The technique of thin-layer chromatography is used to compare ink on a suspect document. This is done by creating a chromatogram through exposing the ink to a solvent and observing the resulting pattern of spots.
Explanation:The technique used to compare ink on a suspect document is A) thin-layer chromatography. Thin-layer chromatography is a type of chromatography that is widely used to separate mixtures in forensic analysis. In this process, the ink sample from the suspect document is placed on a thin layer of absorbent material.
The sample is then exposed to a solvent, which moves up the stationary phase, carrying different components of the ink at different rates. This results in a series of spots, that form a chromatogram, can then be compared to known samples for identification.
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What is the molality of a solution made by dissolving 14.7 g of c6h12o6 into 150.0 ml of water? assume the density of water is 1.00 g/ml?
Final answer:
The molality of the solution is calculated by dividing the number of moles of glucose by the mass of water in kilograms, resulting in a solution with a molality of 0.544 m.
Explanation:
The question is asking to calculate the molality of a glucose solution. To find the molality, we need to know the mass of the solute (glucose) and the mass of the solvent (water) in kilograms.
Steps to Calculate Molality
First, calculate the number of moles of glucose (C6H12O6). Its molar mass is 180.16 g/mol.
Next, convert the mass of water from milliliters to kilograms. Since the density of water is 1.00 g/mL, we simply convert 150.0 mL to grams and then to kilograms.
Finally, use the equation for molality: molality (m) = moles of solute (mol) / mass of solvent (kg).
Let's perform the calculations:
Moles of glucose = 14.7 g / 180.16 g/mol = 0.0816 mol
Mass of water = 150.0 mL * 1.00 g/mL = 150.0 g = 0.150 kg
Molality of the solution = 0.0816 mol / 0.150 kg = 0.544 m
For the reaction, identify the Lewis acid and the Lewis base.
AlF3 + CH3F → CH3+ + [AlF4]-
Electromagnetic waves, such as visible light, travel in a multitude of orientations. A substance that filters the light so that it only passes through in one plane works somewhat like a fence that allows only some light to pass through. This is the principle of -
A. refraction.
B. diffraction.
C. polarization.
D. interference.
A gas occupies 2240.0 l at 373 k. what are the volumes at standard temperature answers
How many grams of barium sulfate, baso4, are produced if 25.34 ml of 0.113 m bacl2 completely react given the reaction: bacl2 + na2so4 → baso4 + 2 nacl?
Answer:
0.668 g of barium sulfate
Explanation:
Given,
Balanced chemical equation: BaCl₂ + Na₂SO₄ → BaSO₄ + 2NaCl.
Volume of BaCl₂ = 25.34 mL x [tex]\frac{1L}{1000 ml }[/tex]= 0.02534 L.
Molarity of BaCl₂ = 0.113 M
Molarilty = [tex]\frac{moles of solute}{L of the solution }[/tex]
Moles of solute = Molarilty x L of the solution
Moles of BaCl₂ = 0.113 M x 0.02534 L = 0.00286 mol.
From the balanced chemical equation there is a 1:1 molar ratio between BaCl₂ and BaSO₄
Therefore, moles of BaCl₂ = moles of BaSO₄
Moles of BaSO₄ = 0.00286 mol.
Mass of BaSO₄ = moles of BaSO₄ x Molar mass of BaSO₄
Mass of BaSO₄ = 0.00286 mol x 233.4 g/mol.
Mass of BaSO₄ = 0.668 g.
what is the key difference between a liquid and a gas?
Answer :
The key differences between a liquid and the a gas is,
Shape and volume :A liquid has no fixed shape but it has a volume.
A gas has neither a fixed shape nor a volume.
Inter-molecular space :A liquid has more inter-molecular space between the molecules.
A gas has larger inter-molecular space between the molecules as compared to the liquids.
Inter-molecular attraction :A liquid has some Inter-molecular attraction between the molecules because of the low Inter-molecular spacing between the molecules.
A gas has very low or minimum Inter-molecular attraction between the molecules because of the larger Inter-molecular spacing between the molecules.
Fluidity :A liquid flow from the higher to the lower region but a gas flow in all the direction.
Liquids and gases differ from each other in the following ways:
1. Intermolecular forces
2. Motion of particles
3. Direction of flow
4. Compressibility
Further Explanation:
Matter can mainly exist in three physical states. These are solid, liquid and gas.
Solid
It is that state of matter that has a definite shape and volume. These have a regular arrangement of its constituent particles. These have the strongest intermolecular forces between their constituent particles and therefore the motion of particles in solid is almost negligible. Table salt, wood, and diamond are some examples of solids.
Liquid
The state of matter with a definite volume but no particular shape is called liquid. The intermolecular forces in the liquids are weaker than that in solids and therefore the motion of particles in liquids is more as compared to that in solids. Milk, water, and bromine are some examples of liquids.
Gas
This state of matter has neither a definite shape nor a definite volume. These have a disordered arrangement of its constituent particles. These have the weakest intermolecular forces between their constituent particles and therefore the motion of particles in a gas is the highest among all states of matter. Nitrogen, hydrogen and carbon dioxide are some examples of gases.
Liquids have a definite volume but gases occupy the volume of the container in which these are kept.
Liquids have stronger intermolecular forces as compared to that of gases so the motion of gas particles is more than that of liquid particles.
Liquids are incompressible whereas gases are highly compressible in nature.
The flow of liquid takes place from higher to lower level while gases can move randomly in all directions.
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Answer details:
Grade: High School
Subject: Chemistry
Chapter: Matter in our surroundings
Keywords: liquid, gas, solid, states of matter, intermolecular forces, shape, volume, matter, strong, weakest, motion of particles.
A chemical supply company sells a concentrated solution of aqueous h2so4 (molar mass 98 g mol−1 ) that is 50. percent h2so4 by mass. at 25°c, the density of the solution is 1.4 g ml−1 . what is the molarity of the h2so4 solution at 25°c?
which pair of elements has the most similar properties?
a. K and He
b. Li and B
c. I and Ca
d. N and P
Option d: N and P
In a periodic table, elements within the same group have similar properties.
(a) K and He: Here, K (potassium) belongs to group 1 , alkali metals and He belongs to group 18, noble gas thus, they cannot have similar properties.
(b) Li and B: Here, Li (lithium) belongs to group 1, alkali metals and B (boron) belongs to group 13, it is the only non-metal in group 13. Thus, they cannot have similar properties.
(c) I and Ca: Here, I (iodine) belongs to group 17, halogen, they electronegative in nature and Ca (calcium) belongs to group 2, alkaline earth metal, they are electropositive in nature. Thus, they cannot have similar properties.
(d) N and P: Here, both N (nitrogen) and P (phosphorus) belongs to group 15, they both are non metals and have 5 electrons in their outermost shell thus, they both have similar properties.
Therefore, option (d) is correct.
What is the oxidation state of an individual phosphorus atom in P O 3 3−?
A gas expands from a volume of 2.00L at 36.0oC to a volume of 2.50 L, what is the final temperature, if the pressure is constant?
The final temperature is 45.45 Celcius
Explanation:
The Combined Gas Law:
The combined gas law allows to derive relationships between the variable that undergoes like pressure, temperature and volume.
[tex]\frac{P_1V_1}{T_1} =\frac{P_2V_2}{T_2}[/tex]
It is given thatpressure is constant so,
[tex]P_1=P_2[/tex]
Hence combined gas law becomes,
[tex]\frac{ V_1}{T_1}=\frac{V_2}{T_2}[/tex]
Substituting the values given in the question,
[tex]\frac{2.00}{36}=\frac{2.50}{T_2}[/tex]
[tex]0.055=\frac{2.50}{T_2}[/tex]
[tex]T_2=\frac{2.50}{0.055}[/tex]
[tex]T_2[/tex]=45.45 C
What is the cause of farsightedness?
The cornea is irregular.
The cornea is opaque.
The eyeball is shortened.
The eyeball is elongated.
Answer:
The eyeball is shortened.
Explanation:
Farsightedness, popularly known as difficulty seeing closely, is a common refractive problem, where the image in the eye forms after the retina rather than exactly over the retina, which hinders the brain's ability to process the image correctly. In farsightedness there is no difficulty in seeing objects from afar, but when you get closer, it becomes very difficult to focus on them.
The eyeball works the same way as a dark box: light enters the pupil and forms the image on the retina. The shape of the eye and cornea is perfect for the image to form in the right place (the macula), and then the information is sent to the brain by the optic nerve.
When you have farsightedness, the eyeball is a little shortened or the flatter cornea, so the image ends up forming after the retina, ie the image the retina captures is not correct.
what is the predicted change in the boiling point of water when 4.00 g of barium chloride is dissolved in 2.00 kg of water
Answer:
0.015 for APEX
Explanation:
An aqueous solution is made up of
A. colloids
B. pure water molecules
C. ions dissociated in solution
D. covalent molecules in a water solution.
A fruit and oatmeal bar contains 142 nutritional calories. Convert this energy to calories
Final answer:
142 nutritional calories (Cal) are equal to 142,000 calories (cal) since one nutritional Calorie is equivalent to 1000 scientific calories (cal).
Explanation:
To convert 142 nutritional calories to calories, you need to understand the relationship between the two units. In nutrition, when we say 'calories', we actually mean 'kilocalories' (kcal). One nutritional calorie (with an uppercase C) is equal to one kilocalorie (kcal), and one kilocalorie is equivalent to 1000 calories (with lowercase c).
