Answer:
28
Explanation:
it states that the atom is neutral, meaning the number of electrons and protons are the same. so if there are 13 electrons, there are 13 protons. And the mass number is neutrons plus protons. So 13+15 is 28
When you touch an object, why do you feel hot or cold?
Answer:
When two different objects touch heat is always transferred from the warmer object to the colder object. If you touch something hot, energy is transferred from the hot object to you.
Explanation:
20. What will be the concentration, in mol dm, of the resulting solution when 200 cm' of
0.200 mol dmhydrochloric acid, HCl(aq) are mixed with 300 cm of 0.100
mol dm HCl(aq)?
Answer:
0.140mol/dm^3.
Explanation:
200cm3 = 0.2dm^3.
0.2dm^3 * 0.200mol/dm^3 = 0.040mol
300cm^3 = 0.3dm^3
0.3dm^3 * 0.100mol/dm^3 = 0.030mol
The number of moles is 0.070mol of HCl (aq).
The volume of the solution is 0.5dm^3.
Hence the concentration is 0.140mol/dm^3.
The concentration is 0.140mol/dm³.
What is concentration?The concentration of solution is the amount of solute that are dissolved in solution.The concentration can be measured by dividing the weight of solute in grams to the volume of solution.200cm³ = 0.2dm³
0.2dm³ x 0.200mol/dm³= 0.040mol
300cm³ = 0.3dm³
0.3dm³ x 0.100mol/dm³ = 0.030mol
The number of moles is 0.070mol of HCl
The volume of the solution is 0.5dm³
Concentration = Number of moles/volume in dm³
= 0.070mol/0.5dm³
= 0.140mol/dm³
Hence, the concentration is 0.140mol/dm³
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The Gateway Arch in St. Louis, MO is approximately 630 ft tall. How many U.S. half dollars would be in a stack of the same height? Each half dollar is 2.15 mm thick.
Answer:
To equal the height of the Gateway Arch in St. Louis, it would take 76810 half dollars.
Explanation:
If the Gateway Arch in St. Louis is 630 feet high, how many half dollars will it take to equal the height if each half dollar is 2.15mm thick?
First, we convert the ft to cm and the cm to mm.
- 1 ft = 30.48 cm
630 ft = 19202.4 cm
- 19202.4 cm = 192024 mm
Now, if a half dollar is 2.15 mm thick, how many half dollars would it take to equal the height of 192024 mm?
1 half dollar = 2.15 mm
X = 192024 mm
X = 192024 mm / 2.15 mm
X = 76810 half dollars.
All naturally occuring polysaccharide have one terminal residue a free anomeric carbon why do these polysaccharide not give a positive chemical test for reducing sugar
Answer: The concentration of reducing ends is too small to detect.
Explanation:
The reducing sugar can be defined as the sugar that is capable of acting as a reducing agent because it possesses an aldehyde group and a ketone group. Some polysaccharides are reducing sugars but all the monosaccharides are reducing sugars. The polysaccharide with reducing sugars do not give a positive test for reducing sugars because the concentration or amount of reducing ends is too small to detect.
in a chemical reaction known as decomposition, carbonic acid breaks down into water, and what other compound?
Answer: it’s carbon dioxide
Explanation:
This is it because decomposition takes place when carbonic acid breaks down So that’s why I put carbon dioxide
Answer:
carbon dioxide
Explanation:
in our country .we have to study it by heart.
trust me
1. A teacher asks a student to give the number of protons, neutrons,
and electrons in an atom of fluorine.
a. Is this enough information to answer the question?
b. If it is, determine the number of p, nº, and eʻs.
c. If not, what other information is needed?
why don't we estimate an additional number on an electrical balance?
What are some ways carbon dioxide enters our atmosphere and subsequently the air we breathe
Answer:
when organisms decompose, or burning fossil fuels and pollution and such
Explanation:
A scientist thinks she has discovered a new element. She took some samples to her colleagues and they performed some tests. Here is what they found: the element is a silver, malleable solid at room temperature the element is not very reactive with metals the element has 4 valence electrons the element has 32 protons in its nucleus Which of the discoveries listed above is the most influential in proving her theory incorrect?
Answer:
Proton number of the supposed discovery debunked the theory.
Explanation:
Proton number of an element is also its atomic number.
For the element in question to have had a proton number that wasn't 119, it could not have been a new element.
Furthermore, the characteristics described (proton number especially) describe exactly the Germanium element.
I believe this was helpful.
