Answer:
They must be selected for a narrow pH range.
Explanation:
Indicators are compounds that change to a specific colour in a solution within a specific pH range.
The chemical indicators does not give the exact value of pH. They only provide the range of pH. They must be selected for a narrow pH range. The correct option is C.
What is chemical indicator?The acid base indicators or neutralization indicators are substances which are employed for the visual detection of the end point on the basis of their ability to change colour during the pH change that occurs in vicinity of the end point.
The chemical indicators are usually weak organic acids or bases which change colour in characteristic pH ranges. The particular range or interval of pH in which an acid-base indicator changes its colour is known as the colour-change interval.
Methyl orange is a weak base which changes its colour in the pH range 3.1-4.4 being red below pH 3.1 and yellow above pH 4.4.
Thus the correct option is C.
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31. Solve this Gibbs' Free Energy Equation:
For a reaction at 200 K, the Delta H has a value of 250 kJ and the Delta S has a value of 0.100 kJ. 1s
the reaction spontaneous or not spontaneous?
Answer:The standard Gibbs energy change at 300K for the reaction 2A⇔B+C is 2494.
Explanation:
ΔG = free energy at any moment.
ΔGo = standard-state free energy.
R is the ideal gas constant = 8.314 J/mol-K.
T is the absolute temperature (Kelvin)
lnQ is natural logarithm of the reaction quotient
Which of the nine substances are made of three elements?
Answer: You are made of mostly 6 elements: Oxygen, Carbon, Hydrogen, Nitrogen, Calcium, and Phosphorus. Some of these elements combine to form compounds in your body.
Explanation:
Why is the distance traveled between seconds 0 and 1 less than the distance traveled between 2 and 3 sceonds
Answer:
The ball speeds up
Explanation:
Write the name of flame used In charcoal cavity test.why?
Answer:
the reducing flame also called the carburizing flame.
Explanation:
because it gets the oxides of the unknown salts
1 mole of any gas is equivalent to?
Answer:
22.4 L at standard temperature and pressure.
Which of the following pairs of elements will combine to produce a covalent bond?
1-Hydrogen and chlorine
2-Magnesium and oxygen
3-Lithium and bromine
Answer:
Hydrogen and Chlorine
ie HCL
The pairs of chemical elements that will combine to produce a covalent bond is: 1. Hydrogen and chlorine.
In Chemistry, the three (3) main types of chemical bonds include:
Ionic bonds: Lithium and bromineHydrogen bonds: Hydrogen and oxygen.Covalent bonds: Hydrogen and chlorine.A covalent bond can be defined as a type of bond that typically involves the sharing of electrons between the atoms of a chemical element.
For example, the type of bond that is produced (formed) between hydrogen atoms and a chlorine atom is a covalent bond.
The hydrogen atom shares it single electron with a chlorine atom that is having seven (7) valence electrons to produce an inert gas such as hydrochloric acid (HCL).
In conclusion, the pairs of chemical elements that will combine to produce a covalent bond is hydrogen and chlorine.
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I went for a walk the other day. I went four blocks east, then seven blocks south, then one block west and finally
eight blocks north
a.What distance did I travel?
b. What's my displacement?
Answer:
a) distance is 4+7+1+8=20 blocks
b) displacement is 10 blocks
Explanation:
find displacement: x and y
x axis displacement = 4-1 = 3 blocks
y axis displacement = -7+8= 1 block
displacement = the square root of 3^2 + 1^2
= 9+1 = 10 blocks.
You can find the angle of displacement with respect to the initial position using trig identities, if you wish.
Why is there a hole in the ozone layer? What do you think the consequences of that hole are?
Answer:
There is a ozone layer because of the special atomphere and chemical conditions that takes place there. I think the consequences of that home area is the very low winter temperatures.
Answer:
There is a hole in the ozone layer because of the pollution on earth. Because of that the UV rays are easily entering the earth through that portion. The consequences of this can be cancers, global warming and disastrous storms.
plz mark as brainliest
Pls 50 points right answer gets brainliest
Explain the meaning of thermal energy transfer and give specific examples of conduction, convection, and radiation.
