Answer: Fluorine.
Explanation:
A chemical formula (such as H20) can be considered a type of model.
O True
O False
Answer:
it is false it cannot be a model
can someone plz help me with science.
Order the items from smallest at the top to largest at the bottom. cell,elephant,human body,school bus,organ,molecule.
Explanation:
Unordered items;
cell, elephant, human body, school bus, organ ,molecule.
This problem deals with the organization of life. We move from cells, to tissues, organs, and then systems.
Molecule
Cell
Organ
Human body
Elephant
School bus
School bus is the largest from the giving items although it is non-living.
Black fit, Gosha, Gosha, gold fangs (Gold fangs)
Long clip, Gosha, Gosha, bang, bang (Bang, bang)
Black fit, Gosha, Gosha, gold fangs (Gold fangs)
Long clip, Gosha, Gosha, bang, bang (Bang, bang)
Black fit, Gosha, Gosha, gold fangs (Gold fangs)
[Outro]
Ayy
Answer:
Gosha Gosha
Explanation:
The reusable booster rockets of the space shuttle use a mixture of aluminum and ammonium perchlorate as fuel. A possible reaction is
3Al (s) + 3NH4ClO4 (s) = Al2O3 (s) + AlCl3 (s) + 3NO (g) 6H2O (g)
Calculate the delta H for this reaction.
ΔH for this reaction : -2668.4 (exothermic)
Further explanationThe change in enthalpy in the formation of 1 mole of the elements is called enthalpy of formation
The enthalpy of formation measured in standard conditions (25 ° C, 1 atm) is called the standard enthalpy of formation (ΔHf °)
(ΔH) can be positive (endothermic = requires heat) or negative (exothermic = releasing heat)
The value of ° H ° can be calculated from the change in enthalpy of standard formation:
∆H ° rxn = ∑n ∆Hf ° (product) - ∑n ∆Hf ° (reactants)
you can search the value of ΔHf on the internet
∆H ° rxn =( ∆H Al₂O₃+∆H AlCl₃+3.∆H NO + 6.∆H H₂O)-(∆H Al+∆H NH₄ClO₄)
[tex]\tt \Delta H^o~rxn=(-1669.8+-704+(3\times 90.4)+(6.\times -241.8)-(3\times 0+3\times -295)\\\\\Delta H6o~rxn=-3553.4+885=-2668.4~kJ/mol[/tex]
Biochemistry which studies the chemical composition, structure, and the reaction of compounds found in non-living organisms.
Select one:
True
False
The answer to this is true.
is disilicon tetraoxide held together by a covalent or polar covalent?
Explanation:
The compound disilicon tetraoxide has the formula;
Si₂O₄;
This compound is held together by a polar covalent bond. A polar covalent bond occurs between two species that shares electrons. In this bond type, the more electronegative element draws the shared electrons more closer to itself.
Oxygen is more electronegative than silicon. It will draw the shared electrons more closer. This leaves a partial positive charge on the silicon and a negative charge on the oxygen.Why can't antibiotics be used on viruses?
Why are gamma rays not able to reflect off a mirrors surface
Answer:
the Ray's go right through it
Explanation:
the Ray's are so small they punch right through them
Answer:
Explanation:
The reason why is based in something called the plasma frequency of the metal of a mirror. A metal, as you may know, is composed of a series of atom (ion, effectively) cores - nuclei, together with some, but not all, of their bound electrons - which contribute the remaining outermost electrons of their unbound forms to a communally shared "electron sea" - kind of like a giant, distributed omnidirectional covalent bond that extends all throughout the whole metal crystal (here we're just considering a single crystal for simplicity). The electrons are quantumed out all over the full extent of the crystal and effectively form a sort of "gas" throughout and permeating the metal.
When an electromagnetic wave approaches that gas, the free charges within it - the electrons - start oscillating, and as they do so, they set up another wave going outward at the same time as the first is going in. This begins as soon as the first wave begins to impinge.
However, if the wave oscillation is fast enough, the electrons can't keep up due to their mass, and thus they are unable to form the reflected wave. The frequency at which this occurs is called the metal's plasma frequency (and is inversely proportional to the square root of the mass, so that a high mass particle would have a lower plasma frequency). The name comes from the fact that the metal can be thought of in a sense as a kind of "solid plasma" - ions with free electrons, the difference with what most people think of as a "plasma" being here the ions are not free to move about of their own accord.
As Mia mixed two substances in a test tube, she noticed that the test tube became warm. She also noticed gas coming from the test tube. Based on Mia's observations, what was most likely occurring inside the test tube?
A.The two substances underwent a physical change
B.The two substances were melting
C.A new substance was forming
D.A change in the mass of the two substances
Answer:
a new substance was forming
Explanation:
Directions: Click the link here to access an interactive simulation where you will explore w hat happens when you change the concentration of different ionic compounds. Complete the steps below and answer the questions. 1. Drag the concentration meter (the purple circle attached to a wire) into the water and select the solute cobalt (II) chloride (CoCl2). 2. Move the shaker continuously to add cobalt (II) chloride until the concentration is 4.330 mol/L. How would you classify this solution? 3. What happened to the color of the solution as you added more of the ionic compound? 4. Tap the faucet to add another 0.5 L of water, bringing the total volume of the solution. When you doubled the water volume, what happened to the concentration? How would you now classify this solution? 5. Complete a similar process for two other ionic compounds. Experiment with different amounts of the ionic solute and the water solvent to observe the changing concentrations.
Answer:2:saturated
3:it got darker
4:it halved/unsaturated
Explanation:
Answer:
Answer:2:saturated
3:it got darker
4:it halved/unsaturated
Explanation:
The rate of a reaction depends on temperature, concentration, particle
size and catalysts. Which statement is not correct?
Answer:
I think the particle size
Explanation:
By decreasing the particle size of a reactant, we are increasing its surface area. The greater the surface area, the higher the chance of collisions, thus the faster the rate of reaction.
increasing the particle size will decrease the rate of reaction.
conclusion:
The smaller the particle size the faster the reaction.
The statement which is not correct is that: the rate of a reaction increases with increasing particle size.
Discussion;
The addition of catalyst, increase in temperature and reactant concentration all are factors which increase the rate of a chemical reaction.
Decreasing the particle size of reactants also increases the rate of reaction. This is because upon decreasing particle size, the surface area of the reactants is increased and the reaction is able to take place at a faster rate.
Read more on rate of reaction;
https://brainly.com/question/24795637
start out as one kind of rock, but large amounts of pressure and heat change them into a different kind.
Answer:
Metamorphic
Explanation:
If 3.0 moles of hydrogen react, how many grams of nitrogen will be used? Round your answer to the nearest whole number. N2 + 3H2 -> 2NH3
Answer:
28g
Explanation:
Given parameters:
Number of moles of hydrogen = 3moles
Unknown:
Mass of nitrogen used = ?
Solution:
To solve this problem, let us establish the balanced reaction equation first;
N₂ + 3H₂ → 2NH₃
From the balanced reaction equation;
3 mole of H₂ will combine with 1 mole of N₂
Now,
Mass of Nitrogen = number of moles x molar mass
Molar mass of N₂ = 2(14) = 28g/mol
Mass of Nitrogen = 1 mole x 28g/mole = 28g
How many moles are in a 111.5 gram sample of sodium chloride, NaCl?
Answer: 1.91 moles
Explanation:
First you want to find the molar mass of NaCL
Na = 22.99g Cl = 35.45g
22.99g + 35.45g = 54.44g
Then divide 111.5g by 54.44g and this will give you moles.
If a wave has low energy it therefore, it has ___________ frequency.
Answer:
I think it would have a LOW frequency rate.
Explanation:
be strong
Hey now, life is every minute
All or nothing
Living on the limits
Hey now, I will sing it loud and sing it strong
Let the echo decide if I was right or wrong
tie your shoe lace get prepared for a race
And a very few feel burn,
And the rest, they may live and learn!
but who knows the world hurts and theres different parts yeah be strong.
Nice written.
Is it written by you yourself or you have copied it from somewhere?
plz help thx brainliest btw :)
Answer:
1. earth metal 2. halogen 3.The elements are arranged in seven horizontal rows, called periods or series, and 18 vertical columns, called groups. ... Elements in the periodic table are organized according to their properties.
Inventor: Dmitri Mendeleev please name most brainliest
If 15.0 g of nitrogen reacts with 15.0 g of hydrogen, 10.5 g of ammonia is
produced. What is the percent yield?
Answer:
Percent yield = 57%
Explanation:
Given data:
Mass of nitrogen = 15.0 g
Mass of hydrogen = 15.0 g
Mass of ammonia produced = 10.5 g
Percent yield = ?
Solution:
Chemical equation:
N₂+ 3H₂ → 2NH₃
Number of moles of hydrogen:
Number of moles = mass/molar mass
Number of moles = 15.0 g/ 2 g/mol
Number of moles = 7.5 mol
Number of moles of nitrogen:
Number of moles = mass/molar mass
Number of moles = 15.0 g/ 28 g/mol
Number of moles = 0.54 mol
Now we will compare the moles of ammonia with nitrogen and hydrogen from balance chemical equation.
N₂ : NH₃
1 : 2
0.54 : 2×0.54 = 1.08
H₂ : NH₃
3 : 2
7.5 : 2/3×7.5= 5 mol
Theoretical yield of ammonia:
Mass = number of moles × molar mass
Mass = 1.08 × 17 g/mol
Mass = 18.36 g
Percent yield:
Percent yield = (actual yield / theoretical yield) ×100
Percent yield = (10.5 g/ 18.36 g) ×100
Percent yield = 0.57 ×100
Percent yield = 57%
If you have more protons in the nucleus, do you think they hold onto electrons tighter or looser?
Answer:
If we have more protons in the nucleus, then they hold it tighter
Use the activity series below to predict whether the following reactions will take place. Activity series from most to least reactive: Upper F Subscript 2; Upper C l Subscript 2; Upper B r Subscript 2; Upper I Subscript 2. Cl2 + 2RbI → 2RbCl + I2 yes no I2 + NiBr2 → NiI2 + Br2 yes no
Cl2 + 2RbI → 2RbCl + I2 is possible while I2 + NiBr2 → NiI2 + Br2 is not possible.
It will do us a lot of good to write out the equations again;
Cl2 + 2RbI → 2RbCl + I2 Yes
I2 + NiBr2 → NiI2 + Br2 No
If we look at the reaction closely, they are displacement reactions. It is worthy to note that a specie can only displace another specie which lies below it in the activity series. The activity series is an arrangement of elements in order of decreasing reactivity.
The activity series of the halogens is; fluorine > chlorine > bromine > iodine.
Since chlorine is above iodine in the activity series, Cl2 + 2RbI → 2RbCl + I2 is possible.
Iodine is less than bromine in the activity series hence the reaction I2 + NiBr2 → NiI2 + Br2 is not possible.
Learn more: https://brainly.com/question/14365792
Answer:
Cl2 + 2RbI --> 2RbCl + I2 = yes
I2 + NiBr2 --> NiI2 + Br2 = no
Explanation:
I just took the assinment
Write a balanced chemical equation for the reaction that occurs when Mg(s) reacts with Cl2(g).
Explanation:
When magnesium reacts with chlorine then it forms magnesium chloride.
Equation -
Mg + Cl₂ → MgCl₂
This is the example of Combination reaction.
3 electron layers in the electron shell and 1 electron in the last electron layer
Answer:
The closest shell to the nucleus is called the "1 shell" (also called the "K shell"), followed by the "2 shell" (or "L shell"), then the "3 shell" (or "M shell"), and so on farther and farther from the nucleus.
The density of a substance having a mass of 9 x 10^5 g and a volume of 3 x 10^-1 cm3 is
Answer:
3,000,000 g/cm³Explanation:
The density of a substance can be found by using the formula
[tex]density = \frac{mass}{volume} \\ [/tex]
From the question we have
[tex]density = \frac{9 \times {10}^{5} }{3 \times {10}^{ - 1} } \\ [/tex]
We have the final answer as
3,000,000 g/cm³Hope this helps you
The nervous system sends messages to control activities in the body. false true
Answer:
true
Explanation:
took test
How many moles are in 1.204 x 1024 atoms of Zn ?
Answer:
2 molesExplanation:
To find the number of moles in a substance given it's number of entities we use the formula
[tex]n = \frac{N}{L} \\ [/tex]
where n is the number of moles
N is the number of entities
L is the Avogadro's constant which is
6.02 × 10²³ entities
From the question we have
[tex]n = \frac{1.204 \times {10}^{24} }{6.02 \times {10}^{23} } \\ [/tex]
We have the final answer as
2 molesHope this helps you
Over the last 800,000 years before humans existed, CO2 levels in the atmosphere have stayed below ________ PPM. Today, CO2 levels are over ________ PPM.
fill in the blanks
What is manganese dioxide in preparation of oxygen?
Answer:
When manganese(IV) oxide is added to hydrogen peroxide, bubbles of oxygen are given off. To make oxygen in the laboratory, hydrogen peroxide is poured into a conical flask containing some manganese(IV) oxide. The gas produced is collected in an upside-down gas jar filled with water.
HELLLLP ASAP PLZ
1. A front forms when ____
A. two air masses move away from each other
B. two air masses bump into each other
2. On a weather map, a red line with half circles shows a(n) ______.
A. occluded front
B. cold front
C. warm front
3. The blue triangles of a cold front point in the direction ______.
A. the front is going
B. the front has come from
C. where the temperature is colder
Answer:
1 is B, 2 is B a cold front
Explanation:
In order for a front to form, two air masses have to collide, and for 2 a cold front is represented by a red ljine with half circles
Two trays of lasagna are identical except for their thermal energies.
Which tray of lasagna has a lower temperature?
Answer:
the one with less thermal energy
Explanation:
thermal energy is heat
Answer:
GOTTTEM
Explanation:
What is required for two atoms to share electrons equally in a chemical bond?
A. The two atoms must have the same number of valence electrons.
B. The two atoms must have equal and opposite charges.
C. The two atoms must be of the same element.
D. The two atoms must both be nonmetals.
Answer:
C. the two atoms must be of the same element