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Related Questions
examples of elements
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Answer: The pH of the solution is 13.
Explanation:
pOH is defined as the negative logarithm of hydroxide ion concentration present in the solution.
[tex]pOH=-\log [OH^-][/tex]
We are given:
Concentration of [tex]Ca(OH)_2=0.05mol/dm^3=0.5mol/L[/tex] (Conversion factor: [tex]1L = 1dm^3[/tex] )
1 mole of calcium hydroxide produces 1 mole of calcium ions and 2 moles of hydroxide ions
Concentration of [tex]OH^-=(2\times 0.05)=0.1mol/L[/tex]
Putting values in above equation, we get:
[tex]pOH=-\log (0.1)\\\\pOH=1[/tex]
We know:
[tex]pH+pOH=14\\\\pH=14-1\\\\pH=13[/tex]
Hence, the pH of the solution is 13.
What happens when one adds (NH4)2S to a solution that contains Al3+? What are the products of the chemical reaction?
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Answer:
What happens when one adds (NH4)2S to a solution that contains Al3+?
Explanation:
When a solution that contains [tex]Al^{3+}[/tex] reacts with ammonium sulfide solution, then a precipitate of aluminum sulfide is formed.
The chemical equation for the reaction is shown below:
[tex]3(NH_{4})_{2} S(aq)+2 Al^{3+}(aq) -> Al_{2} S_3} (s) +3 NH_{4}^{+}[/tex]
How many molecules of SO3 are present in 48g of SO3?
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Answer:
3.6 ×10^23
Explanation:
moles = mass/ molar mass
molar mass= (1×32) +(3×16)= 80
moles = 48/ 80
=0.6
moles = number of molecules/ 6×10^23
number of molecules = moles × 6×10^23
=0.6 × 6×10^23
=3.6 ×10^23
Often, several different labs need to share a very small amount of evidence. It is important that the chain of custody be maintained. If the chain of custody is broken, then the evidence may not be allowed in a court proceeding. Identify the error in the following case. After obtaining the evidence, the first lab technician removed the tape that contained the signatures of the crime scene evidence collector. On completion of her examination of the evidence, the lab technician put the evidence into a paper bindle, and inserted thee bindle into an evidence bag. The technician sealed the bag in the same place as the original crime-scene investigator. After carefully sealing the bag, the lab technician signed her name across the tape. She completed the chain-of-custody form on the outside of the evidence bag and brought the evidence to the next lab technician at the crime lab.
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Answer:
The errors in the case are;
1. Error; Removing the tape containing the signatures of the crime scene evidence collector, which removes the record/signature of the crime scene evidence collector in chain of custody
Correct; The original signature of the crime scene evidence collector should left on the package and the package should be opened at another location
2. Error; Placing the reseal back at the same location of the initial seal placed by the evidence collector
Correct; The package should be opened at a different area from the point in which it was sealed when it is received
3. Incorrect; Resealing the bag at the same point it was opened
Correct; On completion, the lab technician should place the evidence with the package, which was opened at a location different from its original opening, in a new package, which is then sealed and she should sign off on the evidence chain-of-custody log before bringing the evidence to the next lab technician at the lab
Explanation:
Evidence collection process requires the documentation of the specific place or spot that the evidence was located, proper evidence packaging, and maintenance of a correct chain of custody
A complete and proper chain of custody
a) Ensure the number of persons who handle the evidence is limited
b) Verify tat the chain of custody documents lists all the names, dates and identification number
c) Ensure to collect signed or secured receipt when the evidence is being transferred
Please select the word from the list that best fits the definition
Occurs when an axon releases chemicals that allow a signal to jump across synapses between neurons
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Answer:
When a nerve impulse reaches the end of an axon, the axon releases chemicals called neurotransmitters. Neurotransmitters travel across the synapse between the axon and the dendrite of the next neuron. Neurotransmitters bind to the membrane of the dendrite.Explanation:
I hope it's helpful for you ☺️Complete the following statements to describe solids, liquids, and gases. Select the correct answer fror
A solid
A liquid
A gas
va definite volume and
a definite volume and
a definite volume and
v
a definite shape.
a definite shape.
a definite shape.
