Answer:
Energy is never lost, it just changes from one form to another
How many centimeters make an inch?
Answer:
2.54 Centimeters.
PLEASE HELP QUICK!
Your organ systems do not function
independently. Consider the following
scenarios, and explain how different
organ systems are working together.
a) You step on hot pavement in the
summer and quickly pull your foot
back.
(b) after running up the stairs you
breathe a little harder.
(c) A friend has a cold, and three days
later you have a cold too.
Answer:A
Explanation:
Your muscular system is at work
Perform the following operation
and express the answer in
scientific notation.
4.3x102 -7.0x 102
Answer:
-2.7 ×10²
Explanation:
Scientific notation is the way to express the large value in short form.
The number in scientific notation have two parts.
. The digits (decimal point will place after first digit)
× 10 ( the power which put the decimal point where it should be)
for example the number 6324.4 in scientific notation will be written as = 6.3244 × 10³
Given measurements = 4.3×10² - 7.0 ×10²
= -2.7 ×10²
The rearrangement which most likely occurs in the following reaction can be described as a
HBr
(CH3)2CHCH=CH2 →
a. hydride shift from C-2 to C-1.
b. hydride shift from C-3 to C-2.
c. proton shift from C-2 to C-1.
d. methyl group shift from C-3 to C-2.
Answer:
b. hydride shift from C-3 to C-2.
Explanation:
Markovnikov's rule states that *in the addition of a protic acid HX or other polar reagent to an asymmetric alkene, the acid hydrogen (H) or electropositive part gets attached to the carbon with more hydrogen substituents, and the halide (X) group or electronegative part gets attached to the carbon with more alkyl substituents* (wikipedia).
This rule implies that the hydrogen of HBr will be attached to C-1 and the carbocation will be on C-2. Remember that the order of stability of carbocations is tertiary > secondary > primary > methyl. A hydride shift can yield a tertiary carbocation.
C-3 is a tertiary carbon atom. If the hydride on carbon 3 shifts to carbon 2, a tertiary and more stable carbocation is formed. This accounts for the major product in the reaction.
Ethanol has the chemical formula C2H5OH. Write and balance the chemical reaction for the combustion of ethanol
Answer:
C2H5OH(l)+3O2(g)⟶2CO2+3H2O(l)
Explanation:
The balanced equation for the combustion of ethanol will be
[tex]C_{2}H_{5}OH+3O_{2}------- > 2CO_{2}+3H_{2}O[/tex]. According to this carbon dioxide and water will be the product.
What is combustion?
Combustion is a chemical process during which a material reacts quickly with oxygen and generates heat.
The original substance is referred to as the fuel, and the supplier of oxygen is referred to as the oxidizer. The fuel can be solid, liquid, or gas, but it is usually a liquid for airplane propulsion.
Combustion is a chemical reaction between two or more substances, usually involving oxygen, that produces light and heat in the form of a flame.
The products of complete ethanol combustion are carbon dioxide and water, as well as the start releasing of light and heat.
The equation will be:
[tex]C_{2}H_{5}OH+3O_{2}------- > 2CO_{2}+3H_{2}O[/tex]
Thus, in this way, the combustion of ethanol occurs.
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what is the answer i need help
so it is necessary to place the coefficient 2 in the front of HCL to balance the chemical equation to prove that
we have two CL and two H atoms in the products and one Cl and one H atom in the reactants so if we dont put 2 in front of HCL the chemical equation will not be balanced
Which of the following salts will be less soluble in 0.10 M NaCl than it is in pure water?
PbF2
CaCO3
All of the options are less soluble in 0.10 M NaCl than in pure water.
PbCl2
The less soluble salt : PbCl₂
Further explanationGiven
0.1 M NaCl
Required
The less soluble salt
Solution
If we see from the answer option, the salt that is more difficult to dissolve in NaCl is PbCl₂ because it has the same ion (Cl)
When PbCl₂ is dissolved in water, ionization will occur
PbCl₂ ⇒ Pb²⁺+ 2Cl⁻
So, when dissolved in NaCl, NaCl itself will be ionized
NaCl ⇒ Na⁺ + Cl⁻
Based on the principle of equilibrium, the addition of an ion (one of the ions is enlarged), the reaction will shift towards the ion that was not added. In addition to this Cl ion, the reaction will shift to the left so that the solubility of PbCl₂ will decrease (the reaction to the right decreases)
A solution of sulfuric acid (H2SO4, 25.00 mL) was titrated to completion with 34.55 mL of 0.1020 M sodium hydroxide. What was the concentration of the sulfuric acid
Answer:
0.0705 M
Explanation:
We'll begin by writing the balanced equation for the reaction. This is given below:
H₂SO₄ + 2NaOH —> Na₂SO₄ + 2H₂O
From the balanced equation above,
The mole ratio of the acid, H₂SO₄ (nA) = 1
The mole ratio of the base, NaOH (nB) = 2
Next, data obtained from the question. This include the following:
Volume of acid, H₂SO₄ (Va) = 25 mL
Volume of base, NaOH (Vb) = 34.55 mL
Molarity of base, NaOH (Mb) = 0.1020 M
Molarity of acid, H₂SO₄ (Ma) =?
The molarity of the acid, H₂SO₄ can be obtained as follow:
MaVa / MbVb = nA/nB
Ma × 25 / 0.1020 × 34.55 = 1/2
Ma × 25 / 3.5241 = 1/2
Cross multiply
Ma × 25 × 2 = 3.5241
Ma × 50 = 3.5241
Divide both side by 50
Ma = 3.5241 / 50
Ma = 0.0705 M
Therefore, the concentration of the acid, H₂SO₄ is 0.0705 M
Answer:
C=0.140964M
Explanation:
M1V1=M2V2
DATA
M1=?
M2=0.1020M
V1=25.00ML
V2=34.55ML
M*25.00ML=(0.1020M)*(34.55ML)
M*25.00ML=3.5241M*ML
M=3.5241M*ML/25.00ML
M=0.140964M
Therefore, concentration of sulfuric acif is 0.140964M
How many joules of heat are given off when 5.00g of water cool from 348.0K to 298.0K?
Answer:
Q = -1045 J
Explanation:
Given data:
Mass of water = 5.00 g
Initial temperature = 348.0 K
Final temperature = 298.0 K
Heat given off = ?
Solution:
Specific heat capacity:
It is the amount of heat required to raise the temperature of one gram of substance by one degree.
Specific heat capacity of water is 4.18 J/g.K
Formula:
Q = m.c. ΔT
Q = amount of heat absorbed or released
m = mass of given substance
c = specific heat capacity of substance
ΔT = change in temperature
ΔT = 298.0 K - 348.0 K
ΔT = - 50 K
Q = 5.0 g ×4.18 J/g.K× - 50 K
Q = -1045 J
What is the purpose of the cooling tower?
A. pumps cool water into the reactor
B. reduces heat pollution to the environment
C. cools down the electric generator
Answer:
id say c though im not sure
Explanation:
Cooling towers are primarily used for heating, ventilation, and air conditioning (HVAC) and industrial purposes.
Answer:
c
Explanation:
i had this on my test
Phenylephrine is a nasal decongestant and is the active ingredient in Sudafed, which contains phenylephrine hydrochloride (PEHCL). The conjugate acid (PEH+) of phenylphrine has a pKa = 5.5. At a physiological pH of 7.4. what is the ratio of concentrations, [PE]/[PEH+]?
