standard units of measure for density
Answer:
g/cm³ for solids,
g/ml for liquids
g/L for gases.
Explanation:
Though SI unit of density is kg/m³, for convenience we use g/cm³ for solids, g/ml for liquids and g/L for gases. Mathematically, density is defined as mass divided by volume: ρ=m/V
I need help with this please.
What are the units for Rf values? Please help!
Answer:
Microwatts.
Explanation:
RF + EMF Unit Conversion Charts: Interpreting exposure levels. When measuring Radio Frequencies, the most common units of measurement are microwatts per square meter (µW/m2), microwatts per square centimeter (µW/cm2) and volts per meter (V/m).
Answer:
No units
Explanation:
In Thin Layer Chromatography (TLC), retention factor (Rf value) is found by taking the distance travelled by the spot divided by the distance of the solvent front. Rf value is a ratio of distances hence they have no units.
Mathematical derivation
The distance travelled by the spot is in cm, and that of the solvent front is also in cm. Thus, dividing the two units would give us no units for the Rf value.
What is TLC?
TLC is a technique used for separation and identification. The stationary phase is polar while the solvent is relatively nonpolar. Thus, the less polar substance is more attracted to the solvent (according to the principle of 'like attracts like') and travels further and thus have a higher Rf value.
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What’s the first thing you should always do before starting a lab
Review your instructions
curd and milk are what acid
Answer:
lactic acid
Explanation:
and this is broken down by the enzyme lactase
Why will a toy train remain still if you push on the engine with
A force of 3 N and your friend push on the caboose with a
Force of 3 N?
Explanation:
Because when two equal forces are applied from opposite directions, they "eliminate" each other.
The train would go right if a 3N force was only applied in the right direction, and it would go left if the same force was only applied to the left.
If a 3N force was applied to the right and a 2N force to the left, it would equal a 1N force to the right (3-2=1).
But there it's 3-3=0, so in practice the force is 0N. Therefore the train won't move.
49.2 m = _________ hm
Shreya spent $16 on a magazine and some
erasers. If the magazine cost $7 and each
eraser cost $3, then how many erasers did
she buy?
Answer:
she bought 3 erasers an got two dollars back
Explanation:
Which of the following is NOT a "big idea" in chemistry?
A. Every chemical process uses or produces energy.
B. Elements are held together by strong forces called chemical bonds.
C. Matter is created or destroyed in order to form new chemical substances.
D. Chemical reactions are processes in which reactants change to form products.
How many kinds of atoms are there
Answer:
there are more than 109 different types of atom - one for each element.
4. What is the proper way to prepare an acid solution?
Answer:
Always add acid to a large volume of water. The solution may then be diluted with additional water to make one liter. You'll get an incorrect concentration if you add 1 liter of water to the acid.
An acid is concentrated solution hence, it should be added to considerable quantity of water. The required volume can then be adjusted by adding more water.
What are the properties of an acid?Acids form aqueous solution and have the property of electric conductivity. Acids reacts with other molecules by forming a covalent bond.
Acids are corrosive in nature, sticky to touch, tastes sour and have strong smell.
Acids can be qualitatively detected through litmus test. They turn blue litmus paper red. Their pH is < 7 on pH scale.
Acids can be classified as:
Strong acids - are the acids that dissociate in water completely.Weak acids - are the acids that partially dissociate in water.Chemically, acids can react with other metals, carbonates and bases. Common examples of acids are vinegar (acetic acid), hydrochloric acid (HCl), sulfuric acid (H2SO4) etc.
Acids are found in food items such as citrus fruits. Acetic acid is widely used in certain food preparations and as food preservative. Acids are commercially used in dyes, paints and in soft drinks.
Thus, acids are important in many chemical reactions.
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How are elements with atomic masses greater than Uranium’s made?
Answer:Atoms heavier that uranium do not exist in nature.they must be synthesized in a particle accelerator
Explanation:
Which amino acid is least likely to produce a hydrogen bond with water or polar molecules?
Which molecule is sometime referred to as “the recipe book for how to make a protein"?
Answer:
RNA molecules
Explanation:
RNA molecules carry the instructions that are necessary to create proteins
Answer:
RNA molecules
Explanation:
RNA molecules carry the instructions that are necessary to create proteins
When a scientist analyzes experimental results, the scientist is generally:
It has been proposed that mitochondria and chloroplasts are modern descendants of early prokaryotic cells that began to reside and gradually evolve within primitive cells.
Answer:
mitochondria and chloroplasts both have prokaryotic ribososmes
Explanation:
Mitochondria and chloroplasts are the modern descendants of early prokaryotic cells. These lived in primitive cells and later developed into part of them. This hypothesis is supported because both mitochondria and chloroplasts have their own primitive ribosomes. These two organs contain 70s ribosomes.Describe how the charges of the subatomic particles interact with one another.
Answer:
Electrons, Protons, and Neutrons. ... Protons are another type of subatomic particle found in atoms. They have a positive charge so they are attracted to negative objects and repelled from positive objects. Again, this means that protons repel each other
If one gram of water has a volume of one milliliter, what would the mass of one liter of water be in kilograms?