What if we are in a secret alien community and earth is the ghetto so that’s why aliens never visit earth
Answer:
then the cause of Corona is a gas leak
Answer:
Maybe because we have different skin tone we have white, dark, brown or we might not speak the same language as them or look like them they are going to be confused
Explanation:
Can somebody please describe in detail the difference between a chemical and physical change/reaction. Please provide examples and do as much as possible if you can. Will reward brainliest.
Answer
A chemical change happens when one chemical substance is transformed into one or more different substances, such as when iron becomes rust. Chemical changes occur through the process of chemical reactions, and the resulting substances have different properties because their atoms and molecules are arranged differently.
Physical changes are changes affecting the form of a chemical substance, but not its chemical composition. Physical changes are used to separate mixtures into their component compounds, but can not usually be used to separate compounds into chemical elements or simpler compounds
Explanation:
Which of the following is not an adaptation of California thrashers to life in the chaparral biome? a. a long, curved beak for scratching at the ground b. nesting in late March c. a preference for walking over flying d. nocturnal activity Please select the best answer from the choices provided A B C D
Answer:
D
Explanation:
i think option D
hope this helps
Answer:
D) nocturnal activity
Explanation:
edge 2020
why is it important to know what things are made of
Answer:
Explanation:
Knowing what things are made of, especially in the case of a mixture whose constituents still retain there chemical properties, assists in knowing the beneficial and harmful effects of those things.
For a example, a body cream/lotion (a mixture) that contains hydroquinone will give an individual the idea that the body cream is a lightening cream; as hydroquinone is a depigmenting agent that reduces the production of melanin thereby leading to the lightening of the skin.
Another relevant example is the hand sanitizer that is recommended for use of cleaning of hands in order to rid the hands off of corona virus. The recommended hand sanitizer should be made of at least 60% ethanol for effective use (which dissolves the virus). Knowing the components of a sanitizer to be used against the virus will assist an individual at a store make informed decision about purchase.
Which of the following are observations? Select all that apply.
A. Watching table salt dissolve in water.
B. Feeling the sensation of ice held in the hand.
C. Smelling ammonia used in a cleaning solution.
D. Hearing a loud bang when a balloon filled with hydrogen gas is ignited.
E. Looking at the readout of a digital scale when measuring reagents for an experiment.
Answer:
All are correct
Explanation:
Question 5 Multiple Choice Worth 4 points)
(01.02 MC)
Two objects of different masses are sitting on different balance scales. Object A has a greater mass than object B. How will the weights of
the objects compare to each other?
The weights of the objects will be the same.
The weight of object A will be less than the weight of object B.
The weight of object A will be greater than the weight of object B.
This cannot be determined without knowing the actual mass of the objects.
Answer:
This cannot be determined without knowing the actual mass of the objects.
Explanation:
its like trying to compare the letter A and letter B
Answer:
Its A i took the test
Explanation:
What happens to the charge of the atom if one electron is removed
Answer:
if it loses an electron, it becomes positively charged
Explanation:
If electrons are removed from an atom, then it has more positive charges than negative ones, and the atom has an overall positive charge. Positive ions are called cations. The sharing or exchanging of electrons is what forms bonds between atoms.
Which organelle breaks down materials and releases energy into the cell?
Answer:
Nucleus
Explanation:
In an odometer measures the mileage of a car to 1/10, or 0.1, of a mile. Circle the measurement that shows an appropriate level of precision For this odometer.between 60 and 70 miles. 65 miles 65.8 miles. 65.729 miles
Answer:
65.8 miles
Explanation:
4. Anything that has mass and takes up space is an
example of
A. energy
B. chemical change
C. matter
D. temperature
Answer:
Explanation:
C. matter.
Initially, scientists described atoms as the smallest particles of matter. However smaller particles within atoms were
discovered
How did the scientific world respond to this new information?
O by ignoring the new information because it went against a scientific law
O by discarding the old theory about atoms and making a new one
O by revising the theory that explained atoms to include this new information
by designing new technology that would prove the new information was wrong
Answer:
O by revising the theory that explained atoms to include this new information
by designing new technology that would prove the new information was wrong
Answer:
O by revising the theory that explained atoms to include this new information
by designing new technology that would prove the new information was wrong
Explanation:
What is 7.008 x 10^6 in standard form?
Answer:10
6
=
1000000
or a 1 with 6 zeroes.
Explanation:So
5
⋅
10
6
=
5000000
or five million.