Therefore, 142 nutritional calories (Cal) are equivalent to 142,000 calories (cal).
The conversion formula is as follows:
142 Cal * 1000 = 142,000 cal
Which halocarbon has the highest boiling point? 2-dichloropropane 2-chloropropane 1-chloropropane 1,2,3-trichloropropane?
Answer:1,2,3-trichloropropane
Explanation:
What do we call the mass of an element in a compond compared to the entire mass of the compound?
When 2 mol of solid magnesium mg combines with 1 mole of oxygen gas 2 mol of solid magnesium oxide is formed and 1204 kj of heat is released write the thermochemical equation for the combustion reaction?
The thermochemical equation for the combustion reaction of magnesium with oxygen is:
[tex]\[ 2 \text{Mg}(s) + \text{O}_2(g) \rightarrow 2 \text{MgO}(s) \quad \Delta H = -1204 \text{ kJ} \][/tex]
The given reaction is the combustion of magnesium (Mg) with oxygen (O2) to form magnesium oxide (MgO). According to the stoichiometry provided in the question, 2 moles of solid magnesium react with 1 mole of oxygen gas to produce 2 moles of solid magnesium oxide. Along with the formation of products, 1204 kJ of heat is released, indicating that the reaction is exothermic.
In a thermochemical equation, the reactants are written on the left side, and the products are written on the right side, separated by an arrow that points towards the products. The coefficients in the equation (the numbers in front of the chemical formulas) represent the moles of each substance involved in the reaction. In this case, the coefficients are 2 for magnesium, 1 for oxygen, and 2 for magnesium oxide, as given in the question.
The enthalpy change [tex](\(\Delta H\))[/tex] for the reaction is included at the end of the equation to indicate the amount of heat absorbed or released during the reaction. Since the reaction releases heat, the enthalpy change is negative, and it is equal to -1204 kJ for the given reaction. This negative sign indicates that the system releases energy to the surroundings.
Therefore, the complete thermochemical equation, which includes the stoichiometric coefficients and the enthalpy change, is written as:
[tex]\[ 2 \text{Mg}(s) + \text{O}_2(g) \rightarrow 2 \text{MgO}(s) \quad \Delta H = -1204 \text{ kJ} \][/tex]
This equation accurately represents the combustion reaction of magnesium with oxygen, both stoichiometrically and thermochemically.
Both protons and neutrons (and their anti-particles) froze out:
Which of these formulas is the expanded structural formula for an alkane with three carbon atoms? which of these formulas is the expanded structural formula for an alkane with three carbon atoms? c– c– c ch3–ch2–ch3 c3h6 c3h8?
An organic compound which contains only carbon and hydrogen atoms is called the hydrocarbon. The expanded structural formula for an alkane with three carbon atoms (Propane) is CH₃–CH₂–CH₃. The correct option is B.
What are alkanes?The saturated hydrocarbons which consists of only single bonded carbon and hydrogen atoms without any other functional groups are known as alkanes. Their general formula is CₙH₂ₙ ₊ ₂ where 'n' represents the number of carbon atoms.
A formula which denotes all the atoms and bonds present in a compound is defined as the expanded structural formula. But a condensed structural formula omits most of the bonds.
The formula of propane is C₃H₈ and it is a colourless gas. Its expanded structural formula is CH₃–CH₂–CH₃ which contains three single bonds, 8 'H' atoms and 3 'C' atoms.
Thus the correct option is B.
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The expanded structural formula for an alkane with three carbon atoms is CH₃-CH₂-CH₃, which represents propane with the molecular formula C₃H₈.
The expanded structural formula for an alkane with three carbon atoms is CH₃-CH₂-CH₃. This compound is known as propane, which follows the general alkane formula CₙH₂ₙ+2. In this case, with three carbon atoms (n=3), the molecular formula becomes C₃H(₂x₃)₊₂, which simplifies to C₃H₈. Therefore, C₃H₈ is the correct molecular formula for propane, whereas C₃H₆ would be an alkene with a double bond between carbon atoms, not an alkane.
What is a disproportionation reaction?
A 40.00 ml sample of 0.10 m weak acid with ka of 1.8×10−5 is titrated with a 0.10 m strong base. what is the ph after 20.00 ml of base has been added?
In the titration of a weak acid with a strong base, the pH after adding 20.00 mL of base can be determined by considering the concentration of the weak acid and the remaining base after the reaction.
Explanation:To determine the pH after adding 20.00 mL of a 0.10 M strong base to a 40.00 mL sample of a 0.10 M weak acid with a Ka value of 1.8×10−5, we need to consider the reaction between the acid and the base.
Since the acid is weak, it does not dissociate completely. As a result, the pH can be calculated by considering the concentration of the weak acid and the remaining base after the reaction.
Using the titration curve as a reference, you can find the pH value corresponding to 20.00 mL of added base.
