Chemists use substances with distinct physical and chemical properties to separate mixtures into individual substances. These can be pure substances (a single element or compound) or mixtures containing multiple substances. The specific composition of each substance or mixture determines its properties.
Explanation:The substances that chemists use to separate mixtures into individual substances generally have distinct physical and chemical properties. Each compound has a specific composition and demonstrates definitive properties that make them unique from other compounds. These properties include elements such as physical properties like hardness and boiling point, and chemical properties like flammability and acidity.
Substances, in the form of elements and compounds, can be combined in many ways to form different mixtures. A mixture, which is commonly encountered in nature, contains two or more substances physically combined. The relative composition of a mixture plays a key role in determining its properties.
Pure substances consist of only one type of element or compound, while mixtures contain multiple. Pure substances include elements that cannot be further broken down by chemical changes. The known elements are just over 100, with around 90 naturally occurring on earth.
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Nitromethane (ch3no2) burns in air to produce significant amounts of heat. 2ch3no2(l)+3/2o2(g)→2co2(g)+3h2o(l)+n2(g) δhorxn = -1418 kj how much heat is produced by the complete reaction of 3.87 kg of nitromethane?
You are investigating an organic compound you discover that it is an aromatic compound often used as flavoring what type of compound is it likely to be
A. Carboxylic acid
B. Anode
C. Aldegyde
D. Ketone
Answer:
C. Aldehyde
Explanation:
answer for Plato users
If the smallest markings on a ruler are one tenth (1/10) of a centimeter, which of the following measurements could be recorded using that ruler?
A. 2.5 cm
B. 2.52 cm
C. 2.520 cm
D. 2.5200 cm
Answer:
The correct answer is the option: A. 2.5 cm
Explanation:
Hello! Let's solve this!
In a rule we see that it is divided into centimeters, they can be 15 centimeters, 20 centimeters, etc.
It is very easy to see the two centimeters, which are the largest lines. To see after two, we count the smallest stripes and we can reach 2.5 centimeters. But no more than that.
We conclude that the correct answer is the option: A. 2.5 cm
at 65 degrees celsius, which compound has a vapor pressure of 58 kilopascals? 1. ethanoic acid2. ethanol 3. propanone 4. water
The vapour pressure of a substance actually differs relative to the temperature. So to know which compound has the vapour pressure of 58 kilopascals at 65 degrees Celsius, we refer to standard tables of temperature vs Vapour pressure.
From the tables or graph, the answer here is:
2. ethanol
Answer: 2. Ethanol
Explanation:
The attached figure shows the relation between vapor pressure (KPa) and temperature (celsius) for the ethanoic aci, propanone, ethanol and water.Make lines by the values given of the vapor pressure (58.0 KPa) and temperature (65.0 celsius).You will find that the compound is ethanolIdentify the reaction type for each generic chemical equation
A + B → AB: ✔ synthesis
AB → A + B: ✔ decomposition
Hydrocarbon + O2 → CO2 + H2O: ✔ combustion
AB + CD → AD + CB: ✔ replacement
Generic chemical equation for combination, decomposition, displacement and double displacement reactions are given as A+B=AB, AB=A+B,AB+C=AC+B and AB+CD=AC+BD respectively.
What is chemical equation?Chemical equation is a symbolic representation of a chemical reaction which is written in the form of symbols and chemical formulas.The reactants are present on the left hand side while the products are present on the right hand side.
A plus sign is present between reactants and products if they are more than one in any case and an arrow is present pointing towards the product side which indicates the direction of the reaction .There are coefficients present next to the chemical symbols and formulas .
The first chemical equation was put forth by Jean Beguin in 1615.By making use of chemical equations the direction of reaction ,state of reactants and products can be stated. In the chemical equations even the temperature to be maintained and catalyst can be mentioned.
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What is the name of the group of elements that are unreactive gases?
Actinides series
Halogen gases
Lanthanide series
Noble gases
Answer: Option (d) is the correct answer.
Explanation:
Noble gases are the gases of group 18 which are helium, neon, argon, krypton, xenon and radon.
