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Write the number of sig. fig. in four numbers given in the sentence below. An (one) octopus has 8 legs. 13 octopi have 104 legs.
Give four answers.
A. Infinity, Infinity, Infinity, Infinity
B. 1, 1, 2, 3
C. Infinity, Infinity, 2, 3
D. No answer text provided.
Answer:
1, 1, 2, 3
Explanation:
The numbers 1 and 8 both have 1 sig. fig.
The number 13 has 2 sig. figs.
The number 104 has 3 sig. figs.
help with the following would be greatly appreciated!
Explain why caffeine can be extracted from the tea leaves into hot water and how you extracted the aqueous solution and isolated the crude caffeine.
Answer:
The hot water dissolves the flavor and color components.
Explanation:
Caffeine can be extracted from the tea leaves into hot water because the hot water dissolves the flavor and color components away from the solid vegetable. This is an example of a solid-liquid extraction. We can extracted the aqueous solution and isolated the crude caffeine by converting the components of caffeine into their calcium salts which are insoluble in water. Then the caffeine can be extracted from the water by using methylene chloride.
If 6.50 L of water vapor at 50.2 °C and 0.121 atm reacts with excess iron, how many grams of iron(III) oxide will be produced?
2Fe(s)+3H2O(g)⟶Fe2O3(s)+3H2(g)
Answer:
1.60 g of Fe₂O₃
Explanation:
We'll begin by calculating the number of mole water that reacted. This can be obtained as follow:
Volume (V) = 6.50 L
Temperature (T) = 50.2 °C = 50.2 + 273 = 323.2 K
Pressure (P) = 0.121 atm
Gas constant (R) = 0.0821 atm.L/Kmol
Number of mole (n) =?
PV = nRT
0.121 × 6.5 = n × 0.0821 × 323.2
0.7865 = n × 26.53472
Divide both side by 26.53472
n = 0.7865 / 26.53472
n = 0.03 mole
Thus, 0.03 mole of water reacted.
Next, we shall determine the number of mole of Fe₂O₃ produced from the reaction. This can be obtained as follow:
2Fe + 3H₂O —> Fe₂O₃ + 3H₂
From the balanced equation above,
3 moles of H₂O reacted to produce 1 mole Fe₂O₃.
Therefore, 0.03 mole of H₂O will react to produce = (0.03 × 1)/3 = 0.01 mole of Fe₂O₃.
Thus, 0.01 mole of Fe₂O₃ was produced from the reaction.
Finally, we shall determine the mass of 0.01 mole of Fe₂O₃. This can be obtained as follow:
Mole of Fe₂O₃ = 0.01 mole
Molar mass of Fe₂O₃ = (56×2) + (16×3)
= 112 + 48
= 160 g/mol
Mass of Fe₂O₃ =?
Mass = mole × molar mass
Mass of Fe₂O₃ = 0.01 × 160
Mass of Fe₂O₃ = 1.60 g
Therefore, 1.60 g of Fe₂O₃ were produced.
Fill in the blanks with each titration term with its definition.
a. Solution of an unknown concentration that has another solution slowly added to it ________________
b. Process of slowly adding a solution to react with another solution and determine the concentration of one of the solutions based on the reaction between them ______________
c. A reagent added to the analyte solution that changes color when the reaction is complete ______________
d. Glassware that allows a solution to be precisely and slowly added to another solution _____________
e. Solution of known concentration that is slowly added to a solution of unknown concentration ________________
f. When the required amount of one solution has been added to the second solution to complete the reaction ____________
Answer:
Fill in the blanks with each titration term with its definition.
a. Solution of an unknown concentration that has another solution slowly added to it ________________
b. Process of slowly adding a solution to react with another solution and determine the concentration of one of the solutions based on the reaction between them ______________
c. A reagent added to the analyte solution that changes color when the reaction is complete ______________
d. Glassware that allows a solution to be precisely and slowly added to another solution _____________
e. Solution of known concentration that is slowly added to a solution of unknown concentration ________________
f. When the required amount of one solution has been added to the second solution to complete the reaction ____________
Explanation:
a. Solution of an unknown concentration that has another solution slowly added to it is called analyte.
b. Process of slowly adding a solution to react with another solution and determine the concentration of one of the solutions based on the reaction between them is called titration.
c. A reagent added to the analyte solution that changes color when the reaction is complete is called an indicator.
d. Glassware that allows a solution to be precisely and slowly added to another solution is called a pipette.
e. Solution of known concentration that is slowly added to a solution of unknown concentration is called titrant.
f. When the required amount of one solution has been added to the second solution to complete the reaction is called neutralization.
Based upon the intermolecular forces present, rank the following substances according to the expected boiling point for the substance.
a. HCl
b. NaCl
c. N2
d. H2O
Suppose of sodium iodide is dissolved in of a aqueous solution of potassium carbonate. Calculate the final molarity of sodium cation in the solution. You can assume the volume of the solution doesn't change when the sodium iodide is dissolved in it. Round your answer to significant digits.
Answer:
0.2762M Na+ in the solution
Explanation:
2.07g of sodium iodide Is Dissolved In 50.ML Of A 0.30M...
To solve this question we need to find the moles of sodium iodide, NaI, that are the same than the moles of sodium cation, Na+. The volume in liters of the solution is 0.050L. The molarity is:
Moles NaI = Moles Na+ -Molar mass NaI: 149.89g/mol-
2.07g NaI * (1mol / 149.89g) = 0.01381 moles NaI = Moles Na+
Molarity:
0.01381 moles Na+ / 0.0500L =
0.2762M Na+ in the solution
In a closed system, If a gas is transported to a container with double the volume of the previous container, the gas was held in, what is the gases' new volume?
The volume of the gas is fixed and will not change.
The volume of the gas will be half the original volume.
The volume of the gas will be the original volume squared.
The volume of the gas will be double the original volume.
Answer:
The volume of the gas is fixed and will not change.
Explanation:
The volume of the gas will not change because there is no change in temperature. Temperature increases the volume of gases enclosed in a container.
The density of aluminum is 2.7 g/cm3.
Part A
What is its density in kilograms per cubic meter?
Express your answer in kilograms per cubic meter to two significant figures.
Answer:
2700 kg/m³
Explanation:
First let's convert 2.7 g/cm³ to kg/cm³, keeping in mind that 1 kilogram equals 1000 grams:
2.7 g/cm³ * [tex]\frac{1kg}{1000g}[/tex] = 0.0027 kg/cm³Finally we need to convert 0.0027 kg/cm³ to kg/m³, keeping in mind that 1 meter equals 100 centimeters, as follows:
0.0027 kg/cm³ * [tex](\frac{100cm}{1m} )^3[/tex] = 2700 kg/m³The answer is 2700 kg/m³.
What is the molarity of an HCl solution if 43.6 mL of a 0.125 M NaOH solution are needed to titrate a 25.0 mL sample of the acid according to the equation below (show your calculations)? NaOH(aq) + HCl(aq) → H2O(l) + NaCl(aq)
Answer: The molarity of an HCl solution is 0.218 M if 43.6 mL of a 0.125 M NaOH solution are needed to titrate a 25.0 mL sample of the acid.
Explanation:
Given: [tex]V_{1}[/tex] = 43.6 mL, [tex]M_{1}[/tex] = 0.125 M
[tex]V_{2}[/tex] = 25.0 mL, [tex]M_{2}[/tex] = ?
Formula used to calculate the concentration of acid is as follows.
[tex]M_{1}V_{1} = M_{2}V_{2}[/tex]
Substitute the values into above formula.
[tex]M_{1}V_{1} = M_{2}V_{2}\\0.125 M \times 43.6 mL = M_{2} \times 25.0 mL\\M_{2} = 0.218 M[/tex]
Thus, we can conclude that the molarity of an HCl solution is 0.218 M if 43.6 mL of a 0.125 M NaOH solution are needed to titrate a 25.0 mL sample of the acid.
The molarity of the HCl solution used in the neutralization reaction has been 0.218 M.
The reaction of NaOH with HCl has been a neutralization reaction. The resultant will be salt and water.
In the reaction the molarity can be calculated as:
Molarity of HCl [tex]\rm[/tex][tex]\times[/tex] Volume of HCl = Molarity of NaOH
Given,
The volume of HCl solution = 25 ml
Molarity of NaOH = 0.125 M
Volume of NaOH solution = 43.6 ml
Substitute the values in the equation:
Molarity of HCl [tex]\times[/tex] 25 = 0.125 [tex]\times[/tex] 43.6
Molarity of HCl [tex]\times[/tex] 25 = 5.45
Molarity of HCl solution = [tex]\rm \dfrac{5.45}{25}[/tex]
Molarity of HCl solution = 0.218 M
The molarity of the HCl solution used in the neutralization reaction has been 0.218 M.
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Classify each of the following as either macroscopic, microscopic or particulate:
a. a red blood cell.
b. a sugar molecule.
c. baking powder.
Answer:
Classify each of the following as either macroscopic, microscopic or particulate:
a. a red blood cell.
b. a sugar molecule.
c. baking powder.
Explanation:
a. A red blood cell is a microscopic particle.
It can be viewed under a microscope.
b. A sugar molecule is also a microscopic substance.
It can be viewed under a microscope.
c. Baking powder is macroscopic substance.
Each of the following sets of quantum numbers is supposed to specify an orbital. Choose the one set of quantum numbers that does NOT contain an error.
a. n = 4, l = 3, ml =-4
b. n = 2, l = 2, ml =0
c. n = 3, l = 2, ml =-2
d. n = 2, l = 2, ml =+1
Answer:
n = 3, l = 2, ml =-2
Explanation:
Quantum numbers are a set of values which can be used to describe the energy and position of an electron in space.
There are four sets of quantum numbers;
1) principal quantum number
2) orbital quantum number
3) spin quantum number
4) magnetic quantum number.
The values of orbital quantum number include; -l to +l;
The set of quantum numbers without error is ; n = 3, l = 2, ml =-2
from the following equation in which decomposition of CaCO3 takes place, give your justification. CaCO3 gives Ca +CO2
Answer:
CaCO₃(s) => CaO(s) + CO₂(g) ... GpIIA Decomp
Explanation:
Metallic Carbonates decompose into a metallic oxide and carbon dioxide.
Examples:
Na₂CO₃(s) => Na₂O(s) + CO₂(g) ... GpIA Decomp
MgCO₃(s) => MgO(s) + CO₂(g) ... GpIIA Decomp
Platinum is one of the most dense elements (d = 21.5 g/cm3). What is the volume of a 10.0 g sample of the metal?
Answer:
0.465
Explanation:
To find the volume of a substance, divide the mass by the density.
M/D = V
10.0 / 21.5 = 0.4651163
Then round to 3 significant figures: and the density is 0.465
Which one of the following compounds does NOT obey the "octet rule"?
LiF
BF3
H20
CBr4
Answer:
BF3
Explanation:
The octet rule describes atoms' preference and affinity for having eight (8) electrons in their valence shell. Whenever an atom is encircled by eight(8) electrons, it forms a stable configuration. This octet can be composed of its' own electrons as well as some shared electrons. In the periodic table, only the s-block and p-block electrons are considered for the octet rule.
However, out of the given option, only BF3 does not comply with the octet rule: This is because the Bromine contains 2 lone pairs of electrons and 3 other shared bonded pairs of electrons with Flourine making a total of 10 electrons in the valence shell and which does not conform with the octet rule.
What is the law of multiple proportions?
A. The proportion of elements to compounds is constant.
B. All elements are found in equal proportions in nature.
C. Different compounds may contain the same elements but may have different ratios of those elements.
D. All compounds contain the same elements in the same proportions.
Answer:
a. the proportion of elements to compounds is constant.
If 11g of a gas occupies 5.6dm'3at s.t.p., calculate it's vapour density (1.0mol of a gas occupies 22.4dm'3at s.t.p.).
Answer:
[tex]{ \boxed{ \bf{vapour \: density = 2 \times molecular \: mass}}} \\{ \tt{ PV= (\frac{m}{ m_{r}}) RT}} \\ { \tt{3 \times 5.6 = \frac{11}{m _{r}} \times 0.0831 \times 273}} \\ { \tt{m _{r} = 14.85 \: g}} \\ \\ { \bf{vapour \: density = 2 \times m _{r}}} \\ = 2 \times 14.85 \\ = 29.7 \: { \tt{g {dm}^{ - 3} }}[/tex]
When the pH of a solution is 12.83, what is [H +]?
A 7.4 × 10 -12 M
B 9.7 10 -11 M
C 1.5 X 10 -13 M
D 12.8 x 10 -2 M
Answer:
B.9.710-11M
Explanation:
plss tell me if im wrongQuestion 2: Functional Groups (6 points)
A. Methanoic acid is the simplest carboxylic acid molecule. It has one carbon atom. Draw the structural model for methanoic acid (using C and H). (3 points)
B. Methanal is the simplest aldehyde, with one carbon atom. Draw the structural model for methanal (using C and H). (3 points)
11) Methane and oxygen react to form carbon dioxide and water. What mass of water is formed if 0.80 g of methane reacts with 3.2 g of oxygen to produce 2.2 g of carbon dioxide
A gas bottle contains 0.650 mol of gas at 730. mmHg pressure. If the final pressure is 1.15 atm, how many moles of gas were added to the bottle
Answer: There are 0.779 moles of gas were added to the bottle.
Explanation:
Given: [tex]n_{1}[/tex] = 0.650 mol, [tex]P_{1}[/tex] = 730 mm Hg (1 mm Hg = 0.00131579 atm) = 0.96 atm
[tex]n_{2}[/tex] = ?, [tex]P_{2}[/tex] = 1.15 atm
Formula used is as follows.
[tex]\frac{P_{1}}{n_{1}} = \frac{P_{2}}{n_{2}}[/tex]
Substitute the values into above formula as follows.
[tex]\frac{P_{1}}{n_{1}} = \frac{P_{2}}{n_{2}}\\\frac{0.96 atm}{0.650 mol} = \frac{1.15 atm}{n_{2}}\\n_{2} = 0.779 mol[/tex]
Thus, we can conclude that there are 0.779 moles of gas were added to the bottle.
Would 1 pound of peanut butter occupy more or less space than 1 pound of water?
Determine the molarity of the sodium ions when 78.0 g Na2S is dissolved in water for a final volume of 1.0 L.
Answer:
[Na⁺] = 1.99 M
Explanation:
Na₂S is a ionic salt that can be dissociated.
Dissociation equation is:
Na₂S → 2Na⁺ + S⁻²
1 mol of sodium sulfide can give 2 moles of sodium cation.
We convert moles of salt: 78 g . 1mol / 78.06 g = 0.999 moles
As ratio is 1:2, after dissociation we have (0.999 . 2) = 1.998 moles of Na⁺
Molarity is a type of concentration.
It indicates moles of solute in 1 L of solution and in this case, we have 1 L as final voulme.
Moles of Na⁺ are 1.998 moles. Then molarity (mol/L) is:
M =1.99 mol/L
once a recrystallization is completed and filtered, what solvent would be suitable for transferring the leftover solids to filtration funnel
Answer:
To transfer leftover solids to the filtration funnel and wash out crystals after recrystallization, ice cold methanol should be used (the mother liquor used for recrystallization).
Explanation:
Hope this helped
Write a balanced chemical equation for the reaction of aqueous potassium hydroxide with aqueous iron(III) chloride to form solid iron(III) hydroxide and aqueous potassium chloride. Express your answer as a chemical equation including phases. nothing A chemical reaction does not occur for this question.
Answer:
3KOH(aq) + FeCl3(aq) --------> Fe(OH)3 + 3KCl
Explanation:
The rule for balancing chemical equations is that the number of atoms of each element must be the same on both sides of the reaction equation.
Hence, the two reactants are potassium hydroxide and aqueous iron(III) chloride.
The balanced molecular reaction equation is;
3KOH(aq) + FeCl3(aq) --------> Fe(OH)3 + 3KCl
To what volume (in mL) would you need to dilute 20.0 mL of a 1.40 M solution of LiCN to make a 0.0880 M solution of LiCN?
Answer:
To 318.18 mL would you need to dilute 20.0 mL of a 1.40 M solution of LiCN to make a 0.0880 M solution of LiCN
Explanation:
Dilution is the reduction of the concentration of a chemical in a solution and consists simply of adding more solvent.
In a dilution the amount of solute does not vary. But as more solvent is added, the concentration of the solute decreases, as the volume (and weight) of the solution increases.
In a solution it is fulfilled:
Ci* Vi = Cf* Vf
where:
Ci: initial concentration Vi: initial volume Cf: final concentration Vf: final volumeIn this case:
Ci= 1.40 MVi= 20 mLCf= 0.088 MVf= ?Replacing:
1.40 M* 20 mL= 0.088 M* Vf
Solving:
[tex]Vf=\frac{1.40 M* 20 mL}{0.088 M}[/tex]
Vf= 318.18 mL
To 318.18 mL would you need to dilute 20.0 mL of a 1.40 M solution of LiCN to make a 0.0880 M solution of LiCN
Water has a density of 1.00 g/mL. If you put an object that has a density of 0.79 g/mL into water, it will sink to the
bottom.
ANSWER:
True
False
Answer:
False
Explanation:
An object with a density greater than 1.00g/mL (greater than the density of water) will sink. An object with a density less than the density of water, will float.
If the water has a density of 1.00 g/mL. If you put an object that has a density of 0.79 g/mL into water, it will sink to the bottom, this statement is false.
What is density?The density of an actual content is its mass per unit volume. The most common symbol for density is d, but the Latin letter D can also be used.
Three of an object's most fundamental properties are mass, volume, and density. Mass describes how heavy something is, volume describes its size, and density is defined as mass divided by volume.
The density of something is a measure of how heavy it is in relation to its size. When an artifact is more dense than water, it plunges; when an object is less dense than water, it floats.
Density is a property of a substance that is independent of the amount of substance.
As in the given scenario, water is having density 1 g/mL and object in having density less then it so it will float on water.
Thus, the given statement is false as the material will not sink, rather it will float on water.
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An electron in the ground state absorbs a single photon of light and then relaxes back to the ground state by emitting an infrared photon (1200 nm) followed by an orange photon (600 nm). What is the wavelength of the absorbed photon?
A. 400 nm
B. 600 nm
C. 1800 nm
What mass of NaOH would need to be dissolved in 500.0 mL of water to produce a solution with a pH of 12.40
Answer:
0.5024 g
Explanation:
Step 1: Calculate the concentration of H⁺
We will use the definition of pH.
pH = -log [H⁺]
[H⁺] = antilog -pH = antilog -12.40 = 3.981 × 10⁻¹³ M
Step 2: Calculate the concentration of OH⁻
We will use the ionic product of water expression.
[H⁺] [OH⁻] = 10⁻¹⁴
[OH⁻] = 10⁻¹⁴/[H⁺] = 10⁻¹⁴/3.981 × 10⁻¹³ = 0.02512 M
Step 3: Calculate the initial concentration of NaOH
NaOH is a strong base and the molar ratio of NaOH to OH⁻is 1:1. Thus, the initial concentration of NaOH is 1/1 × 0.02512 M = 0.02512 M.
Step 4: Calculate the moles of NaOH
We will use the definition of molarity.
M = moles of NaOH/liters of solution
moles of NaOH = M × liters of solution
moles of NaOH = 0.02512 mol/L × 0.5000 L = 0.01256 mol
Step 5: Calculate the mass of 0.01256 moles of NaOH
The molar mass of NaOH is 40.00 g/mol.
0.01256 mol × 40.00 g/mol = 0.5024 g
Help pls!!!
For groups 13 through 18, the number of valence electrons is equal to the group number
a. minus 10
b. minus the period number
c. plus 1
d. plus the period number
Answer:
a. minus 10
Explanation:
An element in group 13 = Boron ,valence electrons = 3 , therefore, valence electrons in group 13 = group no. -10
An element in group 18 = Neon, valence electrons = 8 , therefore, valence electrons in group 18 = group no. - 10
For groups 13 through 18, the number of valence electrons in an atom is equal to the group number minus 10. Therefore, option (A) is correct.
What is a valence electron?Valence electrons in an atom can be described as the electrons occupying the outer most electron shell of an atom while the electrons in the inner shell are core electrons. Lewis structures can be helpful to calculate the number of valence electrons.
Valence electrons can be filled in several electron shells as they are caused interaction between atoms and responsible for the formation of chemical bonds. Only valence electrons can contribute to the formation of a chemical bond and decide the reactivity of the element.
The general electronic configuration of group 13 is ns²np¹ has three valence electrons. It can be determined as group number - 10 = 13 - 10 = 3.
The general electronic configuration of group 18 is ns²np⁶ has eight valence electrons. It can be determined as group number - 10 = 18 - 10 = 8.
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