.
Which buffer can be suitable to prepare a solution that needs to be buffered at pH 4? Explain your
choice.
A. Formic acid/Formiate buffer
B. Carbonic acid/Bicarbonate buffer
C. Ammonia/Ammonium buffer
D. Any buffer will work.
E. None of the buffers will be suitable.
34 Which of the following will form a buffer when mixed together? Explain a weak acid/base and its conjugate base/acid in the form of salt
NH4Cl + AgNO3 → AgCl + NH4NO3
Approximately 50% of our bone is chemically calcium phosphate, Ca3(PO4)2
If an adult has 12 kg of bone, calculate the mass of calcium is present
the amount of gram - atoms in two gramm of sulfur is (NB: S=32amu)
Answer:
3.76375e+22
Explanation:
(2/32)×(6.022 × 10^23)
You are watching tv and you see something on the corner of your eye what do you do and you're home alone
Talk to the doctor if you see something in the corner of your eye.
What is a visual hallucination?Visual hallucinations involve seeing things that aren't there.
It's called a visual hallucination, and it can seem like your mind is playing tricks on you. Beyond being scary or stressful, it's also usually a sign that something else is going on.
So if it's happening to you, talk to your doctor. That's the first step toward getting better.
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which of the following best describes what happens during nuclear fusion
Answer:
Nuclear fusion is a kind of nuclear reaction in which two lighter nuclei combine under suitable conditions to form heavier nuclei under suitable conditions. A lot of energy is released in this process.
Which TWO of the following processes will increase the concentration of al solution?
(a) Increase the amount of solute.
(b) Decrease the amount of solute.
(c) Increase the amount of solvent.
(d) Decrease the amount of solvent.
Answer:
B decrease the amount of solute
Classify each of the following substances as a compound or element.
a. Gold _____________
b. Ethanol _____________
c. Sugar _____________
d. Sulfur _____________
e. Hydrogen gas______
f. Carbon dioxide_______
Answer:
A. Element
B. Compound
C. Compound
D. Element
E. Compound
F. Compound
Explanation:
Elements are what is already on the periodic table and compounds are the substances created when they are combined.
A hot-air balloon has a pressure of 0.715 atm while the temperature outside is 200C. What will the pressure be if the temperature drops to 5C while the volume remains constant?
1.12 kPa
11.2 atm
1203 atm
1.12 atm
The ideal gas law (PV = nRT) relates the macroscopic properties of ideal gases. An ideal gas is a gas in which the particles (a) do not attract or repel one another and (b) take up no space (have no volume).
From the question given above, the following data were obtained :
Initial pressure (P₁) = 0.715 atmInitial temperature (T₁) = 200 °CFinal temperature (T₂) = 195 °CVolume = constantFinal pressure (P₂) = ?Now, Let's convert celsius temperature to Kelvin temperature ;
T(K) = T(°C) + 273
Initial temperature (T₁) = 200 °C = 200 °C + 273 = 473 KFinal temperature (T₂) = 195 °C = 195 °C + 273 = 462 KNow, we shall can determine the final pressure (P₂) ;
Initial pressure (P₁) = 0.715 atmInitial temperature (T₁) = 473 KFinal temperature (T₂) = 462 KFinal pressure (P₂) = ?P₁ / T₁ = P₂ / T₂
0.715 / 473 = P₂ / 462
473 × P₂ = 0.715 × 462
P₂ = 0.69 atm
Thus, the final pressure of the hot air balloon is 0.69 atm
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Activity 1.3 Put an unlit incense stick in a corner of your class. How close do you have to go near it so as to get its smell? Now light the incense stick. What happens? Do you get the smell sitting at a distance? Record your observations.
QUESTION 1
What happens when water droplets are on a glass surface?
O They scatter around, maintaining their spherical shapes.
They spread and stick to the surface.
They join to form on gigantic sphere.
O They evaporate.
Answer:
It appears all of them are correct
Smaller drops will scatter around while maintaining their shape
Larger drop will spread stick to the surface.
and drops close together will join to form on gigantic sphere(but not perfect sphere)
and if they are in the sun, they'll eventually evaporate
Explanation:
Question 4
2 pts
2 NH3 + 3 CuO g 3 Cu + N₂ + 3 H₂O
In the above equation how many moles of water can be made when 14 moles of NH3 are
consumed?
Answer:
9.33
Explanation:
balanced chemical equation:
2NH₃ + 3CuO → 3Cu + N₂ + 3H₂O
14 moles of NH3
2NH₃ → 3H₂O
14 * 2/3 = 9.33
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Question 18 of 32
What is a covalent bond?
