The statement that describes a physical change is a sculptor casts a statue in molten bronze and allows it to harden. The correct option is C.
What are physical changes?"A physical change is one that simply affects the physical nature of the substance." Usually, increasing the temperature or applying pressure, both, will cause a physical change. In other words, physical changes are reversible.
All the other options like rusting of iron bolts on a bridge is a chemical change when iron reacts with oxygen in the air, it gets rust.
Similarly, silver cups exposed to air react with air is a chemical change, and option d, silver off magnesium that creates light, is also a chemical change.
Thus, the correct option is C. A sculptor casts a statue in molten bronze and allows it to harden.
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describes the temperature at which a
solid's attractive forces are overcome and it
becomes a liquid.
Answer:
Melting point
Explanation:
it's constant temperature at which the bonds of a solid Crystal lattice are broken down by overcoming the attractive forces converting it to liquid
What is immigration and emigration
Answer:
well for me I think
Explanation:
immigration is the movement which involves an individual moving from a present place to another environment
That is going out
WHILE
Emigration is the process where a person comes into a particular environment
That means coming in
15
Question 56 (1 point)
What is the name of the compound with the chemical formula SnSnO3?
Answer: sodium sulfite
Explanation:
d = 7 V = 950 cm M = 95 g
0.1 g/cm3
0.1 cm3
90,250 g
90,250 g/cm3
Answer:
daddy chill
Explanation:
If 33.9g NaCl are mixed into water and the total mass is 578g, what is the CHANGE in freezing if Kb= - 1.82C/M (molal)? Assume NaCl does not dissociate in solution.
Answer:
-1.82 °C
Explanation:
Step 1: Given data
Mass of NaCl (solute): 33.9 gMass of water (solvent): 578 g = 0.578 kgFreezing point depression constant for water (Kb): -1.82 °C/mStep 2: Calculate the molality of the solution
We will use the following expression.
m = mass of solute / molar mass of solute × kg of solvent
m = 33.9 g / 58.44 g/mol × 0.578 kg
m = 1.00 m
Step 3: Calculate the freezing point depression (ΔT)
The freezing point depression is a colligative property that, for a non-dissociated solute, can be calculated using the following expression:
ΔT = Kb × m
ΔT = -1.82 °C/m × 1.00 m
ΔT = -1.82 °C
middle school science help please
Answer:
The answer is 'All of the above'
Explanation:
because the hydrogen ions are represented by the symbol H+, they increase the PH value of a solution if less amount is added but they decrease the PH value of a solution if a larger amount of hydrogen ions are added but still they increase the PH value, and of course, they contribute to a solution by a base.
Answer:
Hydrogen ions are represented by H+.
Explanation:
Hydrogen ions usually decreases the pH value when added to a solution.Hydrogen ions are contributed to a solution by a acid.explain 5 the major innovation made from Abacus to the present fifth generation
Answer:
The major innovation made from Abacus to the present fifth generation is explained below in details.
Explanation:
Industrial Age - 1600
John Napier, a Scottish noble and diplomat consecrated much of his holiday time to the learning of mathematics. He was particularly engrossed in devising methods to aid estimates. His most famous offering was the discovery of logarithms. He listed logarithmic measures on a set of 10 board rods and thus was capable to do multiplication and division by equaling up numbers on the poles. These became recognized as Napier’s Bones.
Explain how atomic
radius, valence electrons
and effect nuclear charge
creates the trend for metal
reactivity.
Answer:A higher effective nuclear charge causes greater attractions to the electrons, pulling the electron cloud closer to the nucleus which results in a smaller atomic radius. Down a group, the number of energy levels (n) increases, so there is a greater distance between the nucleus and the outermost orbital.
Answer:
A higher effective nuclear charge causes greater attractions to the electrons, pulling the electron cloud closer to the nucleus which results in a smaller atomic radius. Down a group, the number of energy levels increases, so there is a greater distance between the nucleus and the outermost orbital.Explanation:
In the acetylene torch, acetylene gas (C2H2)(C2H2) burns in oxygen to produce carbon dioxide, water, and energy: 2C2H2(g)+5O2(g)⟶Δ4CO2(g)+2H2O(g)2C2H2(g)+5O2(g)⟶Δ4CO2(g)+2H2O(g) You may want to reference (Pages 241 - 243) Section 7.7 while completing this problem. Part A How many moles of O2O2 are needed to react with 1.85 molmol of C2H2C2H2? Express your answer to three significant figures and include the appropriate units. nn(O2O2) = nothingnothing SubmitRequest Answer
Answer:
4.63 mol
Explanation:
Step 1: Write the balanced complete combustion reaction of acetylene
2 C₂H₂(g) + 5 O₂(g) ⟶ 4 CO₂(g) + 2 H₂O(g)
Step 2: Establish the appropriate molar ratio
According to the balanced equation, the molar ratio of C₂H₂ to O₂ is 2:5.
Step 3: Calculate the number of moles of O₂ needed to react with 1.85 moles of C₂H₂
We will use the stoichiometric molar ratio.
