Answer:
The immune system responds to antigens by producing cells that directly attack the pathogen, or by producing special proteins called antibodies. Antibodies attach to an antigen and attract cells that will engulf and destroy the pathogen. The main cells of the immune system are lymphocytes known as B cells and T cells.
What elements make up hydrogen peroxide?
Answer:
Hydrogen peroxide is a highly reactive chemical containing the elements hydrogen and oxygen. Pure hydrogen peroxide is a colourless liquid, but it is sold on the market as solutions in water, containing up to 33 – 37% pure hydrogen peroxide and other additives to stop the product decomposing.
Explanation:
Hope this helps <3
The inside window pane in your house feels very cold to touch on a winter night. How does the heat transfer?
Question 9 options:
A. Heat transfers from the window pane to your hand.
B. Heat transfers from your hand to the window pane.
Answer:
its B
Explanation:
Because its can only go cold to hot. -hope this help :)
What type of temperatures and moisture content does Marine time Tropical air have?
Group of answer choices
Cold Temps/ Moist Air
Warm Temps/ Dry Air
Cold Temps/ Dry Air
Warm Temps/ Moist Air
Answer:
D: Warm Temps/ Moist Air
Explanation:
Tropical places usulay have warm mosit air
Maritime Tropical air is associated with warm temperatures and moist air.
Maritime Tropical (mT) air is a type of air mass that forms over warm tropical or subtropical ocean regions. It acquires its characteristics from the ocean's influence, particularly its warm temperatures and high moisture content.
Warm Temperatures: Maritime Tropical air masses originate from regions near the equator or subtropics, where solar radiation is intense and consistently high. As a result, these air masses are typically warm, with temperatures ranging from mild to hot.
The term "Maritime" refers to air masses that have originated from over the ocean, which generally have higher moisture content due to evaporation from the ocean surface. The term "Tropical" indicates that the air mass originates from or near tropical regions, where warm temperatures are prevalent.
Therefore, the correct answer is: Warm Temps/ Moist Air.
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The equation for the reaction of magnesium ribbon and hydrochloric acid is
Mg(s) + 2 HCl(aq) → MgCl2(aq) + H2(g)
If 1.53 g magnesium reacted, how many moles of hydrogen gas was produced?
Report your answer to three significant figures.
Mg = 24.3 g/mol
Answer: .063
Explanation:
1.53g Mg * (1 mol Mg/ 24.3 g Mg) * (1 mol H2/1 mol Mg) = .063 mol H2
The mole of hydrogen gas that will be produced from the reaction would be 0.0630 moles.
From the equation of the reaction:
[tex]Mg(s) + 2 HCl(aq) ---> MgCl_2(aq) + H_2(g)[/tex]
The mole ratio of Mg to H2 gas is 1:1. Thus, for every one mole of Mg consumed by the reaction, 1 mole of H2 is produced, all other things being equal.
Recall that: mole = mass/molar mass
1.53 g of magnesium = 1.53/24.3
= 0.0630 mole (to 3 significant figures)
Since the mole ratio of Mg to H2 is 1:1, it means that the number of moles of hydrogen gas produced would also be 0.0630 moles.
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The temperature at which a particular liquid becomes a gas
5 points
A melting point
B boiling point
C freezing point
D sublimation point
5 points
a substance made of at least two atoms that are chemically combined
Apure substance
B element
C compound
D mixture
Answer:
A: melting point and the other one is i think element
What volume of 12 M NaOH and 2 M NaOH should be mixed to get 2 litres of 9 M NaOH solution?
In this periodic table, which type of element is shown in green boxes?
A. Metalloids
B. Nonmetals
C. Noble gases
D. Metals
Answer: A
Explanation:
Metalloids
Write the thermochemical equation for the combustion of acetylene, C2H2 (g), in oxygen, for which the standard enthalpy of reaction is -1300 kJ per mole of acetylene.
Answer:
C₂H₂(g) + 2.5 O₂(g) ⇒ 2 CO₂(g) + H₂O(l) ΔH° = -1300 kJ/mol
Explanation:
In the combustion of acetylene, it reacts with oxygen to produce carbon dioxide and water. The corresponding chemical equation is:
C₂H₂(g) + 2.5 O₂(g) ⇒ 2 CO₂(g) + H₂O(l)
The thermochemical equation includes the balanced chemical equation, stating the states of aggregation and the enthalpy of the reaction.
C₂H₂(g) + 2.5 O₂(g) ⇒ 2 CO₂(g) + H₂O(l) ΔH° = -1300 kJ/mol
What is the mole fraction of each component if 3.9 g of benzene (C6H6) is dissolved in 4.6 g of toluene (C7H8)
Answer:
Step 1 of 6
(a)
The mass of benzene is  , so calculate the moles of benzene as follows:

The mass of toluene is, so calculate the moles of toluene as follows:

Now, calculate the mole fraction as follows:


Therefore, the mole fraction of benzene and toluene is  and  respectively.
Step 2 of 6
(b)
The formula to calculate the partial pressure is as follows:

Here,  is the partial pressure of benzene,  is the vapour pressure of pure benzene and  is the mole fraction of benzene.
Vapour pressure of pure benzene at  is.
Substitute the values in the equation as follows:

Therefore, the partial pressure is  .
Step 3 of 6
(c)
Vapor pressure of the solution at 1 atm is  .
When the total pressure of the vapour pressure of the mixture is  at a temperature, then, the solution boils. It corresponds to the boiling point of the solution.
Calculate the total pressure of the solution at  as follows:

Since, the total pressure is less than the atmospheric pressure, the solution will not boil at  .
Calculate the total pressure of the solution at  as follows:

Since, the total pressure is greater than the atmospheric pressure, the solution will boil at  .
Therefore, the boiling point of the solution is  .
Step 4 of 6
(d)
Mole fraction of benzene at  is calculated as follows:

Mole fraction of toluene at  is calculated as follows:

Therefore, the mole fractions of benzene and toluene are  and  respectively.
Step 5 of 6
(e)
Vapor pressure of benzene at  is  .
Partial pressure of benzene is calculated as follows:

Vapor pressure of toluene at  is  .
Partial pressure of toluene is calculated as follows:

Step 6 of 6
Weight composition of the vapour that is in equilibrium with the solution is calculated as follows:

Weight composition of the vapour that is in equilibrium with the solution is calculated as follows:

Explanation:
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Describe the bodys first line of defense
Answer:
The main function of the immune system is to provide immunity to the body. Immunity is the body's ability to protect itself from the pathogens it is exposed to. Immunity depends on the body's ability to differentiate between things that belong in the body and those that do not. The immune system's first line of defense includes physical and chemical barriers that are always ready and prepared to defend the body from infection.
The skin acts as a barrier against pathogens. Some structures of the first line of defense include the skin, mouth, eyes, ears, nose, and stomach. The skin produces sweat and oil that work together to keep pathogens from the entering the body. Saliva and tears contain substances the can destroy pathogens. The ears and the stomach help fight pathogens.The ears produce ear wax that prevent pathogens from entering the ears. The stomach produces a liquid the kills pathogens.
Mucus is produce by the nose, lungs, throat, and stomach. Mucus traps pathogens. Mucus also prevent pathogens from getting into deep tissues. Anyway, the very first line of defense against any invasion of the human body is a set of physical barriers between the inside of the body and the outer world.
*my notes from edge2020*
Hope this helps ^-^
If 12.4 mol of Ne gas occupies 122.8 L, how many mol of Ne would occupy 339.2 L under the same temperature and pressure? Record your answer in scientific notation using 3 significant figures.
Answer:
3.43×10¹ mol
Explanation:
Given data:
Initial number of moles = 12.4 mol
Initial volume = 122.8 L
Final volume = 339.2 L
Final number of moles = ?
Solution:
The number of moles and volume are directly proportional to each other at same temperature and pressure.
Formula:
V₁/n₁ = V₂/n₂
Now we will put the values,
122.8 L/ 12.4 mol = 339.2 L / n₂
n₂ = 339.2 L× 12.4 mol / 122.8 L
n₂ = 4206.08 L.mol /122.8 L
n₂ = 34.3mol
In scientific notation:
3.43×10¹ mol
unit factor method
convert a)26 cm in to meter
What is the acceleration of a car moving at the same speed and in the same direction?
Answer:
if it ain't changing direction the acceleration isn't being affected
In acid solution, water can add to the double bond of 2‑butenedioic acid to form 2‑hydroxysuccinic acid.
HOOCCH=CHCOOH+H2O <== H2SO4 ==> HOOCCH2CH(OH)COOH
This reaction is also an important reaction of the tricarboxylic acid cycle in cells, wherein the reaction occurs in neutral solution, so the acid groups are both ionized to the carboxylate form. The reaction is catalyzed by the stereospecific enzyme fumarase that utilizes only the trans form of 2‑butenedioate ion, also known as fumarate, and produces only the (S)‑2‑hydroxysuccinate enantiomer,also known as (s)-malate). Draw the correct stereochemical structures of these two compounds of the fumarase-catalyzed reaction.
fumarate (s)-malate
(trans-2-butenedioate) ((s)-2-hydroxysuccinate)
Fumarase
+ H2O <===========>
Answer:
Explanation:
The stereochemical structures of the two compounds of the fumarase-catalyzed reaction are in the attachment below. The reaction been referred to is illustrated in the equation below
HOOCCH=CHCOOH + H₂O ==> HOOCCH₂CH(OH)COOH
The compounds attached are trans-2-butenedioate (which is one of the reactants) and (s)-2-hydroxysuccinate (which is the product formed)
Note that stereoisomers are isomers that differ in spatial orientation, thus there are other isomers that could contain the same atoms and have slightly but different spatial orientation such as cis-2-butenedioate and (r)-2-hydroxysuccinate
A buffer solution of volume 0.500 L contains 1.68 g NH3and 4.05 g (NH4)2SO4.
Required:
a. What is the pH of this solution?
b. If 0.88 g of NaOH is added to the solution, what will be the pH?
Answer:
wait
Explanation:
a. The pH of this solution is 9.45.
b. If 0.88 g of NaOH is added to the solution, the pH will be 9.74.
What is pH means?a way to gauge how basic or acidic a material or solution is. On a scale of 0 to 14, pH is measured. A pH of 7 indicates neutrality on this scale, which implies it is neither acidic nor basic. More basic substances have a pH value more than 7, whereas more acidic substances have a pH value less than 7.
first of all we should calculate the molarity of the compounds
no. of moles of NH₃ = weight / molecular weight = 1.68 / (14+3) = 0.099
no. of moles of (NH₄)2SO4 = 4.05 / {2×(14+4) + 32 + 64} = 0.031
no. of moles of NH4+ = 2×0.031 = 0.062
[NH₃] = no. of moles / volume(L) = 0.099/ 0.5 = 0.198
[(NH₄⁺] = 0.031/0.5 = 0.124
1) now we know that
pH + pOH = pkw
pOH = pkw - pH = 14 - pH ---- -1
also
pOH = pkb + log ( [salt]/[base])
from 1
14 - pH = pkb + log ( [salt]/[base])
putting values
14- pH = -log(1.8e-5) + log(0.124/0.198)
14 - pH = 4.54
pH = 9.45
2) if 0.88g NaOH is added then as we know that NaOH is a base then it will reduce the buffer capacity
as there would be OH- ions initially present
hence the buffer action will move backward
i.e
pOH = pkb + log {(salt-x) / (base+x)}
where x= molarity of NaOH
no of moles of NaOH = 0.88 / (23+16+1) = 0.022
molarity of NaOH = 0.022/0.5 = 0.044
then 14 - pH = -log(1.8e-5) + log{ (0.124-0.044) / (0.198+0.044) }
14 - pH = 4.26
pH = 9.74
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In addition to hydronium ions which type of ion do acids produce? (Choose all that apply)
A. Anion
B. A negative ion
C. Cation
D.A positive ion
Answer:
B
Explanation:
i just read it na, but i forgot the explanation
Answer:
A. and B.
Explanation:
Anion is negative as well as a negative ion.
(Just took the quiz)
Given the reaction _K(s) +_ Cl2(g) → _KCl(s) what is the amount of K, in grams, needed to completely react with 2 moles of Cl2(g)?
Answer:
156.4g K
Explanation:
I'm not sure if it is correct but I think it should be this
What do we know so far?: 2K + 1Cl2 -> 2KCl, 2 mol of Cl2
What are we looking for?: #g of K
What is the ratio of K to Cl2?: 2:1
Set up equation: 2molCl2 x [tex]\frac{2mol K}{1 mol Cl2}[/tex]
Cancel unwanted units: 2 x [tex]\frac{2mol K}{1}[/tex]
Answer we got: 2 x 2mol K = 4mol K
Converting moles to grams: 4 x 39.1 (molar mass of K) = 156.4g K
While setting up a beaker to boil a solution on a hot plate, you notice that the stirring is erratic and unstable. What should you do to stabilize the stirring solution? a. Clamp the beaker in place at the edge of the hot plate. b. Move the beaker to the center of the hot plate. c. Turn down the stirring speed. d. Completely turn off the stirring function.
Answer:
B. Move the beaker to the center of the hot plate
Explanation:
The erratic and unstable stirring might be caused by the beaker not being properly balanced on the hot place, there by distorting the the center of gravity of the stirring motion.
In properly positioning the stirrer to the hot plate, the magnetic rod is positioned to the center of the fluid, allowing for a more fluid and even effective stirring.
I hope this was helpful.
Muscles in a kangaroo’s legs work because of the cells that make up the muscle. Which component of cell theory does this best illustrate?
( science )
Answer:
cells are a basic unit of structure and function all things
explain what happens to temperature and energy as molecules move from gas to liquid to solid
Answer and Explanation:
As the temperature of the substances increases, the average energy of the molecules increases, and average energy of attraction between the molecules decreases consequently intermolecular spacing between the molecules increases. As a result, a substance change in succession from gas to liquid to solid.
a box has dimensions 0.2 m x 0.4m x 0.6m. what is the volume of the box in cubic meters?
Answer: 0.048 cubic meters
Explanation:
Volume of a rectangular solid is lxwxh. So you multiply the given dimensions.
which phrases describe sedimentary rock? check all that apply.
Answer:
Sedimentary rock, rock formed at or near Earth's surface by the accumulation and lithification of sediment by the precipitation from solution at normal surface temperatures
Explanation:
Saturated solutions of which of these ionic compounds have the highest boiling point?A.Cd(OH)2 (Ksp = 5.9 x 10-15)B.Zn(OH)2C.Mg3(PO4)2D.AgNE.AgI(Ksp = 1.1 x 10-17) (Ksp = 1.0 x 10-25) (Ksp = 7.2 x 10-11) (Ksp = 8.5 x 10-17)
Answer:
D. AgN.
Explanation:
Hello!
In this case, since the boiling point of a solution increases are more solute remains dissolved in the liquid, as more energy is required to start the phase transition, for insoluble solids for which we know the solubility product which has the following relationship with the amount of ions in solution:
"the greater Ksp, the more ions the solution has"
In such a way, for the solid with the greatest Ksp we understand it has most of the ions in solution and therefore the highest boiling point, thus, among the choices, D. AgN is the one with the highest boiling point because it Ksp is 7.2E-11, whcih is the greatest.