For example, electronic configuration of neon is [tex]1s^{2}2s^{2}2p^{6}[/tex]
These elements have completely filled shells so, they do not need to gain or lose an electron as they are stabilized.
As a result, noble gases become unreactive in nature.
Thus. we can conclude that noble gases is the name of the group of elements that are unreactive gases.
The mole fraction of carbon dioxide (xco2) in water is 0.25. determine the molarity of co2. (assume the density of the solution is 1.0 g/ml.)
The molarity of CO2 in a water solution with a mole fraction of 0.25, assuming the density of the solution is 1.0 g/mL, is calculated to be 0.04401 M.
Explanation:To determine the molarity of carbon dioxide (CO2) in a solution with a mole fraction (xCO2) of 0.25, and a density of 1.0 g/mL, we need to use the definition of mole fraction alongside the known density of the solution. The mole fraction is the ratio of the moles of solute to the total moles in the solution. Assuming we have one liter of solution and know that the density is 1.0 g/mL, the total mass of the solution is 1000 g.
First, we calculate the total moles of the solution. Since the mole fraction of CO2 is 0.25, this means that 25% of the moles are CO2. To find the molarity of CO2, we need to find the mass of CO2 based on its mole fraction and then convert this to moles.
Since we are given the mole fraction and we know the density of the solution, we can calculate the mass of CO2 in one liter of solution. Let's assume a total of 4 moles of substance are present (as 0.25 is one-fourth). Hence, one mole of CO2 is present because the mole fraction of CO2 is 0.25. Knowing that the molar mass of CO2 is 44.01 g/mol, we find that the mass of 1 mole of CO2 is 44.01 grams. The molarity is found by dividing the moles of CO2 by the volume of the solution in liters, which gives a molarity of 0.04401 M.
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a chemist wants to combine carbon and iron to form steel. what type of bond will this chemist create between these two elements
Final answer:
The chemist will create a covalent bond between carbon and iron to form steel.
Explanation:
The chemist will create a covalent bond between carbon and iron to form steel.
Covalent bonds form when electrons are shared between atoms. In this case, carbon and iron will share electrons to form a strong bond. Steel is a type of alloy made primarily of iron and carbon, with carbon content typically between 0.2% and 2.1%.
Examples of covalent bonds include the bonding in molecules such as water (H2O), carbon dioxide (CO2), and methane (CH4).
How can an isotope like carbon 14 be used to date dead organisms?
The theoretical yield of a reaction is 75.0 grams of product and the actual yield is 42.0g. what is the percent yield? 75.0 56.0 31.5 178 none of these
A catalyst increases the rate of a reaction by
A. providing an alternative reaction pathway with lower enthalpy change.
B. lowering the potential energy of the reactants in the reaction.
C. providing an alternative reaction pathway with lower activation energy.
D. lowering the potential energy of the products in the reaction.
Answer:
The correct option is C
Explanation:
For a reaction to occur, there is a minimum amount of energy that must be "met". This minimum amount of energy is called activation energy. Activation energy is the minimum amount of energy required for a reaction to occur. When this activation energy is high, it takes a longer time for the reaction to occur, hence it slows down the rate of a chemical reaction but when the activation energy is low, the rate of a chemical reaction is increased.
A catalyst is known to increase the rate of a chemical reaction - it does this by reducing the activation energy of the reaction, providing an alternative reaction pathway for the reaction.
What type of bomb was used in Oklahoma City bombing of 1995
Final answer:
The Oklahoma City bombing on April 19, 1995, utilized a truck bomb made from ammonium nitrate fertilizer mixed with fuel oil. The terrorists hoped to incite a revolution against government control. The attack killed 168 people, injured over 600, and resulted in widespread destruction.
Explanation:
The type of bomb used in the Oklahoma City bombing of April 19, 1995, was a truck bomb. Timothy McVeigh and Terry Nichols constructed the explosive using agricultural grade ammonium nitrate fertilizer mixed with fuel oil, packing the mixture into a rented Ryder truck. This deadly attack led to the loss of 168 lives, including nineteen children, and left over 600 individuals injured. The bombing severely damaged the Alfred P. Murrah Federal Building, along with more than three hundred nearby buildings. The motivations of McVeigh were associated with a desire to start a revolution against government authority, partly in retaliation for the Waco siege that occurred exactly two years prior.
The aftermath of the bombing united Americans across the country, bringing forth an outpouring of generosity and support for the victims and their families. President Bill Clinton's speech helped galvanize the nation towards unity and reconciliation. In response to this tragedy, there was bipartisan government action which included support for the affected and enhanced funding for antiterrorism efforts, aiding in the prevention of future attacks of a similar nature.
Professor Whitney has a sample of lead and a sample of iron. The samples have equal mass. When Whitney heats the samples, the lead reaches a higher temperature than the iron, even though both samples absorbed the same amount of thermal energy. What can Whitney conclude from this experiment?
What is the error in the electron configuration, 1s2 2s2 2p6 3s2 3p5 4s2?
Final answer:
The error in the electron configuration 1s2 2s2 2p6 3s2 3p5 4s2 is that it places electrons in the 4s sublevel before filling the 3d sublevel. The correct order should fill the 3d sublevel before the 4s according to the Aufbau principle.
Explanation:
The student's question is about identifying the error in the given electron configuration, which is 1s2 2s2 2p6 3s2 3p5 4s2. The error in this configuration is the arrangement of electrons in the 4s sublevel before the 3d sublevel is filled. According to the Aufbau principle, which dictates the order in which sublevels are filled based on increasing energy, after the 3p sublevel is filled, electrons should start filling the 3d sublevel before the 4s. However, in the given configuration, it incorrectly shows two electrons in the 4s sublevel before the 3d sublevel has any electrons. The correct electron configuration after 3p6 should be 3d1 before moving to 4s1 or 4s2 depending on the element in question. For example, the correct configuration for potassium (Z=19) is 1s²2s²2p63s²3p64s¹, and for calcium (Z=20), it is 1s²2s²2p63s²3p64s².
Calculate the ph of 0.63 m nh3 (kb=1.8×10−5).
Diamond is made of carbon atoms attached rigidly to each other in three directions making diamond very strong. graphite, as found in a pencil, is easily broken under pressure. since graphite is also made of carbon atoms, why might it have such a different property?
The different properties of diamond and graphite can be attributed to the different arrangement of carbon atoms in each structure. Diamond has a three-dimensional network of carbon atoms, resulting in strong bonds and hardness. Graphite has a two-dimensional sheet structure, with weak bonds between the layers, making it soft and brittle.
Explanation:The different properties of diamond and graphite can be attributed to the different arrangement of carbon atoms in each structure. In diamond, each carbon atom is bonded to four other carbon atoms in a three-dimensional network, resulting in strong bonds that make diamond extremely hard and rigid. On the other hand, graphite consists of layers of carbon atoms arranged in a two-dimensional sheet structure, with weak bonds between the layers. These weak bonds allow the layers to slide over each other easily, making graphite soft and brittle.
Annabeth has 7.2 cups of cookie batter, represented by this model. If each cookie uses 0.45 cup of batter, how many cookies can annabeth make?
How many atoms of carbon are present in 1.0 g of c6h12o6?
0.0055 number of atoms of carbon are present in 1.0 g of C₆H₁₂O₆ .
What do you mean by the number of atoms or mole ?
The mole concept is a convenient method of expressing the amount of a substance.
Mole is the amount of substance that contains as many elementary entities as there are atoms in exactly 12 grams of the carbon−12 isotope.
1 mole=6.022×1023 particles of matter of any chemical substance.
To calculate number of atoms of carbon present in 1.0 g of C₆H₁₂O₆ .
Given ,
mass of carbon =1.0 gm
molar mass =180.01 gm
mole(n)=?
Mole= mass/molar mass
Mole=1/180
Mole=0.0055
Hence, 0.0055 number of atoms are present in 1.0 g of C₆H₁₂O₆ .
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CaCO3 is an example of which type of material?
a. colloid
b. element
c. compound
d. mixture
Topsoil occurs in this layer, which is composed of a combination of organic debris and mineral matter
Which topic might interest a sociologist
Chromium is most commonly mined in the form of chromite, which has the chemical formula fecr2o4. calculate the percent by mass of each element in chromite, and give your answers to four significant digits.
The mass of each elements in chromite is as below
Fe =24.9 %
Cr =46.5%
O = 28.6%
calculation
percent mass = atomic mass of element / atomic mass of FeCr2O4 x 100
from periodic table the atomic mass for Fe = 55.85 g/mol,
Cr =52 g/mol since they are two atoms in FeCr2O4 = 2 x 52 = 104 g/mol
for O = 16 since they are two atoms in FeCr2O4 = 16 x4 = 64 g/mol
Atomic mass for FeCr2O4 is = 55.85 +104+ 64 = 223.85 g/mol
Percent mass for Fe =55.85 /223.85 x100 = 24.9 %
for Cr = 104 / 223.85 x 100 = 46.5%
For 0 = 64/223.85 x 100 = 28.6%
Which reactions are oxidation-reduction reactions?
1. FeS(s) + 2HCl(aq) → H2S(g) + FeCl2(g)
2. AgNO3(aq) + NaCl(aq) → AgCl(s) + NaNO3
3. 2C3H6(g) + 9O2(g) → 6CO2(g) + 6H2O(g)
4. Fe2O3(s) + 3CO(g) → 2Fe(l) + 3CO2(g)
Answer: The correct answer is Option 3 and Option 4.
Explanation:
Redox reactions are termed as the reactions in which reduction and oxidation reactions occur simultaneously.
Reduction reactions are the ones where a substance gains electrons. The oxidation state of the substance gets reduced.
Oxidation reactions are the ones where a substance looses electrons. The oxidation state of the substance is increased.
Fro the given options:
Option 1: [tex]FeS(s)+2HCl(aq.)\rightarrow H_2S(g)+FeCl_2(g)[/tex]
This reaction is a type of double displacement reaction because exchange of ions takes place.
Option 2: [tex]AgNO_3(aq.)+NaCl(aq.)\rightarrow AgCl(s)+NaNO_3[/tex]
This reaction is a type of double displacement reaction because exchange of ions takes place.
Option 3: [tex]2C_3H_6(g)+9O_2(g)\rightarrow 6CO_2(g)+6H_2O(g)[/tex]
On reactant side:
Oxidation state of Carbon = +2
Oxidation state of Oxygen = 0
On product side:
Oxidation state of Carbon = +4
Oxidation state of Oxygen = -2
Here, oxidation state of carbon is increasing from +2 to +4. Thus, it is getting oxidized and oxidation state of oxygen is getting reduced from 0 to -2. Thus, it is getting reduced.
Option 4: [tex]Fe_2O_3(s)+3CO(g)\rightarrow 2Fe(l)+3CO_2(g)[/tex]
On reactant side:
Oxidation state of Iron = +3
Oxidation state of Carbon = +2
On product side:
Oxidation state of Iron = 0
Oxidation state of Carbon = +4
Here, oxidation state of carbon is increasing from +2 to +4. Thus, it is getting oxidized and oxidation state of iron is getting reduced from +3 to 0. Thus, it is getting reduced.
Hence, the correct answer is Option 3 and Option 4.
Why is making a peanut pretzel and cereal mixture a physical change?
The organization of hydrogen atoms around the double bond is called _____ when they are on the same side as the double bond, and _____ when they are on opposite sides of the double bond.
What element has an electron configuration that ends in 2s2 2p4?
The oxygen element has an electronic configuration that ends with 2s²2p⁴.
What is an electronic configuration?The electron configuration can describe how electrons are arranged in different energy levels of an atom of an element. In the electron configuration of an atom, the number of electrons in a particular atomic orbital is written as a superscript. For example, the electron configuration of Helium (He) is written as 1s²2s².
The principal quantum number (n) will decide the maximum number of electrons that can be filled in a shell and is determined from the term 2n², where ‘n’ is the principal quantum number.
The atomic orbitals of an atom of a lower energy level should be completely filled before filling an atomic orbital with a higher energy level.
The atomic number of the oxygen atom is 8 and the electronic configuration is 1s²2s²2p⁴. It has six electrons in its valence shell and an electronic configuration ends with 2s²2p⁴.
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The combustion of methane gas (ch4) forms co2(g)+ h2o(ℓ). calculate the heat produced by burning 2 mol of the methane gas. use these ∆h0 f data to help: ch4(g)= -74.9 kj/mol co2(g)= -393.5kj/mol h2o(ℓ)= -285.8kj/mol. answer in units of kj.
Final answer:
To find the heat produced by the combustion of 2 mol of methane gas, you use the standard enthalpies of formation. The calculated heat produced is -1630.6 kJ.
Explanation:
The question involves using the concept of enthalpy change (ΔH), specifically standard enthalpies of formation (ΔH°f), to calculate the heat produced during the combustion of methane gas (CH4).
Step-by-Step Calculation:
First, write down the balanced chemical equation for the combustion of methane:
CH4(g) + 2O2(g) → CO2(g) + 2H2O(№)
Next, apply Hess's Law using the provided ΔH°f values:
CH4(g): -74.9 kJ/mol
CO2(g): -393.5 kJ/mol
H2O(№): -285.8 kJ/mol
Calculate the total enthalpy change (ΔH) for the reaction:
ΔH = [1 mol(ΔH°f CO2) + 2 mol(ΔH°f H2O)] - [2 mol(ΔH°f CH4)]
ΔH = [1 mol(-393.5 kJ/mol) + 2 mol(-285.8 kJ/mol)] - [2 mol(-74.9 kJ/mol)]
ΔH = (-393.5 kJ - 2×285.8 kJ) - (-2×74.9 kJ)
ΔH = (-393.5 - 571.6 + 149.8) kJ
ΔH = -815.3 kJ
This is the enthalpy change for the combustion of 1 mol of methane. Since we are burning 2 mol of methane, multiply by 2:
Total ΔH = 2 × -815.3 kJ
Total ΔH = -1630.6 kJ
Therefore, the heat produced by burning 2 mol of methane gas is -1630.6 kJ.
Which of the following are not grouped according to similar chemical properties?
A. Cobalt, iron, nickel.
B. Iron, copper, ruthenium.
C. Ruthenium, iridium, palladium.
D. Gold, silver, copper.
B. iron, copper, ruthenium
Answer: The correct answer is Option D.
Explanation:
Elements which belong to same group show similar chemical properties because they have same number of valence electrons.
From the given options:
Option A: Cobalt belongs to Group 9, Iron belongs to Group 8 and Nickel belongs to Group 10. Hence, they will not show similar chemical properties.
Option B: Iron belongs to Group 8, Copper belongs to Group 11 and Ruthenium belongs to Group 8. Hence, they will not show similar chemical properties.
Option C: Ruthenium belongs to Group 8, Iridium belongs to Group 9 and Palladium belongs to Group 10. Hence, they will not show similar chemical properties.
Option D: Gold, Silver and Copper belongs to the same group which is Group 11. Hence, they all will show similar chemical properties.
Thus, the correct answer is Option D.
Urine, at ph 6, contains __________ h+ as household bleach, at ph 13.
Write the complete balanced equation for the following reaction:
C7H6O + O2 yields CO2 + H2O
Explanation:
An equation that consists of same number of atoms on both reactant and product side is known as a balanced chemical equation.
For example, [tex]C_{7}H_{6}O + O_{2} \rightarrow CO_{2} + H_{2}O[/tex]
Number of atoms on reactant side are as follows.
C = 7
H = 6
O = 3
Number of atoms on product side are as follows.
C = 1
H = 2
O = 3
Therefore, to balance this chemical equation we multiply [tex]O_{2}[/tex] by 8 on reactant side. Whereas we multiply [tex]CO_{2}[/tex] by 7 and [tex]H_{2}O[/tex] by 3 on product side.
Therefore, the balanced chemical equation will be as follows.
[tex]C_{7}H_{6}O + 8O_{2} \rightarrow 7CO_{2} + 3H_{2}O[/tex]