Answer:
20
Explanation:
The atomic number is just the number of protons in an atom. So if the atom has 20 protons, the atomic number is also 20.
Express 66.3 L to milliliters.
Answer:66300
Explanation:
1 Liter is equal to 1000 mL, so you would multiply 66.3(1000)
Density is the ratio of a substance ___ to its volume
A. Force B. Mass C. Thickness D. Weight
Answer:
Mass
Explanation:
true or false: after glassware is heated it
should be allowed to cool to
room temperature slowly.
Answer:
True
Explanation:
Glasswares are glass-made substances that cannot be done without in the laboratory. They are used to hold and store chemicals, conduct chemical reactions etc. Common glasswares include conical flask, beakers, test tubes, volumetric flasks, pipette etc.
These glasswares are sometimes used to hold chemicals that needs to be heated, making the glasswares hot as well. Since they are made of glass materials, they are very fragile and must be handled carefully. One of the precautions when handling a glassware is that after hearing, they must be allowed to cool down slowly at room temperature in order to avoid breakage. Hence, the statement is TRUE.
Calculate the amount of solvent needed to prepare 50g of 10% solution of Tincture iodine. Name the solvent.
Answer:
Calculate the amount of solvent needed to prepare 50g of 10% solution of tincture Iodine.
Name the solvent
Explanation:
sodium
Hope it is helpful.....
Perform the following mathematical operations and express each result to the correct number of significant figures. a. 97.381 ÷ 4.2502 + 0.99195 b. 171.5 + 72.915 – 8.23 c. 1.00914 ÷ 0.87104 + 1.2012 d. 21.901 – 13.21 – 4.0215
Answer:
The answer is below
Explanation:
When estimating significant numbers, the following applies:
i) All non zero digits are significant
ii) Zeros before non zero digits are not significant
iii) Zeros placed between non zero digits are significant
iv) Trailing zeros to the right of decimals or trailing zeros in whole number are significant.
When estimating, we use the number with the highest number of significant figure.
a) 97.381 ÷ 4.2502 + 0.99195
=22.912098 + 0.99195 = 23.90405 to 5 s.f
b) 171.5 + 72.915 – 8.23 (72.915 has 5 s.f)
= 236.185 to 3 s.f
c) 1.00914 ÷ 0.87104 + 1.2012 (1.00914 has 6 s.f)
= 2.35975 to 6 s.f
d) 21.901 – 13.21 – 4.0215 (21.901 has 5 s.f)
= 4.4895 to 5 s.f
The elements chlorine and iodine have similar chemical properties because they _____. Group of answer choices have the same number of stable isotopes are both metals and can easily lose electrons to form compounds None of these have the same number of electrons in their outer energy levels are in the same chemical period
Answer:
Have the same number of electrons in their outer energy levels
Explanation:
Elements in the same group have similar chemical properties because they have the same number of valence electron(s) in their outermost shell.
Chlorine and Iodine have similar chemical properties because they have the same number of valence electron in their outermost shell. This can be seen from their electronic configuration as shown below:
Cl (17) => 1s² 2s²2p⁶ 3s²3p⁵
I (53) => [Kr] 4d¹⁰ 5s²5p⁵
From the above illustration:
Outer shell of Cl (3s²3p⁵) = 2 + 5 = 7 electrons
Outer shell of I (5s²5p⁵) = 2 + 5 = 7 electrons
Since they have the same number of valence electrons, therefore, they will have similar chemical properties.
1.what causes a fire tornado to form ?
2. how are firefighters expected to deal with them ?
3. why are fire tornadoes rare ?
Help :(
Convert 539 dag/dm3 to cg/mm3.
Answer: 5390 cg/mm³.
Explanation:
To convert: 539 dag/dm³ to cg/mm³.
Since 1 dag = 1000 cg ( where dag= Dekagram and cg = Centrigram)
and 1 dm = 100 mm (where dm = decimetre , mm= millimetre)
Then,
[tex]539\text{ dag/dm}^3=\dfrac{539\times1000}{100}\text{ cg/mm}^3\\\\=5390\text{ cg/mm}^3[/tex]
Hence, 539 dag/dm³ = 5390 cg/mm³.
