Answer:
21.51g/cm³
Explanation:
To answer this question we need to know that, in 1 unit FCC cell:
Edge length = √8 * R
Volume = 8√8 * R³
And there are 4 atoms per unit cell
The mass of the 4 atoms of the cell, in grams, is:
4 atom * (1mol / 6.022x10²³atom) * (195.09g / mol) = 1.2958x10⁻²¹g
Volume in cm³:
0.1386nm * (1x10⁻⁷cm / 1nm) = 1.386x10⁻⁸cm
Volume = 8√8 * (1.386x10⁻⁸cm)³
Volume = 6.02455x10⁻²³cm³
And density, the ratio of mass and volume, is:
1.2958x10⁻²¹g / 6.02455x10⁻²³cm³ =
21.51g/cm³
Barium – 122 has a half-life of 2 minutes. Suppose you obtain a sample weighing 10.0 g and it takes 10 minutes to set up an experiment. How many grams of Barium – 122 will remain at the point when you begin the experiment
Answer:
0.3125 g
Explanation:
Given data:
Half life of barium-122 = 2 min
Mass of sample = 10.0 g
Mass of barium remain after 10 min = ?
Solution:
Number of half lives = Time elapsed / half life
Number of half lives = 10 min/ 2 min
Number of half lives = 5
At time zero = 10 g
At 1st half life = 10 g/2 = 5 g
At 2nd half life = 5 g/2 = 2.5 g
At 3rd half life = 2.5 g/2 = 1.25 g
At 4th half life = 1.25 g/2 = 0.625 g
At 5th half life = 0.625 g/2 = 0.3125 g
A black object appears black because it reflects all light , and does not absorb any light. True or False
Answer:
False
Explanation:
It is the other way round, a black object appears black because it absorbs all the wavelength of light and does not reflect any light.
A black bucket will appear black because, it absorbs all wavelength of light incident on it. No other wavelength is reflected from the surface of the body. A black color suggests that a body is not reflecting any color. Instead such a body absorbing all the colors. For a white object, they reflect all the wavelength that is incident upon them.
The prefix for one-millionth is micro-.
True
False
How to calculate calories
Answer:If you are sedentary (little or no exercise) : Calorie-Calculation = BMR x 1.2.
If you are lightly active (light exercise/sports 1-3 days/week) : Calorie-Calculation = BMR x 1.375.
Explanation:
A liquid has a volume of 62.7 mL and a density of 2.59 g/mL. What is its mass? (show all work)
Answer:
162.4
Explanation:
The formula for mass is density* volume so 62.7 multiplied by 2.59 equals 162.393. then you round so your anwser would be 162.4
how do you write 652870000 in scientific notations
9
6.5287×10Explanation:This is the correct answerWhich element is more reactive?
A) Flourine B) Oxygen C)Cabron D)Boron
Calculate the mass (in g) of 2.60 x 10^23 molecules of PbSO 4. The molar mass of PbSO 4 is 303.27 g/mol.
Answers:
986 g
7.27 g
1.04 g
131 g
4.74 x 1049 g
Explanation:
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) Do you think the pH of 1,0 M tri-methyl ammonium (CH3)3NH+, pKa = 9.80, will be higher or lower than that of 1.0 M phenol, C6H5OH? What is the difference in pH values for the two acids?
Answer:
1. The pH of 1.0 M trimethyl ammonium (pH = 1.01) is lower than the pH of 0.1 M phenol (5.00).
2. The difference in pH values is 4.95.
Explanation:
1. The pH of a compound can be found using the following equation:
[tex] pH = -log([H_{3}O^{+}]) [/tex]
First, we need to find [H₃O⁺] for trimethyl ammonium and for phenol.
