How many grams of calcium chloride will be needed to make 750 mL of a 0.100 M CaCl2 solution?
Answer:
Molarity or molar concentration is the number of moles of solute that can be dissolved in 1 L of a solution.
Molarity = Number of solute (in moles) / Volume of solution (in liters), or
C = n / V
According to the question,
V = 750 ml and C = 0.100 M
For this, let us convert ml into liters
We know 1 L = 1000 ml
Hence, 750 ml = (750/1000) L = 0.75 L
So, V = 0.75 L
We know that C = n / V
So, n = C x V
n = 0.100 x 0.75 = 0.075
n is the number of moles of solute.
Hence, number of moles of CaCl2 = 0.075 moles
That means there are 0.075 moles of CaCl2 in 750 ml of solution.
In order to determine the mass of CaCl2 in grams, we need to know the molar mass of CaCl2.
For this, we need to find out the atomic mass of each atom (by referring the periodic table).
CaCl2 has 1 Ca atom and 2 Cl atoms.
Atomic mass of
Ca = 40.08 g
Cl = 35.45, Cl2 means 2 x 35.45 = 70.90 g
Adding these values, we get mass of CaCl2 in grams.
Hence, mass of CaCl2 = 40.08 + 70.90 = 110.98 g
Thus, 1 mole of CaCl2 weighs 110.98 g.
Hence, 0.075 moles of CaCl2 will weigh
0.075 x 110.98 = 8.3235 g, rounded to 8.32 g
So restating the question, we can say that 8.32 grams of CaCl2 will be needed to make 750 ml of a 0.100 M CaCl2 solution.
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4. How many grams of ammonium carbonate are needed to decompose in order to produce
6.52g of carbon dioxide? Ammonium oxide is the other product.
(NH4)2(CO,) – (NH4)2O + CO2
Answer:
14.23g of (NH4)2CO3
Explanation:
We'll begin by writing the balanced equation for the reaction.
(NH4)2CO3 –> (NH4)2O + CO2
Next,, we shall determine the mass of (NH4)2CO3 that decomposed and the mass of CO2 produced from the balanced equation. This is illustrated below:
Molar mass of (NH4)2CO3 = 2[14+(4x1)] + 12 + (16x3)
= 2[14 +4] + 12 + 48
= 2[18] + 60 = 96g/mol
Mass of (NH4)2CO3 from the balanced equation = 1 x 96 = 96g
Molar mass of CO2 = 12 + (2x16) = 44g/mol
Mass of CO2 from the balanced equation = 1 x 44 = 44g.
Summary:
From the balanced equation above,
96g of (NH4)2CO3 decomposed to produce 44g of CO2.
Finally, we can determine the mass of (NH4)2CO3 that decomposed to produce 6.52g of CO2 as follow:
From the balanced equation above,
96g of (NH4)2CO3 decomposed to produce 44g of CO2.
Therefore, Xg of (NH4)2CO3 will decompose to produce 6.52g of CO2 i.e
Xg of (NH4)2CO3 = (96 x 6.52)/44
Xg of (NH4)2CO3 = 14.23g
Therefore, 14.23g of (NH4)2CO3 is needed to produce 6.52g of CO2.
Which of these, all of which include earth, most likely contains the most dark matter
Answer: Milky Way Galaxy=b
Explanation:
Why would an unstable radioactive isotope (nuclide) emit a beta particle (high energy electron)?
A)It has too many neutrons
B)It has too many protons
C)It has too many electrons
D)It has too few electrons
Answer:
A)It has too many neutrons
Explanation:
Electrons are emitted from the nucleus when a neutron is converted to a proton, an electron and a neutrino. This process is popularly known as beta emission. It reduces the neutron-proton ratio of a nuclide. The neutrino is a particle of zero mass and zero charge that carries off the excess energy and balances spins.
The loss of an electron from the nucleus occurs when there are too many neutrons in the nucleus. The process of beta emission usually reduces the number of neutrons in an atom thereby decreasing the neutron-proton ratio.
Which element has the lowest ionization energy?
