Which of the following processes
release energy?
A. Water evaporating
B. Ice melting
C. steam condensing
D. wax melting
To determine the molar mass of an element, one must know the element's
a. number of isotopes.
b average atomic mass
c avogradro constant
d atomic number
Answer:
d
Explanation:
from you know the atomic number it should be easy to find
To determine the molar mass of an element, one must know the element's atomic number. Therefore, option D is correct.
What is the atomic number ?An element's atomic number (Z) is the number of protons in the nucleus of each atom of that element. This means that the number of protons is the feature that distinguishes each element from all others. Elements differ based on their atomic number.
Because the combined masses of protons and neutrons account for nearly all the mass of a given atom, the atomic mass of a single atom can be calculated by adding the total number of protons and neutrons of that particular isotope.
The atomic mass of any element on the periodic table can be used to calculate its molar mass.
Thus, option D is correct.
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Explain the method to decrease friction?
Answer:
having a smooth or lubricated surface may help decrease friction.
Explanation:
2Cr^3 + 3Zn(s) -> 2Cr(s) + 3Zn^2 + (aq) which reactant is reduced and which is oxidicided
Answer:
Cr is oxidised
and
Zn is reduced
[ Reduced reactant ] :
Cr^( + 3 ) + 3 e^( - 1 ) ===》 Cr^( 0 )
_____________________________
[ Oxidicided reactant ] :
Zn^(0) ===》Zn^( + 2 ) + 2 e^( - 1 )
Sodium chloride is produced from its elements through a synthesis reaction. What mass of each reactant would be required to produce 22.0 mol of sodium chloride? sodium
Answer:
506.0 g sodium and 778.8 g chlorine gas
Explanation:
The elements from which sodium chloride (NaCl) is composed are sodium (Na) and chlorine (Cl). Thus, the chemical equation for the production of sodium chloride (NaCl) from sodium (Na) and chlorine gas (Cl₂) is the following:
2Na(s) + Cl₂(g) → 2NaCl(s)
According to the balanced equation, 2 moles of NaCl are produced from 2 moles of Na(s) and 1 mol of Cl₂. To produce 22.0 mol of NaCl, we need:
22.0 mol NaCl x 2 mol Na(s)/2 mol NaCl = 22.0 mol Na(s)
22.0 mol NaCl x 1 mol Cl₂/2 mol NaCl = 11.0 mol Cl₂
Now, we convert the moles of each reactant to grams with the molar mass (MM) of the compound:
MM(Na) = 23 g/mol
22.0 mol Na x 23 g/mol = 506.0 g Na(s)
MM(Cl₂) = 35.4 g/mol x 2 = 70.8 g/mol
11.0 mol Cl₂ x 70.8 g/mol = 778.8 g Cl₂
Therefore, it is required a mass of 506.0 grams of Na(s) and a mass of 778.8 grams of Cl₂ to produce 22.0 mol of NaCl.
2. How did the Activator affect the mixture?
Answer:
Activator effects a mixture if you put to much of the activator your using into a product or thing you are using.
Explanation:
For ex.
If you poor to much activator into slime it will make the slime hard and very wet it will ruin your slime completely so you will have to do it just right but start off pouring it slowly and mix and then more if it needs more.
6 a 100 sample of Au - 198 Au 198 be? Decays to 3.125 g in 13.5 days, what would the half-life of au198 be?
Answer:
Half-life = 2.7 days
Explanation:
The radioactive decay of an isotope follows the equation:
Ln[A] = -kt + ln[A]₀
Where [A] could be taken as the amount of A after t time, k is decay constant, [A]₀ initial amount of A.
Replacing to solve k:
Ln[3.125g] = -k*13.5days + ln[100g]
-3.465736 = -k*13.5days
k = 0.2567days⁻¹
Half-life is:
half-life = ln2 / k
Half-life = 2.7 days
Does the excess reactant get used up completely in a reaction??
Answer:
In a chemical reaction, reactants that are not used up when the reaction is finished are called excess reagents. The reagent that is completely used up or reacted is called the limiting reagent, because its quantity limits the amount of products formed.
Explanation:
Does heat flow out of the atmosphere (HQ)
change during the day?
Answer:
The heat flow into Earth's atmosphere varies as the Sun rises and sets, gradually increasing during the day and falling to zero at night.
Explanation:
Heat radiates from the ground into the lower atmosphere. In conduction, heat moves from areas of more heat to areas of less heat by direct contact. Warmer molecules vibrate rapidly and collide with other nearby molecules, transferring their energy.
please mark all that apply!
Answer:
F G there you go the guy on top is right
Explanation:
F G
HELP PLEASE
1. Locations where volcanoes form far from plate boundaries are called
A. islands
B. hot spots
C. divergent zones
Balance this chemical equation
Ca(OH)2 + HCl ---> CaCl2 + H2O
Answer:
The balance equation of Ca(OH)2 + HCl ---> CaCl2 + H2O
is
Ca(OH)2(s) + 2HCl(aq) ---> CaCl2(aq) +2H2O (l) (balanced equation)
CAN SOMEONE PLEASE HELP ME WITH THIS I REALLY NEED HELP
Answer:
B
Explanation:
There's a three in front of the CH3COOH. But let's figure it out without that 3.
1 mol of CH3COOH has 3 H from CH3 and 1 hydrogen at the end. In all 4 hydrogens.
Now put the 3 in front 3CH3COOH multiplies everything by 3. So you had 4 before and with the 3 in front you must have 12.
Try it. Draw it out.
CH3COOH has 4
CH3COOH has 4
CH3COOH has 4
Total 12
That's B
How GM food are produced?
What is genetic modification (GM) of crops and how is it done? GM is a technology that involves inserting DNA into the genome of an organism. To produce a GM plant, new DNA is transferred into plant cells. Usually, the cells are then grown in tissue culture where they develop into plants.
Answer:
GM is a technology that involves inserting DNA into the genome of an organism. To produce a GM plant, new DNA is transferred into plant cells. Usually, the cells are then grown in tissue culture where they develop into plants. The seeds produced by these plants will inherit the new DNA.
Which of the following phase changes describes what is
happening in the following endothermic process?
H20 (1) + heat --> H2O (g)
O melting
o freezing
o boiling
O condensing
Answer:
I think the answer is boiling
90 grams of NaNO3 were added to solution at 10 degrees Celsius. What type of solution was formed?
Answer:
friend me on here and imma send you the link Explanation:
How many grams of water are produced when 12.50 mol oxygen reacts with hydrogen?
Answer: According to reaction below, when one mol of oxygen reacts with two mol of hydrogen, two mol of water is produced. Thus, when 2.5 mol of oxygen reacted with hydrogen, 2 * 2.5 mol = 5 mol of water is produced. The molar mass of water is 18 g/mol.
Explanation:
Not My WORK! I got this info from another site. BUT I HOPE IT HELPS :)
How many ml of a 6.00M HNO would be required to prepare 200ml of a 2.50M
solution?
83.33ml
72.98ml
86.23ml
64.98ml
Answer:
83.33ml
Explanation:
Firstly, let's notice that 200ml are equal to 0.2L
M=number of moles of the solute ÷ number of liters. Let's call the number of liter by x:
2.5=x÷0.2
x=2.5×0.2
x=0.5
It means you'll need 0.5 mol of HNO. But your solution have 6 moles per liter, so how much do you need? Divide the moles by 12 to have 0.5, so now you need to divide the liter per 12 too. The liter is equal to 1000ml, so:
1000ml÷12=83.33ml
Which of the following is a correct statement about water? (3 points)
Hydrogen bonding causes water to be strongly cohesive.
Hydrogen bonding causes water to have a low surface tension.
Water is a universal solvent because polar and nonpolar solutes can dissolve in it.
Water is less dense as a liquid than as a solid because of changes in bond structure.
Answer:
A: Hydrogen bonding causes water to be strongly cohesive.
Explanation:
Water has a high surafce tension. Hence droplets of water
Water cannot dissolve non polar substances like oil; only polar
Water is actually less dense in solid form :)
Hydrogen bonding causes water to be strongly cohesive.
This sticking together of like substances is called cohesion. Depending on how attracted molecules of the same substance are to one another, the substance will be more or less cohesive. Hydrogen bonds cause water to be exceptionally attracted to each other. Therefore, water is very cohesive.
Cohesion
Cohesion, also called cohesive attraction or cohesive force, is the action or property of like molecules sticking together, being mutually attractive. It is an intrinsic property of a substance that is caused by the shape and structure of its molecules, which makes the distribution of surrounding electrons irregular when molecules get close to one another, creating an electrical attraction that can maintain a microscopic structure such as a water drop. In other words, cohesion allows for surface tension, creating a "solid-like" state upon which light-weight or low-density materials can be placed.
Learn more about Cohesion
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Phenolphthalein meaning
Answer:
Phenolphthalein is a chemical compound with the formula C20H14O4 and is often written as "HIn" or "phph" in shorthand notation. Phenolphthalein is often used as an indicator in acid–base titrations. For this application, it turns colorless in acidic solutions and pink in basic solutions.
Answer:
Phenolphthalein is a chemical compound, a colorless crystalline solid, though pink in a alkaline solution, and is also used as an acid-base indicator.
Explanation:
21.) This substance consists of two or more nonmetal elements in a fixed ratio.
a.) element
b.) mixture
c.) molecule
d.) compound
Answer:
Molecule
Explanation:
when two or more than two non-metal elements are combined then it form Molecule.
If a piece of pure gold jewelers weighs 11.81 grams, how many atoms is it made of?
Answer:30.573 Billion atoms are in one gram
Explanation:
based on the graph below, which statement
Answer:
4. Atmospheric pressure decreases as altitude increases.
Explanation:
hope this helps and is right. p.s i really need brainliest :)
The movement of water from an area of high concentration to one of low concentration through a semipermeable membrane is called ?
Balance the following equation: _H2+ __02 - __ H20
Answer:
2
H
2
+
O
2
=
2
H
2
O
Explanation:
From the original equation, you first need to write each component separately.
H
2
+
O
2
=
H
2
O
Left side: H = 2 ; O = 2 (number based on the subscript)
Right side: H = 2 ; O = 1 (number based on the subscripts; no subscript means that the element is just 1)
Notice that the number of H is already balance but the number of O is not. In order to balance the O, you need to multiply the element by 2, but you CANNOT do this by simply changing the subscript.
Hence,
H
2
+
O
2
=
2
H
2
O
Left side: H = 2 ; O = 2
Right side: H = 2 x 2 = 4 ; O = 1 x 2 = 2
Now, notice that the number of O is now balance (both are 2) but the number of H is not (since
H
2
O
is a substance and not an element, you need to multiply everything by 2). So, what to do?
You also multiply the left side H by 2. Hence,
2
H
2
+
O
2
=
2
H
2
O
Left side: H = 2 x 2 = 4 ; O = 2
Right side: H = 2 x 2 = 4 ; O = 1 x 2 = 2
The equation is now balanced.
What element is produced when Mercury - 204 undergoes alpha decay?
Answer:
bismuth
Explanation:
i think if not i am so sorry
Which equation correctly represents the dissociation of a strong acid in water?
Question 26 options:
CH3COOH ↔H++ CH3COO−
NaOH →Na++OH−
HCl →H+ +Cl−
NH3+ H2O↔ NH4++ OH−
The equation that correctly represents the dissociation of a strong acid in water is as follows: HCl → H+ + Cl−
What is acid dissociation?Acid dissociation is the process by which an acid breaks up into it's constituent ions in an aqueous solution.
Acids are known to contain hydrogen ions (H+), hence, dissociate into H+ and an anion.
A strong acid like HCl dissociates completely in an aqueous solution while a weak acid does not dissociate completely.
According to this question, hydrogen chloride (HCl) is said to dissociate into hydrogen ion (H+) and chloride (Cl-) according to the following expression:
HCl → H+ + Cl−
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What is the pOH of a solution of pH 3 acid? (Kw= 1.0 x 10-14)
Answer:
pOH = 11
Explanation:
The pH is an unit of concentration widely used in chemistry to find the quality of a solution.
To solve this question we must, as first, find the [H+] using the pH:
[H+] = 10^-pH
[H+] = 10^-3
Now, using kw:
kw = 1.0x10-14 = [H+] [OH-]
1.0x10-14 = [10^-3] [OH-]
[OH-] = 1.0x10-11
pOH = -log [OH-]
pOH = 11Study the particle below carefully and answer
the questions that followed.
a)ldentify the particle.
b)Write the electronic configuration of the
particle.
c)State
i.Atomic number
ii.Mass number
iii.Proton number
iv.Electron number
d) Calculate the neutron number
e) State the valency
f)What is the valence electrons?
Answer:
b is the answer hope that helps
0.444 mol C2H5OH= how many molecules
Explanation:
hope it make sense to u :)