Explanation:
Galileo found Venus went through the entire phase cycle, proving that she revolved completely around the Sun, as predicted by Copernicus in his heliocentric model. ... The phases of Venus could not be explained by Ptolemy's Geocentric Model. Galileo knew that the Roman Catholic Church was incorrect.
Someone please help me please
Answer:
point 2 and 4
Explanation:
because at those point temperature is constant
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
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).
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:
Which statement about the periodic table is true?
a.Elements in the same column share similar properties.
b.Elements in the same row share similar properties.
c.Elements on the left have a larger nucleus than elements on the right.
d.Elements at the top of each column have the highest atomic mass in that column.
Answer
Two different elements have similar chemical properties when they have the same number of valence electrons in their outermost energy level. ... Elements in the same column of the Periodic Table have the same number of valence electrons – that's why they have similar chemical properties.
Statement that can be considered true as regards periodic table is : A: Elements in the same column share similar properties.
Periodic table can be regarded as the table that give the arrangements of the chemical elements into rows and columns.Option A is right because there is similar properties associated with elements in the same column, this is because there is the same valence electrons associated with them.Option B is wrong, there is no similar properties with element of same row. the same column share similar .Therefore, option A is correct.
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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
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.
I NEED HELP. This is about science
Answer:
independent varible
Explanation:
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:
A chemist adds 485 mL of a 0.0025 mol/L calcium sulfate solution to a reaction flask. Calculate the mass in grams of calcium sulfate the chemist has added to the flask. Round your answer to significant digits.
Answer : The mass in grams of calcium sulfate is 0.16 grams.
Explanation :
Molarity : It is defined as the number of moles of solute present in one litre of solution.
Formula used :
[tex]Molarity=\frac{\text{Mass of solute}\times 1000}{\text{Molar mass of solute}\times \text{Volume of solution}}[/tex]
Solute is, [tex]CaSO_4[/tex]
Given:
Molarity of [tex]CaSO_4[/tex] = 0.0025 mol/L
Molar mass of [tex]CaSO_4[/tex] = 136 g/mole
Volume of solution = 485 mL
Now put all the given values in the above formula, we get:
[tex]0.0025=\frac{\text{Mass of }CaSO_4\times 1000}{136\times 485}[/tex]
[tex]\text{Mass of }CaSO_4=0.16g[/tex]
Thus, the mass in grams of calcium sulfate is 0.16 grams.
Which of the following elements does not form hydride by direct heating with
hydrogen gas?
A. Be
B. Mg
C. Si
D. Ba
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
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.
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.
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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
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
True or false? Salt weathering is when salt spray from the sea gets into a crack in a rock. It may evaporate and crystallize, putting pressure on the surrounding rock and weakening the structure.
1. True
2. False
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 changes are chemical changes?
sugar is dissolved in soda
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.Question (2) If your car
gets 27.8 miles to the gallon, how many liters of gasoline are necessary to travel 112 km?
This problem can be solved in short steps or in one longer step. In either case, please show your work.
Use the following conversion factors:
1 mi = 1.609 km
1 gal = 3.785 L
PLEASE HELP!!!!
Answer:
You need to convert 27.8 miles to km and gallon to liters, then
(km/L) x #L = ?
27.8×112
=?
?×1gal
=?
?×1mi
=?
=?×?×?
answer
Question: Which is the last step in excavation of the skeletal remains?
Answer options:
A: defining the investigation area
B: identifying the layout of the remains
C: exposing the remains
D: screening of the soil
E: lifting the remains
Answer:
B
Explanation:
No explanation needed for it i got 100% on it
Lifting the remains is the last step in the excavation of the skeletal remains. Therefore, option E is correct.
What is the excavation of the skeletal remains?In archaeology, excavation can be described as the exposure, processing, and recording of archaeological remains. An excavation site or "dig" can be the area being studied. These locations are from one to various areas at a time while a project can be conducted over weeks to several years.
Excavation involves the recovery of various types of data from a site. This data includes ecofacts, artifacts, features, and archaeological context. Before excavating, the presence of remains can often be suggested by remote sensings, such as ground-penetrating radar.
During excavation, stratigraphic excavation removes phases of the site one layer at a time and keeps the timeline of the material remains consistent. This is done through mechanical means and the soil is processed via methods like mechanical sieving or water flotation.
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i need help with this
Answer:
hope it helps you.......
Suppose 275 g of NO3- flows into a swamp each day. What volume of CO2 would be produced each day at 17.0°C and 1.00 atm?
I attached the image of the equation for reference
Answer:
264.28 L of CO₂
Explanation:
We'll begin by calculating the number of moles present in 275 g of NO₃¯. This can be obtained as follow:
Mass of NO₃¯ = 275 g
Molar mass of NO₃¯ = 14 + (16×3) = 14 + 48 = 62 g/mol
Mole of NO₃¯ =?
Mole = mass / molar mass
Mole of NO₃¯ = 275 / 62
Mole of NO₃¯ = 4.44 moles
Next, we shall determine the number of mole of CO₂ produced from the reaction. This can be obtained as follow:
2NO₃¯ + 5CO + 2H⁺ —> N₂ + H₂O + 5CO₂
From the balanced equation above,
2 moles of NO₃¯ reacted to produced 5 moles of CO₂.
Therefore, 4.44 moles of NO₃¯ will react to produce = (4.44 × 5) / 2 = 11.1 moles of CO₂.
Thus, 11.1 moles of CO₂ were produced from the reaction.
Finally, we shall determine the volume of CO₂ produced each day. This can be obtained as follow:
Temperature (T) = 17 °C = 17 °C + 273 = 290 K
Pressure (P) = 1 atm
Number of mole (n) of CO₂ = 11.1 moles
Gas constant (R) = 0.0821 atm.L/Kmol
Volume (V) of CO₂ =?
PV = nRT
1 × V = 11.1 × 0.0821 × 290
V = 264.28 L
Thus, 264.28 L of CO₂ would be produced each day.
The volume of [tex]\rm CO_2[/tex] produced has been 264.28 L.
The volume of the carbon dioxide gas produced can be calculated with the ideal gas equation.
The moles of [tex]\rm NO_3^-[/tex] has been:
Moles = [tex]\rm \dfrac{weight}{molecular\;weight}[/tex]
Moles of 275 g [tex]\rm NO_3^-[/tex] has been:
Moles = [tex]\rm \dfrac{275}{62}[/tex]
Moles of [tex]\rm NO_3^-[/tex] = 4.44 moles
The balanced equation gives that with the reaction of 2 moles [tex]\rm NO_3^-[/tex] , 5 moles carbon dioxide has been formed.
Moles of carbon dioxide formed with 4.44 mol [tex]\rm NO_3^-[/tex] has been:
2 moles [tex]\rm NO_3^-[/tex] = 5 moles [tex]\rm CO_2[/tex]
4.44 moles [tex]\rm NO_3^-[/tex] = 11.1 moles [tex]\rm CO_2[/tex].
The volume of the [tex]\rm CO_2[/tex] can be calculated as:
Pressure [tex]\times[/tex] Volume = moles [tex]\times[/tex] Rydberg constant [tex]\times[/tex] temperature
For the [tex]\rm CO_2[/tex] produced:
1 atm [tex]\times[/tex] Volume = 11.1 mol [tex]\times[/tex] 0.0821 atm.L/K.mol [tex]\times[/tex] 290 K
Volume = 264.28 L.
The volume of [tex]\rm CO_2[/tex] produced has been 264.28 L.
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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.
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:
44.90 g of reactants are placed in a beaker
containing 45.00 g of water at 15.00 oC. At the end of the chemical reaction the temperature of the water rises to 25.00 oC. Calculate the energy change of the reaction rounded to the correct number of sig figs.
A
1900 J
B
-1900 J
C
1882 J
D
-1882
E
1884 J
F
-1884 J
PLS help lol
Answer:
D. -1882J
Explanation:
We can solve the energy released in a chemical reaction in an aqueous medium using the equation:
Q = -m*C*ΔT
Where Q is energy (In J),
m is mass of water (45.00g)
C is specific heat of water (4.184J/g°C)
And ΔT is change in temperature (25.00°C - 15.00°C = 10.00°C)
Replacing:
Q = -45.00*4.184J/g°C*10.00°C
Q = -1882J
Right answer is:
D. -1882J
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:
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]
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.