A partial periodic table. 18 columns are shown; all columns align at the bottom. The first column is 6 entries, headed 1 and 1 A. Entries are upper H, upper L i, upper N a, upper K, upper R b, and upper C s. The second column is 5 entries, headed 2 and 2 A. Entries are upper B e, upper M g, upper C a, upper S r, and upper B a. 7 columns of 3 entries each follow; all entries are blank. The next column is 3 entries also; the first entry is upper N i and the rest are blank. 2 more blank columns of three follow. Five further columns of five entries each follow. The first of these is headed 13 and 3 A; entries are upper B, upper A l, and three blank cells. Next column is labeled 14 and 4 A; entries are upper C, upper S i, upper G e, and two blank cells. Next column is labeled 15 and 5 A; entries are upper N, upper P, and upper A s, with 2 blank cells below. The next column is labeled 16 and 6 A; entries are upper O, upper S, and upper S e followed by 2 blank cells. The next column is labele
argon (Ar)
bromine (Br)
cesium (Cs)
nickel (Ni)
Answer:
Cs
Explanation:
This question is formatted oddly, but I understand the gist of it. Essentially, even if the periodic table is cut off by one row and missing the lanthanides and actinides, basic rules of the table still apply.
Remember the general trend of ionization energy: the farther to the right and the farther up, the higher the ionization energy.
As an example, fluorine is the "t-rex" of the elements because it's so electronegative that it hoards electrons, and that means it's hard to take its electrons away, which gives it a high ionization energy.
Out of the given choices, cesium Cs has the lowest ionization energy because it's so far to the left and so low. You can just nab an electron and it won't even mind too much.
Why not the other answer choices? Bromine is a halogen (so it's on the far right of the table) and it's fairly high up, so its ionization energy is much too high. Argon is a noble gas, so it's so stable that it hates it when someone tries to take an electron away; it has a very high ionization energy. Nickel, likewise, is a transition metal, so it's not the answer either.
Answer:
C
Explanation:
If your weight is 120 pounds
and your mass is 54 kilograms, how would those
values change if you were on the moon? The grav-
itational force on the moon is 1/6 the gravitational
force on Earth.
Explanation:
Weight is 120 pounds and mass is 54 kg
The mass of an object is same everywhere. If we were on the moon, its mass will remain to be 54 kg.
Weight of an object is given by :
[tex]W=m\times g[/tex]
g is acceleration due to gravity on that surface
For moon, it is 1/6 the gravitational force on Earth, g = 1.63 m/s²
1 pound = 4.45 N
It means my weight is 533.78 N
On the surface of Moon is will be :
[tex]W=\dfrac{533.78}{1.63}\\W=327.47\ N[/tex]
PLZ HELP For the reaction: 2NO2(g) → N2O4(l),
the ΔH of the reactants, two moles of NO2 (g), is + 66 kJ/mol,
and the ΔH of the products, N2O4 (l), is -20 kJ/mol.
Which of the following shows the ΔH (change in enthalpy) for the reaction as a whole?
Question 8 options:
ΔrxnH =(- 20 kJ/mol) / (+66 kJ/mol)
ΔrxnH = (+66 kJ/mol) + (- 20 kJ/mol)
ΔrxnH =(-20 kJ/mol) - (+ 66 kJ/mol)
ΔrxnH =(+66 kJ/mol) - (- 20 kJ/mol)
Answer: [tex]\Delta H_{rxn}=-20kJ/mol-(+66kJ/mol)[/tex]
Explanation:
Heat of reaction or enthalpy change is the energy released or absorbed during the course of the reaction.
It is calculated by subtracting the enthalpy of reactants from the enthalpy of products.
[tex]\Delta H=H_{products}-H_{reactants}[/tex]
[tex]\Delta H[/tex] = enthalpy change = ?
[tex]H_{products}[/tex] = enthalpy of products
[tex]H_{reactants}[/tex] = enthalpy of reactants
For the given reaction :
[tex]2NO_2(g)\rightarrow N_2O_4(l)[/tex]
[tex]\Delta H=H_{N_2O_4}-2\times H_{NO_2}[/tex]
[tex]\Delta H=-20kJ/mol-(+66kJ/mol)[/tex]
When writing the shorthand notation for sulfur, S, which element would you put in brackets?
balance
KClO3 ⟶ KCl + O2
Answer:
[tex]2KCl O_3 \to 2KCl + 3O_2[/tex]
Explanation:
Balance both sides.
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7th-grade science.
What does the number, such as 98.7 FM, of a radio station represent?
Answer:
The number, such as 98.7 FM, of a radio station represents:
the frequency in which is transmitted the radio signal.Explanation:
The radio FM is the modulated frequency, which means that all the information is sent by just a signal, with different frequencies which difference them, the radio FM use the frequencies from 88 MHz until 108 Mhz (MHz is a measuring unit for the frequency), with a minimal space among them of 0.2 MHz, this last means that you could find a signal in 88.0 MHz, and the next should be 88.2 MHz, next 88.4 MHz and so (at least, regularly the space between two frequencies is more than 0.2 MHz).
What is the formula for this ionic compound and tha name ?
Explanation:
K3P = Potassium phosphide
Which of the following statements are correct regarding the binding energy?
Answer:
You really should have put the options so the other person could have helped then. Luckily, I had this exact same question on a lesson in Chemistry.
- Binding energy is equivalent to the mass that is converted to energy to hold the nucleus together.
- Binding energy is the minimum energy required to split the nucleus.
- Binding energy per nucleon is the ratio of the binding energy to the number of nucleons.
The following exothermic reaction is allowed to reach equilibrium. What
happens when the reaction temperature is decreased? (think about what
side heat would be on in an exothermic reaction)
2 H, + 02 → 2H2O
O Favors the forward reaction
O Favors the reverse reaction
O The reaction is still at equilibrium
CHEM FINAL PLEASE HELP
On a field trip at the UW Marine Biology Center, Destiny learns that mutiple salt compounds exist in the ocean. While most of the salt compounds are NaCl (sodium chloride), other similar elements form salts in the water. Using the periodic table as a reference, which elements could bond to form a compound most like NaCl?
Question 3 options:
Hydrogen (H) and Oxygen (O)
Potassium (K) and Fluorine (F)
Magnesium (Mg) and Iodine (I)
Lithium (Li) and Sulfur (S)
Answer:
Potassium (K) and Fluorine (F)
Explanation:
A salt is formed with a metal and non-metal element from the periodic table of elements. if you look at the online ptable.com the upper right hand corner of each element shows the valence electrons for each element, and how many are in each shell for that element. Fluorine (F) has 7 valence electrons in its outer most shell, which means there is room for 1 more electron since the second shell can hold a max of 8. Potassium(K) has 1 electron in its outer most shell- which means is can fill in the 1 space available that fluorine has in its outer most shell. Since Potassium(K) is a metal and Fluorine(F) is a non-metal they can form an ionic compound, salt.
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Barry is 62 years old. He runs every single day. His BMI is 15. He would like to gain weight, and increase muscle in his upper body, chest, and back.
what exercise should he do?
Answer:
He should eat fruits and vegetables and also skip
Which of the following samples contains the greatest number of atoms?
a. 9 mole of CO2 b. 10 moles of Xe
c. 11 moles of N2O d. 12 moles of CO
Answer:
C. 11 moles of N2O
Explanation:
A. CO2 exists as a molecular compound. The number of atoms present = 1 atom of Carbon and 2 atoms oxygen = 3 atoms * 9 = 18 atoms
B. Xe exists as an atom. Number of atoms present = 10 * 1 atom = 10 atoms
C. N20 contains 3 atoms; 2 atoms of Nitrogen and 1 atom of oxygen.
Number of atoms present = 3 * 11 = 33 atoms
D. CO contains 2 atoms, 1 each of carbon and oxygen.
Number of atoms present = 12 * 2 = 24 atoms
Explain in terms of molecular formulas and structural formulas why 2,2-dimethylbutane is an isomer of hexane
Answer:
The answer to your question is given below.
Explanation:
Molecular formula gives the exact amount of each type of element in a molecule. Hence, it gives the formula of the compound.
Structural formula on the other hand shows how the different elements in a molecule of a compound are arranged in space.
Isomerism is a phenomenon whereby two or more compounds have the same molecular formula but different structural patterns. The compounds involved are called isomer.