Answer:
The ratio of concentrations is 79.4
Explanation:
Using Henderson-Hasselbalch equation we can solve the [PE]/[PEH+] ratio:
pH = pKa + log [A-] / [HA]
Where pH is 7.4
pKa of the phenylphrine is 5.5
[A-] is the weak base = [PE]
And [HA] is the conjugate acid [PEH+]
Replacing:
7.4 = 5.5 + log [PE] / [PEH+]
1.9 = log [PE] / [PEH+]
79.4 = [PE] / [PEH+]
The ratio of concentrations is 79.4
PLEASE HELP!!! WILL MARK BRIANLIST DO NOT GUESS I HAVE ATTEMPTED THREE TIMES
What is the reducing agent in the following reaction
5Fe2+(aq) + MnO4-(aq) + 8H+(aq) → 5Fe3+(aq) + Mn2+(aq) + 4H2O(I)
A. MnO4-
B. Fe3+
C. Mn2+
D. Fe2+
E. H+
Answer: [tex]Fe^{2+}[/tex] is the reducing agent
Explanation:
Oxidation reaction : When there is an increase in oxidation state number.
Reduction reaction : when there is a decrease in oxidation state number.
[tex]5Fe^{2+}(aq)+MnO_4^-(aq)+8H^+(aq)\rightarrow 5Fe^{3+}(aq)+Mn^{2+}(aq) +4H_2O(l)[/tex]
Fe has undergone oxidation, as its oxidation state is changing from+2 to +3.
Mn has undergone reduction, as its oxidation state is changing from +7 to +2.
The chemical agent which itself get oxidized and reduce others is called reducing agent. [tex]Fe^{2+}[/tex] is a reducing agent.
The chemical agent which itself get reduced and oxidize others is called oxidizing agent. [tex]MnO_4^-[/tex] is an oxidizing agent.
.
Which statements describe density? Check all that apply.
O Density is a chemical property of an object.
O The density of an object is constant.
O Density is a derived unit of measure.
D Density is the sum of the mass and volume of an object.
I The density of an object determines whether it will sink or fioat.
Answer:
2,3,5
Explanation:
Got correct on EDG
Which describes the number of protons in the atom of a particular element
Answer:
Atomic Number
Explanation:
The number of protons an atom has is unique to that element. The number of protons is noted as the atomic number for that element on the periodic table.
how will we know that a chemical reaction happened if we cant see atoms??
we can do soo by noticing any colour change, or by the formation of an insoluble precipitate or by the evolution of a gas.
If you ingest a chemical from lab, immediately drink plenty of milk, then contact your instructor and wait for his/her response.
a. True
b. False
Answer:
False
Explanation:
The correct answer would be false.
If a chemical is ingested while working in the lab, the correct thing to do would be to contact the lab instructor right away as eating or drinking of any kind is prohibited in the laboratory.
While drinking milk may help in some cases depending on the nature and amount of the chemical ingested, only the lab instructor has the technical know-how to analyze the situation and administer first aids. Milk has the capacity to act as a buffer in some cases pending the time the victim would be able to get adequate medical attention.
How many protons are in an element with an atomic number of 8 and mass number of 18
Answer:8
Explanation:
Atomic number = 8
Mass number = 18
The number of protons and the number of electrons is equal to the atomic number.
The number of neutrons in the nucleus is given by the difference in mass number and atomic number.
So, number of protons are 8
number of electrons = 8
number of neutrons = 18 - 8 = 10
I REALLY NEED HELP can someone help me please I’ll mark you brainliest! :)
Answer:
A
Explanation:
What is the motion of the particles in this kind of wave?
A hand holds the left end of a set of waves. The waves themselves make a larger set of waves in the same direction as that of the smaller waves. A label Wave motion is above the series of waves and an arrow next to the label points right.
The particles will move up and down over large areas.
The particles will move up and down over small areas.
The particles will move side to side over small areas.
The particles will move side to side over large areas.
Answer:
D
Explanation:
The particles will move side to side over large areas.
Answer:
The particles will move side to side over large areas.