Trimethyl ammonium:
We can calculate [H₃O⁺] using the Ka as follows:
(CH₃)₃NH⁺ + H₂O → (CH₃)₃N + H₃O⁺
1.0 - x x x
[tex]Ka = \frac{[(CH_{3})_{3}N][H_{3}O^{+}]}{[(CH_{3})_{3}NH^{+}]}[/tex]
[tex] 10^{-pKa} = \frac{x*x}{1.0 - x} [/tex]
[tex] 10^{-9.80}(1.0 - x) - x^{2} = 0 [/tex]
By solving the above equation for x we have:
x = 0.097 = [H₃O⁺]
[tex] pH = -log([H_{3}O^{+}]) = -log(0.097) = 1.01 [/tex]
Phenol:
C₆H₅OH + H₂O → C₆H₅O⁻ + H₃O⁺
1.0 - x x x
[tex]Ka = \frac{[C_{6}H_{5}O^{-}][H_{3}O^{+}]}{[C_{6}H_{5}OH]}[/tex]
[tex] 10^{-10} = \frac{x^{2}}{1.0 - x} [/tex]
[tex] 1.0 \cdot 10^{-10}(1.0 - x) - x^{2} = 0 [/tex]
Solving the above equation for x we have:
x = 9.96x10⁻⁶ = [H₃O⁺]
[tex] pH = -log([H_{3}O^{+}]) = -log(9.99 \cdot 10^{-6}) = 5.00 [/tex]
Hence, the pH of 1.0 M trimethyl ammonium is lower than the pH of 0.1 M phenol.
2. The difference in pH values for the two acids is:
[tex] \Delta pH = pH_{C_{6}H_{5}OH} - pH_{(CH_{3})_{3}NH^{+}} = 5.00 - 1.01 = 4.95 [/tex]
Therefore, the difference in pH values is 4.95.
I hope it helps you!
Calculate the atomic mass of nitrogen if the two common isotopes of nitrogen have masses
of 14.003 amu (99.63% abundance) and 15.000 amu (0.37% abundance).
List the following bonds in order of increasing ionic character: potassium to iodine, carbon to oxygen, lithium to fluorine, boron to fluorine. (Enter the two elements of the bond into the appropriate box: KI, CO, LiF, BF)
Answer:
CO < BF < KI < LiF
Explanation:
The magnitude of ionic character in a bond is dependent on the magnitude of electronegativity difference between the atoms in the bond.
Remember that no bond is 100% ionic or covalent according to Linus Pauling. However, the percentage ionic character depends on electronegativity difference between the bonding atoms and polarizability (Fajan's rules).
Between LiF and KI, Fajan's rules become very important. The Li^+ is small and highly polarizing. The stronger the polarising power of the cation and the higher the polarisability of the anion the more covalent character is expected in a bond
An element has 20 protons, 22 neutrons and 18 electrons. What is the charge for this ion?
PLZ HELP I'LL AWARD BRAINLIEST
Answer:
20 protons.
Explanation:
20 protons = 20 + charges
18 electrons = 18- charges.
The difference = 20 - 18 = +2
The charge for this ion is plus 2
It is a calcium ion. The element is number 20 on the periodic table.
The charge of the ion is +2
HOW TO DETERMINE THE CHARGE OF AN ION:
The charge of an ion is a function of the number of protons and electrons in the atom. An atom consists of three subatomic particles namely: neutron, proton and electron. The proton is positively charged while the electron is negatively charged. The charge of an atom is determined by subtracting the number of electrons from protons, that is;Charge = no. of protons - no. of electronsHence, if the protons in an atom is more than the electrons, the charge will be positive and vice versa. In this case, an element has 20 protons, 22 neutrons and 18 electrons.Therefore, the charge of the ion will be 20 protons - 18 electrons = +2
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The process of reviewing information using an investigator is knowledge, training, experience, and expertise is what type of reasoning?
Answer:
Inductive reasoning
Explanation:
Inductive reasoning is based on making broad generalizations from specific observations. We draw conclusions from the data we have. This is the opposite of deductive reasoning, which starts with a general statement and aims to reach a specific conclusion.
Based on this, we can conclude that, if an investigator uses their knowledge, training, experience, and expertise to reach a conclusion, they are using inductive reasoning.
If 1.02 g of nickel reacted with 750. mL of 0.112 M hydrobromic acid, how much of each will be present at the end of the reaction if you captured the gas in a 2.50 L vessel at 30 C
Answer:
35.1% is percent yield
Explanation:
Full question: Assume no volume change. If you formed 0.0910 atm of gas, what is the percent yield?