Answer:
thermal energy: the part of total internal energy that can be transferred (a portion of the kinetic energy)
heat is the thermal energy that flows from one substance to another due to a temperature difference.
Thermal energy is measured in temperature change.
Thermal energy transfer stops when thermal equilibrium is achieved (Both substances at the same temperature).
conduction: Transfer of thermal energy through a solid object like heat transferring up a metal spoon from a hot cup of coffee.
convection: the transfer of thermal energy due to the movement of a liquid or gas caused by differences in temperature. Only in a fluid (liquid or gas). Breezes, ocean currents.
radiation: Transfer energy with or without matter. Warming from the Sun, microwave oven.
Answer:
Conduction is the transfer of thermal energy through direct contact. Convection is the transfer of thermal energy through the movement of a liquid or gas. Radiation is the transfer of thermal energy through thermal emission. Hope this helps!
Explanation:
what is a molecule??
Answer:
molecule is a group of atoms bonded together representing the smallest fundamental unit of a chemical reaction
A 25.00 mL sample of the ammonia solution
was accurately diluted to 250.0 mL. A 25.00mL
aliquot of the diluted ammonia solution was
placed in a conical flask. Indicator was then added
and the solution was titrated with 0.208 molL-1
hydrochloric acid. The indicator changed colour
permanently when 19.64 mL of the acid had been
added. Calculate the concentration of ammonia in
the original solution.
Answer:
1.634 molL-1
Explanation:
The mol ration between NH3 and HCl is 1 : 1
Using Ca Va / Cb Vb = Na / Nb where a = acid and b = base
Na = 1
Nb = 1
Ca = 0.208 molL-1
Cb = ?
Va = 19.64 mL
Vb = 25.00mL
Solving for Cb
Cb = Ca Va / Vb
Cb = 0.208 * 19.64 / 25.0
Cb = 0.1634 molL-1 (Concentration of diluted ammonia solution)
Using the dilution equation;
C1V1 = C2V2
Initial Concentration, C1 = ?
Initial Volume, V1 = 25.00 mL
Final Volume, V2 = 250 mL
Final Concentration, C2 = 0.1634 molL-1
Solving for C1;
C1 = C2 * V2 / V1
C1 = 0.1634 * 250 / 25.00
C1 = 1.634 molL-1
can someone answer this
Answer:
choice B
58Fe^2+
Explanation:
hope this helped
when a rotting log was turned over, pill bugs, termites , ants , fungi , and earthworms were living there. the termites represent ____ in its
a. an environment
b. a population
c. a niche
d. an abiotic factor
weeks and how much money, in dollars, Jamal deposits into the savings account.
Week
Deposit (dollars)
0
10
1
15
2
20
3
25
4
30
Let f ()represent the amount of money Jamal deposits into his savings account at the end of 2 weeks. Based on the table,
what is f(10)?
E
A
50
0
С
D
60
B
10
2.
3
4
5
6
7
8
9
10 11
Next
Activat
Go to Setto
1002A
3/19/20
CH
O
BH
Type here to search
An
196 becase we all rice
Explanation:
before you retire in the evening, you sit down for a snack of milk and cookies. when you waken in the morning, you discover a carton of sour milk on the counter. knowing that milk sours if left in the refrigerator too long, has the reaction rate increased or decreased for the carton of milk on the counter? what has happened to its reaction time
Answer:
Increased
Explanation:
We know that the higher the temperature the higher the rate of reaction. This implies that as the temperature is increased, a reaction tends to proceed faster.
This follows from the collision theory, the higher the temperature, the higher the energy of the reacting particles hence they collide with each other faster and more effectively.
Thus the rate of reaction( or reaction time) for the carton of milk on the counter was increased.
Did anyone do this worksheet (science)
Directions: Show all of your work for each of the following problems.
3. What is the % Ba in Ba(NO3)2?
4. What is the % of each element in Ni3(PO4)2?
5. What is the % of each element in Al2(CrO4)3?
6. What is the % of each element in (NH4)2(SO4)?
Answer:
3.Ba=24.Ni=2...PO4=35.Al=3...CrO4=26.NH4=1...SO4=2Which element would be the most suitable to make a spoon that will melt in
your hot drinks?
A) aluminium
melting point: 660°C
boiling point: 2470°C
B) argon
melting point: -189°C
boiling point:-186°C
C) bromine
melting point: -7°C
boiling point: 59°C
D) gallium
melting point: 30°C
boiling point: 2400°C
E) lithium
melting point: 180°C
boiling point: 1330°C
F)mercury
melting point: -39°C
boiling point:357°C
Answer:
it's A) or E)
others are not suitable cuz their melting point is weak.
Answer:
Gallium
Explanation:
Because the melting point is low and the drinks are usually around 60-70 degrees Celsius so it wil melt
When naming an acid, which of the following is true?
chlorite changes to chloric acid
chlorate changes to chloric acid
none of these is true
chlorate changes to chlorous acid
Answer:
chlorate changes to chlorous acid
At which type of tectonic plate boundary is a volcano least likely to occur?
Answer: the answer is a
Explanation:
I took the test and got it wrong because someone said the answer was divergent boundary and it’s wrong. I hate them I hate them I hate them. I hate it I hate school
Transform boundary is the type of tectonic plate boundary is a volcano least likely to occur.
What is meant by Transform boundary?A transform fault or transform boundary, sometimes called a strike-slip boundary, is a fault along a plate boundary where the motion is predominantly horizontal. It ends abruptly where it connects to another plate boundary, either another transform, a spreading ridge, or a subduction zone.Transform boundary is the type of tectonic plate boundary is a volcano least likely to occur.
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What is the volume of an object that has a mass of 5.80 g and a density of 6.35 g/mL?
Answer:
1.09 mL
Explanation:
Density is a measure of a substance's mass over its volume.
d = m/v
We can rearrange the equation to solve for volume, using algebra.
v = d/m
Therefore v = 6.35/5.80 = 1.09 mL
Which of the nine substances are made of four elements?
Answer:
Oxygen mucury carbon dioxide and platinum
Explanation:
Which feature separates watershed
Answer:
Ridges.
Explanation:
Watersheds are separated from one another by ridges. Ridges are elevated boundaries that divide watersheds.
Which type of solute would have the greatest impact on a colligative property?
A. C6H12O6
B. NaCl
potassium hydroxide , sodium chloride, sodium hydroxide ,calcium chloride , sodium bicarbonate write molecular formula
✧ [tex] \underline{ \underline{ \large{ \tt{A \: N \:S \: W \: E \: R}}}} : [/tex]
[tex] \underline{ \underline{ \large{ \text{Molecular \: Formulaes}}}} : [/tex]
⇾ [tex] \large{ \text{Potassium \: Hydroxide : K \: OH}}[/tex]
⇾ [tex] \large{ \text{Sodium \: Chloride : NaCl}}[/tex]
⇾ [tex] \large{ \text{Sodium \: Hydroxide : NaOH}}[/tex]
⇾ [tex] \large{ \text{Calcium \: Chloride : CaCl}}[/tex]
⇾ [tex] \large{ \text{Sodium \: Bicarbonate} : \tt{Na ( HCO)_{ 3} }}[/tex]
---------------------------------------------------------
☥ [tex] \underline{ \underline{ \large{ \tt{ \: E \: X\: P \: L\: A\: N \: A \: T \: I \: O \: N}}} }: [/tex]
[tex] \underline{ \underline{ \text{Writing \: a \: molecular \: formula}}} : [/tex]
To write a molecular formula , the following steps are usually adopted only when we know the symbol and valencies of elements and radicals present in a molecule.
Step 1 : First , the name of the compound is written.
Step 2 : The symbols of basic and acidic radicals are written side by side.
Step 3 : The valency of each radical is written at the right upper corner of the symbol. The valency of one radical is transferred to another radical and it is written on the right hand side at the bottom corner. If necessary , L.C.M of the valencies us taken to get a simple whole number.
Step 4 : If a compound radical takes part in the molecular formula , the radical is enclosed in brackets and the valency number is written on the right side of the bracket at the bottom of the formula.
