Answer:
1. c
2. d
3. c
4. d
5.
6. a
7. a
8.
PLEASE HELP ASAP‼️ Which of the following elements has the highest metallic character
A. Zt
B. Rh
C. Hf
D. Co
Answer: C
Explanation:
What is the velocity of a wave?
A. How much energy the wave has
B. How quickly the wave travels
C. The distance between two wave peaks
D. The distance between the high and low points of the wave
Solid sodium is reacted with chlorine gas and a crystalline solid was formed. The crystalline solid is evidence that
A. The sodium was broken down into tiny pieces by the chlorine.
B. The reaction caused impurities to fall out.
C. Elements bond in a multitude of ways to make compounds.
D. The chlorine solidified.
Answer:
C. Elements bond in a multitude of ways to make compounds.
As part of a soil analysis on a plot of land, a scientist wants to determine the ammonium content using gravimetric analysis with sodium tetraphenylborate, Na+B(C6H5)−4. Unfortunately, the amount of potassium, which also precipitates with sodium tetraphenylborate, is non‑negligible and must be accounted for in the analysis. Assume that all potassium in the soil is present as K2CO3 and all ammonium is present as NH4Cl.
A 5.025 g soil sample was dissolved to give 0.500 L of solution. A 100.0 mL aliquot was acidified and excess sodium tetraphenylborate was added to precipitate both K+ K + and NH+4 ions completely.
Compound Formula mass
B(C6H5)−4+K+⟶KB(C6H5)4(s) KB(C6H5)4 358.33 g/mol
B(C6H5)−4+NH+4⟶NH4B(C6H5)4(s) NH4B(C6H5)4 337.27 g/mol
K2CO3 138.21 g/mol
NH4Cl 53.492 g/mol
The resulting precipitate amounted to 0.277 g. A new 200.0 mL aliquot of the original solution was made alkaline and heated to remove all of the NH+4 as NH3. The resulting solution was then acidified, and excess sodium tetraphenylborate was added to give 0.105 g of precipitate.
Find the mass percentages of NH4Cl and K2CO3 in the original solid.
______ %NH4CL
______ %K2CO3
Answer:
Mass percentage of NH₄Cl = 3.54%
Mass percentage of K₂CO₃ = 1.01%
Explanation:
If a 200.0 mL aliquot produced 0.105 g of KB(C₆H₅)₄, then a 100.0 mL aliquot would produce 1/2 * 0.105 g = 0.0525 g of KB(C₆H₅)₄.
Therefore, mass of NH₄B(C₆H₅)₄ in the 100.0 ml aliquot = (0.277 - 0.0525)g = 0.2245 g
Number of moles of NH₄B(C₆H₅)₄ in 0.2245 g = 0.2245 g/ 337.27 g/mol = 0.0006656 moles
In 500 ml solution, number of moles present = 0.0006656 * 500/100 = 0.003328 moles.
From equation of the reaction; mole ratio of NH₄⁺ and NH₄B(C₆H₅)₄ = 1:1
Similarly, mole ratio of NH₄⁺ and NH₄Cl = 1:1
Therefore, moles of NH₄Cl in 500 ml sample = 0.003328 moles
Mass of NH₄Cl = 0.003328 mol * 53.492 g/mol = 0.178 g
Mass percentage of NH₄Cl = (0.178/5.025) * 100% = 3.54%
Number of moles of KB(C₆H₅)₄ in 0.105 g (precipitated from 200.0 ml aliquot) = 0.105 g/ 358.33 g/mol = 0.000293 moles
In 500 ml solution, number of moles present = 0.000293 * 500/200 = 0.0007326 moles.
From equation of the reaction; mole ratio of K⁺ and KB(C₆H₅)₄ = 1:1
Similarly, mole ratio of K⁺ and K₂CO₃ = 2:1
Therefore, moles of K₂CO₃ in 500 ml sample = 0.0007326/2 moles = 0.0003663 moles
Mass of K₂CO₃ = 0.0003663 mol * 138.21 g/mol = 0.05063 g
Mass percentage of K₂CO₃ = (0.05063/5.025) * 100% = 1.01%
Which of the following is an example of a pure substance?
A. beer
C. halo-halo
B. ethyl alcohol
D. silver spoon
When two or more different elements unite chemically, they form a
A) compound
B) mixture
C) metalloid
D) solution
Answer:
compound ahhhhhhhhhhhhhgh
If the titration of 0.8094 g of 100% pure
KHP requires 40.25 mL of NaOH, what
is the concentration of the NaOH
solution? Remember KHP is potassium
hydrogen phthalate, KHC2H4O4. Show
this calculation in your lab notebook.
Answer:
Explanation:
molecular weight of potassium hydrogen phthalate = 204
.8094 g of KHP = .8094 / 204 = 3.967 x 10⁻³ moles
3.967 x 10⁻³ moles of KHP must have reacted with 3.967 x 10⁻³ moles of NaOH
concentration of NaOH = 3.967 x 10⁻³ / 40.25 x 10⁻³
= .098 M .
