Answer:
physical
Explanation:
no chemical reaction is occurring
Which of these, all of which include earth, most likely contains the most dark matter
Answer: Milky Way Galaxy=b
Explanation:
4HCl(g) + Si (s) ⇌ SiCl4 (l) + 2H2 (g) would be classified as a(n):
Answer:
it will be classical as gas
HELP HELP HELP HELP HELP HELP!!!!!!
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
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.
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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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.
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
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%
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?
How many grams of carbon dioxide are formed from 25 moles of octane
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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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]
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
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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does anyone know the answer???
When a cube of manganese oxide was added to a solution of hydrogen peroxide, water and oxygen were produced. Manganese oxide
was not used up in the reaction. Which of the following is likely to decrease the rate of the reaction?
Using a larger amount of solution
O Increasing the mass of the cube
O Chilling the hydrogen peroxide solution
O Smashing the cube into pieces
Answer: chilling the hydrogen peroxide solution
This will Decrease the rate of reaction
Chilling of hydrogen peroxide solution will cause a decrease in the rate of the reaction. The correct option is C.
What is rate of reaction?The reaction rate or in some other words the rate of reaction is actually the rate at which a chemical reaction takes place.
It is usually classified as proportional to the alter in product concentration per unit time and the decrease in concentration of reactant per unit time. The rates of reaction of different chemical reactions can vary.
The reaction rate is determined by the amount of the reactants, the temperature, and the catalyst.
As in the given reaction, the cube of manganese oxide was added to a solution of hydrogen peroxide, water and oxygen were produced. Manganese oxide was not used up in the reaction.
By chilling the hydrogen peroxide, the reaction will get altered as the temperature will not be appropriate for the reaction.
Thus, the correct option is C.
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balance
KClO3 ⟶ KCl + O2
Answer:
[tex]2KCl O_3 \to 2KCl + 3O_2[/tex]
Explanation:
Balance both sides.
Which type of fuel can only be used in certain geographic area? A. natural gas B. nuclear C. solar D. Biomass
Answer:
Solar
Explanation:
Ap e x
The type of fuel which can only be used in certain geographic area is nuclear fuel.
What is fuel?The substance which on reacting with other materials will produces energy in the form of thermal energy and heat will be known as fuels.
• Natural gas, solar energy and biogas fuel provides acceptable amount of energy which never causes harm to the environment then they all will be used in all areas.
• Nuclear fuels produces a tremendous amount of energy which has an ability to destroy many lives and environment, so it would be used only is those geographical area where no lives are living.
Hence, nuclear fuel can only be used in certain geographic area.
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Please help... I am begging...
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).
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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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
What color would you expect a weak base to turn the paper?
Kostya randomly chooses a number from 1 to 10. What is the probability he chooses a number less than 5?
A. 1/2
B. 4/9
C. 2/5
D. 3/5
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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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
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.
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.
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.
