\bold {\rho~=~ \frac {m} {V}}}}[/tex]
Density of glycerol :
= m : V
= 25.2 g : 20 ml
= 1.26 g/ml
Mass of 63 ml sample :
= density x volume
= 1.26 g/ml x 63 ml
= 79.38 g
henry moseley showed how the periodic table could be
Answer: Moseley's experiments in X-ray spectroscopy showed directly from their physics that cobalt and nickel have the different atomic numbers, 27 and 28, and that they are placed in the Periodic Table correctly by Moseley's objective measurements of their atomic numbers.
Explanation:
which of the following is required for a reaction to occur?
a. energy
b. collisions
c. activation energy
d. all of the above
How many electrons are there in an atom of carbon?
Answer:
if its a neutral atom there should be 6 electrons because there are 6 protons
Explanation:
