Answer:
The Heat of Reaction (also known and Enthalpy of Reaction) is the change in the enthalpy of a chemical reaction that occurs at a constant pressure. It is a thermodynamic unit of measurement useful for calculating the amount of energy per mole either released or produced in a reaction.
name 2 elements that are liquid at room temperature and describe their colour
Answer:
Bromine
Mercury
Bromine (symbol Br and atomic number 35) is a reddish-brown liquid, with a melting point of 265.9 K. Mercury (symbol Hg and atomic number 80) is a toxic shiny silvery metal, with a melting point of 234.32 K.
How many moles of Mg are needed to react with 20 mol O2?
How does the structure of compounds determines the properties of the compounds?
All of these properties are due to the chemical structure of the compound. The chemical structure includes the bonding angle, the type of bonds, the size of the molecule, and the interactions between molecules. Slight changes in the chemical structure can drastically affect the properties of the compound.
A mixture of two gases with a total pressure of 2.78 atm contains 0.70 atm of Gas A. What is the partial pressure of Gas B in atm
Answer:
2.08 atm
Explanation:
Here we use Dalton's Law of Partial Pressures: Pa+Pb=Ptotal. 0.70 atm + Pb = 2.78 atm. To find the missing pressure of gas b we subtract .7 from the 2.78
Calculate the amount of energy That an obsect Can absorb from Yellow light Whose wave length is 589 nm.
Explanation:
E = hf
c= f × lamda
f= c/ lamda
c= speed of light
f= frequency
lamda = wavelength
E = h c/ lamda
E = 6.626 × 10^-34 Js × 3 × 10^8 ms-1 / 589 × 10^-9 m
= 3.37 × 10^15 J
A mixture of two or more metals is called: A) Mixture B) Compound C) solution D) alloy
Answer:
C
Explanation:
Mixture of 2 or more metals is a compound
example is water which is made up of hydrogen and oxygen.
What is the percent composition of Be(OH)2?
Answer:
Ba 80.148%. H 1.77% O 18.657%
A chemist makes up a solution by dissolving 42.0 g of Mg(NO3)2 in enough water to produce a final solution volume of 213 mL. To calculate the molarity of the solution, what additional information is needed
Answer:
the molar mass of Mg(NO3)2
the mass of the water added the density of the Mg(NO3)2
the volume of water used
Calculate the number of moles of Mg(NO3)2 used to make up this solution. 42.0 g of Mg(NO3)2 is equivalent to___ mol Mg(NO3)2.
Now calculate the molarity of the solution, giving your answer to the correct number of significant digits.
Molarity of Mg(NO3)2 = ___M
a hot air balloon has a volume of 875L. what is the original temperature of the balloon if its volume changes to 955 L when heated to 56
Answer:
using Charles law
v1/t1= v2/ t2
Explanation:
875/t1=955/56+273
t1= 329* 875/955
t1= 302.82k
The initial temperature of the hot air balloon can be calculated from Charles's law. The initial temperature of the balloon was, 51.3 °C.
What is Charles's law?According Charles's law, at constant pressure, the temperature and volume of a gas is in direct proportionality. Thus volume increases with an increase in temperature. Therefore V/T = a constant.
Let V₁ and T₁ be the initial volume and initial temperature and V₂ and T₂ be the final volume and temperature respectively. Thus we can write the relation as:
V₁ /T₁ = V₂/T₂ .
Given that the initial and final volume are 875 L and 955 L respectively. The final temperature is 56 °C. Thus the initial temperature is calculated as :
T₁ = V₁T₂/V₂
= (875 L × 56 °C )/955 L
= 51.3 °C.
Hence, the initial temperature of the hot air balloon was 51.3 °C.
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A gas has a volume of 1140 ml at 37 ºC and 620 mm Hg pressure. Calculate its volume at STP.
1.900
2.800
3.819
4.1000
Answer:
3. 0.819L (819 mL)
Explanation: Before we go about solving this, we need to do some conversions prior to using the gas law, the gas law is as follows...
P(atm)*V(L)=n(mol)*r(constant)*T(in kelvin)
So here are all the conversions you need.
620 mm Hg -> 0.816 atm
1140 mL -> 1.14 L
37 C -> 310.15 K
After plugging in our new converted values, we will proceed to solve the number of moles of the gas present, our n value, so our equation will look like this...(Note: Constant r in this case is 0.08206 L*atm/K*mol)
(0.816 atm)(1.14 L) = n(0.08206)(310.15)
Solving for n we get 0.03653 moles.
Now our second part is to figure out the volume AT STP (standard temperature/pressure). In the STP conditions, your temperature defaults to 0 C (273.15 K) and 1 atm. Now there is an easier way to do this, but I'll also show the more comprehensive way. Here is the easier method...
Since 1 mole of every gas occupies 22.4 L at STP, we can simply multiply this by our number of moles. So (22.4L)(0.3653 mol) to give us 0.818272.
However, a more accurate answer can be given like this...
Plugging n back into the same equation and this time resetting pressure to 1 atm and temperature to 273.15 K and conserving our number of moles we get...
(1 atm)(v) = (0.03653 mol)(0.08206)(273.15 K)
v = (0.03653)(0.08206)(273.15)
v = 0.8188 L = 0.819 L or 819 mL
14. What type of materials are spun together to make yarns?
Answer:
cotton
Explanation:
which is typically spun into fine yarn for mechanical weaving or knitting into cloth.
What’s the answer to this
Answer: 5
Explanation:
please brainliest me
I believe it is 3
Answer:
Explanation:
what do we call the cammell their
Answer:
You have to write the full question
If a barometer were built using water (d=1.0 g/cm3) instead of mercury (d=13.6 g/cm3), would the column of water be higher than, lower than, or the same as the column of mercury at 1.00 atm? If the level is different, by what factor? Explain.