A liquid that occupies a volume of 9.0 L has a mass of 7.2 kg. What is the density of the liquid in kg/L
Answer:
Density = 0.8 kg/LExplanation:
The density of a substance can be found by using the formula
[tex]Density = \frac{mass}{volume} [/tex]From the question
mass = 7.2 kg
volume = 9.0 L
Substitute the values into the above formula and solve for the density
That's
[tex]Density = \frac{7.2}{9} [/tex]We have the final answer as
Density = 0.8 kg/LHope this helps you
Explain how the magnitudes of the solute-solute, solvent-solvent, and solute-solvent interactions compared in order to account for the solution formation process being endothermic or exothermic
Answer:
See explanation
Explanation:
Energy is absorbed by solute molecules as the solute-solute interactions are broken in order to make solute-solvent interactions as a solution is formed. The nature of solven-solvent interaction also determines the possibility of a solute-solvent interaction because like dissolves like. Polar substances can only dissolve in polar solvents and nonpolar substances only dissolve in nonpolar solvents.
Therefore, the solution formation process is exothermic if solute-solvent interaction is greater than solute-solute and solvent-solvent interaction.
Similarly, solution formation process is endothermic if the magnitude of solute-solvent interaction is less than the magnitudes of solute-solute and solvent-solvent interaction.
what does balancing the charges mean when writing an ionic formula
Answer:
Balancing the charges in compound's ionic formula means ensuring that the sum of the charges of the radicals making up the ions is zero that is altogether, there is no net charge of the radicals
Explanation:
The guide to writing an ionic formula is as follows;
The radical with the positive charged ion or cation, is written first and the number of the atom with the charge is written as a subscript followed by the radical with the negatively charged ion, is written and the number of the atom possessing the charge is written as a subscript
The sum charges of the of positive and negative ions must be zero such that must be no net charge of the ions.
What is the density of an object that has a mass of 6.82g and when placed in water displaces the volume from 1.67mL to 7.87mL? Record your answer to the hundreds place.
Answer:
1.10 g/mL
Explanation:
The amount of volume an object displaces is the amount of volume that object takes up.
7.87 - 1.67 = 6.2
The object has a volume of 6.2 mL.
You have the mass (6.82 g) and the volume (6.2 mL). Divide the two value to find the density.
(6.82 g)/(6.2 mL) = 1.10 g/mL
The density of the object is 1.10 g/mL.
When two carbon atoms are joined by a double bond, how many electron pairs are shared between the two carbons
Answer:
Two (2) electron pairs
Explanation:
The sharing of electron pairs by atoms forms a type of bond called COVALENT bond. Atoms that form covalent bonding (share electrons) do so in order to fill their outermost electron shells, hence, gain chemical stability.
However, when two atoms like carbon share TWO PAIRS of electrons with each other, a DOUBLE BOND is formed. An example is the double bond formed in Ethylene (2HC=CH2). A total of four valence electrons (a pair from each carbon) are shared between the two carbon atoms.
How many milliliters of water will it take to fill a 2 L bottle that already contains 1.87 L of water?
Answer:
0.00013
Explanation:
I'm pretty sure. I first subtracted 1.87 from 2. I got 0.13. The conversion from mL to L is 0.001. I multiplied 0.13 and 0.001 and got 0.00013 mL.
(A)Ch3ch2ch2ch2oh + [o] =?
(B)CH3CH2CH(OH)CH3 + H/heat=?
(C) (CH3)2CH=CH2 + Br2/CCl4 =?
(D) cyclohexane + Br2/peroxide
Answer:
d
Explanation: i think
If the gasoline tank in a compact car holds 12.0 US gallons, what is its capacity in liters?
Answer:
45.4249414 or about 45.42 liters
Explanation:
We know the gas tank holds 12 gallons, but we want to find the capacity in liters.
There are 3.785411784 liters in one gallon. Therefore, to convert from gallons to liters, multiply the number of gallons by 3.785411784
liters = 3.785411784 * gallons
The gas tank holds 12 gallons. Plug 12 in.
liters = 3.785411784 * 12
liters = 45.4249414
Let's round to the nearest hundredth. The 4 in the thousandth place tells us to leave the 2 in the tenth place.
liters ≈ 45.42
The capacity in liters is 45.4249414 or about 45.42
Which of the following is NOT a chemical of life? Mineral, water, nucleic acid, carbohydrate
Answer:minerals
Explanation:
Chemicals are the smallest level of organization that makes the cell. The nucleic acids, water, and carbohydrates are crucial for life, but minerals are not chemicals of life. Thus, option A is correct.
What are biochemicals?Biochemicals are substances that are essential for living things and are also produced inside the cells. Major biochemicals are carbohydrates, nucleic acids, lipids, and proteins. They are made up of various chemicals and elements.
These are the most essential chemicals that are crucial for survival and play an important role in various activities and functions. Minerals are not chemicals involved in life. The various chemicals perform various metabolic and cellular functions.
Thus, option A. minerals are not chemicals of life.
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