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Answer:
solid is definite volume and shape
liquid is a definite volume but not a definite shape because it can move around and fit into different shapes, like on different water bottles.
gas is not a definite volume and not a definite shape because gas particles can expand and spread out which affects both volume and shape
Electronegativity6. Which one of the following bonds is the least polar one?
options:
C-F
C-Cl
C-Br
C-I
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It can also be wrong but that’s my opinion
When looking for a mathematical relationship between two variables, use a _____.
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Answer:
Use a line graph
Explanation:
Which statements about a phosphorus atom, P, are correct?
1. The nucleon number is 16.
2. The number of outer electrons is 5.
3. The proton number is 15.
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Answer:
3. The proton number is 15.
Explanation:
Phosphorus, P is the element with the atomic number = 15. The atomic number = Number of protons. That means:
3. The proton number is 15.
Now, the number of protons = Number of electrons = 15.
And, nucleon number = Number of protons + number of neutrons. The must abundant phosphorus atom contains 16 neutrons and nucleon number is: 15+16 = 31.
Thus, we can know which statement is true.
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C3H8(g)+5O2(g)→3CO2(g)+4H2O(g)(propane)
CH4 + 2O2 → CO2 + 2H2O. (Methane)
2C4 H10 + 13O2 → 8CO2 + 10H2 O.(butane)
In some chemical reactions, such as photosynthesis, several different compounds take part in the reaction. How do you think that atoms present at the end of this kind of reaction compare to the atoms present at the beginning of the reaction? Explain.
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Answer:
The atoms present at the beginning of the reaction is equal to the atoms present at the end of the reaction. This is because matter can neither be created nor be destroyed in an ordinary chemical reaction.
Explanation:
During photosynthesis, 6 molecules of water react with 6 molecules of carbon dioxide to form 1 molecule of glucose and 6 molecules of oxygen. The equation for the photosynthesis reaction is
6CO2 + 6H2O --> C6H12O6 + 6O2
At the beginning of the reaction, there is 6 carbon atoms, 18 oxygen atoms and 12 hydrogen atoms while at the end of the reaction, there is 6 carbon atoms, 12 hydrogen atoms and 18 oxygen atoms. This is because according to the law of conservation of mass and matter, it can neither be created nor be destroyed in an ordinary chemical reaction. The number of atoms present at the beginning of the reaction must be equal to the number of atoms present at the end of the reaction.
Grasses, shrubs, and tree are called producers because they make
A. Food
B. water
C. Carbon dioxide
D. Minerals
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The second reaction in the formation of sulfuric acid occurs slowly.
2 upper S upper O subscript 2 (g) plus upper O subscript 2 (g) right arrow 2 upper S upper O subscript 3 (g).
NO2 is added to the reaction to speed it up. In which form would this substance be a homogeneous catalyst for this reaction?
NO2(g)
NO2(l)
NO2(s)
NO2(aq)
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Answer: The correct option is [tex]NO_2(g)[/tex]
Explanation:
A catalyst is defined as the chemical species that increases the reaction rate but does not participate in it and is left behind after the completion.
A homogeneous catalyst is one that is present in the same phase as the reactants and products.
A heterogeneous catalyst is one that is present in different phase as that of reactants and products.
For the given chemical reaction:
[tex]2SO_2(g)+O_2(g)\rightarrow 2SO_3(g)[/tex]
As all the reactants and products are in gaseous state so, the homogeneous catalyst must also be in the gaseous state only.
Hence, the correct option is [tex]NO_2(g)[/tex]
Answer:
a
Explanation:
Which of the following pairs lists a substance that can neutralize H2SO4 and the salt that would be produced from the reaction?
O CaOH2 and Ca(SO4)2
OLIOH and Li2SO4
ONH, and NH,SO4
O NH3 and (NH3)2SO4
sh
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Answer: b
Explanation:
I took the test
The correct answer is LiOH and Li2SO4.
A strong acid is neutralized by a strong base to yield a normal salt.
A neutralization reaction is a reaction between an acid and a base to yield salt and water only.
An acid can be strong or weak. A base can also be strong or weak. "Strong" or "weak" has to do with the extent of ionization of the acid or base in water. Usually, a strong acid is neutralized by a strong base.
Since H2SO4 is a strong acid, it will require a strong base such as LiOH to neutralize it and the product will be the normal salt Li2SO4.
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which synthetic fiber feels like wool and used as a substitute for wool
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Answer:
Acrylic
Acrylic is the synthetic fibre feels like wool and used as a substitute for wool.
ayudenme porfa doy corona xd
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Answer:
e) 5
Explanation:
Because it's H
Which of the following is a method that transports eroded material?
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why plane mirrors are not used as cosmetic mirrors
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A plane mirror is a flat piece of glass that reflects an image that is identical (or nearly identical) to the object in front of it.
ANSWER THIS FOR 15 POINTS!!!
A hot metal plate at 150°C has been placed in air at room temperature. Which event would most likely take place over the next few minutes?
Molecules in both the metal and the surrounding air will start moving at lower speeds.
Molecules in both the metal and the surrounding air will start moving at higher speeds.
The air molecules that are surrounding the metal will slow down, and the molecules in the metal will speed up.
The air molecules that are surrounding the metal will speed up, and the molecules in the metal will slow down.
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Answer:
it is the last one
Explanation:
cause over time the meatl will imit heat and heat up the air around it as it cools down slowly
Why is sodium an active metal
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Answer:
Sodium is very reactive in nature. When exposed in air, it automatically forms Na2O. When it is put in water it reacts vigorously and starts burning on water. Due to the above reasons Sodium is called an active metal
Explanation: hope this helps pls mark as brainliest ty
what are some ways you would expect people and things to be affected by an earthquake that moved the ground that much?
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Answer:
Some of the common impacts of earthquakes include structural damage to buildings, fires, damage to bridges and highways, initiation of slope failures, liquefaction, and tsunami.
According to the kinetic-molecular theory, the average kinetic energy of gas particles depends on which factor?
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Answer:
Temperature.
Explanation:
Kinetic molecular theory of gases states that gas particles exhibit a perfectly elastic collision and are constantly in motion.
According to the kinetic-molecular theory, the average kinetic energy of gas particles depends on temperature.
This ultimately implies that, the average kinetic energy of gas particles is directly proportional to the absolute temperature of an ideal gas. Thus, an increase in the average kinetic energy of gas particles would cause an increase in the absolute temperature of an ideal gas.
Temperature can be defined as a measure of the degree of coldness or hotness of a physical object. It is measured with a thermometer and its units are Celsius (°C), Kelvin (K) and Fahrenheit (°F).
Particle Mass
(\rm g) Atomic mass
units Electrical charge
(C) Relative
charge
electron 9.109 \times 10^{-28} 0.0005486 -1.6.02 \times 10^{-19} -1
proton 1.673 \times 10^{-24} 1.007276 +1.6.02 \times 10^{-19} +1
neutron 1.675 \times 10^{-24} 1.008665 0 0
1) The atomic number is the number of protons in the nucleus of an atom of an element. Each element has a unique number of protons. For example, an atom with 47 protons is always a silver atom and has an atomic number of 47. The atomic number is used to distinguish different elements from one another.
The mass number A is the sum of the number of protons and neutrons in the nucleus of an atom of an element. Atoms that have the same atomic number but different mass numbers are called isotopes. For example, all atoms with atomic number 6 are carbon atoms, but carbon atoms with mass numbers of 12 and 13 are isotopes of one another.
