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.
1. Which of the combinations in the lab activity had indications that a chemical change occured? Defend your argument with evidence.
2. Which of the combinations in the lab activity had indications that a physical change occured? Defend your argument with evidence.
3. Are all physical changes reversible? Explain your answer using an example you've observed in your everyday life.
4. Give an example of something you've observed in your everyday life that is a chemical reaction. How did you know it was a chemical reaction?
Answer:The green growing on the penny of copper and the rust forming on the nail of iron are chemical changes. Boiling away salt water, scraping iron filings from a mixture of sand with a magnet, and breaking a rock with a hammer, are physical changes.
Explanation:
Explain what happens when water reacts with sodium metal. Support your answer with the relevant
equation.
Sodium metal reacts rapidly with water to form a solution of sodium hydroxide (NaOH) and hydrogen gas (H2). This reaction is exothermic.
Equation:
2Na + 2H²0 --------}- 2NaOH + H²
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
Would 1 pound of peanut butter occupy more or less space than 1 pound of water?
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.
For more information about the molarity, refer to the link:
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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.
Liquid A is poured into Liquid B and a single, clear layer results. More Liquid A is added and two distinct layers form. The solution is now_____and there is a_____equilibria occurring.
Answer:
Explanation:
Liquid A is poured into Liquid B and a single, clear layer results. More Liquid A is added and two distinct layers form. The solution is now unsaturated and there is a static equilibria occurring
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
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)
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
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.
Learn more about valence electrons, here:
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Og is the noble gas after Rn. To go from [Rn] to [Og], you must fill four subshells (s, p, d, and f) with a total of 32 electrons. Thus, the atomic numbers of 6th and 7th period elements of the same group differ by 32.
a. To go from [Og] to the next noble gas, however, you would theoretically fill five subshells (s, p, d, f, and g). How many electrons are needed to fill all five subshells?
b. Element 106 in the periodic table is Sg Determine the atomic number of the element just below Sg in the periodic table.
Answer:
See explanation
Explanation:
Since we have to fill five subshells in moving from Og to the next noble gas in the eight period, we have to know the maximum electrons contained in each of those subshells;
s= 2, p=6, d= 10, f= 14, g = 18
This means that we need a total of 50 electrons to fill all the five subshells.
Hence, the element just below Sg in the eight period will have an atomic number of 156.
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
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.
Organic foods do not contain chemicals.
True
Or
False
Answer:
True
Explanation:
The word Organic refers to the methods used to cultivate and process farm agricultural products. Organic foods are edible and nutritious substances consumed (both plants and animals) that are free from the use of synthetics and chemicals. In plants, the include the use of organic manure that serves as fertilizers and carrying out the weeding process by hand weeding. In animals, diseases can be prevented by maintaining a clean house or rotational grazing.
The benefit of organic foods are to produce food substances with no chemical substances.
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.
1 or 2 topics or two lessons should be explained in an illustrated childrens book minimum of 10 pages must have 3 or more sentences
Answer:
Yes because same topic are long
A sample of hydrogen nitrate or nitric acid, HNO 3 contains 18.8 x 1022 molecules.
How much mass of nitric acid are in the sample?
Answer:
19.7 g.
Explanation:
Hello there!
In this case, according to the given information, it turns out possible for us to realize this problem can be solved by using a molecules-moles-mass relationship, starting with the given molecules, using the Avogadro's number and the molar mass of nitric acid (63.01 g/mol):
[tex]18.8x10^{22}molec*\frac{1mol}{6.022x10^{23}molec}* \frac{63.01g}{1mol} \\\\=19.7g[/tex]
Regards!
How many atoms in each elemental sample?
4.9 mol Cu
5.4•10^-3 Mol C
24.0 Mol Hg
0.160 mol Na
Answer:
2.9 × 10²⁴ atoms Cu; 3.3 × 10²¹ atoms C; 1.44 × 10²⁵ atoms Hg; 9.63 × 10²² atoms Na
Explanation:
To convert moles to atoms, we need a conversion factor: Avogadro's number. There are 6.02 × 10²³ atoms in 1 mole of atoms.
4.9 mol Cu × 6.02 × 10²³ atoms Cu/1 mol Cu = 2.9 × 10²⁴ atoms Cu
5.4 × 10⁻³ mol C × 6.02 × 10²³ atoms C/1 mol C = 3.3 × 10²¹ atoms C
24.0 mol Hg × 6.02 × 10²³ atoms Hg/1 mol Hg = 1.44 × 10²⁵ atoms Hg
0.160 mol Na × 6.02 × 10²³ atoms Na/1 mol Na = 9.63 × 10²² atoms Na
The number of moles of aluminum that react with 15.7 grams of oxygen according to the equation 4 Al + 3 0 2 - 2 Al 20 3
Answer:
Explanation:
1mol of [tex]O_2=2*16{gr\over{mol}}=32{gr\over{mol}}\\\\15.7gr->15.7gr*{1\over{32{gr\over{mol}}}}=0.491mol~of~O_2[/tex]
as 1mol of molecular oxigen reacts with 4 mol of aluminium
1 mol of O2 -----------------------------> 4 mol of Al
0.491 mol of O2 ------------------------------> x
[tex]x={0.491*4\over{1}}~mol~of~Al=1.9625~mol~of~Al[/tex]
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.
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
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.
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]
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.
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.
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
what is sterilization
Answer:
Sterilization refers to any process that removes, kills, or deactivates all forms of life and other biological agents like prions present in a specific surface, object or fluid, for example food or biological culture media.
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
