helppp pleaseee i really need to pass this class
What element has 70 electrons and 102 neutrons?
Answer:
The answer is Ytterbium but it is one of it isoptoped so techniacally it would be Ytterbium 102.
Select the correct answer.
Which of the following does the Sun orbit?
A.
The center of the Milky Way
B.
The Earth
C.
The Moon
D.
The stars
How many grams of MgO are produced from the complete reaction of 94.2 g Mg?
Answer:
157 g of MgO
Explanation:
the reaction:
2Mg + O2 ➡️ 2MgO
1) find the mol of Mg
mol = mass / molar mass
mass = 94.2 g
molar mass = 24
mol = 94.2 / 24
mol = 3.925 mol
2 mol = 3.925 moles
2) find mass of MgO
mass = mol × molar mass
mol = 3.925
molar mass = 24+16 = 40
mass = 3.925 × 40
= 157 g
hey siri how do you make ice cube ????????????????????????????????????
Answer:
1.Get a ice cub tray.
2. fill cold water to the top.
3. Put the tray in the freezer.
4 let them sit for 3-4 hours.
5.Enjoy!
Explanation:
Answer:
put hotdogs in water boil em. put the water in the cube thingy and put it in the freezer
A sample of 254.2 grams of copper completely reacted with oxygen to form 286.2 grams of copper oxide product how many grams of oxygen reacted
During a chemical reaction nb of atoms and mass is always conserved , so mass of Reactants is equal mass of Products.
what is a physical change
cutting a piece of paper
Explanation:
Answer:
A physical change occurs when a substance changes, but no new substance is formed.
Explanation:
Give me a summary on Jupiter 3-5 paragraphs
Can someone help me pls I don’t have time Time is almost ran out pls help
Answer:
Can you get a closer picture, then I can help! It looks like it says something on rain, hail and something else. I cant see it though! :)
Explanation:
I NEED HELP PLEASE!!!! CHEMISTRY QUESTION: If 38 g of Li3P and 15 grams of Al2O3 are reacted, what total mass of products will result? Why?
Answer:
21.5 g.
Explanation:
Hello!
In this case, since the reaction between the given compounds is:
[tex]2Li_3P+Al_2O_3\rightarrow 3Li_2O+2AlP[/tex]
We can see that according to the law of conservation of mass, which states that matter is neither created nor destroyed during a chemical reaction, the total mass of products equals the total mass of reactants based on the stoichiometric proportions; in such a way, we first need to compute the reacted moles of Li3P as shown below:
[tex]n_{Li_3P}^{reacted}=38gLi_3P*\frac{1molLi_3P}{51.8gLi_3P}=0.73molLi_3P[/tex]
Now, the moles of Li3P consumed by 15 g of Al2O3:
[tex]n_{Li_3P}^{consumed \ by \ Al_2O_3}=15gAl_2O_3*\frac{1molAl_2O_3}{101.96gAl_2O_3} *\frac{2molLi_3P}{1molAl_2O_3} =0.29molLi_3P[/tex]
Thus, we infer that just 0.29 moles of 0.73 react to form products; which means that the mass of formed products is:
[tex]m_{Li_2O}=0.29molLi_3P*\frac{3molLi_2O}{2molLi_3P} *\frac{29.88gLi_2O}{1molLi_2O} =13gLi_2O\\\\m_{AlP}=0.29molLi_3P*\frac{2molAlP}{2molLi_3P} *\frac{57.95gAlP}{1molAlP} =8.5gAlP[/tex]
Therefore, the total mass of products is:
[tex]m_{products}=13g+8.5g\\\\m_{products}=21.5g[/tex]
Which is not the same to the reactants (53 g) because there is an excess of Li₃P.
Best Regards!
what is this balanced?
Al2O3---> Al+O2
The balanced equation :
2Al₂O₃⇒ 4Al+3O₂
Further explanationGiven
Reaction
Al₂O₃⇒ Al+O₂
Required
Balanced equation
Solution
A chemical reaction is said to be balanced if the number of elements involved in the reaction is the same (either the reactants or the products)
The reaction above is said to be unbalanced because the number of elements Al and O in the reactants and products is not the same.
The balancing step
1. Give a coefficient
Al₂O₃⇒ aAl+bO₂
2. Make an equation
Al, left = 2, right = a⇒a=2
O, left = 3, right = 2b⇒2b=3⇒b=3/2
The equation becomes :
Al₂O₃⇒ 2Al+3/2O₂ x2
2Al₂O₃⇒ 4Al+3O₂
how would you describe a solid substance appearance before melting
What is tree rings tell us?
Answer:each of a number of concentric rings in the cross section of a tree trunk, representing a single year's growth.
Explanation:it tell whats the age of the tree.
According to the law of conservation of mass, how much mercury was present in the mercury (II) oxide? *
Mass of Mercury(Hg) : 55.8 g
Further explanationGiven
Reaction
2HgO ⇒ O₂ + 2Hg
Required
Mass of Mercury
Solution
Conservation of mass applies to a closed system, where the masses before and after the reaction are the same
So mass of reactants = mass of products
Mass of reactants = mass HgO = 60 g
Mass of products = mass O₂ + mass Hg
60 g = 4.2 g + mass Hg
mass Hg = 60 - 4.2
mass Hg = 55.8 g
The solubility in water of ionic compound X is measured and found to be 0.776g/mL at 15.°C. Calculate the volume of a saturated solution of X in water that would contain 34.0g of X at this temperature. Be sure your answer has the correct unit symbol and 3 significant digits.
Answer: The volume of a saturated solution of X in water that would contain 34.0g of X is 43.9 ml
Explanation:
Solubility is defined as the amount of solute dissolved per 100 ml of the solvent at a fixed temperatur.
Given : solubility of ionic compound X in water at [tex]15^0C[/tex] = 0.776 g/ml
0.774 g of X is contained in = 1 ml
Thus 34.0 g g of X is contained in = [tex]\frac{1}{0.774}\times 34.0=43.9 ml[/tex]
Thus the volume of a saturated solution of X in water that would contain 34.0g of X is 43.9 ml
the mixture of carbon dioxide and water tastes salt why
Answer:
When carbon dioxide reacts with water carbonic acid is formed, from which hydrogen ions dissociate increasing the acidity of the systemCarbon dioxide emissions to the atmosphere can therefore increase the acidity of land, sea and air
Explanation:
NEED HELP FAST!!!!!!!!!!!!
How many moles of Na are in 42 g of Na?
Given 2AL + 6HCL → 2ALCL3 + 3H2, how many grams of aluminum do I need to produce 11 L of hydrogen gas at STP?
Mass of Aluminum= 8.829 g
Further explanationGiven
Reaction
2Al + 6HCl → 2AlCl₃ + 3H₂
Required
mass of Aluminum
Solution
At STP, 1 mol gas = 22.4 L
For 11 L of Hydrogen :
= 11 : 22.4
= 0.491
From equation, mol ratio Al : H₂ = 2 : 3, so mol Al :
= 2/3 x mol H₂
= 2/3 x 0.491
= 0.327
Mass Aluminum(Ar=27 g/mol) :
= 0.327 mol x 27 g/mol
= 8.829 g
which of the following is the best characterization of the nature of light?
Answer: Light is a transverse, electromagnetic wave that can be seen by the typical human. The wave nature of light was first illustrated through experiments on diffraction and interference
Explanation:
Answer:
Light energy
Explanation:
What is Displacementsubject Physics,
Explanation:
Displacement is the distance travelled in a specific direction. Unlike distance, displacement is a vector quantity with both magnitude and directional attribute.
When we specific displacement values, we must indicate the direction of motion to complete its description.
For example, 50m is a distance value. It has a magnitude but no direction.
When we say 50m due south, this is a displacement because both magnitude and direction are accurately specified and defined.
A nuclear magnetic resonance, or NMR, spectrometer is an instrument that can be used to characterize molecules based upon the excitation of inner shell electrons. the behavior of the nuclei of certain atoms in a magnetic field. the nuclear radiation emitted by certain molecules. vibrations of portions of the molecule brought about by the absorption of infrared radiation.
Answer:
The correct answer is A)
Explanation:
An NMR or Nuclear Magnetic Resonance Spectrometer is an equipment that can be used to study the nature of molecules after their nuclei have been excited with the use of radio waves. Radio waves generated is converted into nuclear magnetic resonance.
The resonance produced can be recognized or decoded by special radio receivers.
Besides recognizing the molecular structure of a chemical compound, it's purity and its content can also be analyzed.
Cheers!
Question 4
How many moles are contained in 67 L of CO2 gas at STP? Round your answer to three significant figures and include units.
Answer:
2.99 mol
Explanation:
Number of moles of CO₂ = ?
Volume = 67 L
Temperature and pressure = standard
Solution:
The given problem will be solve by using general gas equation,
PV = nRT
P= Pressure
V = volume
n = number of moles
R = general gas constant = 0.0821 atm.L/ mol.K
T = temperature in kelvin
By putting values,
1 atm × 67 L = n ×0.0821 atm.L/ mol.K × 273.15 K
67 atm.L = n×22.43 atm.L/ mol
n = 67 atm.L/22.43 atm.L/ mol
n = 2.99 mol
How would the
In an isolated system, two copper
bars at different temperatures transfer energy until both are at the same temperature.
of energy be different if the bars were in an open system?
transfer
O A. Energy transfer would occur only between the copper bars.
between the copper bars and the surroundings
O B. Energy transfer would occur between the copper
© c. No energy transfer would occur between the
copper bars or the surroundings.
D. Energy transfer would occur only with the surroundings.
Answer: Energy transfer would occur only between the copper bars and the surroundings.
Explanation:
It should be noted that in the open system, there is transfer of both energy and mass from the system and also into the system as well.
Assuming the bars were in an open system, the transfer of energy would occur only between the copper bars and the surroundings.
Explanation:
In an isolated system, two copper bars at different temperatures transfer energy until both are at the same temperature. How would the transfer of energy be different if the bars were in an open system?
A.
Energy transfer would occur only between the copper bars.
B.
Energy transfer would occur between the copper bars and the surroundings.
C.
No energy transfer would occur between the copper bars or the surroundings.
D.
Energy transfer would occur only with the surroundings.
which wave carris most energy
Answer:
Gamma Rays
Explanation:
Hope it helps!! :))
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Explanation:
3. Do objects of different masses fall at different rates? Why or why not? *
Answer:
yes.it depends on acceleration due to gravity,weight .
Consider the combustion of propane: A balloon is being inflated to its full extent by heating the air inside it. In the final stages of this process, the volume of the balloon changes from L to L by the addition of J energy as heat. Assume that all the heat comes from the combustion of propane. What mass of propane must be burned to furnish this amount of energy assuming the heat transfer process is 50.% efficient?
Answer:
5162.539 g
Explanation:
Let assume that the volume changes from [tex]4.00 \times 10^6 \ L[/tex] to [tex]4.50 \times 10^6 \ L[/tex].
And if the addition of energy as heat is [tex]1.3 \times 10^8 \ J[/tex]
Then; we can say that the total heat that is taken by the ballon = [tex]1.3 \times 10^8 \ J[/tex]
[tex]= 1.3 \times 10^5 \ kJ[/tex]
The total heat supplied = total heat coming from the combustion of propane
∴
[tex]= \dfrac{100}{50} \times 1.3 \times 10^5 \ kJ[/tex]
[tex]= 2.6 \times 10^5 \ kJ[/tex]
[tex]C_3 H_{8(g)} + 5O_{2(g)} \to #CO_{2(g)} + 4H_2O_{(l)} \ \ \Delta H = -2221 \ kJ[/tex]
If 2221 kJ is produced as a result of the combustion of 44.1 g [tex]C_3H_{8(g)}[/tex]
Then;
[tex]2.6 \times 10^5 kJ[/tex] will produce [tex]= \Big( \dfrac{44.1 \times 2.6 \times 10^5}{2221} \Big ) \ g[/tex]
= 5162.539 g
Thus, the mass of the propane that must be burned = 5162.539 g
Considering the following polymer size fractions of a given polymer sample:
Fraction Molecular Weight Number of Chains
1 6,500 400
2 10,000 1000
3 1,000,000 8
(a) Calculate the number-average molecular weight of the polymer.
(b) Calculate the weight-average molecular weight of the polymer.
(c) Which average molecular weight did the 8 chains of molecular weight of 1,000,000 most significantly affect? why?
(d) Calculate the polydispersity index(PI = (Mw/Mn) of the polymer
Answer:
Explanation:
From the information given:
Molecular weight Mi Number of chains (Ni) NiMi
400 6500 2600000
1000 10000 10000000
8 1000000 8000000
[tex]\sum_{Ni} = 1408[/tex] [tex]\sum _{NiMi}[/tex] = 20600000
Thus, the average number of molecular weight = [tex]\dfrac{\sum_{NiMi}}{\sum_{Ni} }[/tex]
[tex]= \dfrac{20600000}{1408}[/tex]
= 14630.68
b)
weight-average molecular weight = [tex]\dfrac{\sum _{NiMi^2} }{\sum _{NiMi}}[/tex]
[tex]Ni[/tex] [tex]Mi[/tex] [tex]Mi^2[/tex] [tex]Ni[/tex] [tex]Mi^2[/tex]
400 6500 42.25 × 10⁶ 16.9 × 10⁹
1000 10000 100 × 10⁶ 100 × 10⁹
8 1000000 1 × 10¹² 800 × 10⁹
[tex]\sum _{NiMi^2} = 916.9 \times 10^9[/tex]
weight-average molecular weight [tex]=\dfrac{916.9 \times 10^9 }{20.6 \times 10^6}[/tex]
= 44509.71
c)
The number average molecular weight is most significantly affected. This is because the number average molecular weight value is worth more in comparison to the weight-average molecular weight.
d)
The polydispersity index (PI) = [tex]\dfrac{\overline {M_W}}{\overline {M_n}}[/tex]
[tex]PI = \dfrac{44509.71}{14630.68}[/tex]
PI = 3.04
Is plastic pollution likely to become more or less of a problem in the future?
Answer:
More bro
Explanation:
Pollution is only increasing
Answer: Yes and no, no because people are constantly polluting the earth with plastic which is a big issue. Yes, because things are being invented to help with plastic pollution, and there is a great number of people who recycle, so however you look at it there's really a 50/50 chance.
Explanation:
Are these sentences true or false? Tick the boxes
True False
a) The substance is an element.
b) The substance contains five atoms.
c) There is carbon in the substance.
d) The substance contains nitrogen and hydrogen.