Best regards!
Give the location in the Periodic Table of Elements that have the same number of electron shells
all columns (groups) have the same number of shells
all periods (rows) have the same number of shells
only the transition metal elements have the same number of shells
Group VIII
Explanation:
All period have the same number of shells
A ball has a kinetic energy of 4.50 kJ. If the ball has a mass of 120.0 g, how fast is the ball traveling, in meters per second?
Answer:
273.9m/s
Explanation:
Given parameter:
Kinetic energy of the ball = 4.5kJ
Mass of the ball = 120g
Unknown:
Speed of the ball = ?
Solution:
Kinetic energy of a body is the energy due to the motion of a body.
K.E = [tex]\frac{1}{2}[/tex] m v²
where m is the mass
v is the speed
Convert the quantities to the appropriate units;
4.5kJ to J = 4.5 x 10³J
120g to kg = 0.12kg
Now insert the parameters and find the unknown:
4500 = [tex]\frac{1}{2}[/tex] x 0.12 x V²
9000 = 0.12V²
V² = [tex]\frac{9000}{0.12}[/tex] = 75000
V = 273.9m/s
How many moles of O2 are required to react completely with 5.00 moles of C4H10?
A) 10.0
B) 20.0
C) 26.5
D) 32.5
Answer:
32.5
Explanation:
2C⁴H¹⁰ needs 13 O²
5 C⁴H¹⁰ needs (13/2 × 5) O² = 32.5 O²
The answer is D, 32.5
(I took the test)
This is a Periodic Pun! A cool dude might exclaim this in response to a perfect test score
Answer:
???
Explanation:
not really sure lol
Some organizations are buying sections of forest. Once purchased, these sections will never be cut down. What is most likely the main reason for protecting these sections of forest? A Cause the extinction of undesirable animal species, B Prevent these trees from reproducing too fast, C Maintain the diversity of the living environment. D Crovide more land for agricultural purposes.
Answer:
I think is C
Explanation:
'Cause the questions says "these sections will Never cut down", so that means is proctecting the environment
What mass of solid aluminum hydroxide is produced when 50.0 mL of 0.20 M aluminum nitrate is added to 200.0 mL of 0.100 M potassium hydroxide?
Answer:
0.52g of Al(OH)₃
Explanation:
The reaction of aluminium nitrate, Al(NO₃)₃, reacts with KOH, as follows:
Al(NO₃)₃ + 3KOH → Al(OH)₃ + 3 KNO₃
That means 1 mole of aluminium nitrate reacts with 3 moles of potassium hydroxide.
To find moles of aluminium hydroxide we need to determine the limiting reactant finding moles of each reactant:
Moles aluminium nitrate:
0.050L * (0.20mol / L) = 0.01 moles Al(NO₃)₃
Moles KOH:
0.200L * (0.100mol / L) = 0.02 moles of KOH
Thus, for a complete reaction of 0.02 moles of KOH are needed (Using the chemical equation)
0.02 moles of KOH * (1 mol Al(NO₃)₃ / 3 mol KOH) = 0.0067 moles of Al(NO₃)₃.
As there are 0.01 moles of Al(NO₃)₃, this is the excess reactant and KOH is the limiting reactant.
The 0.02 moles of KOH produce:
0.02 moles of KOH * (1 mol Al(OH)₃ / 3 mol KOH) = 0.0067 moles of Al(OH)₃
In mass (Using molar mass of Al(OH)₃: 78g/mol):
0.0067 moles of Al(OH)₃ * (78g/mol) =
0.52g of Al(OH)₃PLS HELP!!!!
How do the products of chemical reactions compare to their reactants?
The products usually have more atoms than the reactants.
The products usually weigh more than the reactants.
The products often have completely different properties than the reactants.
The products are usually more toxic than the reactants.
How do the products of chemical reactions compare to their reactants?
Answer:
The products often have completely different properties than the reactants.
The correct answer to the question is: The products often have completely different properties than the reactants.
In a chemical reaction, the reactants and products of the reaction have different properties because during the reaction, bonds were broken and new bonds were formed which generate a new substance called the product.
However, chemical equations must be balanced in order to conform to the law of conservation of matter which states that matter can neither be created nor destroyed during a chemical reaction but can be transferred from one form to the other.
For example, the reaction of Hydrogen gas (H₂) and oxygen gas (O₂) to produce water (H₂O)
2H₂(g) + O₂(g) —> 2H₂O(l)From the equation, we can see that the reactants are gases but the product is a liquid which has a different properties from the gaseous reactants.
Therefore, the correct answer to the question is: The products often have completely different properties than the reactants.
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