1.85 mol C₂H₂ × (5 mol O₂/2 mol C₂H₂) = 4.63 mol O₂
Question 1 / 1
Which of the following is a covalent bond?
A. CO2
B. NaCl
C. Fe2O,
Answer:
Chemistry deals with matter, and there is a tremendous variety of matter in the universe. The behavior of matter depends on the type of elements that are present and on the structure of those elements—how they are connected to make a molecule. In this exercise, you will evaluate some representative models to develop the rules used to classify a compound, to predict the formula of a compound, and to name the compound. This exercise is just the beginning of the work needed to be done to master the rules of writing formulas and nomenclature. Your textbook has tables of the names and formulas of common cations and anions, and discusses the rules of nomenclature in detail. You will need to spend some time with this material, as the formal rules of nomenclature may not be presented in lecture, although they will certainly be used in discussions of Lewis structures and reaction chemistry.
Explanation:
In a covalent compound, valence electrons are shared between the two atoms in the bond. These can be evenly shared (covalent bond) or unevenly shared (polar covalent bond). In an ionic bond, electrons are localized to one of the atoms (giving it an overall negative charge), while the other atom has an overall positive charge. The difference in electronegativity between the two atoms in the bond can help predict whether the bond is likely to be ionic, covalent, or polar covalent, as can the type of atoms involved (metals or non-metals). A bond with two identical atoms is always pure covalent, while a covalent bond with two different atoms is likely to be polar covalent.
Consider the equation:
4Al + 3O2 = 2Al2O3
Is this equation balanced? Why or why not?
The equation is balanced. There are 4 aluminium atoms and 6 oxygen atoms on each side.
What type of reaction occurs between an element and a compound?
Answer:
exothermic reaction
Explanation:
because it occurs in the presence of heat
Law of Universal Gravitation (what factors affect gravity and how?)
Explanation:
Hey there!
According to the law of gravitation, the factors that affects the gravity are:
Mass of the heavenly bodies.Distance from the centre of the body to next body.Mass of heavenly bodies:The mass of heavenly bodies affect the gravity. We know that gravity is directly proportional to the mass of heavenly bodies. so, when the mass is more there is more gravity and where there is less mass there is less gravity.
Distance from the centre of the body to next body: It is one of the factor to influence gravity. When there is more distance there is less gravity and where there is distance more force is there. Is means gravity is inversely proportional to the distance between the bodies.
Hope it helps...
How does adding a lone pair affect the position of existing atoms and lone pairs
Answer:
How does adding a lone pair affect the position of existing atoms and lone pairs? It decreases the angles between the atoms - the atoms are moving closer because they are being repelled further away from the lone pairs then they are from the other atoms
Explanation:
hope it helps!
A paint chip is placed in ethanol and curls what type of paint is it
Answer:
it is probably acrylic or latex
Explanation:
There are two types of chemical compound one is covalent compound and other is ionic compound, covalent compound formed by sharing of electron and ionic compound formed by complete transfer of electron. Therefore, the type of paint is acrylic or latex.
What is chemical Compound?Chemical Compound is a combination of molecule, Molecule forms by combination of element and element forms by combination of atoms in fixed proportion.
An ionic compound is a metal and nonmetal combined compound. Ionic compound are very hard. They have high melting and boiling point because of strong ion bond. If the chip remains flat when put in ethanol, it is probably an oil-based paint. If the chip curls, it is probably acrylic or latex. So, The type of paint is acrylic or latex.
Therefore, the type of paint is acrylic or latex.
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Which of the following would be most useful in trying to obtain procedural information to replicate an experiment previously published?
Answer: Peer-reviewed journal article is the most useful because the information in them had been carefully scrutinized and aproved by people who are experts in that particular field.
Which part of the immune system can be "trained" using vaccines?
Calculate the energies of the n=2 and n=3 states of the hydrogen atom in Joules per
atom
Answer:
See Explanation
Explanation:
Positional Energy for electron as function of principle energy level (n)
=> Eₙ = -A/n²; A = 2.18x10⁻¹⁸J
Positional Energy for electron in n=2 => E₂ = -2.18x10⁻¹⁸/(2)² = -5.45x10⁻¹⁹J
Positional Energy for electron in n=3 => E₃ = -2.18x10⁻¹⁸/(3)² = -2.42x10⁻¹⁹J
ΔE(n=3→2) = -5.45x10⁻¹⁹J - (-2.42x10⁻¹⁹J) = -3.03x10⁻¹⁹J
Help me with this . I'm bad at chemistry . I’ll give you a brain list . Don’t answer if u don’t know at all .
Answer:
2.
a.Sodium bromide
b. Magnesium dichloride
c. Lithium iodide
not sure about 3 or 4 sry
Which event would most likely lead to a thunderstorm g i v i n g b r a i n l e s i t HELP
--
Answer:
A
Explanation:
hope it helps
Answer:
A
Explanation:
I got right
which force does the truck use to move the car with it A.push B.pull C.gravity D.Friction
it is push i think to move the car
Answer:
Either A. Push or B.Pull because the truck is either pushing or pulling the car to move it. So it depends on if it's pushing or pulling the car.
