is silver tarnishing a physical change or a chemical change?
Answer:
chemical
Explanation:
Some bronze objects tarnish to a dark brown color. Chemical properties can be identified by the changes they produce. The change of one substance into another substance is called a A piece of wood burning, an iron fence rusting, and a silver spoon tarnishing are all examples of chemical changes.
Which of the following laboratory procedures best illustrates the law of conservation of mass? (Assume the product of the reaction includes the mass of any unused reactants.) (3 points)
Reacting 12 g of C with 32 g of O2 to form 44 g of CO2
Weighing 100 g of Cu powder and 100 g of Fe filings
Heating 100 g of CaCO3 to produce 56 g of CaO
Dissolving 10 g of NaCl in 100 g of water
Answer: Reacting 12 g of C with 32 g of O2 to form 44 g of CO2
Explanation: I took the test just now, and the law of conservation of mass means to energy and that is exactly what they do in this answer!
Answer:
A
Explanation:
6. There are three isotopes of silicon. They have mass numbers of 28, 29 and 30. The average atomic mass of silicon is 28.086amu. What does this say about the relative abundances of the three isotopes?
Answer:
That means that the isotope that has a mass number of 28 is probably the most abundant. This is because your average atomic mass is 28.086 amu, which is closest to 28.
Formula used to calculate average atomic mass follows:
average atomic mass=(atomic mass of an isotope)*(fractional abundance)
we are given=
Three isotopes of Silicon, which are Si-28, Si-29 and Si-30.
Average atomic mass of silicon = 28.086 amu
As, the average atomic mass of silicon is closer to the mass of Si-28 isotope. This means that the relative abundance of this isotope is the highest as compared to the other two isotopes.
Percentage abundance of Si-28 isotope = 92.2%
Percentage abundance of Si-29 isotope = 4.7 %
Percentage abundance of Si-30 isotope = 3.1%
Hence, the abundance of Si-28 isotope is the highest as compared to the other isotopes.
For an atom of chlorine-35, what number would you put as the SUPERSCRIPT in the atomic notation?
How many valence electrons are in Lithium
Answer:
Por ejemplo, el Litio se ubica en el grupo 1A, entonces tiene 1 electrón de valencia.
Explanation
Excepto los grupos 3-12 (los metales de transición), el dígito de las unidades del número de grupo identifica cuántos electrones de valencia se pueden asociar con un átomo neutro de un elemento listado en dicha columna.E
_________feedback is a type of feedback in which a system is triggered to produce an output.
Answer:
positive
Explanation:
Answer:
Positive feedback is a type of feedback in which a system is triggered to produce an output.
Explanation:
Have a great rest of your day
#TheWizzer
How are elliptical galaxies different from spiral galaxies?
a. They contain older stars and less gas and dust.
b. They contain younger stars and more gas and dust.
c. They are bigger than spiral galaxies.
d. They are smaller than spiral galaxies.
Answer:
A. They contain older stars and less gas and dust.
Explanation:
There are three types of galaxies:
elliptical galaxiesspiral galaxieslenticular galaxiesElliptical galaxies are galaxies shaped like an ellipse, while spiral galaxies consist of a flat, rotating disk that contains stars, gas, and dust, and a central concentration of stars called the bulge.
The difference between elliptical and spiral galaxies is in the amount of gas and dust they contain. Spiral galaxies contain large amounts of gas and dust, which means that new stars are born very often. This makes them brighter than relatively dim elliptical galaxies, which contain less gas and dust. This is why fewer new and brighter stars are born in elliptical galaxies, leaving them with older, dimmer stars.
How many neutrons are in the nucleus of an atom with a mass number of 80 and an atomic number of 35?
Answer: 45
Explanation:
mass number = number of protons and neutrons
atomic number = number of protons
to find neutrons subtract atomic number from mass number
so 80 - 35 = 45 neutrons
Question 12 of 25
Which sentence describes all atoms of one element?
O A. They have the same number of protons.
OB. They have the same number of neutrons.
O C. They have the same number of isotopes.
D. They have the same properties.
Answer:
D They have the same properties.
Explanation:
The same no. of isotopes doesnot describes because isotopes have same symbol but didderent atomic mass.
