Answer:
because they are actually moving, or because they reflect our motion through space.
Explanation:
Stars making a circular motion across the sky is evidence of the earth's rotation.
This is because when the earth rotates it appears to us like the stars are moving.
what is base? what Is the sugar also a base?
Answer:
base is also known as alkaline
n sugar is not a base
1 How many moles of solute are in:
a 500 cm of solution, of concentration 2 moldm"?
b 2 litres of solution, of concentration 0.5 mol/dm?
Pls answer I will mark the person brainliest
Moles of solute for both a and b are the same = 1 mol
Further explanationGiven
a 500 cm³ of solution, of concentration 2 mol/dm³
b 2 litres of solution, of concentration 0.5 mol/dm³
Required
moles of solute
Solution
Molarity shows the number of moles of solute in every 1 liter of solution or mmol in each ml of solution
Can be formulated :
[tex]\large \boxed {\bold {M ~ = ~ \dfrac {n} {V}}}[/tex]
a.
V = 500 cm³ = 0.5 L
M = 2 mol/L
n=moles = M x V
n = 2 mol/L x 0.5 L
n = 1 mol
b.
V = 2 L
M = 0.5 mol/L
n=moles = M x V
n = 0.5 mol/L x 2 L
n = 1 mol
What i
Chemistry:
Collect information regarding periodical development of fundamental
particles and structure of atom with different atomic models and display
then information Chart.
Answer:
Periodical development of fundamental particles and structure of atoms can be explained from different atomic models .
Explanation:
Periodical development of fundamental particles :
About 2600 years ago an Indian sage called kanada proposed that all forms of matter are composed of very small particles called as Anu and each Anu is made up of smaller particles called Parmanu .
Later Greek philosopher Democritus called these atoms and according to him atoms are indivisible and indestructible .
John Dalton's theory describes elements in terms of atoms which he believed to be indivisible particles.But Later John Dalton's postulate which suggests that atom is indivisible is disproved by various experiments conducted by various scientists :
1. Electron - J.J Thomson discovered the electron while experimenting with cathode rays in 1897.
2. Proton - Proton was discovered by Gold stein in 1920.
3. Neutron was discoverer by James Chadwick in 1932 by bombardment of alpha particle at beryllium . Structure of atom :
J.J Thomson atomic model : After the discovery of electrons ; he proposed his plum and pudding model which shows that electrons are embedded throughout the positively charged material.Rutherford alpha particle scattering experiment : This experiment lead to the discovery of nucleus . According to this experiment all the positive charge and most of the mass of atom is concentrated in a small core called nucleus . According to this model nucleus is composed of neutrons and protons . Electrons are distributed around the nucleus and occupy most of the volume. Bohr atomic model : Bohr modified Rutherford atomic model of atom by suggesting that electrons move in specific energy levels around nucleus.Schrodinger's model of atom : This model is most precise model and is used in present days . According to him electrons are present in a particular region or space around the nucleus called as orbitals where probability of finding the electrons are more.
Based on its position on the periodic table, which of the following elements is a nonmetal?
A. Potassium (K)
B. Vanadium (V)
C. Nickel (Ni)
D. Bromine (Br)
Answer:
D. Bromine (Br)
Explanation:
Based on its position on the periodic table Bromine is the only non-metal from the given choices of elements.
Potassium is an alkali-metal and it belongs to group 1 on the periodic table. Vanadium and Nickel are transition metals which belongs to the d-block on the periodic table. Bromine, Br is a halogen which belongs to group 7 on the periodic table. The group is a group of non-metalsWhich of the following words/phrases can be used to describe table salt (NaCl)?
Select one or more:
a.Compound
b.Element
c.Mixture
d.Pure substance
These are the last two questions on the sheet I need help with haha, help only the ones you can! (most helpful answer will get brainliest)
Answer:
the 7 question answer is c the 24 question answer is b
Explanation:
1. Which statement describes the earliest model of
the atom?
Answer:
A). An atom is an indivisible hard-sphere.
Explanation:
The 'Atomic Theory' of Dalton is characterized as the earliest model(came in 1803) which described the atoms as the indivisible and resistant spheres. He used the example of watermelon to elaborate that the atoms of a specific element share similar characteristics and the atoms of distinct elements differ in their mass as well as their size. Thus, option A is the correct answer.
What is misleading about the terms “melting point” and “boiling point”?
Answer:
The melting point is when a solid is turning into a liquid, boiling point is when a liquid turns into a gas. The thing that is misleading is that they are both changing state because of heat.
Explanation:
When a solid melts into a liquid, the melting point has been reached, and when a liquid changes into a gas, the boiling point is reached.