HELP! WILL MARK BRAINLIEST!! please in your own words!! due today!! doesn't need to be long!!
Answer:
A Drug That Slowly Cures Cancer
Explanation:
They create a lot of drugs so maybe a drug that would slowly kill off the cancer in the person's body. It would save many lives.
Answer:Chemists analyze substances. They determine what is in a substance, how much of something is in a substance, or both. ...
Chemists create, or synthesize, new substances. ...
Chemists create models and test the predictive power of theories. ...
Chemists measure the physical properties of substances.
i WOULD LIKE Nanopesticides
Nano-formulated pesticides can deliver active ingredients where they are needed without polluting the environment or – like neonicotinoids have been accused to do – indiscriminately kill essential wildlife. And more efficient agrochemicals are urgently needed to support a global population that will reach 10 billion by 2050.
So far, only a few studies have shown that nanoagrochemicals are actually more efficient than their traditional counterparts, and none of them have been tested in the field yet.
An engineering team designs a new rocket that is faster and lighter than any other model being produced. However, the materials end up being so expensive that no company can afford to buy them. Which step of the engineering process should have addressed this problem?
Answer:
Evaluate the answer or Know the background may be the answer. Same question was asked by a person name razielhernandez10 and he got these answers.
Evaluate the answer that should address this problem.
The answer is option A.
What is the correct order of the engineering process?Engineering layout Loop: the stairs of the design technique encompass: identifying the need, studying the trouble, increasing possible solutions, picking out the maximum promising solution, assembling a prototype, checking and examining the prototype, speaking the layout, and redecorating.
The engineering layout method starts off evolved via defining a problem and completing heritage studies at the hassle. Requirements are targeted and a solution is selected. A prototype of the solution is constructed after which examined. If the answer built meets the necessities then the outcomes may be shared.
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in which order did the events formings our solar sytem occur
Answer:
The solar nebula spun faster and faster and flattened into a rotating disk. Most of the gas was pulled toward the center, where it became hot and dense, forming the Sun.
Explanation:
what do you understand by Project of National Pride
Answer:
National Pride Projects are a set of infrastructure projects by the government of Nepal based on the proposal by the National Planning Commission.
The half-life of the carbon 14 isotope is 5730 years. If there were 4 billion atoms of C-14 in a particular organism at the time it died, how many atoms of C-14 would there be in the remains of that organism 11,460 years after it died?
Answer:
1 billion
Explanation:
The computation of the number of atoms for C-14 is shown below:
Because it is mentioned
Half the isotope for carbon 14 is 5,730 years
Currently if there had been 4 billion it would equate to 2 billion
Now that the 2 billion would've been 1 billion in the next 5,730 years
And it'll become 3 half-life
Therefore the number of C-14 atoms is 1 billion
Complete the statement about the environment and its components.
An environment is when its components, such as forests, parks, houses, and schools, contribute favorably to the people living in that environment.
Reset
the environment is Healthy
What do Art, Science, and Religion have in common? How are they different? (Google Classroom Question)
Can someone please fill those green boxes for me
(open the image)
Answer:
1. The behaviour of molecules in different phases of matter represents a balance between the kinetic energies of the molecules and the attractive forces between them. All molecules are attracted to each other. At the same time, all molecules are in constant motion, and their kinetic energies increase with the temperature.
2. When heat is added to a substance, the molecules and atoms vibrate faster. As atoms vibrate faster, the space between atoms increases. The motion and spacing of the particles determines the state of matter of the substance. ... Solids, liquids and gases all expand when heat is added.
Explanation:
The half-life of radium-226 is 1590 years. if a sample contains 100 mg, how many mg will remain after 1000 years?
Answer:
64.52 mg.
Explanation:
The following data were obtained from the question:
Half life (t½) = 1590 years
Initial amount (N₀) = 100 mg
Time (t) = 1000 years.
Final amount (N) =.?
Next, we shall determine the rate constant (K).
This is illustrated below:
Half life (t½) = 1590 years
Rate/decay constant (K) =?
K = 0.693 / t½
K = 0.693/1590
K = 4.36×10¯⁴ / year.
Finally, we shall determine the amount that will remain after 1000 years as follow:
Half life (t½) = 1590 years
Initial amount (N₀) = 100 mg
Time (t) = 1000 years.
Rate constant = 4.36×10¯⁴ / year.
Final amount (N) =.?
Log (N₀/N) = kt/2.3
Log (100/N) = 4.36×10¯⁴ × 1000/2.3
Log (100/N) = 0.436/2.3
Log (100/N) = 0.1896
Take the antilog
100/N = antilog (0.1896)
100/N = 1.55
Cross multiply
N x 1.55 = 100
Divide both side by 1.55
N = 100/1.55
N = 64.52 mg
Therefore, the amount that remained after 1000 years is 64.52 mg
A 1.0-gram sample of solid iodine is placed in a tube and the tube is sealed after all of the air is removed. The tube and the solid iodine together weigh 27.0 grams. The tube is then heated until all of the iodine evaporates, filling the tube with iodine gas. After heating, the total mass will be:
Answer:
27.0
Explanation:
Because Mass can neither be created nor be destroyed hence total mass of sample of iodine and tube remain equal as it is sealed.
The radius of a aluminum atom is 143 pm. How many aluminum atoms would have to be laid side by side to span a distance of 2.36 mm?
Answer:
1.65x10⁷ atoms of Al have to be laid side by side to span a distance of 2.36mm
Explanation:
We can assume Aluminium atoms as balls ordered side by side. As the radius of 1 atom is 143pm = 143x10⁻¹²m, the space that 1 atom occupies is 2 radius = 286x10⁻¹²m. That means to occupy 2.36mm = 2.36x10⁻³ you require:
2.36x10⁻³m ₓ ( 1 atom Al / 143x10⁻¹²m) =
1.65x10⁷ atoms of Al have to be laid side by side to span a distance of 2.36mm8 aluminum atoms would have to be laid side by side to span a distance of 2.36 mm.
Convert the radius of an aluminum atom from picometers (pm) to millimeters (mm). Since 1 pm is equal to 1 × 10⁻³ mm, the radius of an aluminum atom in millimeters is:
143 pm × (1 × 10⁻³ mm/pm) = 0.143 mm
The diameter of an aluminum atom is:
2 × 0.143 mm = 0.286 mm
Number of atoms = Total distance / Diameter of an aluminum atom
Number of atoms = 2.36 mm / 0.286 mm
Number of atoms = 8.24
Therefore, 8 aluminum atoms laid side by side to span a distance of 2.36 mm.
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state their effects of aqueous solution of AL2(SO4)3 on litmus paper
Answer:
Turns blue litmus paper red
Explanation:
Aluminium sulphate Al₂(SO₄)₃ is a water soluble salt. It dissolving in water in an exothermic process to form an acidic solution. Solid aluminium sulfate could have a corrosive effect on metals, while aluminium sulfate in aqueous form has a pH lower than 7
Due to its acidic nature, aluminium sulfate can be added to garden soil to reduce its pH by forming dilute sulfuric acid, H₂SO₄ and crystals of aluminium hydroxide, Al(OH)₃.
what property of the wood would you need to know to predict how fast the wood would start to burn?
Answer:
The chemical property of combustion.
Explanation:
Combustion is a chemical reaction that occurs between a combustible material, a substance that causes or favors the combustion of other substances that is oxidizer and oxygen, all this accompanied by outgoing energy in the form of heat (exothermic energy) and incandescent energy.
In this case, wood is the combustible material, and combustion is generated by separate energy, fire, phosphors, sparks.
We have that There is no particular property of wood that allows us to predict is combustion
There is no particular property of wood that allows us to predict is combustion but this is what can be said.
Wood combustion is dependent on so may variable e,g
WeatherTemperatureHumidityBut Wood of small size tends to ignite faster than those with larger density
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Given 57 grams of NO2,
A. How many moles of NO2, are present?
B. How many atoms of oxygen are present?
Answer:
N=14 O=16
Explanation:
46 g = 1 mole of NO2
Now, 57g =(1/46) ×57 mole of NO2
= 1.24 mole of NO2
Peer: Someone who belongs to the same group in society and is equal in rank or level. Scientists have their research reviewed by their peers, who are other scientists. As a student, you have your work reviewed by your teachers and parents but they are not your peers. Who are your peers ?
Answer:
see below (I hope this helps!)
Explanation:
You are a student, therefore, the people who are the same "rank" as you are your fellow students, this makes them your peers.
which particle determines the nuclear charge?
answer:
atomic number
the same chemical element is characterized by the number of protons in the nucleus that determines the total positive charge.
Which of the following is an example of a chemical change? A. Boiling water B. Burning paper C. Dissolving sugar in water D. Melting gold
Answer:
burning paper
Explanation:
all the other choices dont actually affet the item itself in a chemical way only physically. Any time a substance is burned it causes combustion therefor a chemical reaction takes place.
What is component of John Dalton’s atomic theory?
Answer:
•Matter is made up of smallest indivisible particle named as atom.
•All atom of same element have equal atomic mass and identical properties.
•Compounds are made up two or more different types of atoms.
•In a chemical reaction rearrangement of atoms takes place.
•Atoms of different elements differ in mass and size.
You are planting flowers in large pots. You plan to plant flowers in 10 pots. 15 cups of potting soil will fill one pot. A bag of potting soil contains 25 cups. How many bags of potting soil do you need? show work
Answer:
I will need six (6) bags of potting soil
Explanation:
Since you plan on planting in 10 pots and need 15 cups of potting soil per pot, the total amount of potting soil you need (in cups) is 10 X 15 = 150 cups of potting soil.
We have that a bag contains 25 sups. to get the number of bags needed, we have to divide 150 by 25. This will give us 150 / 25 = 6 bags.
Therefore, I will need six (6) bags of potting soil
Which of the follow is not a physical change?
a. The boiling of room temperature water to produce steam.
b. The combustion of hydrogen gas and oxygen gas to produce liquid water.
c. The cutting of a block of sharp cheddar cheese to make smaller pieces for hors d'oeuvres for a social gathering
d. The slow melting of solid coconut oil on the stove.
Answer:
d. The slow melting of solid coconut oil on the stove.
Explanation:
Matter can exist in three major states; solid, liquid and gas. These state can be converted from one to another through various processes that could lead to a physical or chemical change or both.
A physical change is a process that involves the transformation, i.e change of state, of a substance with no chemical change. While a chemical change would produce one or more products different from the initial substance.
From the question, the slow melting of solid coconut oil on the stove requires both physical and chemical change.
How do scientists determine the energy and frequency of photons?
Answer:
We can calculate the energy of a photon in two ways. If you already know the frequency, f, of the photon in Hz, then use E = hf. Another form of Planck's equation uses the simple relationship that c = λ f, where λ is the wavelength of the photon
hope this helped good luck!
Answer:
Explanation:
the energy of photon can be determined by the formula that is
E=hf where h is plancks constant and its value is 6.63*10^-34 j.s and f is the frequency of photon to find out the frequency we have to divide the energy of photon by plancks constant
f=E/h
How many moles are in 1 gram of potassium chloride
0.0134 moles.
Explanation:
We will use conversion factors to solve this problem.
Potassium chloride has the chemical formula KCl.
1 gram of KCl is written on the left side of the conversion factor equation.
KCl has a molar mass of 74.5513 g/mol. This is found by adding together the atomic mass of each element. This means that 1 mole of KCl = 74.5513 grams
The conversion factor will look like this. To solve the equation we start with what is on the left, 1 gram. 1 is multiplied by the number in the numerator, and divided by the number in the denominator. When 1 is divided by 74.5513 it equals .0134. The unit grams cancel giving us our final answer in moles.
I hope this satisfied your request. Feel free to ask any questions. I apologize, my handwriting is a bit messy.