Chemistry High School
Answers
Answer 1
Answer:
1. Element
2. Element
3. Compound
4 Homogeneous mixture
Explanation:
An element is a pure substance with only one kind of atom that cannot be broken into simpler substances by chemical or physical means. Therefore when you break the nitrogen gas or oxygen gas you will still get the same element.
Compound are pure substance that can be broken into the constituent elements by a chemical means but not physical means. N2O is a compound with two different atoms. And can be broken into it constituent element through chemical means.
Homogeneous mixture are mixture that contain two or more pure substance that appear uniform through out. The mixture is evenly distributed. Example of homogeneous mixture is Air.
Related Questions
Explain why the enthalpies of vaporization of the following substances increase in the order CH4 < NH3 < H2O, even though all three substances have approximately the same molar mass.
Answers
Explanation:
More is the intermolecular forces present between the molecules of a substance more will be the boiling point of the substance.
Since, water is able to form hydrogen bonding and it also have dipole-dipole interaction as these are stronger than the forces present in ammonia. Hence, boiling point of water is greater than the boiling point of .
In , there are only dispersion forces present in it and these forces are weakest intermolecular forces.
As a result, the enthalpies of vaporization of the following substances increase in the order .
Carbon-12 is the most common isotope of carbon, and has an atomic mass of 12 daltons. A mole of carbon in naturally occurring coal, however, weighs slightly more than 12 grams. Why? A) The atomic mass does not include the mass of electrons.
B) Some carbon atoms in nature have an extra proton.
C) Some carbon atoms in nature have more neutrons.
D) Some carbon atoms in nature have a different valence electron distribution.
E) Some carbon atoms in nature have undergone radioactive decay.
Answers
Answer:
C
Explanation:
Although the atomic mass unit of the carbon atom is 12, this does not play down the fact that there are other isotopes of the element carbon, for example carbon-14.
For the atomic mass unit of carbon to be 12, this shows that the carbon-12 has the highest amount of abundance in nature. Hence, we are saying that the relative high amount of abundance of the carbon-12 makes it have a greater overall effect when calculating the relative atomic mass unit.
Now, one mole of the carbon in coal weighs more than the supposed 12g, this is due to the presence of another isotope of the element carbon in that particular coal sample. Isotopes are only different in terms of the number of neutrons, they contain the same number of protons as no single element can have different atomic number.
Thus, the difference between the elements is simply that one contains more neutrons than the standard carbon 12 which translates to it having more weight
Since reactions occur as a result of collisions between particles, the particles are in a reaction vessel, the the concentration of particles, the more collisions are possible. The collisions that occur, the faster the reaction rate.
Answers
Answer:
This question is not complete
Explanation:
For a reaction to occur, the reactant particles must collide with each other. This forms the basis of the collision theory. However, not all collisions leads to a chemical reaction or forms a product during a chemical reaction. The collisions that causes the formation of a product is known as effective collision. Effective collision occurs when the reactant particles hit each other well enough to surmount the activation energy of the reaction and hence for the formation of product. Activation energy is the minimum amount of energy required for a reaction to occur.
From the above, it can be deduced that the higher the concentration of the reacting particles, the higher the chances of collision and subsequently effective collision. And if effective collision increases, the rate of the reaction also increases.
One way to increase the number of effective collisions is the addition of catalyst which reduces the activation energy. Once activation energy is reduced, more collisions will lead to product since there will be more effective collisions.
There are a couple of "new" coal-fired electricity electricity generation technologies that are much cleaner and more CO2 sequestration ready than current plants. One is gasification, the other is [answer] combustion.
Answers
Answer:
Fluidised-Bed Combustion (FBC)
Explanation:
Attainment of conventional emission
abatement targets by new advanced combustion technologies that use alternative means is shown by two new and prominent technologies are
1). Integrated Gasification Combined Cycle (IGCC) and
2). Fluidised-Bed Combustion (FBC).
When the glucose solution described in part A is connected to an unknown solution via a semipermeable membrane, the unknown solution level rises. Based on this information, what can be said about these two solutions? 1. The unknown solution had the lower concentration.
2. The unknown solution had the higher concentration.
3. The two solutions have the same concentration.
Answers
Answer: The unknown solution had the lower concentration
Explanation: concentration will always move from higher to lower region. If the concentration of the unknown solution has increased, it therefore means that the initial concentration of the unknown solution was low
Totalitarianism _____. A) is the equivalent of a police state
B)allowed for independently run churches
C) is the same as authoritarianism
D) was the governmental model in Japan and Turkey in the 20th century
Answers
Answer:
A) is the equivalent of a police state
Explanation:
trust me
Answer:
equivalent to police state
Explanation:
Ethanedioic acid, a compound that is present in many vegetables, has a molar mass of 90.04 g/mol and a composition of 26.7% Carbon, 2.2% Hydrogen, and 71.1% oxygen. Calculate the empirical formula and determine the compound formula.