Which option will increase the rate of reaction?
A) removal of one of the reactants
B) decrease the volume of container
C) lower the temperature of reaction
D) reduce the pressure in the container
Answer:
B
Explanation:
when you increase the pressure of a closed container , its volume decreased.
in general when pressure is increased, rate of reaction is increased.
HELPP!!! ASAP!!!! BRAINLIEST!!!
Complete the following sentences. Energy is required to _______ bonds in a molecule and released when bonds are _______.
Answer:
Energy is required to break bonds in a molecule and released when bonds are made.
Explanation:
Energy is added to break bonds and released when making bonds.
Which of the following causes a physical change in the shape of an object?
A. Using a wire to conduct electricity
B. Heating a piece of iron until it glows
C. Placing a penny in acid to make it shiny
D. Sharpening the tip of a pencil
please helppp
Answer:
B
Explanation:
Heating a piece of iron until it glows.
Heating a piece of iron until it glows causes a physical change in the shape of an object. Therefore, option B is correct.
What is physical change ?The term physical change is define as a type of change where the physical properties of matter change. In physical change, composition and chemical nature of matter does not change.
It involves in change in physical properties. The examples of physical changes are textural change, shape, size, color, volume and density.
Heating a piece of iron until it glows causes a physical change in the shape of an object, because it involves physical property. The changes in which only physical properties of substances are changed, and no new substance is formed
Thus, option B is correct.
To learn more about the physical change, follow the link;
https://brainly.com/question/3680148
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Which of the following structures are found in eukaryotes, but not prokaryotes?
A) Cytosol
B) Cilia
C) Golgi body
Answer:
B
Explanation:
What sport was used to demonstrate Newton's 3 Laws?
8. An atom of element Z has the
electronic configuration 2.8.6. Which
one of the following statements
about element Z is correct? *
Answer:
See explanation
Explanation:
The question is incomplete but i will try to answer it to the best of my ability.
An element of configuration 2.8.6 is in group 16. This element will form a divalent anion Z^2-
Z is a nonmetal which combines with metals to form ionic bonds. Z can also react with other non metals to form covalent compounds.
Z is expected to have high electronegativity and electron affinity since it is a nonmetal of group 16.
The oxides of Z will dissolve in water to yield acidic solutions.
Which ion has smaller size and why?Mg++ or Na+.
Answer:
Explain your answer. mg2+ would be the smaller ion this is because each ion has the same number of electrons however mg2+ has a greater number of protons and therefore is more charge dense and the outer electrons feel a greater pull from the nucleus.
Hope this helps, have a great day/night, and stay safe!
What type of ions do nonmetals naturally form?
Answer:
Negative Ions
Explanation:
Nonmetals naturally form Negative Ions by gaining electrons to fill the valence shell
How many atoms are in 1.65 mol of potassium
Answer:
9.93 × 10²³ atomsExplanation:
The number of atoms of potassium can be found by using the formula
N = n × Lwhere n is the number of moles
N is the number of entities
L is the Avogadro's constant which is
6.02 × 10²³ entities
From the question we have
N = 1.65 × 6.02 × 10²³
We have the final answer as
9.93 × 10²³ atomsHope this helps you
7
Select the correct answer.
Which quantity is a graduated cylinder designed for measuring?
O A. length
ОВ.
mass
O C. temperature
D.
time
O E. volume
PLEASE HELPPP
A(n) _________is a
group of atom. joined by chemical bonds.
THIS IS SCIENCE NOT CHEMISTRY
Answer; molecule
Explanation:
What is the half life of an atom that goes from 16000 g to 125 g in 163.24 days.
Answer:
[tex]23.32\ \text{days}[/tex]
Explanation:
N = Final mass of atom = 125 g
[tex]N_0[/tex] = Initial mass of atom = 16000 g
t = Time taken = 163.24 days
[tex]t_{1/2}[/tex] = Half life
We have the relation
[tex]N=N_0\dfrac{1}{2}^{\dfrac{t}{t_{1/2}}}\\\Rightarrow 125=16000\times \dfrac{1}{2}^{\dfrac{163.24}{t_{1/2}}}\\\Rightarrow \dfrac{125}{16000}=\dfrac{1}{2}^{\dfrac{163.24}{t_{1/2}}}\\\Rightarrow \ln0.0078125=\dfrac{163.24}{t_{1/2}}\ln0.5\\\Rightarrow t_{1/2}=\dfrac{163.24\times\ln0.5}{\ln0.0078125}\\\Rightarrow t_{1/2}=23.32\ \text{days}[/tex]
The half life of the atom is [tex]23.32\ \text{days}[/tex].