2,2-dimethylbutane is an isomer of hexane because they both have the same molecular formula but different structural patterns.
Hexane can be rearrange to obtain 2,2-dimethylbutane.
The attached photo shows that 2,2-dimethylbutane and hexane have the same molecular formula i.e C6H14 but their structural arrangement is different. Hence they are called isomers.
Isomerism is a phenomenon whereby two or more compounds have the same molecular formula but different structural patterns. The compounds involved are called isomer.
2,2-dimethylbutane is an isomer of hexane because they both have the same molecular formula but different structural patterns.
Hexane can be rearrange to obtain 2,2-dimethylbutane.
In the attached figures, 2,2-dimethylbutane and hexane have the same molecular formula i.e. C₆H₁₄ but their structural arrangement is different. Therefore, they are called isomers.
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Calculate the theoretical yield and percent yield for this experiment
Answer:
A. Theoretical yield of KCl is 36.49g
B. Percentage yield of KCl is 90.4%
Explanation:
The balanced equation for the reaction is given below:
2KCLO3 —> 2KCl + 3O2
Next, we shall determine the mass KClO3 that decomposed and the mass KCl produce from the balanced equation. This is illustrated below:
Molar mass of KClO3 = 39 + 35.5 + (16x3) = 122.5g/mol
Mass of KClO3 from the balanced equation = 2 x 122.5 = 245g
Molar mass of KCl = 39 + 35.5 = 74.5g/mol
Mass of KCl from the balanced equation = 2 x 74.5 = 149g.
From the balanced equation above,
245g of KClO3 decomposed to produce 149g of KCl.
A. Determination of the theoretical yield of KCl. This is illustrated below:
From the balanced equation above,
245g of KClO3 decomposed to produce 149g of KCl.
Therefore, 60g of KClO3 will decompose to produce = (60 x 149)/245 = 36.49g of KCl.
Therefore, the theoretical yield of KCl is 36.49g
B. Determination of the percentage yield of KCl. This can be obtaine as follow:
Actual yield = 33g
Theoretical yield = 36.49g
Percentage yield =..?
Percentage yield = Actual yield /Theoretical yield x 100
Percentage yield = 33/36.49 x 100
Percentage yield of KCl = 90.4%
Select the word or phrase from the drop-down menu to describe ionic compounds. A formula unit represents the simplest ratio of elements in a of an ionic compound. A crystal is made up of There are two magnesium ions for every two sulfide ions in magnesium sulfide. The ratio of Mg to S in the formula unit is .
Answer:
A formula unit represents the simplest ratio of elements in a
✔ crystal
of an ionic compound.
A crystal is made up of
✔ many atoms that are arranged in a regular pattern.
There are two magnesium ions for every two sulfide ions in magnesium sulfide. The ratio of Mg to S in the formula unit is
✔ 1:1
.
Explanation:
did it on edge 2020
In a crystal of an ionic compound, a formula unit denotes the most basic elemental ratio.
What do you mean by ionic compound?
Ions, which have positive and negative charges respectively, are the building blocks of ionic compounds, which are neutral substances.
In a crystal of an ionic compound, a formula unit denotes the most basic elemental ratio.
A crystal is composed of several atoms that are organised in a predictable way.
In magnesium sulphide, there are two magnesium ions for every two sulphide ions. The formula unit has a 1:1 Mg to S ratio.
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how many atoms are in FeS2
How does pollution affect air resources?
Answer: it gets inside the air and then it infects the air's resourses
Explanation:
Calculate the answer. Express it in scientific notation and include the correct number of significant figures. (12 x 10^4 ) x (5 x 10^-2 ) = _____
Answer:
60 x 10^6
Explanation:
12 x 5 = 60
add the exponents 4+2 so 10^6
60 x 10^6 is the answer
Ethanol, C2H5OH, is considered clean fuel because it burns in oxygen to produce carbon dioxide and water with few trace pollutants. If 325.0 g of H2O are produced during the combustion of ethanol, how many grams of ethanol were present at the beginning of the reaction?
Answer:
277.8 grams of ethanol
Explanation:
C2H5OH(l)+3O2(g)⟶2CO2(g)+3H2O(l)
It is important to understand that before we can proceed with solving any problem that has to do with stoichiometry, we must first note down the correct and balanced chemical reaction equation.