Answers
Answer:
Empirical CHO2
Molecular C2H2O4
Explanation:
To determine the formulas, firstly, we need to divide the percentage compositions by the atomic masses.
Kindly note that the atomic mass of carbon, oxygen and hydrogen are 12, 16 and 1 respectively. We proceed with the division as follows:
C = 26.7/12 = 2.225
H = 2.2/1 = 2.2
O = 71.1/16 = 4.44375
We then proceed to divide by the smallest value which is 2.2 in this case
C = 2.25/2.2 = 1
H = 2.2/2.2 = 1
O = 4.44375/2.2 = 2
Thus, the empirical formula is CHO2
We now proceed to get the molecular formula as follows
[12+ 1 + 16(2) ]n = 90.04
45n = 90.04
n = 90.04/45 = 2
The molecular formula is :
C2H2O4
Assume that some protein molecule, in its folded native state, has one favored conformation. But when it is denatured, it becomes a "random coil", with many possible conformations. How will the contribution of ΔS for native → denatured affect the favorability of the process? What apparent requirement does this impose on ΔH if proteins are to be stable structures?
Answers
Answer:
Gibbs Free Energy is given by the next equation: ΔG = ΔH - TΔS, where
ΔH - change in enthalpy
T - temperature in Kelvin
ΔS - change in entropy
ΔG can be:
- ΔG>0 positive(not spontaneous reaction)
- ΔG0 is required. Which means that ΔH has to be large and positive to counteract the influence of ΔS.
Antacids are taken to counterbalance excess hydrochloric acid, HCl, in the stomach. Complete and balance the following neutralization reactions involving various antacid tablets. If there should be only one mole of the product or reagent in the reaction, then leave the option blank. (A blank answer corresponds to 1 and coefficients of 1 are not expressly written in chemical formulas.) 2, 3, CaCl2, CaCl, MgCl2, 4, MgCl (<-------The options to choose from)
______CaCO3+______HCl -----> _______ /_______+_______H2O+_______CO2
Mg(OH)2+ ______HCl------>________ /________+________H2O
Balance each element on each side of the reaction arrow by adding coefficients to the reactants and products.
The antacid Brioschi, which has been used to relieve heartburn, is mainly sodium bicarbonate. Predict the products, then write the balanced neutralization reaction for the antacid Brioschi in the stomach where the main acid present is hydrochloric acid, HCl.
Express your answer as a chemical equation.
Answers
Answer:
1. CaCO3 + 2HCl —> CaCl2 + H2O + CO2
2. Mg(OH)2 + 2HCl —> MgCl2 + 2H2O
3. Na2CO3 + 2HCl —> 2NaCl + H2O + CO2
The second reaction in the formation of sulfuric acid occurs slowly. 2 upper S upper O subscript 2 (g) plus upper O subscript 2 (g) right arrow 2 upper S upper O subscript 3 (g). NO2 is added to the reaction to speed it up. In which form would this substance be a homogeneous catalyst for this reaction?
Answers
Answer:NO2 is added in the reaction in the form of a gas.
Explanation:
Homogenous catalysts are catalysts which exists in the same form as the reactants and since the reactants are gaseous in nature i.e SO2 and O2, so the catalyst that is used is in gaseous form too.
Answer:
Overall, the formation of sulfuric acid occurs as further:
1. ⇒ - sulfur containing compound gets oxidized
2. ⇒ - sulfur dioxide oxidizing to sulfur trioxide
3. ⇒ - sulfur trioxide further reacts with water
enters the cycle after the first step as a gas. It oxidises the sulfur dioxide, resulting in sulfur trioxide, and itself becomes nitrogen monoxide. However, due to the oxygen in the air. it gets oxidised again and becomes readily available to oxidise another molecule of sulfur dioxide. This process repeats and repeats until all are converted.
All reagents in equations 1 and 2 are in gaseous state!
In the 3rd equation, the water is liquid and sulfuric acid itself is aqueous.
When 14.4 g of an unknown, non-volatile, non-electrolyte, X was dissolved in 100. g of water, the vapor pressure of the solvent decreased from 23.8 torr to 23.5 torr at 298 K. Calculate the molar mass of the solute, X.
Answers
Answer:
The molar mas of the X is 203.06 g/mol.
Explanation:
The pressure of the pure solvent = p = 23.8 Torr
Vapor pressure of the solution =
Mass of solute =14.4 g
Molar mass of solute = M
Moles of solute =
Mass of solvent or water = 100.0 g
Moles of water =
Mole fraction of solute =
The relative lowering in vapor pressure of the solution with non volatile solute is equal mole fraction of solute in solution.
Solving for
The molar mas of the X is 203.06 g/mol.
A reaction at evolves of sulfur tetrafluoride gas. Calculate the volume of sulfur tetrafluoride gas that is collected. You can assume the pressure in the room is exactly . Round your answer to significant digits.
Answers
This is an incomplete question, here is a complete question.
A reaction at 12.0 °C evolves 358 mmol of sulfur tetrafluoride gas. Calculate the volume of sulfur tetrafluoride gas that is collected. You can assume the pressure in the room is exactly 1 atm. Round your answer to 3 significant digits.
Answer : The volume of sulfur tetrafluoride gas collected is, 8.38 L
Explanation :
Using ideal gas equation :
where,
P = Pressure of gas = 1 atm
V = Volume of gas = ?
n = number of moles of gas = 358 mmol = 0.358 mol (1 mmol = 0.001 mol)
R = Gas constant =
T = Temperature of gas =
Putting values in above equation, we get:
Thus, the volume of sulfur tetrafluoride gas collected is, 8.38 L
A substance has a vapor pressure of 0.138 atm at 371 K. What is the normal boiling point of the substance in kelvin? Normal boiling is when vapor pressure = 1 atm or 760 mmHg. ΔHvap = 12.3 kJ/mol
Answers
Answer: Normal boiling point of the substance is 248 K
Explanation:
The vapor pressure is determined by Clausius Clapeyron equation:
where,
= initial pressure at normal boiling point= 1 atm (standard atmospheric pressure
= final pressure at 371 K= 0.138 atm
= enthalpy of vaporisation = 12.3 kJ/mol = 12300 J/mol
R = gas constant = 8.314 J/mole.K
= normal boiling point = ?
= boiling point at pressure of 0.138 atm = 371 K
Now put all the given values in this formula, we get
Thus the normal boiling point of the substance in kelvin is 248
Zinc phosphate is used as a dental cement. A 50.00-mg sample is broken down into its constituent elements and gives 16.58 mg oxygen, 8.02 mg phosphorus, and 25.40 mg zinc. Determine the empirical formula of zinc phosphate.
Answers
Answer:
Zn3P2O8
Explanation:
In this particular question, it is necessary to convert the respective masses to percentages. We convert to percentages by placing each mass over the total mass and multiplying by 100%. Since the total is 50mg, conversion to percentage can be done by multiplying the masses by 2 as 100/50 is 2
For Oxygen = 16.58 * 2 = 33.16%
For phosphorus = 8.02 * 2 = 16.04%
For zinc = 25.40 * 2 = 50.80%
We then proceed to divide these percentages by their respective atomic masses. The atomic mass of oxygen, phosphorus and zinc are 16, 31 and 65 respectively.
O = 33.16/16 = 2.0725
P = 16.04/31 = 0.5174
Zn = 50.80/65 = 0.7815
Now, we divide by the smallest value which is that of the phosphorus
O = 2.0725/0.5174 = 4
P = 0.5174/0.5174 = 1
Zn= 0.7815/0.5174 = 1.5
Now, we need to multiply through by 2. This yields: O = 8, P = 2 and Zn = 3
The empirical formula is thus: Zn3P2O8
Barium acetate, Ba(C2H3O2)2, is a common barium salt that is highly poisonous. It was featured in a 2001 episode of Forensic Files, which recounted the murder of a man by his teenaged daughter. The LD50 (the dose that will be lethal to 50% of people that consume the compound) for barium acetate is 921 mg/kg of body weight. A sample that contains 1.98x10^24 carbons atoms has a mass of ____ grams.
Answers
Answer:
209.68
Explanation:
The only number that is relevant (though the rest are quite interesting) is the last one 1.98 * 10^24
1 mole of Barium Acetate Contains 6.02*10^23 particles.
There are 4 moles of carbon to every mole of Barium Acetate.
1.98 * 10^24 atoms / (4*6.02*10^23)
0.8223 moles of Ba(C2H3O2)2
Ba = 137
4C = 4*12 48
6H = 6*1 6
4O = 4*16 64
1mole 255 grams
0.8223 * 255 = 209.68 grams
I have used rounded masses for these elements depending on the periodic table you use. Go through the question with your masses to get a more accurate answer. My answer will not differ by much. It is a guide.