The reaction that is occurring is:
Ni + 3HBr → NiBr₃ + 3/2H₂(g)
First, we will determine moles of Ni and HBr to determine limiting reactant and theoretical yield
Using ideal gas law, we can determine the moles of hydrogen formed. Thus, we can find percent yield:
Moles Ni (Molar mass: 58.69g/mol):
1.02g * (1mol / 58.69g) = 0.01738moles Ni
Moles HBr:
0.750L * (0.112mol/L) = 0.084 moles of HBr.
For a complete reaction of the 0.084 moles of HBr you need:
0.084mol HBr * (1 mole Ni / 3 moles HBr) = 0.028 moles of Ni.
As there are just 0.01738 moles of Ni, the Ni is limiting reactant. Assuming a theoretical yield, moles of H₂ produced are:
0.01738moles Ni * (3/2 H₂ / 1 mol Ni) = 0.02607 moles H₂
Now, moles of H₂ produced are:
PV = nRT
PV/RT = n
Where P is pressure (0.0910atm)
V is volume (2.50L)
R is gas constant (0.082atmL/molK)
T is absolute temperature in Kelvin (30°C + 273.15 = 303.15K)
And n are moles
PV/RT = n
0.0910atm*2.50L/0.082atmL/molK*303.15K = n
0.00915 moles = n
And percent yield (Produced moles / Theoretical moles * 100) is:
0.00915 moles / 0.02607moles =
35.1% is percent yieldg Calculate the mass percent of sodium bicarbonate in the solution that has 7.00 g of solution and 0.052 Kg of water.
Answer:
11.86%
Explanation:
First, we convert both solvent and solute to the same unit, say, kg. We have.
Mass of Sodium Bicarbonate = 7g = 7/1000 kg = 0.007 kg
Mass of water = 0.052 kg.
Formula for the mass percent is
% of sodium bicarbonate = [(mass of sodium bicarbonate) / (mass of total solution) * 100%]
Total mass of solution = 0.007 + 0.052 Total mass of solution = 0.059
% of sodium bicarbonate = 0.007 / 0.059 * 100%
% of sodium bicarbonate = 11.86%
Therefore, the mass percent of sodium bicarbonate I'm the solution is 11.86%
What two particles make up matter?
Answer:
Protons,electrons,and neutrons make up matter
Explanation:
i studied this so hope it helps
What best describes the location of an atom's electrons?
All living things are made of one or more cells. Which is true of all cells?
When an aqueous sodium hydroxide solution of sodium benzoate is acidified, what precipitate is formed, and why does it precipitate?
Answer:
Insoluble benzoic acid is formed
Explanation:
When benzoic acid is dissolved in sodium hydroxide solution, sodium benzoate is formed. This compound is highly soluble in the aqueous layer.
If this solution is now acidified, the equilibrum position shifts towards the undissociated benzoic acid and a precipitate appears.
An insoluble substance formed during crystallization or precipitation is called a precipitate. The precipitate of the reaction formed is of benzoic acid.
What is a precipitation reaction?A precipitation reaction is a type of reaction in which an insoluble salt or substance is formed as the result of the reaction between the soluble salt solutions.
The substance or the salt produced that does not get dissolved in the solution is called a precipitate.
In the reaction, benzoic acid reacts with the sodium hydroxide salt and forms sodium benzoate salt as shown,
[tex]\rm C_{6}H_{5}COOH(s) + NaOH(aq) \rightarrow C_{6}H_{5}COO^{-}Na^{+}(aq) + H_{2}O(l)[/tex]
When the salt of sodium benzoate is acidified then the precipitation of benzoic acid is formed. The precipitate occurs because the equilibrium shifts towards the undissociated benzoic acid.
Therefore, a precipitate of benzoic acid is formed.