Explanation:
Deuterium is the isotope of hydrogen of mass number 2, with a proton and a neutron in its nucleus. The chemistry of deuterium is nearly identical to the chemistry of hydrogen, except that C−D bond is slightly (5.0KJ/mole) stonger than the C−H bond. Reaction rates tend to be slower if a C−D bond as opposed to a C−H bond is broken in a rate limiting step. This effect on the rate is called a kinetic isotope effect.
a. True
b. False
Answer:
True
Explanation:
We know that the zero-point-energy of a C-D system is quite lower than the zero point energy of the C-H bond so the C-D bond is stronger.
Kinetic isotope effect refers to the change in the rate of reaction owing to a change of one of the atoms of the reactants by replacing it with one of its isotopes.
Since we know that the C-D bond is stronger than the C-H bond, when we replace hydrogen with deuterium in a reaction's rate determining step we experience a little lag in the rate of reaction. This is referred to as the kinetic isotope effect in physical organic chemistry.
Acids are substances that surround us in our everyday life. The uses of acids range from providing essential nutrients for our bodies to dissolving metals. Some acids are safe to handle with our bare hands or even use in food preparation. Other acids will severely burn human skin. Why these substances can all be acids and yet have such different properties?
Answer: Strong and Weak Acids
Explanation:
Acids, also known as electrolytes, are compounds that break down into cations (positively charged ions) and anions when dissolved in water (negatively charged ions). Solid Electrolytes (Acids) fully ionize,
Whereas weak electrolytes (acids) only partly ionize.
HELP!!!
Which climate favors mechanical weathering?
dry limate
cold climate
warm climate
desert climate
Explanation:
cold climates hope this helps :)
Answer:
Cold climates
Explanation:
Warm climates favor chemical weathering. Cold climates favor mechanical weathering. Chemical reactions occur faster at higher temperatures.
what's the alkalinity of lemon?
Answer:
Hey mate here's your answer ⤵️
Lemon juice in its natural state is acidic with a pH of about 2, but once metabolized it actually becomes alkaline with a pH well above 7
Hope it was helpfulll
5. What percentage of energy generation is
produced by fossil fuels? sc.7.P.11.2
to
(A) 19.5%
B) 33.2%
66.9%
D 86.4%
Answer:
It's actually D. 86.4%
Explanation:
When you combine coal, other gases, petroleum, nuclear, and natural gas, you get 86.4, which is the correct answer.
Write a complete chemical formula, including physical state symbol, for each element listed below in its standard state.The first row of the table has been completed.Element FormulaIron Fe(s)Phosphorus Neon Chlorine
Answer:
Phosphorus P (s)
Neon Ne (g)
Chlorine Cl (g)
Explanation:
Iron: Fe(s) - The (s) denotes that iron is in its solid state.
Phosphorus: P(s) - The (s) indicates that phosphorus is in its solid state.
Neon: Ne(g) - The (g) signifies that neon is in its gaseous state.
Chlorine: Cl₂(g) - The (g) indicates that chlorine exists as a diatomic gas, with the formula Cl2, in its standard state.
Iron (Fe):
Iron is a chemical element commonly found in its solid state under standard conditions. The chemical symbol for iron is Fe, which is derived from the Latin word "ferrum." Iron is a lustrous, silvery-gray metal and is known for its strength and ability to be magnetized. In its standard state, iron exists as a solid, denoted by the (s) symbol. Therefore, the complete chemical formula for iron in its standard state is Fe(s).
Phosphorus (P):
Phosphorus is an element that exists in various forms, with the most common form being a solid known as white phosphorus. Under standard conditions, white phosphorus is the most stable and prevalent form. It is a waxy, white-to-yellowish solid that is highly reactive and combustible. The chemical symbol for phosphorus is P, and it is represented by the (s) symbol to indicate its solid state. Therefore, the complete chemical formula for phosphorus in its standard state is P(s).