Compression is the type of stress that deforms rock at which location ?
Answer:
Compression is common at convergent boundaries, tension in divergent boundaries, and shear at transform boundaries.
Explanation:
The three main types of stress go along with the three types of plate boundaries. Rocks can bend and fold. Rocks can also fracture and break.
A student needs to use sodium nitride in an experiment and finds a chemical with the formula NaNO3 . Is this the correct compound? Why or why not?
A. Yes, NaNO3 is the formula for sodium nitride.
B. No, NaN is the formula for sodium nitride; NaNO3 is the formula for sodium nitrate.
C. No, NaN is the formula for sodium nitride; NaNO3 is the formula sodium nitrite.
D. No, Na3N is the formula for sodium nitride; NaNO3 is the formula for sodium nitrat
Answer:
Yes, NaNO3 is the formula for sodium nitride.
What type of reaction would NI3+ ->lead to?
Answer:
Reduction potential (Eo) is defined as a tendency of a chemical species to be reduced by gaining an electron and is defined with electrochemical reference of hydrogen, which is globally given the reduction potential of zero [24].
Explanation:
Being farther from the nucleus and with more electrons shielding the protons results in the valence electrons being held ...
Answer:
electrons
Explanation:
since they are at the outer part of nucleus
Answer:
Weakly
Explanation:
Being farther from the nucleus and with more electrons shielding the protons results in the valence electrons being held weakly.
The effect of the nuclear pull will not be felt so strongly by the valence electrons. The valence electrons are the outermost electrons that occupies a shell. When the inner orbital electrons are much and the atomic radius is large, the valence electrons are well shielded. This results in electropositivity and a low ionization energy.Someone help me please i’ll give brainly
Answer:
Ionization
Melting
Vaporization
Explanation:
▶Ioniztion changes the charge of an electron, this usually happens between a chemical reaction. It takes a small amount of energy. Most of the time energy is absorbed instead of expelled!
▶ Melting changes the shape of the item and takes about 334 Joules/gram of energy.
▶ Vaporization changes the state of matter that the item is in and requires 2260 Joules/gram.
Brainliest is much appreciated! Hope I helped!
10. calcium fluoride ca
11. sodium nitride
12. magnesium chloride
In formulas
Answer:
10=CaF2
11=Na3N
12=MgCl2
Explanation:
Answer:
10. CaF2
11. Na3N
12. MgCl2
Explanation:
Compounds are combinations of elements. The combination of those elements is specific to the compound. Some compounds have the exact same elements but in different amounts. Look at C6H12O6, which you hopefully recognize as glucose (think cellular respiration and photosynthesis. But ribose is a 5 carbon sugar and its formula is C5H10O5, which you hopefully recognize (think RNA). They both have the same elements, but have different numbers of each element (sugars all have the 1:2:1 ratio). When you're looking at a formula, it's wise to look for the capital letters. That indicates when a different element is present. For glucose, there's a capital C - carbon, a capital H - hydrogen, and a capital O - oxygen. Behind elements, the subscripts help indicate the number of each element that's present. In glucose, there are 6 carbons, 12 hydrogens, and 6 oxygens. How many carbons, hydrogens, and oxygens does ribose have in its formula?
Question 4 options:
5, 12, 5
1, 2, 1
5, 10, 5
6, 12, 6
Explanation:
Omg How Am I supposed to get the answer tell me what to do
The diagram below shows an oxygen molecule formed when two oxygen atoms bond. Which is likely to be the nature of bonding formed?
Answer:
Covalent bonding
Explanation:
covalent bonding
Which procedure is an attempt to correct a genetic disorder by replacing a mutated gene with a normal allele?
selective breeding
cloning
artificial selection
gene therapy
Answer:
Hi, the answer is C. Artificial Selection
I know this becasue I just finished my test
Explanation: