Answer:
a)215000
b) 3.2
c) 2.08
d) 27439.74
Explanation:
Significant figures:
When we add or subtract the values the number of significant figures after decimal in result must be equal to the given measurement having less number of decimal places.
b) 5.45 -2.3
3.2
d) 14.98 + 27,340 + 84.7593
27439.74
When we multiply or divide the values the number of significant figures must be equal to the less number of significant figures in given value.
a) 628 × 342
214776
we will round off this value into 3 significant figures.
215000
c) 28.0/13.483
2.08
Ralph conducted an experiment to study the effect of temperature change on the heart rate of
Daphnia, transparent aquatic invertebrates commonly known as water fleas. Ralph heated three
different beakers of water containing Daphnia to a different temperature: 30°C, 32°C, and 34°C.
He put a drop of water from each beaker on a slide mount. He then used a microscope to observe
Daphnia in each sample. He counted the number of heartbeats in one minute and averaged his
results. Which of the following could be a step in a replication of this experiment?
Answer:
c. Ralph's classmate observing Daphnia in water at 30oC, 32oC and 34oC
Explanation:
When we talk about replication, we actually mean, repetition of a scientific procedure carried out by another scientist and obtaining the same results as he/she previously did.
Replication is carried out under identical conditions as the first scientist did. If Ralph's classmate wants to replicate Ralph's work, then identical temperature conditions of 30oC, 32oC and 34oC must be used, hence the answer above.
what is the correct?
Answer:
it is c
Explanation:
burning magnesium is introduced into steam
Answer:
It produces magnesium oxide and hydrogen gas.
Explanation:
When magnesium burns with steam it produces magnesium oxide which is white in color and hydrogen gas. When magnesium burns, it mixes with the oxygen present in the air produces magnesium oxide in powder form. Magnesium react with oxygen by giving two electrons present in its valance shells while the oxygen needs two electron for completing their valance shell and becomes stable.
The energy transformations shown below document the
changes that are a part of what energy resource?
Kinetic --> Mechanical --> Electrical
Solar Enega
Nuclear Energy
o Wind Energy
Fossil Fuels
____describes a
solution in which the amount of
solute dissolved in a given amount
of solvent is less than
the solubility limit.
A. Soluble
B. Supersaturated
C. Saturated
D. Unsaturated
Dentify the compound in each of the following pairs that reacts with sodium iodide in acetone at the faster rate:__________. (a) 1-Chlorohexane or cyclohexyl chloride (b) 1-Bromopentane or 3-bromopentane (c) 2-Chloropentane or 2-fluoropentane (d) 2-Bromo-2-methylhexane or 2-bromo-5-methylhexane (e) 2-Bromopropane or 1-bromodecane
Answer:
a) 1-Chlorohexane
b) 1-Bromopentane
c) 2-Chloropentane
d) 2-bromo-5-methylhexane
e) 1-bromodecane
Explanation:
One important fact that we must have behind our minds as we approach the problem is the fact that sodium iodide in acetone will lead to an SN2 reaction because the nucleophile (iodide ion) is naked and not solvated. Also, the iodide ion is a good nucleophile and the solvent is a polar aprotic solvent. All these factors together make the reactions to tilt towards SN2 mechanism.
In a) 1-Chlorohexane offers less steric hinderance and more ease of SN2 reaction hence the answer.
In b) 1-Bromopentane offers less steric hinderance being a primary alkyl halide hence the answer.
c) In c) 2-Chloropentane contains chlorine which is more polarizable and a better leaving group than fluorine.
In d) 2-bromo-5-methylhexane is a secondary alkyl halide and undergoes SN2 reaction with less steric hindrance. 2-Bromo-2-methylhexane is a tertiary alkyl halide and does not undergo SN2 reaction due to steric hindrance.
e) 1-bromodecane is a primary alkyl halide and offers less steric resistance to the approaching nucleophile than 2-Bromopropane.
A student walks 15 km in 3 hours. What is the student’s average speed?
A :45 km/h
B :5 km/h
12 : km/h
18 : km/h
Answer:
5 km/h
Explanation:
divide the hours to the distance
Q. Which of the following scenarios describes a process with a negative system entropy change?
A) build a skyscraper
B)An igloo melting
C)A clean room becomes cluttered
D)Osmosis
What is used to determine the number of each atom in an ionic formula?
A. The oxidation state of each atom
B. The number of bonds in the formula
C. The electronegativity of each atom
D. The period of the metal in the formula
the oxidation state of each atom
2. Classify each of these species as a Brønsted acid
ør
base, or both:
(a) H20, (b) OH-(c) H3O+d) NH3, (e) NH..
(f) NH, (g) NO, (h) CO2 (1) HBr, j) HCN
According to Bronsted lowry, the chemical species that donate H+ ions is called acid, and the one that accepts it is called a base.
So here:
Bronsted acids are H3O+, NH4+, HBr, and HCN.
Bronsted bases are : OH- , NH2- , NO3- ,CO32-
Both: H2O, and NH3.
Substances that accept protons from other substances are called Bronsted bases. HCl is a Bronsted-Lowry acid because it is a proton donor, and H2O is a proton acceptor and Bronsted-Lowry base. Consider the example of hydrochloric acid HCl reacting with basic ammonia NH3. In this reaction, HCl donates its proton to NH3.
Therefore, HCl is a Bronsted-Lowry acid. NH3 is a Bronsted-Lowry base because it has a lone pair of electrons that it uses to accept a proton. Ammonia, NH3, is a Lewis base and has a lone pair of electrons. Donates electrons to compounds that accept electrons. NaOH is both an Arrhenius base and a Bronsted-Lowry base. Arrhenius bases are substances that generate OH^ ions in aqueous solutions, and NaOH does this. Bronsted-Lowry bases are proton-accepting substances.
Learn more about Bronsted acids here:-https://brainly.com/question/12377772
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What is the maximum number of electrons that an L shell may contain?
Answer:
Eight
Explanation:
The L shell only holds eight electrons.
8
The L shell can only holds eight electrons
A block is pulled 0.90 m to the right in 2.5 s.
What is the block’s average speed to the nearest hundredth of a m/s?
The block’s average speed : 0.36 m/s
Further explanationDistance is the length traveled by an object within a certain of time .
Average speed = total distance/total amount of time ,
Can be formulated :
[tex]\tt avg.s(speed)=\dfrac{\Delta D}{\Delta t}[/tex]
ΔD= total distance
Δt= total time
A block is pulled 0.90 m to the right in 2.5 s :
ΔD= total distance = 0.9 m
Δt= total time = 2.5 s
The block’s average speed :
[tex]\tt avg.s=\dfrac{0.9}{2.5}=0.36~m/s[/tex]
Which of the following electronic transitions would emit the lowest energy photon?
B- n=2 to n=1
C-n=3 to n=2
D-n=5 to n=2
Answer:
i will think c-n=3 to NM=2
An ionic bond is a bond between _____.
Answer:
An ionic bond is a bond between two ions of opposite charge (a cation (+) and an anion (-).
Explanation:
I really hope this helps! :)))
I REALLY NEED HELP can someone help me please I’ll make you brainliest ! :)
Answer:
C
Explanation:
All thing in option c is flammable
Answer:
D
Explanation:
Which of the following equations does not represent a redox reaction?
a. NH3+ HCl → NH4Cl
b. 2H2O2+ → 2H2O + O2
c. 2O3 → 3O2
d. 3NO2+ H2O → NO+ 2HNO3
e. LiCl → Li^+ + Cl
Answer:
a. NH3+ HCl → NH4Cl
c. 2O3 → 3O2
Explanation:
A redox reaction is a reaction in which there is loss or gain of electrons. As a result of that , there is a change in the oxidation number of the species involved in the reaction.
If we look at the species shown in the answer, there isn't any change in oxidation number as we move from left to right hence they are not redox reactions.
Redox reactions lead to change in oxidation number of species from left to right.
Select the keyword or phrase that will best complete each sentence.
a. alkenes
b. -ene-
c. syn and anti
d. alkanes
e. syn
f. nucleophiles
g. -yne-
h. -ane-
i. alkynes
f. electrophiles
g. anti
Compounds that contain a carbon-carbon double bond are known as________
Alkenes are electron rich; therefore, simple alkenes do not react with_______ or bases, but will react with _______or acids.
