Answer:
0.021 in scientific notation is 2.1 x 10^-2
Explanation:
Since there are two zeros before the non-zero digits, 10 should be raised to -2.
hope this helps
Using scientific notation, one can express extremely big or extremely small values. When a number between 1 and 10 is multiplied by a power of 10, the result is represented in scientific notation. 0.021 in scientific notation is 2.1 x 10⁻².
A way to express numbers that are either too large or too little to be conveniently stated in decimal form is through scientific notation. It is also known as "scientific form" in Britain, because scientists, mathematicians, and engineers frequently use it for intricate calculations involving large numbers.
A condensed manner of writing numbers is known as scientific notation (also known as standard form). A number is represented by a number from 1 to less than 10, multiplied by a power of 10, when it is written in scientific notation.
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this table resembles a condensed version of the modern periodic table. using the full periodic table as a reference, type the symbols for the elements from part A into this table based on their appropriate group and period.
Explanation:
H, He ---------
Li, Be, --,C, F, Ne
Na, Mg, --,Si, Cl, Ar
K, Ca, Cu, Ge, Br, Kr
Rb, Sr, Ag, Sn, I, Xe
Cs, Ba, Au, Pb, At, Rn
Please give brainliest, I spent a lot of effort on this.
Balancing oxidation-reduction reactions
Mg+ N2—>Mg3N2
Answer:
[tex]{ \sf{3Mg_{(s)} + N_{2(g)} →Mg _{3}N_{2(s)}}}[/tex]
What distinguishes a chemical property from a physical property?
A. Chemical properties describe the characteristics of a substance that are directly observable without changing the substance.
B. Chemical properties are only observable when a substance changes into a new substance.
C. Chemical properties always change depending on temperature or pressure.
D. Chemical properties only describe subjective characteristics that cannot be measured with scientific tools.
C. Chemical properties always change depending on temperature or pressure.
Physical Change v/s Chemical Change:
Physical changes are reversible in nature while chemical change leads to the formation of new products.No new substance is formed in a physical change while it occurs in case of chemical change.A physical property is a characteristic of a substance that can be observed or measured without changing the identity of the substance while a chemical property describes the ability of a substance to undergo a specific chemical change.When the reactants are mixed, the temperature change caused by the reaction is an indicator of a chemical change. Thus we can say that chemical properties always change depending on temperature or pressure.Learn more:
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A student is working hard on a chemistry lab experiment that uses a strong acid. Halfway through the lab, the student gets hungry and starts eating a bag of chips. When the student licks their fingers, they start to have a severe reaction. summary
Calculate the empirical formula of a compound that has a composition of 5.9% (by mass) hydrogen and 94.1% (by mass) oxygen.
Answer:
[tex]oxygen \: at \: 94.1\% \: hydrogen \: at \: 5.9\% \\ at \: 100gram \: oxygen \: \\ \: 94.1\% = .941 \times 100g \\ = 94.1 \times \frac{1mol}{16g} = 5.88g \\ hydrogen \: \\ 5.9\% = .059 \times 100 = 5.9 \times \frac{1mol}{1.002g} = 5.88g \\ here \: oxygen = hydrogen \: so \: ratio \\ = 1 \: \: \: 1 \: \\ emperical \: formula \: = oh\\ thank \: you[/tex]
Composition:
5.9% Hydrogen and 94.1% Oxygen (by mass)
in a 100 gram sample:
5.9 gram Hydrogen
94.1 gram Oxygen
Finding the number of moles:
Moles of Hydrogen:
moles = given mass/ molar mass
moles = 5.9 / 1 [molar mass of Hydrogen = 1g/mol]
moles of hydrogen = 5.9 moles
Moles of Oxygen:
number of moles = given mass / molar mass
number of moles = 94.1 / 16 [molar mass of Oxygen = 16g/mol]
moles of Oxygen = 5.88 ≈ 5.9 moles
Empirical Formula:
Moles of Hydrogen : Moles of Oxygen
5.9 : 5.9
Moles of Hydrogen : Moles of Oxygen = 1:1
Empirical Formula = OH
A factor is an experiment that can change is a(n)
Answer:
Option 2 variable
Explanation:
Answer:
variable.
Explanation:
A variable is anything that can change or be changed. In other words, it is any factor that can be manipulated, controlled for, or measured in an experiment.
What are the uses of hydrogen?
Answer:
Hydrogen finds a variety of application due to its dual nature. Following are some important uses of hydrogen:
Hydrogen is used in the synthesis of ammonia and the manufacture of nitrogenous fertilizers.
Hydrogenation of unsaturated vegetable oils for manufacturing vanaspati fat.
It is used in the manufacture of many organic compounds, for example, methanol.
Hydrogen chloride is a very useful chemical and is prepared from hydrogen.
Hydrogen can reduce many metal oxides to metals by metallurgical processes.
Hydrogen is used as rocket fuel in many space research activities.
Hydrogen fuel is being experimented within the automotive industry with hydrogen fuel cells.
Engineers use scientific knowledge to help them design solutions to problems. GUK (sodium polyacrylate) is a chemical with some unusal properties. Think of a community problem or a global problem that could benefit from the properties of GUK. Discuss your vision of how GUK could be used to solve this problem in 3-5 sentences.
Sodium can be used to solve the problem of
Water pollutionSodium polyacrylate is a sodium salt of polyacrylic acid. It is a super absorbent polymer (SAP) that has great adsorption abilities enabled by the presence of sodium. These abilities find great application in many consumer products as it solves a lot of problems.
Metal ions can be removed from water in industries and water bodies using sodium polyacrylate because it has the ability to increase the surface area of porous substances so that there can be more transfer of mass.
Summarily, the problem of metal ions in water which causes pollution can be solved using GUK.
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1. A (blank) determines what will be tested in a scientific experiment.
Answer:
Hypothesis
Explanation:A hypothesis is what gives the user the directions of the lab and what needs to be done for the procedure
Which of following affects liquifaction of gases except
(2 Points)
Melting point
Volume
Temperature
Pressure
Answer:
pressure
Explanation:
gas convert to liquid at high pressure.
What correctly describes the melting of a solid
The particles in the solid LOSE enough energy to OVERCOME the interactions between the particles
The particles in the solid GAIN enough energy to FORM the interactions between the particles
The particles in the solid GAIN enough energy to OVERCOME the interactions between the particles
The particles in the solid LOSE enough energy to raise the temperature of the solid enough to turn it into a
liquid
Answer:
A reaction in which heat is absorbed by reactant molecules and energy of products become more than reactants is known as an endothermic reaction
the nucleus of an atom is positively charged why
Answer:
hello ~~
look nucleus is mixture of neutrons and protons.. right?
and we know neutrons have no charge and protons are positively charged so overall charge of nucleus is positive
How is the atomic mass of an element determined?
A. by adding the masses of the protons and electrons
B. by adding the masses of the neutrons and electrons
C. by determining the number of protons
D. by adding the masses of the protons, neutrons, and electrons
Answer:
D
Explanation:
Atomic mass is the total mass of protons, neutrons and electrons of an atom at rest
If particles of a solid move slow and particles of
a gas move fast, which would have higher
kinetic energy (KE)?
Answer:
The gas particles would have higher Kinetic energy.
Explanation:
From the formular of kinetic energy:
[tex]{ \sf{KE = \frac{1}{2}m {v}^{2} }}[/tex]
KE is the kinetic energy possessed by particle.
KE is the kinetic energy possessed by particle.m is the particle mass.
KE is the kinetic energy possessed by particle.m is the particle mass.v is the velocity attained by a particle
[tex]{ \sf{KE = \{ \frac{1}{2} m \}} {v}^{2} }[/tex]
keeping the mass, m constant:
[tex]{ \sf{KE = k {v}^{2} }}[/tex]
Therefore, KE is directly proportional to v² :
[tex]{ \sf{KE \: \alpha \: {v}^{2} }}[/tex]
so, when velocity increases, KE also increases.
EASY 30 POINTS! PLS HELP ME T-T
1. True or false? All atoms in an element contain an identical number of neutrons.
2. An atom with a _______ charge has the same number of protons and electrons.
3. An atom that has a different number of electrons and protons is called a(n) _______.
Answer:
1.false
2.neutron
3.neutron
Answer:
1. false
2. zero
3. isotopes
hope it helps
You want to determine the effect of a certain fertilizer on the growth of orchids grown in a greenhouse.
Materials that are available to you include: greenhouse, 100 orchid plants, water, fertilizer, and soil. You
want to know if the orchids will hgrow best with a weak concentration of fertilizer, a medium concentration
of fertilizer, or a high concentration of fertilizer. How will you design an experiment to test different
concentrations of this fertilizer?
how do you set up a controlled experiment
Which element would most likely lose electrons to form positive ions when bonding with other elements?
rubidium (Rb)
gallium (Ga)
argon (Ar)
iodine (I)
The correct answer to the question is Rubidium (Rb)
Rubidium (Rb) is a group 1 element and as such, it can form bond by losing it's valence electron (i.e 1 electron) easily.
Gallium (Ga) is a group 13 element. It can only form bond by losing it's 3 valence electrons.
Argon is a group 18 element. This group has completely filled outermost shell and are very stable. They do not involve in bond formation.
Iodine (I) is a group 17 element. It is more difficult for this group to lose its 7 valence electrons hence, they form bond by accepting 1 electron.
With the above information, we can conclude that Rubidium will most likely lose electron to form bond.
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Answer:
(Question 1)Which element would most likely lose electrons to form positive ions when bonding with other elements?
(Answer) rubidium (Rb)
(Question 2) Which statement about sodium chloride is correct?
(Answer) The sodium atom transfers electrons to the chlorine atoms to form ionic bonds.
(Question 3) Based on their locations in the periodic table, which two elements are most likely to form covalent bonds with each other?
(Answer) nitrogen (N) and oxygen (O)
(Question 4) Which phrase best describes electronegativity?
(Answer) the relative strength with which an element attracts electrons in a chemical bond
(Question 5) Based on the information in the table, which pair of elements would likely form the least polar bonds with each other?
(Answer) bromine and nitrogen
Explanation:
just finished the quick check enjoy UwU
How many kilojoules are required to raise the temperature of a 150. g sample of silver from 25 °C to 135 °C? Silver has a specific heat of 0.235 J/g °C.
Answer:
3.8775 kJ
Explanation:
The formula is Q=mcdeltat
We know m (mass) is 150, c (specific heat) is 0.235, and delta t (change in temperature) is 135-25=110
Plug that in and solve for Q
150*0.235*110=3877.5 J
The problem is that this is still in joules so we have to convert to kilojoules
3877.5 J * 1 kJ/1000 J = 3.8775 kJ
A student reacts 3.0 g of magnesium with 2.5 mol / dm3 sulfuric acid.Calculate the minimum volume of sulfuric acid that reacts with all the magnesium
3.og idbj mass of mjemantg 2.oml
What series does the following compound belong to?
Answer:
B
Carboxylic acid
Explanation:
I'm not entirely sure, but this should be it
How does the amount of oxygen in the water affect the oyster population constant/variables and what is the hypothesis/predication
Answer:
Lack of oxygen can cripple the oysters' ability to fight off the parasite Perkinsus marinus that causes Dermo and slowly takes over their bodies.
Help me with this easy chemical change question!!!!
Answer:
1, just I) color.
Physical properties are the properties that can be observed without changing the composition of a substance, such as color, temperature, density, and boiling point.
A physical change is a change in the substance that only modifies its aggregation state, such as solidification, and boiling.
Chemical properties are the properties that need a reaction to being observed, such as combustibility, which needs a combustion reaction to being quantified.
When a chemical reaction occurs, and the composition of the substance change, it's a chemical change.
So, heating copper with carbon is a chemical reaction, and purification by electrolysis is too. Color is the only physical property.
What does the atomic number of an element represent?
A. number of isotopes
B. number of protons
C. number of bonds
D. number of atoms
Answer:
protons
Explanation:
btw you protons and electrons are always the same
prcAnswer:
e c. proton
Explanation:
i pueslist
A gas occupies 250mL, and it's pressure is 0.724 atm at 25 degrees c.r = 0.0821 L•atm/mol•k. Solve for moles !! Plzzzz
Answer:
0.0074 moles
Explanation:
We'll have to use this forumla: PV = nRT
P = Pressure (0.724)
V = Volume in liters (0.25)
n = moles
R = 0.0821
T = temperature in kelvins (25 + 273 = 298)
Our equation will look like this:
(0.724)(.25) = n(0.0821)(298)
0.181 = 24.4658n
Divide both sides by 24.4658 to isolate n
0.181/24.4658 = 24.4658n/24.4658
n = 0.00739808
3
A substance dissolves in water to form a colourless solution. This solution reacts with aqueous
silver nitrate in the presence of dilute nitric acid to give a yellow precipitate.
What is the possible identity of the substance?
A А
calcium iodide
B
copper(II) chloride
Ciron(II) iodide
D
sodium chloride
Answer:
D) sodium chloride
i think this is the answer
Explanation:
Someone plz help me !!
Science
Or
Bias?
what is the molecular weight of H2so4?
Lets find
[tex]\\ \sf\longmapsto H_2SO_4[/tex]
[tex]\\ \sf\longmapsto 2(1u)+32u+4(16u)[/tex]
[tex]\\ \sf\longmapsto 2u+32u+64u[/tex]
[tex]\\ \sf\longmapsto 34u+64u[/tex]
[tex]\\ \sf\longmapsto 98u[/tex]
difference between atom and ion
plz plz answer
Answer:
Atoms are neutral; they contain the same
samenumber of protons as electrons. By
definition, an ion is an electrically charged
particle produced by either removing
produced by either removingelectrons from a neutral atom to give a
produced by either removingelectrons from a neutral atom to give apositive ion or adding electrons to a neutral atom to give a negative ion.
Polar molecules have partial positive and partial negative charges. An electrical
attraction between the partial positive charge of one polar molecule and the partial
negative charge of another polar molecule is called a/an
Answer:
Image result for Polar molecules have partial positive and partial negative charges. An electrical attraction between the partial positive charge of one polar molecule and the partial negative charge of another polar molecule is called a/an
A polar molecule has a net dipole as a result of the opposing charges (i.e. having partial positive and partial negative charges) from polar bonds arranged asymmetrically. Water (H2O) is an example of a polar molecule since it has a slight positive charge on one side and a slight negative charge on the other.
Explanation:
A brick has a mass of 100 G and a volume of 25CM3 what is the density of the brick
Answer:
[tex]\boxed {\boxed {\sf 4 \ g/cm^3}}[/tex]
Explanation:
We are asked to find the density of a brick. Density is a substance's mass per unit volume. The formula for calculating density is as follows.
[tex]\rho= \frac{m}{v}[/tex]
The mass of the brick is 100 grams and the volume is 25 cubic centimeters.
m= 100 g v= 25 cm³Substitute the values into the formula.
[tex]\rho= \frac{ 100 \ g}{25 \ cm^3}[/tex]
Divide.
[tex]\rho=4 \ g/cm^3[/tex]
The density of the brick is 4 grams per cubic centimeter.