Mercury is a compound denser than water and when this happen, it stays lower.
So, in this case, water stays higher than mercury because its density is low.
The level is different by a factor of 13.6 times taller.
Hey :3 please help with this. Will mark brainlist if you’re right
Answer: 4
Explanation:
20 points! Please Help!!
Based on what you have read what is the opportunity cost of the glass-making company's decision?
a higher quaity tem
a greater proft
a loss of equipment
a longer production time
Answer:
a greater profit......
Question 10
What is this structure name?
CH3 – CH2 - CH
CH – CH – CH2 - CH2
CH; CH – CH, -CH,
СН
CH3
cosh(-cosh(-CH
Simplify the expression using the symmetry of hyperbolic functions
cosh(cosh(CH))
Simplify the expression using the symmetry of hyperbolic functions
the answer is cosh(cosh(CH))
375cm³ of a gas has a pressure of 770 mm Hg, find it Volume if the pressure is reduced to 750 mm Hg
Answer:
Explanation:
Givens
v1 = 375 cm^3
P1 = 770 mm Hg
V2 = ?
P2 = 750 mm Hg
Formula
V1 P1 = V2 P2
Solution
375 * 770 = V2 * 750 Combine the left
288750 = V2 * 750 Divide both sides by 750
288750/750 = V2
V2 = 385
HELPP PLISS :(
Achemist analyzes two samples. One sample contains 14 g of element X and 6.0 g of element Y. The second sample contains 28 g of element X and 6.0 g of element Y. Does it appear that the two samples are the same substance? Explain the reasons for your answer.
A chemist analyzes two samples. One sample contains 14 g of element X and 6.0 g of element
Which ion with a
+2
charge has the electron configuration
1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6?
Answer:
atomic # 38 or strontium (Sr)
Explanation:
Which ion with a
+2charge has the electron configuration
1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6?
ADD THE ELECTRONS AND ADD 2 MORE FOR THE +2 CHARGE
so
2 +2 +6 +2 +6 +2 + 10 + 6 +2
so if it is now neutral (you added 2 e's to ofsetr the +2 charge) it has 38
protons, so it is atomic # 38 or strontium (Sr)
what does feldspar mean?
Answer:
an abundant rock-forming mineral typically occurring as colorless or pale-colored crystals and consisting of aluminosilicates of potassium, sodium, and calcium.
Explanation:
Answer:
Feldspars are a group of rock-forming aluminium tectosilicate minerals, containing sodium, calcium, potassium or berium
(e) alkaline earth element with the least massive atoms
The alkaline earth element with the least massive atoms is beryllium (Be). Beryllium, located in Group 2 of the periodic table, possesses the lowest atomic number and atomic mass within the alkaline earth elements.
Among the alkaline earth elements, which are found in Group 2 of the periodic table, beryllium (Be) stands out for having the least massive atoms. The periodic table is organized in a way that elements are ordered by increasing atomic number, which corresponds to the number of protons in an atom's nucleus. For alkaline earth elements, the atomic numbers increase from beryllium (Be) with atomic number 4 to radium (Ra) with atomic number 88.
Atomic mass, on the other hand, takes into account the sum of protons and neutrons in an atom's nucleus, as electrons contribute very little to the overall mass. Since beryllium (Be) has the lowest atomic number in the alkaline earth group, it also has the fewest protons and neutrons among its isotopes, leading to a lower atomic mass compared to other elements in the same group.
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Describe the experiment that Chadwick conducted which led to his discovery of the neutron.
Answer:
James Chadwick conducted an experiment where he assailed the element Beryllium with alpha particles that came from the radioactive decay of Polunium. The experiment results showed highly penetrating radiation emitted from the Beryllium. In this, Chadwick proposed that radiation consisted of uncharged particles, which were later founded as neutrons.
Help please With this :)))
Answer: 3
Explanation:
True or false?
Increasing the temperature can help slow down chemical reactions by "burning away" unnecessary molecules
please fast but right no link or bot
help! giving brainliest.
Answer:
A
Explanation:
will group 2 elements gain electrons to bond with non-metals in group 16 in a 2:1 ratio
how to draw ethyl structural formula?
Answer:
c2H5
Explanation:
H. H
|. |
C-C- H
|. |
H. H
If acid comes in contact with your skin, why must you flush the area with plenty of cold water, rather than neutralizing the acid with a base?
Answer:
that would just create a bigger mess if you flush it with ice water it can reduce swelling and help dull your nerves
Explanation:
If acid comes in contact with your skin, because having an excessive amount of base can also be harmful. Acid is weakened and rendered ineffective by water.
What is acid?A chemical species known as an acid absorbs electrons and/or provides protons or hydrogen ions. When a hydrogen atom is bound to an acid, it can release (dissociate) and produce a cation as well as an anion in water. A substance's acidity and solution pH increase according to the amount of hydrogen ions it produces.
There are various definitions for acids. When someone uses the term "an acid," they typically mean an Arrhenius or Brnsted-Lowry acid. Often, a Lewis acid being referred to as a "Lewis acid." If acid comes in contact with your skin, because having an excessive amount of base can also be harmful. Acid is weakened and rendered ineffective by water.
Therefore, if acid comes in contact with your skin, because having an excessive amount of base can also be harmful. Acid is weakened and rendered ineffective by water.
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Stems are important plant structures because they _________.
A.
are the main sites of photosynthesis for plants
B.
are the only site of water and nutrient transport
C.
allow plants to absorb water and nutrients from the soil
D.
give the plant structure and support
Answer:
c
Explanation:
allow plants to absorb water and nutrients from the soil