In the IUPAC system, an alkene is identified by the suffix -ene-
Addition reactions in which two parts Of a reagent are added to the same side of
a double bond are known as _________additions.
Addition reactions in which two parts of a reagent are added from opposite
sides of a double bond are called ________ additions
Halogenation and halohydrin formation occur with ________-additions.
Answer:
alkenes
nucleophiles
electrophiles
syn
anti
syn and anti
Explanation:
Compounds that contain a carbon-carbon double bond are known as alkenes
Alkenes are electron rich; therefore, simple alkenes do not react with nucleophiles or bases, but will react with electrophiles or acids.
In the IUPAC system, an alkene is identified by the suffix -ene-
Addition reactions in which two parts Of a reagent are added to the same side of
a double bond are known as syn additions.
Addition reactions in which two parts of a reagent are added from opposite
sides of a double bond are called anti additions
Halogenation and halohydrin formation occur with syn and anti -additions.
Further explanations:
Compounds that contain a carbon-carbon single bond are known as alkanes. Compounds that contain a carbon-carbon double bond are known as alkenes. Compounds that contain a carbon-carbon triple bond are known as alkynes.
Nucleophiles are electron rich so they react with electron deficient centers while Electrophiles are electron deficient so they react with electron rich centers.
The table shows the average distance between the molecules of a substance in the solid, liquid, and gaseous states.
Distance Between Molecules
State Distance
X 10−9 cm
Y 10−11 cm
Z 10−7 cm
Which of the following is the correct order of the relative strengths of the intermolecular forces in the three states?
Y > Z > X
Z > X > Y
X > Z > Y
Y > X > Z
Answer:
Y > X > Z
Explanation:
The intermoecular forces refer to forces that exist between molecules of a substance. They are the secondary bond forces that hold particles of a substance together in a particular state of matter.
The shorter the distance between molecules, the greater the magnitude of intermolecular force between the molecules.
The molecules of Y are at the shortest distance from each other hence they have the highest magnitude of intermolecular forces. Followed by X and lastly Z with the greatest distance between the largest intermolecular distance.
What are some examples of HIGH resistance? Question 2 options: wide wire, short wire, less resistors narrow wire, less resistors, long wire long wire, wide wire, more resistors long wire, narrow wire, more resistors
Answer:
The answer is long wire, narrow wire, more resistors
Explanation: I just took the test and it's right.
A certain mass of hydrogen gas collected over water at 10°C and 750mmHg pressure has a volume of 57cm3. Calculate the volume when it is dry at S.T.P ( S.V.P of water at 10°C = 9.2 mmHg .
The volume of gas when it is dry at S.T.P : 53.6 cm³
Further explanationGiven
P tot=750 mmHg
V₁=57 cm³
T₁=10 °C = 283 K
P₂ = 760 mmHg(STP)
T₂ = 273 K(STP)
Required
P dry gas at STP
Solution
Dalton's Law
P tot = P H₂O + P gas
P gas = 750 mmHg - 9.2 mmHg
P gas = 740.8 mmHg = P₁
Combined gas Law
[tex]\tt \dfrac{P_1.V_1}{T_1}=\dfrac{P_2.V_2}{T_2}\\\\V_2=\dfrac{P_1.V_1.T_2}{T_1.P_2}\\\\V_2=\dfrac{740.8\times 57\times 273}{283\times 760}=53.6~cm^3[/tex]
SO2Cl2 rightarrow SO2 (g) + Cl2 (g)At 600 K, SO2Cl2 will decompose to form sulfure dioxide and chlorine gas via the above equation. If the reaction is found to be first order overall, which of the following will cause an increase in he half life of SO2CL2?A. Increasing the initial concentration of SO2,CI2.B. Increasing the temperature at which the reaction occurs.C. Decreasing the overall pressure in the container.D. None of these will increase the half life.
Answer: D. None of these will increase the half life.
Explanation:
Half life is the amount of time taken to decay to half of its original value. The half life is related to rate constant by the following relation for a first order reaction:
[tex]t_{\frac{1}{2}}=\frac{0.693}{k}[/tex]
As half life is independent of concentration , temperature and pressure, none of these factors would affect the half life.
Thus in the reaction, [tex]SO_2Cl_2 \rightarrow SO_2(g)+Cl_2(g)[/tex] following first order kinetics, none of the factors will increase the half life.
How does heat differ from temperature?
O Temperature is the measure of heat.
O Temperature and heat are the same thing.
O Temperature measures thermal energy, and heat is the flow of thermal eneroy
O Temperature measures the loss of energy, and heat measures the gain of eneray.
Answer: Temperature measures thermal energy, and heat is the flow of thermal energy
Explanation:
Heat describes the transfer of thermal energy between molecules within a system. Heat measures how energy moves or flows. It is measured in Joules.
Temperature measures the hotmess or coldness of a body or how much thermal energy it contains . Temperature describes the average kinetic energy of molecules within a material or system. It is measured in Celsius (°C), Kelvin(K), or Fahrenheit (°F).
Thus the correct option is Temperature measures thermal energy, and heat is the flow of thermal energy
Answer:
its c
Explanation:
edg 2021
How can you get the sugar out of the sweet tea?
Freeze the water and the sugar will appear as clumps inside the ice.
Just let the sweet to stand and the sugar will settle to the bottom of the glass.
Heat the water Cevaporating iD and you will be left with the sugar.
Which of the following is a chemical property?
O volume
O flammability
O color
O weight
Answer:
your answer is flammability
What is the molality of a solution of 10 g NaOH in 500 g water?
Molar mass NaOH = 40 g
Explanation:
Moles of NaOH = 10g / (40g/mol) = 0.25mol.
0.25mol / 500g = 0.50mol / 1000g = 0.50mol/dm³.
The molarity is 0.50mol/dm³.
Initial Phenomena Question: Magnesium metal reacts with hydrochloric acid to produce magnesium chloride and hydrogen gas; how can you prove that?
Answer:
See explanation
Explanation:
The reaction equation is as follows;
Mg(s) + 2HCl(aq) -------> MgCl2(aq) + H2(g)
Firstly, the appearance of bubbles of gas shows that a gas is evolved in the reaction.
Secondly, If we hold up the flame of a butane fireplace lighter above the appearing hydrogen bubbles, we will hear audible pops as the hydrogen gas ignites showing that a combustible gas is produced in the reaction.
Lastly, as the reaction proceeds, the magnesium ribbon disappears as MgCl2 is formed. If a set up such as the image attached is used, hydrogen gas is collected over water.
Image credit: RSC education
24. H.SO, has
a) Ionic bond
b) both lonic and covalent bonds
c) ionic covalent and coordinate bonds
d) covalent bond
Answer:
b
Explanation:
Both ionic and covalent bonds when it has dissolved into water it will become ionic compound but when it was in gas situation it was covalent compound.
Magnesium reacts with sodium fluoride to produce sodiunfluoride and elemental sodium.
Explanation:
Mg+NaF. NaF+Mg
are use sure about the question
Explain what is meant by a half-life of 150 years. Then, write a function that models the amount, A, of a 100-mg sample remaining after T years for a substance with a half-life of 150 years. Use graphing software to graph the equation. Answer in complete sentences.
Answer:
Half-life of 150 years are those year that a radioactive element take to disintegrate to a half of it's original value.
I don't have graphical software
The waste product of nuclear energy which is a possible pollutant is:
A.smoke
B.hot air
C.radiation
D.heat pollution to lake
Answer:
CCCCCCC
Explanation:
Answer:
C. radiation
Explanation:
the possible pollutant is radiation because nuclear energy causes ; electromagnetic waves are radio waves, light, infrared rays, UV rays, X rays, Gamma rays. These are well known and are used extensively in the fields of communications, industry, medicine and research.
Radiation is a term given for waves caused by electromagnetism and high energy particles .Radioactive substances have High energy particles which are tiny bits of matter that are made to move at high speeds releasing nuclear radiation. There are about 50 naturally occurring radioactive substances and More than 2000 man-made ones. There are three kinds of radioactive radiation – alpha particles, beta particles and gamma radiation.