Stainless steel is an alloy of iron, chromium, nickel, and carbon that does not rust. This allows it to be used without degradation for many years. Many people use "silverware" at home and restaurants that is produced from stainless steel rather than silver. The primary source of nickel that is used to produce stainless steel is mined from nickel (II) chloride, NiCl2. If a company mines 18 kg of NiCl2 a day, they are mining ____ moles of NiCl2 each day.
Answers
Answer:Most compounds of transition metals are paramagnetic, whereas virtually all compounds of the p-block elements are diamagnetic. The electronegativities of the first-row transition metals increase smoothly from Sc (χ = 1.4) to Cu (χ = 1.9). Thus Sc is a rather active metal, whereas Cu is much less reactive.
Explanation:
A solution forms when the attractive ___ between the solute and solvent are ___ in strength to the solvent-solvent and solute-solute attractions and are therefore able to replace them.
Answers
Answer: A solution forms when the attractive _forces_ between the solute and solvent are _similar/higher_ in strength to the solvent-solvent and solute-solute attractions and are therefore able to replace them.
Explanation: Intermolecular forces between solute and solvent must be able to match or exceed the natural intramolecular forces between the solvent-solvent atoms/molecules and solute-solute atoms/molecules.
This is where the solubility law of 'like dissolves like (polar dissolves polar and likewise)' comes into play. Only polar compounds can form such attractive forces with fellow polar compounds and the same story goes for non-polar compounds.
A sample of wine consists of water, sugar, some amount of ethyl alcohol, and grape juice. These ingredients blend together uniformly to give clear and tasty wine. Which term or terms could be used to describe this sample of wine?
1) mixture
2) heterogeneous mixture
3) homogenous mixture
4) solution
5) pure chemical substance
6) compound
7) element
Answers
Answer: mixture, homogenous mixture, solution
Explanation:
1) Mixture is a substance which has two or more components which do not combine chemically and do not have any fixed ratio in which they are present.
2) Heterogeneous mixtures : It is a mixture that has non-uniform composition throughout the solution and the particle size or shapes are also different. There is a physical boundary between the dispersed phase and dispersion medium. Example: Air
3) Homogeneous mixtures : It is a mixture that has uniform composition throughout the solution and the particle size or shapes are not different.There is no physical boundary between the dispersed phase and dispersion medium. Example: Wine
4) Solution is a mixture made up of solute and solvent which do not combine chemically. They can be homogeneous or heterogeneous.
5) Compound is a pure substance which is made from atoms of different elements combined together in a fixed ratio by mass.It can be decomposed into simpler constituents using chemical reactions. Example: water
6) Element is a pure substance which is composed of atoms of similar elements.It can not be decomposed into simpler constituents using chemical reactions. Example: Iron
Thus a sample of wine in which ingredients blend together uniformly to give clear and tasty wine is considered as a mixture, homogenous mixture and solution.
Technician A says that a leaking head gasket can be tested for by using a chemical tester. Technician B says that a leaking head gasket can be found using an exhaust gas analyzer. Who is correct?
Answers
Answer: Both technicians are correct
Explanation: A chemical tester and exhaust gas analyzer are two important ways to check for gasket leakage
If the theoretical yield of the reaction below corresponds to 71.0 g and the percent yield of the reaction is known to be reproducibly 81.1%, calculate the actual yield. Given: Li2O+H2O→2LiOH
Answers
Answer:
m = 57.581 g
Explanation:
The actual yield or experimental yield of a reaction is always calculated using the theorical yield and the experimental, using the following expression:
%yield = Exp yield/theo yield * 100 (1)
If we know the theorical yield and the percent of yield, we can calculate the experimental or actual yield by solving the expression above:
Exp yield = %yield * theo yield/100
Replacing the values we have:
Exp yield = 81.1 * 71 / 100
Exp yield = 57.581 g
And this would be the actual yield of the reaction
FAQs
Is N2 a homogeneous or heterogeneous mixture? ›
is a molecule of element nitrogen that forms a homogenous mixture.
What is the classification of N2? ›It is a diatomic nitrogen, a gas molecular entity and an elemental molecule.
Is N2 an element or compound? ›Nitrogen is a chemical element with an atomic number of 7 (it has seven protons in its nucleus). Molecular nitrogen (N2) is a very common chemical compound in which two nitrogen atoms are tightly bound together. Molecular nitrogen is a colorless, odorless, tasteless, and inert gas at normal temperatures and pressures.
Is nitrogen a homogenous mixture? ›Oxygen and nitrogen are homogeneous mixture in a scuba tank because we cannot see the phases (invisible gases are mixed together). If it was a heterogeneous mixture then we could see the different phases of the mixture.