Answer:
Their number
Explanation:
Freezing is the process of decreasing the activity of the molecules in the medium and their arrangement will change to take on the new shape but no new molecules are added or taken away
PLEASE HELP AND EXPLAIN!Calculate the energy required to heat 187.0 g of ammonia from 36.1 °C to 52.9 °C. Assume the specific heat capacity of ammonia under these conditions is
4.703.g. K. Round your answer to 3 significant digits.
Answer:
[tex]E=1.48x10^4J[/tex]
Explanation:
Hello!
In this case, since the energy implied in a heating process is computed by using the following equation:
[tex]E=mC(T_f-T_i)[/tex]
Whereas m is the mass, C the specific heat and T the temperature. In such a way, by plugging in the given mass, specific heat and temperatures, we obtain the following energy:
[tex]E=187.0g*4.703\frac{J}{g\°C} (52.9\°C-36.1\°C)\\\\E=1.48x10^4J[/tex]
Considering that the specific heat can by used by unit of °C or K because their difference is equivalent.
Regards!
If the oxygen isotope 20O has a half-life of 15 seconds, what fraction of a sample of pure 20O remains after 1.0 minute?
Answer:
1/16
Explanation:
We have the half life of ²⁰O = 15 seconds
This half life means that the reactant 8s going to be half at this time
Now we have 60 seconds = 1 minute
Then in 60 seconds we are going to have 4 half life.
Then ²⁰O will be 1/2⁴
1/2⁴ = 1/16
This is the answer to this question.
Thank you!
1/16 fraction of a sample of pure ²⁰O remains after 1.0 minute
Given:
The half life of ²⁰O = 15 seconds
This half life means that the reactant 8s going to be half at this time
Now, we have 60 seconds = 1 minute
Then in 60 seconds we are going to have 4 half life.
Then ²⁰O will be 1/2⁴
1/2⁴ = 1/16
Thus, the fraction of a sample of pure ²⁰O remains after 1.0 minute is 1/16.
Learn more:
brainly.com/question/1160651
What happen when potassium react with cold water?
Answer:
the metal melts and floats
Explanation:
When potassium is added to water, the metal melts and floats. It moves around very quickly on the surface of the water. The hydrogen ignites instantly. The metal is also set on fire, with sparks and a lilac flame.
Answer:
It reacts rapidly to form a colorless solution of potassium hydroxide.
Explanation:
Potassium metal reacts very rapidly with water to form a colorless basic solution of potassium hydroxide (KOH) and hydrogen gas (H 2). The reaction continues even when the solution becomes basic. The resulting solution is basic because of the dissolved hydroxide. The reaction is exothermic.
Which of the changes are chemical changes?
sugar is dissolved in soda
what's the valency of lead in pbO2
The valence of lead is 4.
Hence the name of the compound is called Lead (IV) oxide.
Further explanationGiven
PbO₂ compound
Required
The valence of Pb
Solution
The oxidation number of element O in the compound = -2, except for OF₂ the oxidation state = + 2 and the peroxides (Na₂O₂, BaO₂) the oxidation state = -1 and superoxide, for example KO₂ = -1/2.
The oxidation state in the uncharged compound = 0,
So The oxidation state of Pb :
Pb + 2.(-2) = 0
Pb - 4 = 0
Pb = +4
Diego runs away from zombies at 11 km/h for 3 h.
How far does he go?
Answer:
33 km in 3 hours
11/1= 11
11*3=33
Explanation:
7. Balance the following equation. What is the coefficient for Oxygen?*
C.H. +0,-> C0, +H20
2
4
5
8
8. Pentane (CsH22) undergoes a combustion reaction. What is the coefficient
required in front of pentane in its balanced equation? *
C.H2 +0,-> C0, + H2O
5
4
2
1
I know it’s tho questions but PLEASE PLEASE help me it’s for a test and I don’t wanna fail I would REALLY appreciate it if someone could help me with this thanks youu !!!
Answer:
of 7 I guess the and is 2 I don't know anything about 8
NEED ANSWER NOW! 40 POINTS
Read the chemical equation.
Fe2O3 + CO → Fe + CO2
if 1.8 moles of Fe2O3 react with 2.7 moles of CO, how many moles of each product are formed?
5.4 moles Fe and 1.8 moles CO2
2.7 moles Fe and 0.9 moles CO2
3.6 moles Fe and 5.4 moles CO2
1.8 moles Fe and 2.7 moles CO2
Answer:1.8 moles Fe and 2.7 moles CO2
Explanation:
Answer:
1.8 moles Fe and 2.7 moles CO2
Question 5 (1 point)
How many moles of oxygen gas is needed to produce 36 grams of water?
Answer:
1 Oxygen atom has a mass of 16 grams, thus diatomic oxygen weights twice as much- 32 grams. Hence 32 grams is needed.
i need help with this
Answer:
hope it helps you.......
compare earths compositional layers with its structural layer
Answer:
The Earth has different compositional and mechanical layers. Compositional layers are determined by their components, while mechanical layers are determined by their physical properties. The outermost solid layer of a rocky planet or natural satellite. Chemically distinct from the underlying mantle.
2 AgNO3(aq)+(NH4)2CO3(aq)->Ag2CO3(s) +2NH4NO3(aq)
The given question is incomplete. the complete question is:
Write the net ionic equation for the reaction [tex]2AgNO_3(aq)+(NH_4)_2CO_3(aq)->Ag_2CO_3(s)+2NH_4NO_3(aq)[/tex]
Answer: [tex]2Ag^+(aq)+CO_3^{2-}(aq)\rightarrow Ag_2CO_3(s)[/tex]
Explanation:
Spectator ions are defined as the ions which does not get involved in a chemical equation or they are ions which are found on both the sides of the chemical reaction present in ionic form.
The given chemical equation is:
[tex]2AgNO_3(aq)+(NH_4)_2CO_3(aq)->Ag_2CO_3(s)+2NH_4NO_3(aq)[/tex]
The complete ionic equation is:
[tex]2Ag^+(aq)+2NO_3^-(aq)+2NH_4^+(aq)+CO_3^{2-}(aq)\rightarrow Ag_2CO_3(s)+2NH_4^+(aq)+2NO_3^-(aq)[/tex]
The ions which are present on both the sides of the equation are ammonium and nitrate ions and hence are not involved in net ionic equation.
Hence, the net ionic equation is [tex]2Ag^+(aq)+CO_3^{2-}(aq)\rightarrow Ag_2CO_3(s)[/tex]
Electron X can change to a higher energy level or a lower energy level. Which statement is true of electron X?
1
Electron X emits energy when it changes to a higher energy level.
2
Electron X absorbs energy when it changes to a higher energy level.
3
Electron X absorbs energy when it changes to a lower energy level.
4.
Electron X neither emits nor absorbs energy when it changes energy level.
Answer: 2) Electron X absorbs energy when it changes to a higher energy level.
Explanation:
The electrons in an atom exist in various energy levels. When an electron moves from a lower energy level to a higher energy level, energy is absorbed by the atom. When an electron moves from a higher to a lower energy level, energy is released (often as light).
In Ms. Baker’s science class, students filled two glass bottles with equal amounts of water and attached a balloon to the top of each bottle. The bottle on the right is heated on a hot plate to 80°C (176°F), while the bottle on the left is kept at room temperature, 21°C (70°F). After several minutes, the students observe that the balloon on the right inflates. (SC.5.P.9.1)
Which statement best explains the students’ observation?
The heat slows down a chemical change, producing the gas to fill in the balloon.
The heat speeds up a chemical change, producing a new substance.
The heat slows down a physical change, causing the water level to decrease.
The heat speeds up a physical change, causing the liquid to turn into a gas.
this is a science question but science doesnt show up
Answer:
D. The heat speeds up a physical change, causing the liquid to turn into a gas.
Explanation:
I NEED HELP. This is about science
Answer:
Independent variable
Explanation:
What is the wavelength in meters of a wave with a frequency of 3000Hz?
a. 100000m
b. 9x1011m
c. 2.21x10-37m
d. 1000m
Answer:
yes thats right
Explanation:
Which of the following elements does not form hydride by direct heating with
hydrogen gas?
A. Be
B. Mg
C. Si
D. Ba
Which of the following atoms has the lowest first ionization energy: nitrogen, phosphorus, or arsenic?
Answer:
Arsenic
Explanation:
The atom that has the lowest first ionization energy is Arsenic.
The first ionization energy is the energy needed to remove the most loosely bound electron of an atom in the gas phase in the ground state.
Ionization energy generally deals with the measure of the readiness of an atom to lose an electron.
Generally, down a group from top to bottom, ionization energy decreases because of the increasing atomic radii and increasing shielding /screening effect on the outermost shell electrons hence the electrons are held less tightly to the nucleus. So, nitrogen, phosphorous and arsenic belongs to the same group and arsenic will have the least first ionization energy.Heat left over from when the earth was formed about 4.6 billion years ago is one source of INTERNAL energy. What is the other source?
Question 6 options:
the sun
the ocean
radioactive substances in the earth's interior layers
Answer:
the gravity
Explanation:
i hope you help this answer
Answer:
the ocean
Explanation:
C(s)+H2(g)-> C2H6(g)
Explanation:
2 C(s) + 3 H2(g) = C2H6(g)
True or False: The climate in landlocked areas is usually more moderate than in coastal areas.
Answer:
False
Explanation:
Water is said to have a higher heat capacity than soil and stones, so the ocean takes much longer to heat and to cool than the land. 2. Coastal areas have more moderate temperatures than landlocked areas because of the heat capacity of the ocean and hence the answer is false.
Answer:
False.
Explanation:
What is the theoretical yield of aluminum that can be produced by the reaction of 60.0 g of aluminum oxide with 30.0 g of carbon according to the following chemical equation? ALLO, + 3C SH 2Al + 3CO
a. 31.8 g
b. 30g
c. 101.2 g
d. 45 g
e. 7.9 g
Answer: 31.8 g
Explanation:
To calculate the moles :
[tex]\text{Moles of solute}=\frac{\text{given mass}}{\text{Molar Mass}}[/tex]
[tex]\text{Moles of} Al_2O_3=\frac{60.0g}{102g/mol}=0.59moles[/tex]
[tex]\text{Moles of} C=\frac{30.0g}{12g/mol}=2.5moles[/tex]
[tex]Al_2O_3+3C\rightarrow 2Al+3CO[/tex]
According to stoichiometry :
1 mole of [tex]Al_2O_3[/tex] require 3 moles of [tex]C[/tex]
Thus 0.59 moles of [tex]Al_2O_3[/tex] will require=[tex]\frac{3}{1}\times 0.59=1.77moles[/tex] of [tex]C[/tex]
Thus [tex]Al_2O_3[/tex] is the limiting reagent as it limits the formation of product and [tex]C[/tex] is the excess reagent as it is present in more amount than required.
As 1 mole of [tex]Al_2O_3[/tex] give = 2 moles of [tex]Al[/tex]
Thus 0.59 moles of [tex]Al_2O_3[/tex] give =[tex]\frac{2}{1}\times 0.59=1.18moles[/tex] of [tex]Al[/tex]
Mass of [tex]Al=moles\times {\text {Molar mass}}=1.18moles\times 27g/mol=31.8g[/tex]
Thus 31.8 g of [tex]Al[/tex] will be produced from the given masses of both reactants.
38 points!! >:D
Witch best describes what is required for sny sound wave to travel?
Empty space
Any medium
Solid
Liquid
Answer: which*
Explanation:
which one of these would be the best example for kinetic energy
A roller coaster at the top of the tallest hill
A pendulum at the greatest height of it's swing
A drawn bowstring prior to being released
A marble about to reach the bottom of the slope
Answer:
a marble about to reach the bottom of the slope
Explanation:
hope this helps
What is exfoliation?
Answer:
Exfoliation involves the removal of the oldest dead skin cells on the skin's outermost surface. Exfoliation is involved in all facials, during microdermabrasion or chemical peels. Exfoliation can be achieved by mechanical or chemical means.
Explanation:
I did copy off internet!
:P
is it a compound or mixture when they are separated by chemical bonds
Answer:
Compounds
Explanation:
It is a compound when they are separated by chemical bonds.
Compound are substances composed of two or more kinds of atoms that are joined together in a definite grouping.
The properties of a compound are distinct and different from those of the individual elements that are combined in its make-up.
There are several millions of compounds known. The compounds are derived from the elements. Compounds are usually represented by chemical formulaWithin a compound there are chemical bonds.
Which statement compares the attractive forces that hold particles together?
A. Covalent bonding and Van der Waals forces join molecules
together; ionic and hydrogen bonding produce compounds.
B. Metallic bonds and Van der Waals forces are weakly attractive;
covalent and hydrogen bonds are strongly attractive.
C. Metallic and covalent bonds are weakly attractive; hydrogen
bonding and Van der Waals forces are strongly attractive.
D. Metallic and covalent bonds are strongly attractive; hydrogen
bonding and Van der Waals forces are weakly attractive.
Answer:Metallic and covalent bonds are strongly attractive; hydrogen
bonding and Van der Waals forces are weakly attractive.
Answer:
Metallic and covalent bonds are strongly attractive; hydrogen bonding and Van der Waals forces are weakly attractive..
trust me i just did it
Explanation:
The density of water is 1.0 mg
true or false ?
Answer:
True. the density of water is 1.0 mg
While in Europe, if you drive 101 km per day, how much money would you spend on gas in one week if gas costs 1.10 euros per liter and your car's gas mileage is 31.0 mi/gal ? Assume that 1euro=1.26dollars.
Answer:
per day means - and if means + and of means × lmk if u need help
Someone please help me please
Answer:
point 2 and 4
Explanation:
because at those point temperature is constant