Learn more about precipitation here:
https://brainly.com/question/9325169
Is air a homogeneous heterogeneous mixture or substance
Answer:
look at the explanation
Explanation:
The air that you breathe is a homogeneous mixture of oxygen, nitrogen, argon, and carbon dioxide, along with other elements in smaller amounts. Because each layer of the Earth's atmosphere has a different density, each layer of air is its own homogeneous mixture.
Hope this helps. :)
SOMEONE PLEASE HELPPP
the moon lost its volcanic __ beacuse of its weak gravity
Answer:
Explanation:
the moon is still volcanic
Discuss the relationship between atoms, elements and compounds. Include in your discussion if these are mixtures or pure substances and why.
Answer:
Elements are the simplest complete chemical substances. Each element corresponds to a single entry on the periodic table. An element is a material that consists of a single type of atom. Each atom type contains the same number of protons.
Chemical bonds link elements together to form more complex molecules called compounds. A compound consists of two or more types of elements held together by covalent or ionic bonds.
Explanation:
how many grams of oxygen are there in 66.2 g of nitrous acid
Answer:
15.9994 grams
You can view more details on each measurement unit: molecular weight of Oxygen or grams The molecular formula for Oxygen is O. The SI base unit for amount of substance is the mole. 1 mole is equal to 1 moles Oxygen, or 15.9994 grams.
Explanation:
Answer:
First you need to know the Chemical formula for Nitrous acid which is HNO₂
Explanation:
A big bully is having a tug-of-war with a small child. There is a ball attached to the middle of the rope.
Toward whom will the ball move?
Answer:
the ball will move towards the big bully
What is the correct systematic name for ICl5?
Answer:
iodine pentachloride
Explanation:
Hereditary information is passed on from:
O nucleus to nucleus
O cell to cell
O cell to nucleus
O nucleus to cell
Answer:
D - Nucleus to Cell
Explanation:
Hope it helps!!
:D
On average, about ____________ of incoming solar radiation is reflected back to space.
A 50%
B 30%
C 20%
D 10%
Kc = 3.07 x 10-4 at 24°C for 2NOBr(g) ↔ 2NO(g) + Br2(g). If the initial concentration of NOBr = 0.878 M, what is the equilibrium concentration (in M to 4 decimal places) of NO?
Answer:
The equilibrium concentration of NO is 0.02124 M.
Explanation:
Given that,
Initial concentration of NOBr = 0.878 M
[tex]k_{c}=3.07\times10^{-4}[/tex]
Temperature = 24°C
We know that,
The balance equation is
[tex]2NOBr\Rightarrow 2NO+Br_{2}[/tex]
Initial concentration is,
[tex]0.878\Rightarrow 0+0[/tex]
Concentration is,
[tex]-2x\Rightarrow 2x+x[/tex]
Equilibrium concentration
[tex]0.878-2x\Rightarrow 2x+x[/tex]
We need to calculate the value of x
Using formula of concentration
[tex]k_{c}=\dfrac{[NO][Br_{2}]}{[NOBr]^2}[/tex]
Put the value into the formula
[tex]3.07\times10^{-4}=\dfrac{[2x][x]}{[0.878-2x]^2}[/tex]
[tex]2x^2=3.07\times10^{-4}\times(0.878)^2+3.07\times10^{-4}\times4x^2-2\times2x\times0.878\times3\times10^{-4}[/tex]
[tex]2x^2=0.0002367+0.001228x^2-0.0010536x[/tex]
[tex]2x^2-0.001228x^2+0.0010536x-0.0002367=0[/tex]
[tex]1.998772x^2+0.0010536x-0.0002367=0[/tex]
[tex]x=0, 0.01062[/tex]
We need to calculate the equilibrium concentration of NO
Using formula of concentration of NO
[tex]concentration\ of\ NO=2x[/tex]
Put the value of x
[tex]concentration\ of\ NO=2\times0.01062[/tex]
[tex]concentration\ of\ NO=0.02124[/tex]
Hence, The equilibrium concentration of NO is 0.02124 M.
Which of the following contribute(s) to most of the mass of an atom? Question 5 options: A) Neutrons only B) Protons and electrons C) Protons and neutrons D) Protons only
Answer:
C
Explanation:
Hope this helps :)