Melting point and Boiling point:The melting point is defined as the temperature at which solid and liquid phases are in equilibrium, whereas the boiling point is defined as the temperature at which a liquid's vapor pressure equals the external pressure.
What's confusing is that they're both changing states as a result of heat.
Find out more information about 'Melting point'.
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The balanced equation for combustion in an acetylene torch is shown below: 2 upper C subscript 2 upper H subscript 2 plus 5 upper O subscript 2 right arrow 4 upper C upper o subscript 2 plus 2 upper H subscript 2 upper O. The acetylene tank contains 35.0 mol C2H2, and the oxygen tank contains 84.0 mol O2. How many moles of O2 are needed to react completely with 35.0 mol C2H2? mol O2
Answer:
87.5 mol of O2 is required to completely react with 35.0mol of C2H2
Explanation:
The equation is given as;
2C2H2 + 5O2 --> 4CO2 + 2H2O
The acetylene tank contains 35.0 mol C2H2, and the oxygen tank contains 84.0 mol O2.
From the balanced equatioon, the realtionship between the reactants is given as;
2 mol of C2H2 reacts with 5 mol of O2
How many mol of O2 would then react with C2H2?
2 mol C2H2 = 5 mol O2
35 mol C2H2 = x mol O2
Upon solving for x;
x = 35 * 5 / 2
x = 87.5 mol of O2
Answer:
87.5
Explanation:
An element has a half-life of 5.0 days. How many days would
pass before only 1/8th of the original amount of a sample of this
element remained?
Look at the simplified Periodic Table in the attachment. Each letter
represents an element but the letter is not the real chemical symbol.
Use your knowledge to sort the letters to say whether they are metal
or non-metal elements.
W
Y
V
Z
x
Answer:
According to this picture w and y are metals and v z and x are non metals
Explanation:
2H2 + O2- 2H20
Which conversion factors will you need to calculate the
mass of H2O that is made when 8 grams of H2 react?
Conversion factor : molar mass/molecular weight
Mass of H₂O produced = 72 g
Further explanationGiven
Reaction
2H2 + O2- 2H20
8 grams of H2
Required
Conversion factors
Solution
We can use the molar mass of the components and the mole ratio as conversion factors for the above equation
mol H₂ (MW = 2 g/mol) :
[tex]\tt mol=\dfrac{8}{2}=4~mol[/tex]
From the equation, mol ratio of H₂ : H₂O = 2 : 2, so mol H₂O = 4 mol
mass H₂O(MW = 18 g/mol) :
mass = mol x MW
mass = 4 x 18
mass = 72 g
how do stars generate energy??
Answer:
The energy source for all stars is nuclear fusion. Stars are made mostly of hydrogen and helium, which are packed so densely in a star that in the star's center the pressure is great enough to initiate nuclear fusion reactions. In a nuclear fusion reaction, the nuclei of two atoms combine to create a new atom.
Explain the particles in Solutions of sodium sulfate alone and lead nitrate alone explain what happens to these particles of the two solutions are added together steered then allowed to sit for a couple minutes
Answer:
white precipitates of PbSO4 will appear
Explanation:
Now let us first consider the reaction equation;
Na2SO4(aq) + Pb(NO3)2(aq) ---->2NaNO3(aq) + PbSO4(s)
So, if i mix solutions of sodium sulfate and lead II nitrate, stir it and allow it to stand for a couple of minutes, i will begin to see the appearance of white precipitates of PbSO4.
This follows from the solubility rules. Sulphates are soluble in water except those of group II ions, Pb^2+ and silver I ion.
*
Which of the following would NOT be found in an animal cell?
Chloroplasts
Endoplasmic Reticulum
Cell Membrane
Nucleus
Answer:
chloroplasts
Explanation:
chloroplasts are what make plants green, they are not included in animal cells
Are electrons shared with ionic or covalent bonds
Define Isotopes with an example.
Answer:
One or more number of species which have same number of atomic number but different mass number are called isotopes.
For example, [tex]^{1}_{1}H, ^{2}_{1}H, ^{3}_{1}H[/tex] are the isotopes of hydrogen.
So here, the atomic number of each of these isotopes is 1 and have different mass number, that is, 1, 2, 3.
Which of the following industrial processes involves a voltaic cell rather than electrolysis?
coating forks and knives with silver ?
extracting sodium from sodium hydroxide ?
reinforcing the hull of a ship so that it resists corrosion ?
converting energy stored in chemical bonds to electricity ?
Answer: D. Converting energy stored in chemical bonds into electricity.
Explanation:
100% on edg 2021 quiz.
Answer:
D. converting energy stored in chemical bonds to electricity
Explanation:
Edge 2020
when does mass change?
Answer:
the mass of an does not change with speed but changes when we add or cut a part of it.
Explanation:
Answer:
weight
Explanation:
What is the mid-ocean ridge? Two complete sentences.
Answer:
A mid-ocean ridge is an underwater mountain range, formed by plate tectonics.Mid-ocean ridges represent one of the most important geologic processes shaping the Earth
Hydrogen and oxygen combine in the ratio of 1:8 by mass to form water. How many grams of hydrogen are needed to react completely with 6.4 g of oxygen gas? Show complete working. Which law of chemical combination will govern your answer? Write the law.
Explanation: Number of moles of water = mass of water/ molar mass.
Molar mass of H2O = (1*2) + 16 = 18.0
Now we only need to calculate the number of moles of water.
The chemical reaction is as follows
CH4 + 2O2 ---> CO2 + 2H2O
From the eqn, the moles of H2O = 2*moles of CH4
Molar mass of CH4 = 12 + 4 = 16. Number of moles of methane = mass/
molar mass. No of moles = 6.4/16 = 0.4. So the number of mole of water = 2* 0.4 = 0.8. We already calculate its molar mass earlier. So mass of water = molar mass * number of moles = 18 * 0.8 = 14.4
In the pie chart below, which of the following represents the amount of Earth's water located in the oceans?
A pie chart with part A representing 2%, part B representing .8%, part C representing .2% and part D representing 97%.
© 2011 FLVS
A only
A and B
C only
D only
Answer:
D. 97%
Explanation:
♪＼(*＾▽＾*)／＼(*＾▽＾*)／
Answer:
d
Explanation:
acronyms for the first 20 elements
Answer:
HHeLiBeBCNOFNeNaMgAlSiPSClArKCaAnswer:
Acronym Elements Symbols
He Hydrogen H
has Helium He
light Lithium Li
brain Beryllium Be
but Boron B
can Carbon C
not Nitrogen N
offer Oxygen O
full Fluorine Fl
nine Neon Ne
subjects Sodium Na
must Magnesium Mg
all Aluminium Al
silly Silicon Si
people Phosphorus P
stop Sulphur S
calling Chlorine Cl
a Argon Ar
pope Potassium K
christ Calcium Ca
question in the picture thank you sm!!!!
Answer:
Explanation:
Reactants Product
H = 2 H=2
Cl=2 Cl=2
Zn=1 Zn=1
Total number of atoms 5 Total number of atoms 5
What is a scientific theory?
A theory is a summary of a scientific fact based on observation.
A theory is an explanation of why a scientific process occurs.
A theory is a proven scientific law.
A theory is a guess as to what will happen.
Answer:
Explanation:
I'm guessing B)
I'm 86.7% sure that might be right.
Answer:
A theory is a broad, natural explanation for a wide range of phenomena.
Dr. Laude doesn’t care for fancy definitions of a mole. He prefers the idea that a mole is:
A) an amount of a substance you can hold in your hand.
B) the amount of a substance you can store in a shoebox.
C) the amount of a substance you can place on the head of a pin.
D) the amount of a substance you can see with a microscope.
Answer:
A
Explanation:
Dr. Laude prefers the idea that a mole is an amount of a substance you can hold in your hand.
What is a mole?Mole is defined as the unit of amount of substance . It is the quantity measure of amount of substance of how many elementary particles are present in a given substance.
It is defined as exactly 6.022×10²³ elementary entities. The elementary entity can be a molecule, atom ion depending on the type of substance. Amount of elementary entities in a mole is called as Avogadro's number.
It is widely used in chemistry as a suitable way for expressing amounts of reactants and products.For the practical purposes, mass of one mole of compound in grams is approximately equal to mass of one molecule of compound measured in Daltons .Molar mass has units of gram per mole . In case of molecules, where molar mass in grams present in one mole of atoms is its atomic mass.
Learn more about mole,here:
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sulpher is a non metal
Answer:
Sulphur is a non-metal because it's valency is 6 and it have many character of non-metal.
What are the 3 reactants necessary for photosynthesis
Answer:
Carbon dioxide
Water
Glucose
Answer:
To perform photosynthesis, we need three things: Carbon Dioxide WaterSunlightIron (III) chloride reacts with potassium hydroxide to produce iron (III) hydroxide and
potassium chloride.
Answer:
The balanced chemical equation is :
FeCl3 + 3KOH → Fe(OH)3 + 3KCl
Help me please in science !! ( 10 points )
Answer: Nuclear
Explanation:
Nuclear energy generates power through fission, which involves splitting uranium atoms to produce energy. The heat released by fission is used to create steam that rotates turbine to generate electricity.
The energy produced by nuclear plants is carbon free but the products formed are radioactive and hence their transportation, storage, and disposal is a big problem. It can not be dumped like normal waste.