Number of moles of water formed= mass of water/ molar mass of water
Molar mass of water = 18gmol-1
Number of moles of water = 325g/18 gmol-1= 18.1 moles of water
From the balanced reaction equation;
1 mole of ethanol yields 3 moles of water
x moles of ethanol yields 18.1 moles of water
Hence;
x= 18.1 × 1 / 3 = 6.03 moles of ethanol
Molar mass of ethanol= 46.07 g/mol
Therefore mass of ethanol originally present= 6.03 moles × 46.07 g/mol = 277.8 grams of ethanol
does anyone know the answer???
In a lab, 33 g of potassium chloride is formed from 60.0 g of potassium chlorate decomposing. Calculate the theoretical yield and percent yield for this experiment.
Answer: The theoretical yield and percent yield for this experiment are 40 g and 82% respectively.
Explanation:
[tex]2KClO_3\rightarrow 2KCl+3O_2[/tex]
According to avogadro's law, 1 mole of every substance weighs equal to the molecular mass and contains avogadro's number [tex](6.023\times 10^{23})[/tex] of particles.
To calculate the moles:
[tex]\text{Moles of potassium chloride}=\frac{\text{Mass of potassium chloride}}{\text{Molar mass of potassium chloride}}=\frac{33g}{74.5g/mole}=0.44moles[/tex]
[tex]\text{Moles of potassium chlorate}=\frac{\text{Mass of potassium chlorate}}{\text{Molar mass of potassium chlorate}}=\frac{66g}{122.5g/mole}=0.54moles[/tex]
According to stochiometry:
2 moles of [tex]KClO_3[/tex] produce = 2 moles of [tex]KCl[/tex]
0.54 moles of [tex]KClO_3[/tex] should produce = [tex]\frac{2}{2}\times 0.54=0.54moles[/tex] of [tex]KCl[/tex]
Thus theoretical yield is [tex]moles\times {\text {Molar mass}}=0.54mol\times 74.5g/mol=40g[/tex]
But Experimental yield is 33 g.
[tex]{\text {percentage yield}}=\frac{\text {Experimental yield}}{\text {Theoretical yield}}\times 100\%[/tex]
[tex]{\text {percentage yield}}=\frac{33g}{40g}\times 100\%=82\%[/tex]
The theoretical yield and percent yield for this experiment are 40 g and 82% respectively.
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How many grams of carbon dioxide are formed from 25 moles of octane
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A wave's frequency refers to _____________. *
the number of wavelengths passing by a given point in a period of time
the heigh of a wave as it passes a given point
the length of a wave
the strength of a wave
Answer:
The length of a wavelength.
Explanation:
"A wave frequency refers to..." The length of a wavelength, or how long the wavelength is.
Hope this helped :)
In what direction does heat flow?
A. Heat flows back and forth between objects.
B. Heat flows from an object of higher temperature to an object of
lower temperature.
C. Heat flows from an object of lower temperature to an object of
higher temperature,
D. Heat flows only if objects are at the same temperature,
The direction in which heat flows in a system is that: B. heat flows from an object of higher temperature to an object of lower temperature.
What is heat?Heat is also referred to as thermal energy and it can be defined as a form of energy that is transferred from one object (body) to another, especially due to a difference in temperature.
This ultimately implies that, heat is primarily transferred between objects that have different degrees of temperature during the process of heat conduction.
According to the kinetic-molecular theory, heat is generally transferred from a hotter object with higher temperature to a cooler object with lower temperature.
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Oxidation numbers are written with the positive or negative sign _____ the number. after before over under
Answer:
The answer to this question is over
Oxidation numbers are written with the positive or negative sign over the number.
What is oxidation number?Oxidation number of any element gives idea about the exchangeable number of electrons from the outermost shell of that element.
If electrons are losing from the valence shell then the element will show positive oxidation number and if electrons are gained to the valence shell then element will show negative oxidation state.
Elements with oxidation state will be shown as Mg²⁺, O²⁻ means oxidation state is expressed at the top or over of the symbol of element.
Hence oxidation states are written over the numbers.
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