Answer:
[tex]\Delta H=-92.7kJ[/tex]
Explanation:
Hello there!
In this case, according to the given information, we can infer that 890 kJ of energy are released when 1 mole of methane is burned; however, to find the total heat when 1.67 grams are burned, we first need to calculate the moles in this mass of methane:
[tex]1.67gCH_4*\frac{1molCH_4}{16.04gCH_4}=0.104molCH_4[/tex]
And thus, for calculating the resulting ∆H, we proceed as follows:
[tex]\Delta H=-890kJ/mol*0.104mol\\\\\Delta H=-92.7kJ[/tex]
Regards!
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.
PLEASE QUICKLY. I'll give BRAINLIEST. A sample contains 25% parent isotope and 75% daughter isotopes. If the half-life of the parent isotope is 72 years, how old is the sample?
144 years old
216 years old
288 years old
360 years old
From the calculations and the principles of radioactivity, the age of the parent isotope is 144 years
What is radioactivity?The term radioactivity has to do with the spontaneous decay of a substance.
We know that we have about 25% parent isotope still remaining hence;
[tex]0.693/t1/2 =2.303/t log No/N\\When N =0.25 No and t1/2 = 72 years\\0.693/72 =2.303/t log No/0.25No\\0.0096 = 2.303/t *0.60206\\0.0096 = 1.3865/t\\t = 1.3865/0.0096\\t =144 years[/tex]
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Answer:
A. 144 years old
Explanation:
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
How many formula units are there in 14.50 moles of any compound?
___X 10^___formula units
Answer:
8.73 × 10²⁴ formula units
Explanation:
To calculate the number of formula units a substance contain, we multiply the number of moles by Avagadro number (6.02 × 10²³)
number of formula units = 14.50 moles × 6.02 × 10²³
= 87.29 × 10²³
= 8.73 × 10²⁴ formula units.
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 :)
please mark all that apply!
Answer:
F G there you go the guy on top is right
Explanation:
F G
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:
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:
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.
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 )
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.
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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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.
Use the equation below:
2Na + Cl2 ==> 2NaCl
+ O
How many grams of NaCl are produced when 1.25 moles of Cl2 reacts with Na?
Explanation:
2/1×1.25
=2.5 mole of NaCl are produced
weight of NaCl produced = moles × molar mass of NaCl
weight of NaCl produced = 2.5×58.5
weight of NaCl produced =146.5 grams
How many moles of aluminum sulfide will be produced if 12 moles of Sg react?
Answer:
Molar mass = [9(12.0)+8(1.01)+4(16.0)] = 180.1 g/mol Moles = 112 g 1 mol x 180.1 g = 0.622 mol (3 sig figs)
Explanation:
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:
why metal in the middle of metal activity series can't be obtained by heating ors in air
Answer:
See Explanation
Explanation:
The way by which a metal is obtained from its ore is determined by the chemical reactivity of the metal.
Metals that are highly reactive are chiefly obtained by electrolysis of the metal salt. These metals are found high up in the metal activity series.
Metals that are at the middle of the series are moderately reactive and are obtained by electrolysis or by reduction since they still form ionic salts.
Metals that are far lower in the series can only be obtained by heating them in air because they are mostly unreactive.
Hence, moderately reactive metals at the middle of the series are not obtained by roasting in air.
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.
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)
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.
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:
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 = 11What element is produced when Mercury - 204 undergoes alpha decay?
Answer:
bismuth
Explanation:
i think if not i am so sorry
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.
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Balance the following equation:
Cr + __02 +_Cr203
Answer:
4Cr + __302 -->_2Cr203.....
0.444 mol C2H5OH= how many molecules
Explanation:
hope it make sense to u :)
The movement of water from an area of high concentration to one of low concentration through a semipermeable membrane is called ?
Study 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