Explanation:
Will give brainliest
Answer:
C
Explanation:
The concept behind, is mole ratio of Al:FeO
How many protons, neutrons, and electrons does 35/17 Cl ^ 1- have?
Answer:
In accordance to the pic
The number of protons in Cl-35 is 17 and the number of neutrons is 18. The number of Cl is 17 whereas the chloride ion Cl⁻ have 18 electrons.
What is chlorine?Chlorine is 17th element in periodic table. Cl is includes in the 17th group of p -block. Cl contains 7 valence electrons and it needs one more electron to attain complete configuration. It is highly electronegative and will easily gain an electron to achieve octet.
Atoms in neutral state have equal number of electrons and protons and this number is equal to the atomic number. The mass number is the sum of number of protins and neutrons.
The atomic number of Cl is 17. Hence the number of protons is 17 and the mass number is 35. So that number of neutrons is 35 - 7 =18. When Cl gains an electron it forms the anion Cl⁻. Hence, the number of electrons in Cl⁻ is 18.
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An ideal gas sample is confined to 3.0 L and kept at 27 °C. If the temperature is raised to 77 °C and the initial pressure was 1500 mmHg, what is the final pressure?
The gas is confined in 3.0 L container ( rigid container) ⇒ the volume remains constant when the temperature is increased from from 27oC to 77oC and therefore V1=V2 .
Hope it helps you please mark as brainlistIdeal gas law is valid only for ideal gas not for vanderwaal gas. Ideal gas is a hypothetical gas. Vanderwaal gas can behave as ideal gas at low pressure and high temperature. Therefore the final pressure is 1,750 mmHg.
What is ideal gas equation?Ideal gas equation is the mathematical expression that relates pressure volume and temperature.
Mathematically the relation between Pressure, volume and temperature can be given as
PV=nRT
where,
P = pressure of gas
V= volume of gas
n =number of moles of gas
T =temperature of gas
R = Gas constant = 0.0821 L.atm/K.mol
At constant volume, the above equation can be rearranged as
P₁/T₁ = P₂/T₂
Substituting all the given values in the above equation, we get
1500 ÷300= P₂÷350
P₂ =1,750 mmHg
Therefore the final pressure is 1,750 mmHg.
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How can the rate of a reaction be increased?
(A) decreasing the amount of reactants
(B) having more surface area
(C) diluting a solution
(D) lowering the temperature
Explanation:
Rate of reaction can be increased by having more surface area.
Therefore,
Option B is correct✔
Answer:
b
Explanation:
What happens to molecular energy(heat) in water when water vapor becomes a liquid?
Group of answer choices
Water vapor gives up heat energy.
Water vapor absorbs heat energy.
As water's mass increases it absorbs energy.
Water vapor retains the same heat energy.
Answer:
Water vapor retains the same heat energy.
Answer:
water vapor gives up heat energy.
Explanation:
Took a quiz and got it right
what's the formula for na and f , ca and br , mg and O
Answer:
NaF, CaBr2, MgO
Explanation:
Hi! For this problem, you are going to want to look at the charges of the elements in order to write their formulas.
NaF: Na has a charge of +1 and F has a charge of -1. This means that they have a 1:1 ratio and the formula is written as such - NaF.
CaBr2: Ca has a charge of +2 and Br has a charge of -1. For this problem you want to make sure that their formal charge (the charge of the entire molecule) equals 0. This means that the negative charges need to equal the positive charges. Looking at this, you are going to need to Br ions with a charge of -1 to equal one Ca ion with a charge of +2 - CaBr2.
MgO: Mg has a charge of +2 and O has a charge of -2. This means that they have a 2:2 ratio which simplifies to a 1:1 ratio and the formula is written as such - MgO.
Hope this helps!
Which is a pure substance?
They are chemically bonded together.
They can be classified as pure substances.
They have fixed ratios between their components.
They can be separated by physical processes.
Answer: C. They have fixed ratios between their components.
Describe the reaction of zinc with sulphuric acid
Answer:
Zinc reacts with dilute sulphuric acid to produce hydrogen gas (H2) and zinc sulphate. This is an example of displacement reaction of a non-metal by a metal. ... ZnSO4 is different in chemical composition and chemical properties than Zn and H2SO4 so it is a chemical change.
Answer:
Reaction of Zinc with Dilute Sulphuric Acid
Zinc is more reactive than hydrogen and it displaces hydrogen from dilute acids. Zinc reacts with dilute sulphuric acid to form zinc sulphate and hydrogen gas is evolved. This is a single displacement reaction of a non-metal by a metal. ... So, this reaction is a chemical change.
An elemental metal contains how many types of atoms?
a. 1
b. 2
c. 3
d. 4
Answer:
a
Explanation:
all elemental metals are made up of only one type of element
Answer:
It is 1.
Explanation: