Answer:
where are the choices?
Explanation:
1. Amy's science teacher shows her class a model of an atom. Why is a model useful for studying atoms?
A. All atoms exist in the gas phase, and atmospheric gases are invisible.
B. A model is helpful to observe the behavior of the parts of an atom.
C. The parts of an atom cannot be directly observed.
D. A model of an atom is the same for all atoms.
Answer:
The parts of an atom cannot be directly observed.
Explanation:
An atom is the smallest indivisible particle of a substance that can take part in a chemical reaction.
Atoms are not observed with naked eyes because they are found in the realm of very small particles. It is impossible to observe the parts of an atom directly.
As a result of this, models suffice in explaining the parts of an atom. Hence the answer.
ASAP MULTIPLE CHOICE WILL MARK BRAINLIEST
A specific, electrically neutral atom of boron contains a total of 16 particles (protons, neutrons, and electrons).
What is the mass number of this atom of boron?
5
6
11
21
Answer:
11
Explanation:
2NaOH+CO2----->Na2CO3+H2O
calculate the mass of sodium carbonate produced when 10.0 g of sodium hydroxide reacts with carbon dioxide.
Answer:
13.2 g Na2CO3
Explanation:
Convert 10.0 g NaOH to mol.
10.0 g x 1 mol/39.997 g = 0.250 mol
Use mol ration given by the equation: 2 mol NaOH to 1 mol Na2CO3
0.250 mol NaOH x 1 mol Na2CO3/2 mol NaOH = 0.125 mol Na2CO3
Finally, convert the moles of Na2CO3 to grams.
0.125 mol Na2CO3 x 105.99 g/1 mol = 13.2 g
According to stoichiometry,13.25 g of sodium carbonate is produced when 10 g of sodium hydroxide reacts with carbon dioxide.
What is stoichiometry?It is the determination of proportions of elements or compounds in a chemical reaction. The related relations are based on law of conservation of mass and law of combining weights and volumes.
Stoichiometry is used in quantitative analysis for measuring concentrations of substances present in the sample.
For the given reaction according to stoichiometry 2 molecules of sodium hydroxide react to give 1 molecule of sodium carbonate.
That is 80 g sodium hydroxide gives 106 g sodium carbonate
∴10 g sodium hydroxide will produce 10×106/80=13.25 g of sodium carbonate.
Thus, 10 g sodium hydroxide produces 13.25 g of sodium carbonate.
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As continents come together to form a supercontinent,
a. the ocean that jad separated them disappears
b. a giant ocean forms on the outside of the supercontinent
c. mountain ranges rise where continental plates converge
d. all of these
How does a balanced equation satisfy the Law of Conservation of Mass
Answer: I think d
Explanation:
What do you call this process that happened in crayons and candles where it’s liquid phase turned into solid?
Answer:
Freezing/Solidification
Which of the following is a heterogeneous mixture
Answer:
a heterogeneous mixture is a mixture of two or more liquid substances that are immiscible that is they cannot mix
Answer:
dude I'm telling you now just think A. a fruit salad
Explanation:
Why is the force of gravity greater for an object orbiting Earth than for the
same object orbiting Pluto?
A. Earth has only one moon, while Pluto has three.
B. Earth is closer to the sun than Pluto.
C. Earth has a heavy atmosphere and Pluto does not.
D. Earth is more massive than Pluto.
Answer:
d) Earth is more massive than Pluto.
Explanation:
The force of gravity is greater for an object orbiting the Earth than for the same object orbiting Pluto, because Earth is more massive than Pluto.
The common factor is that the greater the planet's mass, the greater its gravitational force acting on an object. Hence, the option (d) is the correct answer.
which of the following is a compound?
what is the role identification of work performance
Explanation:
It is one of the most important factors that encourage workers to put forth great efforts and work more efficiently.
Which is an example of making a quantitative observation?
a. measuring the mass of metal used in a reaction
b. recording the color of a solid formed in a reaction
c. describing a liquid as having a slippery feel
d. rating an odor on how nice it smells
Answer:
A) measuring mass of metal used in a reaction
Explanation:
Quantitive observations is data involving statistics and numerical values.
Which of these is NOT a type of natural force? A) gravity B) friction C) throwing D) magnetism
Throwing isn't classified as a force so I'd say C but it is a force just not a type
Answer:
C- throwing
Explanation:
You physically have to throw it while the other forces act on their own.
in which of the following are photosynthesis and resperation alike
Answer:
i need a picture or more info to understand
Answer: photosynthesis puts together a glucose molecule, but cellular respiration takes it apart and uses its energy.
वार्षि
एउटा व्यक्तिले रु. 46875 को कर्जा लिएछ । यदि प्रतिवर्ष प्रति रुपैयाँ चक्रिय व्याजदर 4 पैसा भए कति वर्षमा रु. 5853 च.
25 ETSIT ? (A person took loan of Rs 46875. If the rate of compound interest is 4 paisa per rupee
year, in how many years will the compound interest be Rs 5853.) [2065 B, 067 D] Ans: 3
तार्षिक
पत्ता
Rs
200/-
Answer:
3 years
Explanation:
P= Rs 46875
R= 4 Pisa per rupee per year = 4% per annum
C. I = Rs 5853
t= time (the unknown)
Given;
Amount= P(1 + R/100)^t
Amount = (P + CI)
(46875 + 5853) = 46875 (1 + 4/100)^t
1.124864 = (1 + 4/100)^ t
1.124864 = (1.04)^t
t= 3 years
1. What was the name of battle where the "shot heard around the world" happened?
7. What is the wavelength of a 4.34 x 10^15 /s wave?
Among electromagnetic waves, UV rays are most dangerous because exposure to these radiation cause serious problems in living organism. The wavelength of wave is 6.9x 10⁻⁸m.
What is electromagnetic wave?Electromagnetic wave is a wave which contain two component one is electric component and other is magnetic component. The electric and magnetic component are perpendicular to each other. There are so many wave that comes under electromagnetic wave like infrared wave , radio wave, light wave.
There is a relation between frequency of wave, and wavelength of wave
Mathematically,
ν=c÷λ
where,
ν=frequency of light=4.34 x 10¹⁵s⁻¹
c is speed of light that is 3×10⁸m/s
λ is the wavelength of light=?
Substituting all the values
4.34 x 10¹⁵=3×10⁸m/s÷λ
λ= 3×10⁸÷4.34 x 10¹⁵
λ=6.9x 10⁻⁸m
Therefore, the wavelength of wave is 6.9x 10⁻⁸m.
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What do these two changes have in common?
water evaporating from a lake
sediment settling to the bottom of a muddy puddle
Select all that apply.
Both are only physical changes.
Both are chemical changes.
Both are caused by heating.
Both are caused by cooling.
Answer:
Both are caused by heating. Both are Chemical changes.
Explanation:
Water evaporates from the Sun's heat and is transformed into a gas.
Sediment is the particles of an object. When heat hits it, it starts breaking up, or in dry cases, heating and cracking.
The study of chemicals is called chemistry.
The correct answer is B.
There are two types of changes in the chemical reaction. These changes are as follows:-
Physical changeChemical change.The change which is reversible is called a physical change. For example - evaporating of water.
The change which is irreversible and can not get back to is original form is called chemical change. For example - the digestion process in a human.
According to the change, the correct answer is A that is a physical change because both can change back to their original form.
Hence, the correct answer is A.
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The half-life of tritium (H-3) is 12.3 years. If 48.0mg of tritium is released from a nuclear power plant during the course of a mishap, what mass of the nuclide will remain after 49.2 years?
Answer:
The amount left after 49.2 years is 3mg.
Explanation:
Given data:
Half life of tritium = 12.3 years
Total mass pf tritium = 48.0 mg
Mass remain after 49.2 years = ?
Solution:
First of all we will calculate the number of half lives.
Number of half lives = T elapsed/ half life
Number of half lives = 49.2 years /12.3 years
Number of half lives = 4
Now we will calculate the amount left after 49.2 years.
At time zero 48.0 mg
At first half life = 48.0mg/2 = 24 mg
At second half life = 24mg/2 = 12 mg
At 3rd half life = 12 mg/2 = 6 mg
At 4th half life = 6mg/2 = 3mg
The amount left after 49.2 years is 3mg.
chlorine is an active non metal
Chlorine in group 17 in the periodic table and includes halogens (also fluorine, bromine, and iodine)
Electron configuration of Cl : [Ne] 3s² 3p⁵
From this configuration, it can be seen that to obtain stability like the noble gas Ar - [Ne] 3s² 3p⁶, Chlorine will need one more electron so that its configuration is the same as Ar( become anion-Cl⁻)
Then it is said that Cl is reactive
And the Cl element is included in the non-metal group because it attracts electrons (electronegative)
The elements that include non-metals are halogens, noble gases, and 7 elements H, C, N, O, P, S, Se.
help i need help WITH this
Answer:
The Internet started in the 1960s as a way for government researchers to share information. ... This eventually led to the formation of the ARPANET (Advanced Research Projects Agency Network), the network that ultimately evolved into what we now know as the Internet.
Not sure how to do these, one example would prolly help me do the rest
Answer:
3. a. I⁻
Explanation:
The charge of the ion is determined by which group (vertical on the periodic table) the element is in. Iodine is in the halogens and therefore is most likely to have a 1- charge.
ASAP MULTIPLE CHOICE WILL MARK BRAINLIEST
An atom of gallium has 31 protons and a mass number of 70.
What is the atomic number for an atom of gallium?
31
35
39
70
Answer:
31
Explanation:
When a change of substance occurs, and when solutions are
made, the changes that take place are known as
changes.
Physical or chemical change
Answer:
They are known as physical changes
compare catalytic and thermal cracking
Answer:
Catalytic cracking is an important process in the oil industry where petroleum vapor passes through a low-density bed of catalyst, which causes the heavier fractions to 'crack' producing lighter more valuable products
Thermal cracking is an extraction process in which hydrocarbons such as crude oil are heated to a high temperature to break the molecular bonds. Thermal cracking is a refining process in which heat and pressure are used to break down, rearrange, or combine hydrocarbon molecules.
Explanation:
please help mw with this
Answer:
I cannot see any picture
Explanation:
Please put a picture
Answer:
sure what's the question
Explanation:
What is the area called in which the electrons are found ?
Answer:
orbitals
Explanation:
Which is the atomic number of an alkali metal?
10
11
12
13
Answer:
11 is the atomic number of alkali metal
Explanation:
The Group 1 elements are called the alkali metals. ... All the Group 1 elements are very reactive . They must be stored under oil to keep air and water away from them. Group 1 elements form alkaline solutions when they react with water, which is why they are called alkali metals.
what is chemistry ? Explain its types.
Answer:
Fundamentally, chemistry is the study of matter and change. The way that chemists study matter and change and the types of systems that are studied varies dramatically. Traditionally, chemistry has been broken into five main subdisciplines: Organic, Analytical, Physical, Inorganic and Biochemistry.
Explanation:
hope this helps
A molecular compound is?
Answer:
Molecular compounds are inorganic compounds that take the form of discrete molecules. Examples include such familiar substances as water (H2O) and carbon dioxide (CO2). Rather than forming ions, the atoms of a molecule share their electrons in such a way that a bond forms between pairs of atoms. ...
Explanation:
ym
The correct name for Fe 2(SO 4) 3 is -
Answer:
Iron (III) sulfate
Explanation: