Answer:
Explanation:
1.). A pure substance has a/an ___definite____ composition.
Pure substances have a definite composition and all their parts are same throughout.
2.). A/An ___mixture____ is composed of two or more types of matter that can be present in varying amounts.
Mixture is a blend of two or more types of matter.
3.). A solution is a/an ___homogeneous ____ mixture.
Solutions are homogeneous mixtures of solutes and solvents.
4.). A mixture that is not uniform throughout is a/an ___heterogeneous ____ mixture.
A mixture that is not uniform throughout is said to be heterogeneous.
5.). A pure substance that cannot be broken down chemically is a/an _______.
An element : is a distinct substance that cannot be split-up into simpler substances.
6.). A characteristic of matter that’s not associated with a change in its chemical composition is known as a/an __physical_____ property.
Physical property tells us everything about what a substance is when no change is occuring to its constituents.
7.).Wax melting is an example of a/an ___physical change____ change in the state of matter.
Physical change is one that alters the physical properties of matter.
8.). A banana peel turning brown is an example of a/an ___chemical____ change in the state of matter.
Chemical change is one in which a new matter is formed.
Answer:
The value for the equilibrium constant for the reaction at 298K .
What would be the value for the equilibrium constant for the following reaction at the same temperature?
Explanation:
The Kc value for the reverse reaction of the first reaction that is:
For the reverse reaction,
So, it is the inverse of the first Kc value.
Hence, the new Kc value is:
Answer is :
Kc=2.5*10^-25.
From the periodic table you get the atomic masses of each element.
These are the values that I have in my periodic table (use those numbers of your periodic table if your teache gave you a specific one)
Na: 23 g/mol
O: 16 g/mol
H: 1 g/mol
C: 12 g/mol
Ca: 40 g/mol
S: 32 g/mol
Mg: 24 g/mol
P: 31 g/mol
Now I will do some examples and you do the others:
1) NaOH: 1 atom of Na * 23 g/mol + 1 atom of O * 16 g/mol + 1 atom of H * 1 g/mol
=> 1*23g/mol + 1*16g/mol + 1*1g/mol = 40 g/mol
2) H2O
=> 2 atoms of H * 1 g/mol + 1 atom of O * 16 g/mol = 2*1g/mol + 1*16g/mol = 18 g/mol
3) Glucose: C6H12O6
6*12 g/mol + 12 * 1g/mol + 6*16 g/mol = 72g/mol + 12g/mol + 96 g/mol = 180 g/mol
4) CaSO4:
1*40 g/mol + 1*32g/mol + 4*16g/mol = 136 g/mol
Now you only have to do the last one by your own.
The volume of 4.92 grams of hydrogen gas at STP is 55 L.
<u>Explanation</u>:
1 mole of an ideal gas will occupy 22.4 L
To find volume, the molar volume of a gas is
22.4 L / 1 mole H
2 → this takes you from moles of H
2 to liters
Now, to find the number of moles present in 4.92 g of hydrogen gas, you can use the gas' molar mass
4.92 g 1 mole H
2 / 2.016
g = 2.44 moles H
2
This sample of hydrogen gas will thus occupy
2.44 moles H
2 22.4 L / 1 mole H
2 = 54.6 L = 55 L.
Option (a) Ca, Mn, Co are paramagnetic elements in the fourth period of the periodic table due to unpaired electrons.
A substance's electron configuration can be used to assess if it has magnetic properties: The material is paramagnetic if any of its electrons are unpaired, and it is diamagnetic if all of its electrons are paired.
Materials with hindered electrons that are drawn to magnetic fields are considered to be paramagnetic. In the absence of a magnetic field, they become less magnetic. The magnetic moment of the material and, consequently, the paramagnetism, increase with the number of unpaired electrons.
is the ion with the most paramagnetic behaviour because it has the most unpaired electrons when two electrons are lost.
In this instance, calcium is a paramagnetic element as well. This is an anomaly. Due to the ability of one of calcium's electrons in the S orbital to jump to the D orbital, the element is paramagnetic. Since calcium is in Period 4, its D orbital is unoccupied. D orbitals exist in elements with period 4. Thus, this provides that electron with a destination.
Three electrons are not paired in cobalt. It is hence paramagnetic. Three unpaired electrons are present in the outermost subshell.
Learn more about Paramagnetic elements here:
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