OA. A bond in which molecules share electrons
OB. A bond in which atoms share electrons
C. A bond between ions of the same charge
Answer: A. A bond in which molecules share electrons
What is the number of elements in 2Ca(OH)2
Consider this reaction, which occurs in the atmosphere and contributes to photochemical smog:
2Fe(s) + 3Cl2(g) →2FeCl3(s)
If there is 15.52 g Fe and excess Cl2 present, the reaction yields 34.5 g FeCl3. Calculate the
percent yield for the reaction.
%
2Fe(s) + 3Cl₂(g) →2FeCl₃(s)
mol Fe = 15.52 : 56 g/mol = 0.277
mol FeCl₃ = mol Fe = 0.277 (same coefficient)
mass FeCl₃ = 0.277 x 162.2 g/mol = 44.93 g
% yield = 34.5 : 44.93 = 76.79 %
What type of reaction is illustrated?
Answer:
Synthesis
Explanation:
Carbon + Difluorine = Tetrafluoromethane.
1 mole of Carbon [C] reacts with 2 moles of Difluorine [F2] to form 1 mole of Tetrafluoromethane [CF4]
Which of the following statements would correct one of the roles listed in the table?
O Glucose combines with water to form carbon dioxide,
OGlucose reacts with carbon dioxide during photosynthesis.
OOxygen is formed along with glucose during photosynthesis.
O Chlorophyll stores chemical energy needed for photosynthesis.
Answer:
a
Explanation:
glucose combined with water to form carbon dioxide
Answer:
Option C
Explanation:
Because during photosynthesis the reaction is as per following
CO_2+H_2O—»C_2H_12O_6+O_2Clearly
Glucose nd oxygen are formed
Identify bond types as either ionic, metallic or covalent
HCN
Fe
PbO
Si
Answer:
In ionic bond one element should be metal and next should be non metal. in covalent both element should be met Alice. if there valence electron is less than 4 than it is metal or more than 4 it is non metal.
light frequency 1.40x10^15 Hz strike a surface causing photoelectrons to leave with a KE of 1.05 eV what is the work function in eV
Answer:
The Work Function is 4.74eV.
Explanation:
The photoelectric effect is a phenomenon in which a beam of light is projected towards a metal plate and this leads to the ejection of electrons from the metal. The minimum amount of energy required for this ejection of electrons is known as the work function. When the energy of the light beam is less than the work function, then the electrons are not emitted.
The photoelectric effect is represented by the equation:
E = φ + KE where
E = energy of the incident photons
KE = kinetic energy of photoelectrons
φ = Work function of the metal
This can also be written in terms of frequency as:
h = h₀ + [tex]\frac{1}{2}[/tex] mv²
= frequency of the incident light beam
₀ = frequency of the photoelectrons
m = mass of the electron
v = velocity of the electron
h = Plank's constant 6.623 x 10⁻³⁴Js
Conversion factor: 1eV = 1.602 x 10⁻¹⁹ J
So, 1.05eV = 1.682 10⁻¹⁹ J
Using the formulas,
(6.623 x 10⁻³⁴Js)(1.40x10¹⁵ s⁻¹) = φ + 1.682 x 10⁻¹⁹ J
(9.272 x 10⁻¹⁹) - (1.682 x 10⁻¹⁹) = φ
φ = 7.590 x 10⁻¹⁹ J = 4.74 eV
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When the human body is exposed to extreme cold, hypothermia can result and the body’s temperature can drop to 28.68°C. Convert this temperature to K.
Answer:
299.83°K
Explanation:
So, kelvin is a means of measuring temperature, as the question implies. To convert Celsius, one form of measuring temperature, to Kelvin, another form of measuring temperature, we must know the conversion median. Our median is that 0°C = 273.15°K. So, now, as we know that 0°C = 273.15°K, 26.68°C = 273.15°K + 26.68°. Because 273.15K might as well be zero degrees celsius (according to our median 0°C = 273.15°K), we simply add 26.68° to 273.15K and get 299.83°K
Questions 1. Why does the colour change not occur instantly? Questions 1 . Why does the colour change not occur instantly ?in the reaction between carbon dioxide and water
Answer:
which is an example of analog device
Due to the reaction's slow process of producing ppt or a change in color.
What is chemical reaction?Chemical reaction is defined as a procedure where one or more compounds, known as reactants, are changed into one or more new substances, known as products. Chemical reactions result in the formation of new chemical bonds between the atoms of the reactant molecules and the product particles' atoms. While there are the same number of atoms both before and after the chemical transition, there will be a change in the number of molecules.
When carbon dioxide and water combine, carbonic acid is created. The indicator changes color as a result of the water becoming slightly acidic due to carbon dioxide gas from exhaled breath. Dissolution causes a change in pressure. This suggests a physical alteration.
Thus, due to the reaction's slow process of producing ppt or a change in color.
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What is an open system?
A. A system that allows energy to move in and out but not mass
B. A system that allows energy and mass to move in and out of it
C. A system that allows mass to move in and out but not energy
OD. A system that does not allow energy or mass to move in or out of
it
Answer:
Open system :-
B. A system that allows energy and mass to move in and out of it.
Hope it helps!
HELP!!! LOTS OF POINTS AND I GIVE BRIANLEST NO FAKE ANSWERS
Given the following data for water:
Heat of fusion = 334 J/g
Heat of vaporization = 2,256 J/g
Specific heat of solid = 2.09 J/(g °C)
Specific heat of liquid = 4.184 J/(g °C)
Specific heat of gas = 1.84 J/(g °C)
Calculate how much energy is needed to change 50.0 grams of ice at −15.0 °C to liquid water at 50.0 °C. (3 points)
a
11,900 J
b
16,300 J
c
18,300 J
d
21,100 J
Answer:
18300 J
Explanation:
this is because the amount of energy can be changed
how many neutrones does the isotope n-14 have
Answer: 7
Explanation:
Proton/atomic number + Neutron = atomic mass
atomic mass - protons/atomic number = neutrons
14 - 7 = 7
Is XeCl4 a molecular compound?
Answer:
Hint for Naming XeCl4
We have two non-metals so this is a molecular (sometimes called covalent) compound.
Consider the following reaction.
2Fe2O3(s)+3C(s)−→−heat4Fe(s)+3CO2(g)
Calculate the number of grams of Fe2O3 needed to react with 18.3 g C.
Answer:
162 g Fe₂O₃
Explanation:
To find the mass of Fe₂O₃, you need to (1) convert grams C to moles C (via molar mass from periodic table), then (2) convert moles C to moles Fe₂O₃ (via mole-to-mole ratio from reaction coefficients), and then (3) convert moles Fe₂O₃ to grams (via molar mass). It is important to arrange the ratios/conversions in a way that allows for the cancellation of units. The final answer should have 3 sig figs to reflect the given value.
Molar Mass (C): 12.011 g/mol
2 Fe₂O₃(s) + 3 C(s) ---> 4 Fe(s) + 3 CO₂(g)
Molar Mass (Fe₂O₃): 2(55.845 g/mol) + 3(15.998 g/mol)
Molar Mass (Fe₂O₃): 159.684 g/mol
18.3 g C 1 mole 2 moles Fe₂O₃ 159.684 g
-------------- x ---------------- x ------------------------- x ----------------- = 162 g Fe₂O₃
12.011 g 3 moles C 1 mole
Please help asap!!!!!!
Answer:
my increasing the amount of input force inorder to lift the load
Hydrogen peroxide is a liquid that decomposes to form oxygen gas and
water. The occasional bubble you might see in a beaker that contains
hydrogen peroxide is evidence of this reaction. But if a small amount of
manganese oxide powder is added to the beaker, many small bubbles start
forming in the liquid. What part does the manganese oxide play in this
reaction?
A. It is a catalyst that increases the rate of the reaction.
B. It is a substance that supplies extra energy for the reaction.
C. Its addition to the liquid makes molecules of hydrogen peroxide
move faster.
D. It is a reactant that is necessary for the reaction to begin.
SUBMIT
If aluminum has a density of 2.7 g/cm³, what is the volume of 2.7 grams of aluminum?
Answer:
Solution Density of aluminium = 2.7 g/Cm 3 In kg/ m 3 = 27 × 1000 10 =2700 kg/ m 3
Explanation:
Not much of one
Glucose, C₂H12O6, is a product of photosynthesis.
It has the following structure.
HICIO
HICIOH
HOIC-H
HICIOH
HICIOH
HICIOH
I
H
How many chiral centres does the molecule have?
A 1
B2
C 4
D 6
Answer:
C
Explanation:
four chiral centers
1. 50.0 g of an unknown metal was heated to 95.0 °C and added to 45.0 g of water at 25.0 °C
in a calorimeter. Once the system reached equilibrium the final temperature was 28.5 °C.
Calculate the specific heat capacity of the metal with correct units.
2. 60.0 g of nickel heated to 100.0 °C was added to 55.0 g of water at 25.0 °C inside a
calorimeter and the system was allowed to reach equilibrium. What would be the final
temperature of the metal and water? (specific heat of Ni = 0.44 J/g °C)
.
3. One challenge during calorimetry is to minimize the heat lost to the environment during
the experiment. Suggest how you would minimize the heat loss during the experiment (read
the steps of the experiment before you answer the question)
Answer
Q = mcΔT
Qwater = -Qmetal
(100 g)(4.18 J/g°C)(25°C - 20°C) = -(50 g)c(25°C - 90.0°C)
2090 J = (3250 g °C)c
c = 0.643 J/g °C