Each element is assigned a unique chemical symbol. For example, the symbol for hydrogen is H, and the symbol for oxygen is O. Some elements have symbols based on their names in languages other than English. For example, the symbol for iron is Fe, which is based on the Latin ferrum.
The atomic number, mass number, and chemical symbol are often combined to describe a given atom. For example, an atom of lithium (Li) with atomic number 3 and a mass number of 7 could be written 7/3 Li . Since the atomic number and the symbol are both unique to a given element, the atomic number is often left off of this notation, leaving ^7 Li.
i) Which subatomic particle(s) are found in the nucleus of the atom?
Enter the subatomic particle or particles separated by commas.
ii) The atomic number of oxygen is 8. What is the mass number of an oxygen atom with 7 neutrons?
Mass number = ?
iii) An atom has a mass number of 25 and 13 neutrons. What is the atomic number of this atom?
Atomic number = ?
iv) An atom of sulfur is represented by \rm ^{33}_{16}S. How many neutrons are in the nucleus of this atom? neutrons in \rm ^{33}_{16}S = ?
V) Give the nuclear symbol for the isotope of silicon (Z = 14) for which A = 29?
Enter the nuclear symbol for the isotope (e.g., \rm ^4_2He).
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Answer:
(i) Protons, Neutrons
(ii) Mass number = 15
(iii) Atomic number = 12
(iv) Neutrons present in the atom = 17
(v) Nuclear symbol for the silicon isotope with mass number, A = 29 is ²⁹₁₄Si
Explanation:
(i) An atom is composed of three fundamental sub-particles: electrons, protons and neutrons. Electrons are found in orbits or energy levels some distance away from The nucleus of the atom. The nucleus of an atom contains the protons and neutrons which accounts for the mass of the atom.
(ii) The mass number of an atom of an element is the sum of the protons and neutrons present jn the nucleus of the atom.
The mass number of an atom of oxygen with proton or atomic number 8 and neutron number 7 is 8 + 7 = 15
(iii) Atomic number of an atom of an element is equal to the number of protons in the atom of the element.
Mass number = proton number + neutron number
Proton number = mass number - proton number
Proton number = 25 - 13 = 12
(iv) In the atom of sulfur represented bymthe symbol, the number in superscript is the mass number A, and the number in subscript is the atomic number Z.
Mass number = proton number + neutron number
Neutron number = Mass number - proton number
Neutron number = 33 - 16 = 17
(v) The nuclear symbol for the silicon isotope with mass number, A = 29 is ²⁹₁₄Si
Where the number in superscript is the mass number A, and the number in subscript is the atomic number Z.
By referring to the particulate theory of mater, explain the following statement: Oxygen gas is very easy to compress when pressure is applied
By referring to the particulate theory of matter, explain the following statement: A solid lump of iron has a high density .
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Answer:
See explanation
Explanation:
According to the particulate theory of matter, gas particles do not interact with each other. A gas is composed of isolated particles moving at high velocities and collide frequently with each other and the walls of the container.
Since the particles of a gas are mostly isolated, it is easy to compress the gas when pressure is applied thereby bringing the gas particles closer together.
On the other hand, in the solid state, the particles that compose matter are close together. These particles only vibrate about their mean positions due to strong intermolecular interaction between particles. The fact that the particles of the solid ion are so close together makes the solid iron lump to possess high density.
What is the main source of energy in stars?
A. Combustion
B. Gravity
C. Fission
D. Fusion
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Answer:
D. Fusion
Explanation:
D. Fusion
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Please answer. Brainliest!
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Answer:
the equation is balanced
Explanation:
the equation is balanced
Explanation:
the equation is blanced
a what is acrylic
b state the important use of acrylic fiber
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what is the pound mole of co2
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Answer:
3rd or 4th answer is correct
OPTION B is the correct answer