For instance :
[tex] \text{Calcium \: \: \: \: \: \: Sulphate}[/tex] [ compound ]
1. [tex] \sf{Ca \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: SO_{4} }[/tex] [ Symbol of basic and acidic radicals ]
2.We know : Valencies of calcium and sulphate are 2 and 2 respectively
3. [tex] \sf{Ca_{2} \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: (SO_{4} )_{2} }[/tex] [ Valencies are exchanged and compound radical is enclosed in bracket ]
4.[tex] \sf{CaSO_{4}}[/tex] [ L.C.M is taken to get molecular formula of calcium sulphate ]
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Use a scientific calculator to calculate [H+] for the following pH values:
7 (a neutral solution)
5.6 (unpolluted rainwater)
3.7 (first acid rain sample in North America)
How many times higher is the concentration of H+ in the Hubbard Brook sample than in unpolluted rainwater?
Answer:
pH = 7 ⇒ [H⁺] = 1.0x10⁻⁷ M
pH = 5.6 ⇒ [H⁺] = 2.5x10⁻⁶ M
pH = 3.7 ⇒ [H⁺] = 2.0x10⁻⁴ M
H⁺ concentration in the Hubbard Brook sample is 80 times higher than in unpolluted rainwater.
Explanation:
To answer this problem we need to keep in mind the definition of pH:
pH = -log[H⁺]Meaning that after isolating [H⁺] we're left with:
[H⁺] = [tex]10^{-pH}[/tex]Now we proceed to calculate [H⁺] for the given pHs:
pH = 7 ⇒ [H⁺] = [tex]10^{-7}[/tex] = 1.0x10⁻⁷ MpH = 5.6 ⇒ [H⁺] = [tex]10^{-5.6}[/tex] = 2.5x10⁻⁶ MpH = 3.7 ⇒ [H⁺] = [tex]10^{-3.7}[/tex] = 2.0x10⁻⁴ MFinally we calculate how many times higher is [H⁺] when pH = 3.7 than when pH = 5.6.
2.0x10⁻⁴ / 2.5x10⁻⁶ = 80Answer:
1. 7 (a neutral solution)
Answer: 10-7= 0.0000001 moles per liter
2. 5.6 (unpolluted rainwater)
Answer: 10-5.6 = 0.0000025 moles per liter
3. 3.7 (first acid rain sample in North America)
Answer: 10-3.7 = 0.00020 moles per liter
The concentration of H+ in the Hubbard Brook sample is 0.00020/0.0000025, which is 80 times higher than the H+ concentration in unpolluted rainwater.
Explanation: -
When does the energy in the H atom get closer
Answer:
3.48 g
Explanation:
Because its useful.
Revise this statement to make it true:
Running water makes rock edges very sharp and pointy.
NEED HELP NOW PLEASE!! WHOEVER ANSWERS FIRST GETS BRAINIEST!!! No links or I’m reporting your answer.
Answer:
Running water makes rock edges very dull because of erosion.
Explanation:
hope this helps ^_^
how many moles is 130g of cocl2
Answer:
1.3142 mol CoCl2
Explanation:
Well, to answer this we need to find out how many grams are in a single mole of CoCl2. Two find that we need to get the molar mass of CoCl2
Co = 28.0101 g Co per mole
Cl = 35.453 * g Cl per mole
28.0101 + 2 * 35.453 = 98.9161 g CoCl2 per mole
Now, we divide:
130/98.9161 = 1.3142 mol CoCl2
There are 1.31 moles in 130grams of cobalt chloride (CoCl2). Details about how to convert mass to moles can be found below.
How to calculate number of moles?The number of moles of a substance can be calculated by dividing the mass of the substance by its molar mass.
According to this question, there are 130g of CoCl2.
molar mass of CoCl2 = 28 + 35.5(2) = 99g/mol
moles = 130g ÷ 99g/mol
moles = 1.31 moles
Therefore, there are 1.31 moles in 130grams of cobalt chloride (CoCl2).
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A 500-gram block of solid cheese is melted in a pot. Which is most likely be the mass of the cheese after it is melted?
pleaseeeeeeeeee answer
Answer:
due to the law of conservation of mass, the mass would stay the same.