The power to conduct elections is what type of power
Answer:
Unlike delegated powers, they are not listed specifically, but are guaranteed by the Tenth Amendment: "The powers not delegated to the United States by the Constitution, not prohibited by it to the States, are reserved to the States respectively, or to the people." Some traditional reserved powers include regulating ...
Explanation:
A car drives with constant speed of 112km/h. How long will it take to travel to distance of 56 kilometers?
112 km is travelled by car in 60 minutes
1 km is travelled by car in 60/112 minutes
56 km is travelled by car in 60/112*56 = 30 minutes = 0.5 hours
Explanation:
49. Carry out the indicated temperature conversions.
40 °C to Fahrenheit degrees
b. -40 °F to Celsius degrees
c. 232 K to Celsius degrees
d. 232 K to Fahrenheit degrees
Answer:
sorry but dorks dont learn maths
Explanation:
just kidding no offense but i think umm 1st one will stay same
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When salt is placed on ice the ice melts. explain why?
Explanation:
When salt is added to ice, salt first dissolves in the film of liquid water that is always present on the surface, thereby lowering the ice's freezing point
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which best represents a particle containing 28 protons, 26 electrons,and 34 neutrons?
Answer:
This question lacks options, but the question can be answered based on knowledge of proton, electron and neutron number. The answer is:
62 Ni2+ particle
Explanation:
Nickel is a chemical element with atomic number 28. This means it has 28 electrons and 28 protons in its neutral atom. However, the isotope of nickel being described in the question has a mass number of 62. The mass number is calculated by adding the proton number with the neutron number. That is;
Mass number = number of protons + number of neutrons
Mass number = 28 + 34
Mass no. = 62
An element with mass number 62, which has lost two electrons to become positively charged (two positive charges) is described in the question. Hence, the particle that best fits this description is positively charged Nickel particle (Ni2+).
Ni2+ has 28 protons, 26 electrons (reduced by 2) and 34 electrons.
Note that, the 2+ charge is as a result of the loss of two electrons, hence, reducing the electron number by 2.
Which of the samples pictured is most likely a nonmetal?
Answer:
its C
Explanation:
If 5.0 g of copper cools from 35.0oC to 22.6 oC and loses 23.6 J of heat, what is the specific heat of copper? a. 0.038 J/(g. oC) b. 0.62 J/(g. oC) c. 0.076 J/(g. oC) d. 0.38 J/(g. oC)
Answer:
c = 0.38 J/(g-°C)
Explanation:
Given that,
Mass of copper, m = 5 g
Initial temperature, [tex]T_i=35^{\circ} C[/tex]
Final temperature, [tex]T_f=22.6^{\circ} C[/tex]
When copper cools, it looses 23.6 J of heat. We need to find the specific heat of copper. The heat lost is given by :
[tex]Q=mc\Delta T[/tex]
c is specific heat
[tex]c=\dfrac{Q}{m\Delta T}\\\\c=\dfrac{23.6}{5\times (22.6-35)}\\\\c=0.38\ J/g-^{\circ} C[/tex]
Hence, the correct option is d.
What is the answer 24.3m
Why are some isotopes radioactive and some are not?
Answer: there are atoms that either have too many or too few neutrons or protons in their nuclei. This results in an imbalance between the jedi forces holding them together, which leads to an excess of internal energy. Such atoms are said to be unstable or radioactive.
Explanation:
This element has three fewer protons than oganesson 
Answer:
ununpentium
Explanation: this is element 115, Oganesson has 118
The atomic number of oganesson is 118. The element which is having three fewer protons than oganesson is moscovium (Mc) (115).
What is oganesson?
Oganesson is a newly found element synthesized in 2002 and is placed as 118'th element in the periodic table. In modern periodic table, the elements are arranged based on their atomic number.
Atomic number is the number of protons in the atom as well it is the number of electrons in the neutral atom. For a neutral atom the number of electrons are protons are equal.
Thus in a neutral atom the positive charges are neutralized by equal number of negative charges.
Thus, for 118'th element, there are 118 protons, three fewer from this means, there are 115 protons, the 115'th element in the modern periodic table is moscovium.
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As a star uses up its hydrogen supply, it changes from a main sequence star to a -
A.) dwarf
B.) supernova
C.) black hole
D.) giant
As a star uses up its hydrogen supply, it changes from the main sequence star to a Giant. Thus, the correct option for this question is D.
What is a Star?A star may be defined as a type of huge celestial body that is generally constructed of hydrogen and helium that produce light and heat from the churning nuclear forges inside their cores. They are the luminous bodies that are visible in the sky at night.
A giant is a type of star that has utilized its hydrogen supply in its cores and transformed itself into the thermonuclear fusion of hydrogen in the shell that envelops its surroundings.
This creates an outwards force and stimulates fusion that initiates to increase and hence the star can not able to maintain its equilibrium longer.
Therefore, as a star uses up its hydrogen supply, it changes from the main sequence star to a Giant. Thus, the correct option for this question is D.
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Which rock is an example of a clastic sedimentary rock
Answer:
common sedimentary rocks include sandstone, limestone, and shale.