Answer:
1. The compound 2NaCl consists of:
» B. 1 atom of chlorine element.
» D. 1 atom of sodium element.
2. The valency of iron in iron (III) sulphate is:
» A. 3 [ valency of only iron ]
» B. 2 [ valency of only sulphate ion ]
3.The systematic name of the compound CuSO4:
» B. Copper (II) sulphate
Explanation:
[tex].[/tex]
Answer:
1) A.
2) A.
3) A.
Draw a sketch of a hot air balloon and of a helium balloon. Define the systems by identifying the system boundaries. Show inputs and outputs of matter and energy in each. Use your Evidence Notebook if necessary.
Explanation:
When you heat the air it expand its volume, but its mass remain the same, so the density of the hot air balloon is smaller than the density of the air outside it, so the hot air balloon can float.
In the case of the helium balloon, there's no source of energy, but the helium is naturally lighter than the atmospheric air, so its density is naturally smaller than the air, and the helium balloon have a smaller density than the air too, so it can float.
A closed system can interchange energy with its surrounding, but not matter.
A closed system can exchange energy but not matter, with its surrounding environment. The energy that enters into a closed system may derive from different forms (e.g., heat or work, kinetic energy)Conversely, an open system can exchange both energy and matter with its surrounding.In conclusion, a closed system can interchange energy with its surrounding, but not matter.
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If scientists want to determine if a skin cream is effective against fighting acne, what would be the independent variable?
Answer:skin cream
Explanation:
the independent variable is the variable that is always changed or manipulated. in this case the skin cream is the independent variable.
question : what are isotopes
Answer:
Isotopes are versions of the same element. They have the same number of protons and electrons as the element but different mass numbers and number of neutrons.
Explanation:
one of two or more species of atoms of a chemical element with the same atomic number and position in the periodic table.
Two skaters stand on ice. one weights 250 N, and the other weights 500 N. They push against each other and move in opposite directions. Describe the momentum of each skater after they push away from each other.
Answer:
Because law of momentum, makes it equal
A cup of hot tea cools down
a
Chemical Change
b
Physical Change
Answer:
Physical change
Explanation:
No new substances were produced so it is physical change.
Answer:
Physical Change
Explanation:
Since only the temperature is changing not the structure of tea its a physical change. Good luck ;)
Bond order, bond length, and bond energy are closely related. The shorter a bond, the _____ its bond strength. A shorter bond will therefore have a higher bond energy than a longer bond. Bond order also plays a role. For a given pair of atoms, the higher the bond order, the shorter and _____ the bond will be.
Answer: greater, stronger
Explanation: Bonds that form as a result of sharing their electrons are called covalent bonds. A lot of energy is contained in those bonds, especially if they are higher order. A single bons is bond order 1, A triple bond is bond order 3. An example of a triple bond is acetylene. It combusts with a very hot flame when it's triple bond is broken with oxygen.
chất có ở đâu ? nước tự nhiên là chất hay hỗn hợp
Answer:
Water, H2O, is a pure substance, a compound made of hydrogen and oxygen. Although water is the most abundant substance on earth, it is rarely found naturally in its pure form. Most of the time, pure water has to be created. Pure water is called distilled water or deionized water.
[ ] CH4 + [ ] O2 → [ ] CO2 + [ ] H2O
Answer:
Explanation:
These kinds of equations are very mechanical. They are all done the same way.
First the hydrogen. There are 4 hydrogens on the left and only 2 on the right. So you must put a two in front of the the water.
[ ] CH4 + [ ] O2 → [ ] CO2 + [ 2] H2O
Now the carbons. There's one on the left and one on the right, so they are balanced. I'd put a 1 on both anyway.
[ 1] CH4 + [ ] O2 → [1 ] CO2 + [ 2] H2O
Finally the oxygens. There's 2 on the CO2 and 2 on the water (that 2 in front multiplies the 1 water into 2 oxygens because the right is really H2O + H2O.)
So 2 from CO2 and 2 From H20 makes 4 altogether.
There's only 2 on the right, so you have to multiply the O2 by 2
[1 ] CH4 + [2 ] O2 → [1 ] CO2 + [2 ] H2O
4.250 x 10-6 nm in standard form , please help!!
Answer: 4,250 x 10 - 6
Explanation: ok so we have a decimal number, what you do with that is
[tex]4.250 x 10^{3}[/tex] = 4.250 x 1,000 = 4,250 now you can just move the decimal every time without that equation but its better safe. I'm pretty sure that's how they want it, because its not expanded or word.
Which of the following is a result of
condensation?
A. deserts
B. seasons
C. clouds
D. rocks
Answer: should be c. clouds :)
Explanation: condensation is the change of water to a gaseous form. it generally occurs in the atmosphere when warm air rises, cools, and loses its capacity to hold the water vapor. excess water vapor condenses to form cloud droplets.
Answer: clouds
Explanation: theyre air and water
Should I take chemistry in high-school? Is it easy or hard?
Answer:
Yes, If you understand it's easy
Explanation:
Although, chemistry is a fun subject which includes learning about chemical and experiments.
"If you like my answer mark as brainlist" ☺️.
Answer:
may be
Explanation:
if u want to study chemistry.then here are some advantages.Chemistry teaches useful skills. Because it is a science, learning chemistry means learning how to be objective and how to reason and solve problems. Helps you to understand current events, including news about petroleum, product recalls, pollution, the environment and technological advances.
which one is more reactive out of fluorine and chlorine. why?
Answer:
fluorine
Explanation:
because it is at the top of the halogen group, which is the second to right group on the periodic table. With halogens, the higher an element is in the column, the more reactive it is. Halogens are reactive because the outer shells that orbit the nucleus lack electrons.
also because it has low dissociation energy and the valence bonding is seen close to the nucleus hence the attraction for a new electron is greater and can gain an extra electron more easily.-if ur in a higer grade u will understand this
. Arrange the following in order of increasing radius:
a) Mg2+, Na+, Al3+
b) Na+, Al3+ , Mg2+
c) Mg2+ , Al3+ , Na+
d) Al3+ , Mg2+, Na+
guys pls help i will venmo you money
Answer:
Al3+<Mg2+<Na+
Explanation:
this is because of nuclear charge (no. of protons)
atomic radius is inversely proportional to nuclear charge.
Give an example of a non-biological chemical reaction that involves carbon. Name the process that converts a solid compound into a gas.
Answer: The combustion of methane (CH4) with O2.
Explanation: This is a chemical reaction involving carbon:
CH4 + 2O2 = CO2 + 2H2O
out of magnesium and Calcium which element is more reactive give reason
Answer:
Calcium is more reactive.
Explanation:
It is higher in the reactivity series, and contains more energy levels.
What is the molar mass of C3H8O2? (Round to three significant figures)
Answer:
The molar mass of [tex]C_3H_8O_2[/tex] (rounded to three significant figures) is 76.1 amu.
Step-by-step explanation:
Hey there!
To answer this question, you will need access to a periodic table. You need to know the atomic masses of carbon (C), hydrogen (H), and oxygen (O) in order to answer this question. With that out of the way, let's begin!
We have a chemical formula: [tex]C_3H_8O_2[/tex].
The letters are element symbols, which are basically the code for an element. Think of it as an abbreviation or something similar to an ID.The subscripts (numbers) help us identify how many atoms of each element are included in the substance.The first thing we should do is locate C, H, and O on a periodic table and figure out the atomic masses for each element. This will help us determine the total molar mass of the substance.
Determining the Atomic Mass of CIf we locate C on a periodic table, we see that its atomic mass is roughly 12.01 amu (atomic mass units). Then, we have a subscript of 3, so we simply multiply the subscript by the given atomic mass in order to find the atomic mass of the three atoms of carbon.
[tex]3 \times 12.01 = 36.03 \text{ amu}[/tex]
This means that C accounts for 36.03 amu of the molar mass of the substance.
Determining the Atomic Mass of HUsing the same principle as before, we want to find the atomic mass of one atom of H. This is 1.008, so we will multiply 1.008 by the eight atoms (pay attention to the subscript) in order to find the atomic mass of hydrogen in the substance.
[tex]8 \times 1.008 = 8.064 \text{ amu}[/tex]
This means that H accounts for 8.064 amu of the molar mass of the substance.
* An important note to add is that we should never round our values until the end of the problem so we make sure to get as close as possible (this is why you learn about accuracy and precision in a chemistry class).
Determining the Atomic Mass of OFinally, we want to find the atomic mass of O in the substance, so we'll use the same method as before and locate the atomic mass of one atom of oxygen. We find that this is 15.999, which would definitely round to 16.00, but remember the rules for rounding in chemistry in order to be as accurate as possible. Since our subscript is 2, we know that there are two oxygen atoms, so we will multiply the atomic mass of oxygen by 2.
[tex]2 \times 15.999 = 31.998 \text{ amu}[/tex]
This means that O accounts for 31.998 amu of the molar mass of the substance.
Summation of the Determined Atomic MassesAfter you have determined the atomic masses of the atoms in the chemical substance, you have to add these together. This is performed with simple addition.
C = 36.03 amuH = 8.064 amuO = 31.998 amuNow, let's add these together.
[tex]36.03 \text{ amu} + 8.064 \text{ amu} + 31.998 \text{ amu} = 76.092 \text{ amu}[/tex]
Therefore, the total atomic mass is 76.092 amu.
Rounding to Meet Significant Figures RequirementsSignificant figures are used to determine the accuracy of a problem. A basic rule is to use scientific notation to determine how to meet the significant figure request. Since we are rounding to three significant figures, we want to make sure these three figures are significant. There are three basic rules to remember when computing significant figures:
Any zeroes to the left of the first non-zero number (ex: 0.0981) are insignificant.Any zeroes "trapped" in between other non-zero numbers (ex: 9.81075) are significant.Any zeroes to the right of the last non-zero number (ex: 5900) are significant ONLY IF they are added after a decimal point and included in the measurement (ex: 5900.)Therefore, since we need three significant figures, we have to round our value first and then determine the appropriate number of significant figures.
76.092 will round to 76.09 first, and then round to 76.1. We cannot use 76.09 since there is a trapped zero, which is considered significant.We must use 76.1 since there are three significant figures in the value.Final AnswerSince we have determined that 76.1 fits our requirements for three significant figures, we can safely determine that the molar mass of [tex]C_3H_8O_2[/tex], as determined, is 76.1 amu.
= 3 × Mass of C + 8 × Mass of H + 2 × Mass of O
= (3 × 12.01 + 8 × 1.008 + 2 × 15.999) g/mol
= (36.03 + 8.064 + 31.998) g/mol
= 76.092 g/mol
Answer:
76.092 g/mol
Hope you could get an idea from here.
Doubt clarification - use comment section.
 A famous scientist has a hypothesis that is different from the current scientific theory. What should happen to the scientist hypothesis?
Answer:
The hypothesis is just a question based upon an observation. The hypothesis would have to be tested in order to evival the theory.
Explanation:
The metal zirconium becomes superconducting at temperatures below 3.4000K.
Calculate the temperature at which zirconium becomes superconducting in degrees Celsius. Be sure your answer has the correct number of significant digits.
Answer:
-269.75 degrees Celsius
Explanation:
You have two pure substances that you cannot identify. Each sample is solid at room temperature. Describe at least five stopes in the appropriate sequence that you wpild take to be able to identify the substance
this is for anyone who’s good with science coz I absolutely hate it. ILL BRAINLIST U AND GIVE U 5 STAR TO WHOEVER IS GOOD;) be specific and use ur own words please! thankyou. and good luck LOL.
conclusions:
The burning candle is an example of a combustion reaction.
a) What do all combustion reactions require?
b) What do all combustion reactions produce?
c) Write a general word equation for the combustion reaction.
Answer:
A) Oxygen
B) Heat
C)
Explanation:
Hope it helps
Answer:
a) oxygen is nessasary for all combustion to occur
b)carbon dioxide and water
c)for example combustion of methane:
CH4+2O2 -------> CO2+H2OThe strength of van der Waals forces increases as:
A. molecular size decreases
B. molecular size increases
C. number of electrons increases
D. number of electrons decreases
Answer:
B and C
Explanation:
is it multiple choice question??
Van der Waals forces are the interaction between the molecules and the atoms. It increases with an increase in the molecular size and the number of electrons. Thus, options B and C are correct.
What are Van der Waals force?
Van der Waals forces are the weak forces of attraction and repulsion present between the atoms and the molecules of the compounds. They are also called London Dispersion Forces and dipole-dipole forces.
An increase in the number of electrons and size of the molecule increases the surface area and the electron cloud which in turn, increases the Van der Waals force.
The intermolecular force increases as in large atoms or molecules the valence are held loosely as they are far from the nucleus or the center of the atom.
Therefore, the size and the electron increase the Van der Waals force.
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Detection of nitrongen ??
Answer:
The extract is boiled with FeSO4 and acidified with concentrated H2SO4. The appearance on Prussian blue colour indicates the presence of nitrogen
Explanation:
PLS mark it brainliest
Which statement correctly compares the number of protons and electrons in atom of rubidium (Rb) and Calcium (Ca)?
The question is incomplete, the complete question is;
Which statement correctly compares the number of protons and electrons in atoms of rubidium (Rb) and calcium (Ca)?
Rubidium has fewer protons and fewer electrons than calcium.
Rubidium has fewer protons and more electrons than calcium.
Rubidium has more protons and fewer electrons than calcium.
Rubidium has more protons and more electrons than calcium.
Rubidium has 37 electrons and protons as well as 48 neutrons. Calcium has 20 electrons, protons and neutrons.
Rubidium is a group 1 element while calcium is a group 2 element. Rubidium has more protons and more electrons than calcium.
Rubidium is an element in group one of the periodic table. It has 37 electrons and protons as well as 48 neutrons.
Calcium is an element in group two of the periodic table. It has Calcium has 20 electrons, protons and neutrons.
From the foregoing, we can see that Rubidium has more protons and more electrons than calcium hence the answer.
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An element has an atomic number of 16. An ion of this element has a 2- charge. How is the ion formed?
Answer: Atomic number 16 is sulfur (S). It has 6 valence electrons and needs two more to complete it's outer shell to 8 electrons. It will steal those electrons from elements theat need to lose electrons to achieve a full valence shell (lower energy shell).
Explanation: Sulfur's valence shell is 3s^2_3p^4. It needs two more electrons to fill the 3p orbital to 6 electrons. This is a lower energy state and so sulfur will remove, or share, electrrons from elements that benefit from losing an electron to achieve a lower energy state.
A scientist who wants to study the effects of a new fertilizer on plants would probably
Answer:
1 no is answer give each experiment group the same amount of fertilizer
Acid rain damaging marble
a
Chemical Change
b
Physical Change
Answer:
B
Explanation:
Acid rain
damaging a marble statue or anything else
is a physical change. <3
What is the best definition of
molecule?
A. A molecule is an atom that cannot be broken
down.
B. A molecule is a positively charged partide.
C. A molecule is the smallest part of a substance
that is still that substance
Answer:
C
Explanation:
A molecule is a smallest particle of a substance that has all of the physical and chemical properties of that substance. or
Molecules are two or more atoms chemically joined together.
How many moles are there in 4.6g of sodium
Answer:
0.20moles
Explanation:
1 mole Na contains 23 g Na
23 g Na =1 mole of Na
1 g Na= 1/23 moles of Na
4.6 g Na= 1/23×4.6= 4.6/23=0.2 moles
Therefore 0.2 moles are present in 4.6 g of Na
Answer:
the 4.6g sodium has 0.2 moles
Describe the formation of a hot spot?
Please help!
Answer:
A volcanic "hotspot" is an area in the mantle from which heat rises as a thermal plume from deep in the Earth. High heat and lower pressure at the base of the lithosphere (tectonic plate) facilitates melting of the rock. This melt, called magma, rises through cracks and erupts to form volcanoes.
How is energy stored in a Van der Graaf generator?
A. Energy is stored in the nucleus
B. Energy is not stored
C. Energy is stored in the chemical bonds
D. Energy is stored in an electrical field
Answer:
C
Explanation:
A Van de Graaff generator is an electrostatic generator which uses a moving belt to accumulate electric charge on a hollow metal globe on the top of an insulated column, creating very high electric potentials. It produces very high voltage direct current (DC) electricity at low current levels