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What volume will 50.2 grams of co2 (g) occupy at stp?
Final answer:
The volume at STP that 50.2 grams of CO2 will occupy is found by converting the mass to moles and then multiplying by the molar volume of a gas at STP, which is 22.4 liters per mole.
Explanation:
To find the volume at STP that 50.2 grams of CO2 (g) will occupy, we first need to convert the mass of CO2 to moles using the molar mass of CO2, which is approximately 44.01 g/mol. Next, we apply the concept that one mole of any gas at STP will occupy 22.4 liters. The calculation involves dividing the mass of CO2 by its molar mass to get the moles, and then multiplying the number of moles by 22.4 L/mol to find the volume.The steps are as follows:Calculate the number of moles: number of moles = mass (g) / molar mass (g/mol)
Calculate the volume at STP: volume (L) = number of moles x 22.4 L/mol
By following these steps, we can determine the volume of CO2 gas at STP conditions.
if 24500 J is applied to 125g of water at 35 C, what will the final temperature of the water be?
What conditions favor the formation of ionic compounds from elements? both atoms must be non metals. you must have a metal and a nonmetal. both atoms must be metals. you must have a metal atom and a halogen?
The formation of ionic compounds is favored when a metal, which loses electrons, combines with a nonmetal, which gains electrons. This process results in an ionic compound stabilized by ionic bonds between ions of opposite charges, a well-known example being sodium chloride (NaCl). It's also possible for an ionic compound to form between a metal atom and a halogen.
Explanation:The conditions favoring the formation of ionic compounds typically involve a metal and a nonmetal. This is because metals, which have low ionization potential, tend to readily lose electrons and nonmetals, with high electron affinities, tend to gain electrons. In this process, such as the formation of sodium chloride (NaCl), the metal (sodium) loses an electron to form a cation (Na+), and the nonmetal (chlorine) gains an electron to form an anion (Cl-), resulting in an ionic compound. The compound is stabilized by ionic bonds, which are electrostatic attractions between ions of opposite charges.
The formation of ionic compounds ensures that both the metal and nonmetal achieve a stable electron configuration, often referred to as an octet. Additionally, ionic compounds can also form between a metal atom and a halogen as halogens are a group of nonmetals that are extremely electron-affinitive.
Lastly, it's important to note that not all combinations of metals and nonmetals produce ionic compounds. For instance, compounds that do not contain ions but consist of atoms bonded tightly together in molecules, usually form from two nonmetals and are called covalent compounds.
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A gas occupies 2.0 m3 at 100.0k and exerts a pressure of 100.0kPa. What volume will the gas occupy if the temperature is increased to 400.0 K and the pressure is increased to 200.0kPa
The ideal equation relates the temperature with the pressure and the volume of the gas. When the temperature is increased then the volume will be 4 cubic meters.
What is an ideal gas equation?An ideal gas equation depicts the relation between the temperature to that of the volume and the pressure of the gas.
The formula is given as,
[tex]\rm \dfrac{P_{1}V_{1}}{P_{2}V_{2}} = \rm \dfrac{T_{1}}{T_{2}}[/tex]
Given,
Initial pressure = 100 kPa
Initial volume = 2 cubic meter
Initial temperature = 100 K
Final pressure = 200 kPa
Final volume = ?
Final temperature = 400 K
The final volume is calculated as:
[tex]\begin{aligned} \rm V_{2} &= \rm \dfrac{P_{1}V_{1}T_{2}}{T_{1}}\\\\&= \dfrac{100\times 2 \times 400}{200 \times 100}\\\\&= 4 \;\rm m^{3}\end{aligned}[/tex]
Therefore, 4 cubic meters is the volume of the final gas.
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If the temperature of a 5 L sample of gas is lowered from 400k to 200k, what will the resulting volume of the gas be?
Question 4 options:
10 L
50 L
2.5 mL
2.5 L
The answer would be 2.5ML
Which class of compounds is responsible for the scents and flavors of many fruits? amides amines ethers esters
Answer: Esters for Plato
Explanation:
what is the empirical formula for a compound that is 83.7% carbon and 16.3% hydrogen?
The empirical formula should be [tex]C_3H_7[/tex]
The calculation is as follows:C: 83.7% = 83,7 g
H: 16.3% = 16.3 g
Now
[tex]C = 83.7 \div 12 = 6.975 mol\\\\H = 16.3 \div 1 = 16.3 mol[/tex]
The above does not represent the integers
So,
[tex]C = 6.975 \div 6.975 = 1\\\\H = 16.3 \div 6.975 = 2.3[/tex]
Therefore the above empirical formula should be used.
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How many atoms are in a sulfur molecule that has the elemental formula s8?
The ratios of volumes of the gaseous reactants and products in a chemical reaction at constant temperature and pressure can be determined from the