10. What are the upper and lower extremes of
the moisture content of wood?
14. Identify the type of reaction: Pb + 2 AgCl → 2 Ag+ PbCl2
a. Combination/synthesis
b. Decomposition
c. Double replacement
d. Single replacement
Complete each statement by choosing the correct answer from the drop-down menu.
are the types of muscle tissue found in the human body.
Muscle cells are specialized to
are the two specialized proteins found in muscle.Muscle Tissue
Answer:
smooth, skeletal, cardiac
contract
actin and myosin
Explanation:
edge
Answer:
The correct answers are
smooth, skeletal, cardiac
contract
actin and myosin
How would a descriptive model of Earth's layers be categorized?
a. abstract model
b. prototype model
c. concrete model
d. conceptual model
A descriptive model of Earth's layers can be categorized as prototype model. Hence, option B is correct.
What is a descriptive model?
A descriptive model describes a system or other entity and its relationship to its environment.
The Earth has different compositional and mechanical layers. Compositional layers are determined by their components, while mechanical layers are determined by their physical properties.
The outermost solid layer of a rocky planet or natural satellite. Chemically distinct from the underlying mantle.
Hence, option B is correct.
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QUESTION 1
Consider the following reaction: CH4 + 202 --> 2H2O + CO2
How many moles of water can be formed from 1.1 moles of CH4?
How many elements are shown in the diagram below for Hydrogen Peroxide?
Ten
Seven
Four
Two
Answer:4
Explanation:
4
Which of the following compounds is the MOST polar?
H−Br
H−F
H−Cl
H−I
calulate the molarity
The first solution contains 0.600 mol of NaOH in 2.10 L of solution.
The second solution contains 10.3 g of NaCl in 675 mL of solution.
Determine the mass defect for the following atom. The mass of a 20 Ne atom is 19.992 44 amu.
Answer:
I will not consider electronic mass here. We know (the masses should have been provided in the question!) that the neutron mass is
1.008701
⋅
amu
and the proton mass is
1.007316
⋅
amu
.
Explanation:
Question answered
A element is having atomic number 82. find the number of its protons and electrons
Answer:
The number of its protons and electrons are 82 each
Explanation:
Atomic no of an element = 82
Atomic no = No of protons
⇒ No of protons = 82
Electrons are negatively charged particle and Protons are positively charged particles.
No of electrons = 82
Hence, the element is Lead with 82 protons and electrons
Match the descriptions below with the graphs. Be sure to explain your answers.
5. Explain why the particle diagram below represents a chemical change.
plsss help!!!
Answer:
the atoms are rearranged
Explanation:
they are just in a diff order
The particle diagram represents a chemical change because the breaking of old chemical bonds and the formation of new chemical bonds occurs and a completely new substance is formed.
What is the chemical change?A chemical change is when a chemical substance is completely transformed into one or more different types of substances. Chemical changes occur through chemical reactions and result in substances with different and new chemical and physical properties.
Chemical changes are irreversible in nature and are also known as permanent changes. When chemical responses occur, the molecules are modified and joined by an energy change as new molecules are produced.
Examples of chemical changes: burning of coal, rusting of iron, digestion of food, adding vinegar to baking soda, germination of seeds, ripening of fruits, cooking an egg, etc.
The given diagram is quite similar to the water formation reaction:
2H₂ + O₂ [tex]\longrightarrow[/tex] 2H₂ O
In which the bond between the hydrogen atoms and oxygen atoms is broken and the formation of the O-H bond, therefore, is a chemical change.
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what is the chemical formula for the magnesium ion and the carbonate ion?
Answer: The formula for magnesium carbonate is MgCO_3.
Explanation:
A sample of a metal has a mass of 23.4 g and a volume of 3.0 mL. What is the sample’s most likely identity?
A. Aluminum (2.8 g/mL)
B. Iron (7.8 g/mL)
C. Copper (8.9 g/mL)
D. Gold (19.3 g/mL)
Answer:
B. Iron (7.8 g/mL)
Explanation:
23.4/3 = 7.8
7.8g/mL
The identity of a sample of a metal that has a mass of 23.4 g and a volume of 3.0 mL is iron with a density of 7.8g/mL.
How to calculate density?The density of a substance can be calculated by dividing the mass of the substance by its volume. That is;
Density = mass (g) ÷ volume (mL)
According to this question, a sample of a metal has a mass of 23.4 g and a volume of 3.0 mL. The density of the metal is as follows:
Density = 23.4g ÷ 3mL
Density = 7.8g/mL
Therefore, the identity of a sample of a metal that has a mass of 23.4 g and a volume of 3.0 mL is iron with a density of 7.8g/mL.
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The circular flow model interacts between which sectors of the economy? Select THREE answers.
Private
Government
Foreign
Tech
Households
Answer:
2,3,5
Explanation:
When ignited, a uranium compound burns with a green flame. The wavelength of the light given off by this flame is greater than that of _____.
Answer:
Ultraviolet light.
Explanation:
Uranium is a natural radioactive chemical element with the chemical symbol "U" and an atomic number of 92. Uranium is used for generating nuclear fuels which are typically used in powering atomic bombs and nuclear reactors in the field of electricity generation.
When ignited, a uranium compound burns with a green flame. The wavelength of the light given off by this flame is greater than that of ultraviolet light which typically ranges from 100nm to 400nm. Where, nm is represents nanometer.
Basically, when ignited, a uranium compound burns with a green flame having a wavelength of 4.30 x 10^-7m to 5 x 10^-7m.
Balance the following equation. ZnCl2 + (NH4)3PO4 ->__Zn3(PO4)2 + NHACI
Answer:
3ZnCl2 + 2(NH4)3PO4 → Zn3(PO4)2 + 6NH4Cl
Explanation:
Zinc Chloride + Tribasic Ammonium Phosphate = Zinc Phosphate + Ammonium Chloride
Reaction Type
Double Displacement (Metathesis)
Reactants
Zinc Chloride - ZnCl2
Zinc(II) Chloride Zinc Chloride, Anhydrous Dichlorozinc Butter Of Zinc Zinc Chloride Zn-65
Molar Mass of ZnCl2 Oxidation State of ZnCl2
Tribasic Ammonium Phosphate - (NH4)3PO4
Ammonium Phosphate
Molar Mass of H12N3O4P Oxidation State of H12N3O4P
Products
Zinc Phosphate - Zn3(PO4)2
Zinc(II) Phosphate
Molar Mass of O8P2Zn3 Oxidation State of O8P2Zn3
Ammonium Chloride - NH4Cl
Amchlor Ammoneric Ammonium Muriate Darammon Sal Ammonia Sal Ammoniac Salammonite Salmiac
Molar Mass of ClH4N Oxidation State of ClH4N
What are the four main types of tissues in the human body?
Answer:
epithelial tissue, connective tissue, muscle tissue, and nerve tissue
Explanation:
a typical baseball has a mass of 350g and takes up a volume of .780L. what is the density of a baseball in g/l and g/ml?
Answer:
449 g/L
0.449 g/mL
Explanation:
Step 1: Given data
Mass of a typical baseball (m): 350 gVolume of a typical baseball (V): 0.780 LStep 2: Calculate the density (ρ) of the baseball in g/L
The density is equal to the quotient between the mass and the volume.
ρ = m / V
ρ = 350 g / 0.780 L
ρ =449 g/L
Step 3: Convert ρ from "g/L" to "g/mL"
We will use the conversion factor 1 L = 1000 mL.
449 g/L × (1 L/1000 mL) = 0.449 g/mL
Can someone explation for me ? I can’t understand.
Thanks
Answer:
2 Nitrogen
Explanation:
This is because it says Diammonium Hydrogen Phosphate. Here. (NH4)3PO4 is one way to write this. However, another way to write this is (NH4)2HPO4. There should be in fact two ammonium groups, NH4 and 1 Hydrogen to get 3+ charge to balance the 3- charge from the Phosphate.
Identify the placement of items A-E using the drop-down menus.
A)
⇒No
⇒Yes
B)
⇒No
⇒Yes, when liquid or solution
⇒Yes, when solid
C)
⇒No
⇒Yes
D)
⇒No
⇒Yes
E)
⇒No
⇒Yes
Answer:
A=no
B= yes when liquid or solution
C=yes
D=no
E=yes
Explanation:
According to the given table, the placement of items A-E are
A) ⇒ No
B) ⇒Yes, when liquid or solution
C) ⇒Yes
D) ⇒No
E) ⇒Yes
What is conductivity and Malleability?
Malleability - Those metals that can be beaten into thin sheets with a hammer or any heavy object. For example - Cu, Au etc
Conductivity - Conductivity is the measure of the ease at which an electric charge or heat can pass through a material. For example - Metals are good conductors of heat and electrolytic solution is conductors of electricity.
Therefore, according to the given table, the placement of items A-E are
A) ⇒ No
B) ⇒Yes, when liquid or solution
C) ⇒Yes
D) ⇒No
E) ⇒Yes
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When all colors of light are absorbed, what do you see?
Black
Orange
Pink
Yellow
Answer:
Black
Explanation:
hope it helps
have a nice time ..,
2. Using the following data, calculate the average atomic mass of magnesium (give your answer to the nearest
.01 ) : Show all work!
Isotope: Mg Percent abundance: 78.70%
24
Isotope: 'Mg Percent abundance: 10.13% 25
Isotope: Mg Percent abundance: 11.17% 26
Answer: 24.309amu
Explanation: