Answer:
Physical change
Explanation:
There are two types of changes: physical change and chemical change. Physical change is defined as the change that changes the physical appearance of the substance and do not affcet the chemical composition of the substance whereas chemical change causes changes in the chemical composition of the susbstance.
The given example shows physical change because solid calcium undergoes sublimation. process in which a solid substance changes into gaseous phase directly without undergoing liquid phase.
Hence, the correct answer is "Physical change".
describe the relationship between the mass volume and density of material
Answer: For a given mass and volume, how much physical space a material takes up, of an object or substance, the density remains constant at a given temperature and pressure. The equation for this relationship is ρ = m / V in which ρ (rho) is density, m is mass and V is volume, making the density unit kg/m3.
Explanation:
Radioactive isotope X has a half-life of 500,000 years. This isotope may be found in some types of volcanic rocks. A particular sample of volcanic rock taken from a layer that covered up some of the earliest known human-like footprints contains 0.125 mg of isotope X. The volcanic rock sample originally contained 8.00 mg of isotope X. How long ago were these footprints made. I need the equation. Thanks. please I am stuck on this question. PLEASE
Answer: The footprints were made [tex]2.99\times 10^6years[/tex] years long ago.
Explanation:
Radioactive decay follows first order kinetics.
Half-life of isotope X= 500,000 years
[tex]\lambda =\frac{0.693}{t_{\frac{1}{2}}}=\frac{0.693}{500000}=0.00000139year^{-1}[/tex]
The equation for first order kinetics is :
[tex]N=N_o\times e^{-\lambda t}[/tex]
N = amount left after time t = 0.125 mg
[tex]N_0[/tex] = initial amount = 8.00 mg
[tex]\lambda[/tex] = rate constant
t= time
Putting the values we get:
[tex]0.125=8.00\times e^{- 0.00000139years^{-1}\times t}[/tex]
[tex]0.0156=e^{- 0.00000139years^{-1}\times t}[/tex]
[tex]t=2.99\times 10^6years[/tex]
The footprints were made [tex]2.99\times 10^6years[/tex] years long ago.
Which has the least potential energy?
gases
liquids
solids
Answer
The answer is SOLIDS
Explanation:
Because of metallic bonding, when light is pointed at metals, they become
Oshiny
O malleable.
O ductile.
O conductive,
Owing to the electronic configuration of metals ,metallic bonding exists in metals because of which when light is pointed at them they become shiny.
What is electronic configuration?Electronic configuration is defined as the distribution of electrons which are present in an atom or molecule in atomic or molecular orbitals.It describes how each electron moves independently in an orbital.
Knowledge of electronic configuration is necessary for understanding the structure of periodic table.It helps in understanding the chemical properties of elements.
Elements undergo chemical reactions in order to achieve stability. Main group elements obey the octet rule in their electronic configuration while the transition elements follow the 18 electron rule. Noble elements have valence shell complete in ground state and hence are said to be stable.
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Is Magnesium less reactive than Aluminum ? Yes or No
Answer:
The answer is no
Answer:
yes
Explanation:
some metals are reactive than others. Example: (a) Magnesium is more reactive than silver. (b) Magnesium reacts with oxygen but silver doesn't because magnesium is more reactive than silver.
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Which statement best describe what happens during a chemical change
Answer:
both the identity and the properties of a substance change.
Answer:
its A both the identity and the properties of a substance change
Explanation:
got it right on edge
Explain how your answer to CTQ 6 is consistent with your answer to CTQ 5.
Answer:
up 1
Explanation:
does this picture show a physical or chemical change?
Answer:
Those photos are a chemical change
If you had 4 protons and 5 neutrons you created which element *
Answer:
Beryllium
Explanation:
No. of protons = 4
No. of electrons = 4 (number of protons and neutrons are the same)
No. of neutrons = 5
You need to look at the number of electrons of the outer shell (group no.) there are and how many shells there are (period no.)
Then look at the period table of elements to find the element
How much energy is required to heat 0.24 KG lutetium from 296.2K to 373.5 K? The specific heat for lutetium is 0.154 J/g-K
Answer:D. 2857 joules
Explanation:
Not going to lie I guessed but got it right
According to specific heat capacity, 3596.208 joules of energy is required to heat 0.24 kg of lutetium from 296.2 K to 373.5 K.
What is specific heat capacity?Specific heat capacity is defined as the amount of energy required to raise the temperature of one gram of substance by one degree Celsius. It has units of calories or joules per gram per degree Celsius.
It varies with temperature and is different for each state of matter. Water in the liquid form has the highest specific heat capacity among all common substances .Specific heat capacity of a substance is infinite as it undergoes phase transition ,it is highest for gases and can rise if the gas is allowed to expand.
It is given by the formula ,
Q=mcΔT
Substitution in above formula gives, q= 0.24×154×97.3=3596.208 Joules.
Thus, 3596.208 joules of energy is required to heat 0.24 kg of lutetium from 296.2 K to 373.5 K.
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1. Calculate the number of moles in each of the following masses:
a. 64.1 g of aluminum ans: 2.38 mol Al show work
Answer:
2.38 mol of Al
Explanation:
To find the number of moles in a substance, you simply divide by the atomic mass. In this case, the conversion table would look as follows:
[tex]\frac{64.1 g}{1}[/tex] * [tex]\frac{1 mol}{26.98 g}[/tex]
The gram units cancel, and you are left with the answer of about 2.38 moles of Aluminum.
PLeaseee Help Asap!!!
I need help with this. Plzzzzz
Answer:what do you nned help with
Explanation:
How many moles (of molecules or formula units) are in each sample?
A) 32.66 g CF2Cl2
B) 24.2 kg Fe (NO3) 2
C) 0.5912 g C8H18
D) 104 kg CaO
Express all answers to 4 sig figs
Answer:
A = 1.627 ×10²³ molecules of CF₂Cl₂.
B = 809.4 ×10²³ molecules of Fe(NO₃)₂.
C = 0.03117 ×10²³ molecules of C₈H₁₈.
D= 1116 ×10²³ molecules of CaO.
Explanation:
A)
Given data:
Mass of CF₂Cl₂ = 32.66 g
Number of moles = ?
Number of molecules = ?
Solution:
Number of moles = mass/ molar mass
Number of moles = 32.66 g/ 120.9 g/mol
Number of moles = 0.2701 mol
Number of molecules:
1 mole = 6.022×10²³ molecules
0.2701 mol×6.022×10²³ molecules / 1mol = 1.627 ×10²³ molecules of CF₂Cl₂.
B) Given data:
Mass of Fe(NO₃)₂ = 24.2 Kg (24.2×1000 = 24200 g)
Number of moles = ?
Number of molecules = ?
Solution:
Number of moles = mass/ molar mass
Number of moles = 24200 g/ 180 g/mol
Number of moles = 134.4 mol
Number of molecules:
1 mole = 6.022×10²³ molecules
134.4 mol×6.022×10²³ molecules / 1mol =809.4 ×10²³ molecules of Fe(NO₃)₂.
C) Given data:
Mass of C₈H₁₈= 0.5912 g
Number of moles = ?
Number of molecules = ?
Solution:
Number of moles = mass/ molar mass
Number of moles = 0.5912 g/ 114.22 g/mol
Number of moles = 0.005176 mol
Number of molecules:
1 mole = 6.022×10²³ molecules
0.005176 mol×6.022×10²³ molecules / 1mol =0.03117 ×10²³ molecules of C₈H₁₈.
D) Given data:
Mass of CaO = 104 Kg (104×1000 = 104,000 g)
Number of moles = ?
Number of molecules = ?
Solution:
Number of moles = mass/ molar mass
Number of moles = 104,000 g/ 56.1 g/mol
Number of moles = 1854 mol
Number of molecules:
1 mole = 6.022×10²³ molecules
1854 mol×6.022×10²³ molecules / 1mol = 1116 ×10²³ molecules of CaO.
What group of organic compounds include starch?
a Carbohydrates
b Lipids
Thing
C Proteins
d Nucleic Acids
please help asappp
will mark branliest!!
Answer:c
Explanation:
Answer:
C is the answer
are in the outermost energy level
psoriasis is a disease that causes a red rash on the skin. which body system does psoriasis affect?
a. respiratory
b. integumentary
c. immune
d. digestive
e. circulatory
Answer:
The answer to this question is integumentary.
Explanation:
The answer is that because that is your skin area and so if you have a rash then if will affect that part.
It's b. integumentary
I got the test right
Most metals are NOT ____ ? Liquid at room temperature, ductile, malleable, good conductors of heat and electricity.
Most metals are not liquid at room temperature. Therefore, option A is correct.
Most metals are not liquid at room temperature, except for a few specific exceptions such as mercury (Hg) and gallium (Ga). These metals have relatively low melting points, which allows them to exist in a liquid state at or near room temperature.
The majority of metals, however, exhibit a solid state at room temperature. This solid state is characterized by a regular arrangement of atoms or ions in a crystal lattice structure. The strength of metallic bonds holds the atoms together, giving metals their solid and rigid form.
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Which metal is most likely to form more than one kind of positively charged ion?
A.Sodium
B.Barium
C.Nickel
D.Magnesium
Answer:
D.Magnesium
Explanation:
Cause imma nerd
which describes the substances that form covalent bonds
Answer:
both Non metal's G
Explanation:
i did the test
PLEASE APEZ HELP I DONT UNDERSTAND
A teacher placed a plastic cup of warm coffee with a lid in the freezer.
Which statement describes the frozen coffee in comparison with the warm
coffee?
A. The amount of coffee is the same.
B. The speed of the coffee molecules has increased.
C. The temperature of the coffee has increased.
D. The arrangement of the coffee molecules is the same.
Answer: The answer is A
Explanation:.
Which of the following is a chemical property of a sheet of paper?
A. The paper can be burned.
B. The paper can be crumbled.
C. The paper does not attract a magnet.
D. The paper does not conduct electricity.
Answer:
A
Explanation:
Flammability is a chemical property. The paper crumbling would be a physical property. The inability to attract a magnet or conduct electricity would be considered electrical properties
During which process of the water cycle does water change from gas to liquid
If you worked at a job for 9.00/hour, what type of correlation is the number of hours worked and your take-home pay?
Answer:
There is a linear correlation between the number of hours worked and take-home pay. And more exactly, a direct proportionality. [tex]C = 9\cdot t[/tex]
Explanation:
From statement we deduce that amount of hours worked ([tex]t[/tex]) (Independent variable, measured in hours) is directly proportional to take-home pay ([tex]C[/tex]) (dependent, measured in monetary units), since proportionality ratio is constant and, therefore, there exists a linear correlation between both variables. That is:
[tex]C \propto t[/tex]
[tex]C = k\cdot t[/tex] (Eq. 1)
Where [tex]k[/tex] is the proportionality ratio, measured in monetary units per hour. If we know that [tex]k = 9\,\frac{m.u.}{h}[/tex], then the resulting correlation is:
[tex]C = 9\cdot t[/tex]
There is a linear correlation between the number of hours worked and take-home pay.
if an object has a mass of 30 grams and a volume of 6 cubic cm. what is its density
Answer:
5
Explanation:
mass/volume = density
30/5 = 5
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Answer: it is a
Explanation:
Explain the term catalyst and how it affects the rate of a chemical reaction.
Answer:
Catalyst. A catalyst speeds up a chemical reaction, without being consumed by the reaction. It increases the reaction rate by lowering the activation energy for a reaction. Energy diagrams are useful to illustrate the effect of a catalyst on reaction rates.
Explanation:
is sandy, silt, or clay loam better? and why?
2. Mixtures can be solid, liquid or gas. It can be homogeneous or
heterogeneous and are made up of two or more components. Which of
the following mixtures where components are not visible??
Answer:
A solution is a special type of homogeneous mixture where the ratio of solute to solvent remains the same throughout the solution and the particles are not visible with the naked eye, even if homogenised with multiple sources.
Explanation:
Mixtures can be either homogeneous or heterogeneous': a mixture in which constituents are distributed uniformly is called homogeneous, such as salt in water, otherwise it is called heterogeneous, such as sand in water.
organize the following location's from the smallest to largest respectively
A.Texas
B.United states
C.North America
D.City of Mission
E.Hidalgo county