Neon (Ne):
Neon is a chemical element that exists as a gas under standard conditions. It is a noble gas and is known for its bright red-orange glow when used in signs and lighting. Neon is chemically inert, meaning it does not readily react with other substances. The chemical symbol for neon is Ne, and it is represented by the (g) symbol to indicate its gaseous state. Therefore, the complete chemical formula for neon in its standard state is Ne(g).
Chlorine (Cl):
Chlorine is a halogen element that exists as a diatomic gas under standard conditions. It is a highly reactive and corrosive substance with a yellowish-green color and a pungent odor. Chlorine exists as a molecule with two chlorine atoms bonded together, forming Cl₂. The (g) symbol is used to indicate that chlorine exists as a gas. Therefore, the complete chemical formula for chlorine in its standard state is Cl₂(g).
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The half-life for a first-order reaction is 32 s. What was the original concentration if, after 2.0 minutes, the reactant concentration is 0.062 M?
Answer:
0.834 M.
Explanation:
Hello!
In this case, since this is a first-order reaction, we can infer that the half-life and the rate constant are related via:
[tex]t_{1/2}=\frac{ln(2)}{k}[/tex]
Thus, we are able to compute the rate constant:
[tex]k=\frac{ln(2)}{t_{1/2}} =\frac{ln(2)}{32s}\\\\k=0.0217s^{-1}[/tex]
Next, since we have the resulting concentration of the reactant and we need the initial one, we proceed as shown below with the rate law:
[tex]A=A_0exp(-kt)\\\\A_0=\frac{A}{exp(-kt)} \\\\A_0=\frac{0.062M}{exp(-0.0217s^{-1}*2.0min*\frac{60s}{1min} )}\\\\A_0=0.834M[/tex]
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I want to prepare 4 Liters of 0.25 M aqueous sodium chloride solution. How many grams of the salt will I need to weigh out?
Answer:
Mass = 58.5 g
Explanation:
Given data:
Volume of solution = 4 L
Molarity of solution = 0.25 M
Grams of NaCl required = ?
Solution:
Formula:
Molarity = number of moles / volume in L
By putting values,
0.25 M = number of moles / 4 L
Number of moles = 0.25 mol/L × 4 L
Number of moles = 1 mol
Mass in gram:
Mass = number of moles × molar mass
Mass = 1 mol × 58.5 g/mol
Mass = 58.5 g
Calculate the pH after 10.0 mL of 0.125 M NaOH is added to 30.0 mL of 0.105 M HCHO2.
Ka (HCHO2) = 1.8 × 10-4
Answer:
pH = 3.57 after adding 10ml of 0.125M NaOH
Explanation:
NaOH + HCHO₂ => NaCHO₂ + H₂O
=> 10ml(0.125M NaOH) + 30ml(0.030M HCHO₂)
=> 0.01(0.125)mol NaOH + 0.036(0.030)mol HCHO₂ ***(see reference note at end of problem)
=> 0.00125mol NaOH + 0.00315mol HCHO₂
=> (0.00315mol - 0.00125mol) HCHO₂ = 0.0019mol HCHO₂ in excess
+ 0.00125mol NaCHO₂ formed.
HCHO₂ ⇄ H⁺ + CHO₂⁻
C(i): 0.0019mol/0.040L 0.00M 0.00125mol/0.40L
= 0.0475M = 0.0313M
ΔC: -x +x +x
C(eq): 0.0475 - x x 0.0313 +x
Ka = [H⁺][CHO₂⁻]/[HCHO₂] = (X)(0.0313 + x)/(0.0475) = 1.8 X 10⁻⁴
=> x² + 0.03168x + (-8.55 x 10⁻⁶) = 0
Solve with quadratic equation ...
x = 2.68 x 10⁻⁴M = [H⁺] at equilibrium
pH = - log[H⁺] = -log(2.68 x 10⁻⁴) = -(-3.57) = 3.57
___________________________________
*** remember, => moles = Molarity x Volume in Liters
What do u call a snowman in the summer
Answer:
A puddle
Explanation:
BAHAHAHAHA