Answer:Explanation:
The statement that best describes the people of the Mississippian Period is that they were farmers who used simple tools to grow their food in small gardens. They would also fish and gather food such as muscles, in order to create a large enough food supply in addition to produce from these gardens and farms.
Tobacco use: The _____ _______ cause of ______ death
Answer:
Tobacco use: The most preventable cause of cancer death
Explanation:
cancer might not be right
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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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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What is the frequency of a photon of light (in Hz) that has an energy of 2.50 x 10-18 J?
Answer:
The answer is
[tex]3.77 \times {10}^{15} \: \: \: Hz[/tex]
Explanation:
The frequency of the photon can be found by using the formula
[tex]f = \frac{E}{h} \\ [/tex]
where
E is the energy
f is the frequency
h is the Planck's constant which is
6.626 × 10-³⁴ Js
From the question
E = 2.50 × 10^-18 J
So we have
[tex]f = \frac{2.50 \times {10}^{ - 18} }{6.626 \times {10}^{ - 34} } \\ [/tex]
We have the final answer as
[tex]3.77 \times {10}^{15} \: \: \: Hz[/tex]
Hope this helps you
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.
Match the descriptions below with the graphs. Be sure to explain your answers.
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
Distinguishing solutions and colloids
Which techniques would be best for separating the solute from the solvent in a solution ?
Answer:
Distillation will be the best method for the separation of solute from the solvent in a solution.
Explanation:
How many elements are shown in the diagram below for Hydrogen Peroxide?
Ten
Seven
Four
Two
Answer:4
Explanation:
4
What are the four main types of tissues in the human body?
Answer:
epithelial tissue, connective tissue, muscle tissue, and nerve tissue
Explanation:
PLS HELP ITS URGENT
Some plant cells need energy to carry nutrients across the cell membrane. Which type of energy transformation does these plant cells use to bring the nutrient molecule inside the cell membrane?
thermal energy to kinetic energy
potential energy to light energy
chemical energy to kinetic energy
kinetic energy to potential energy
Answer:
Answer
The answer is option 4
The energy transformation during nutrients transportation across the cell membrane is transformation from chemical energy to kinetic energy, where the uphill and downhill movements of molecules based on concentration gradient carries the whole process.
What is energy transformation?The total energy in a system is always conserved. However, one form of energy can be transformed into another form. For example we uses electrical devices such as bulbs fan etc, wherever the energy transformation is getting way from electrical energy to light or mechanical energy.
In plant cells nutrient molecules and ions are balanced inside and outside the cell and hence they are transported across the cell membrane by a concentration gradient with a chemical energy produced by the molecules.
The chemical energy inside of the ions and molecules converts to kinetic energy to transport itself through downhill and uphill mechanisms with aid of various enzymes and electron channels.
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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:
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
WILL mark Brainliest
Answer:
Ok what question
Explanation:
QUESTION 1
Consider the following reaction: CH4 + 202 --> 2H2O + CO2
How many moles of water can be formed from 1.1 moles of CH4?
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%
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.
Which of the following compounds is the MOST polar?
H−Br
H−F
H−Cl
H−I
why is water a neutral substance
Answer: Water is considered neutral because the concentration of hydrogen and hydroxide ions is the same
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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PLEASE HELP ASAP‼️ Which of the following elements has the highest metallic character
A. Zt
B. Rh
C. Hf
D. Co
Answer: C
Explanation:
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
what is the chemical formula for the magnesium ion and the carbonate ion?
Answer: The formula for magnesium carbonate is MgCO_3.
Explanation:
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 .
How many moles are in 2.16 x 1026 atoms of magnesium?*
Answer:
The answer is 358.80 molesExplanation:
To find the number of moles in a substance given it's number of entities we use the formula
[tex]n = \frac{N}{L} \\ [/tex]
where n is the number of moles
N is the number of entities
L is the Avogadro's constant which is
6.02 × 10²³ entities
From the question we have
[tex]n = \frac{2.16 \times {10}^{26} }{6.02 \times {10}^{23} } \\ = 358.80398671...[/tex]
We have the final answer as
358.80 molesHope this helps you
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
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
Which of the elements listed below would
require the least amount of energy to remove an
electron?
Beryllium
Calcium
Lithium
Sodium?
Answer:
Lithium would require the least amount of energy to remove an electron
Answer:
The answer is actually sodium
Explanation:
Lithium actually requires more than sodium.
Explain how scientists know the composition of the bottom layer of the cust?
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: