Answer:
The idea here is that you can use the heat absorbed by the solution to find the heat given off by the dissolution of the salt.
More specifically, you can assume that
Δ
H
diss
=
−
q
solution
The minus sign is used here because heat lost carries a negative sign.
To find the heat absorbed by the solution, you can use the equation
q
=
m
⋅
c
⋅
Δ
T
−−−−−−−−−−−−−
Here
q
is the heat gained by the water
m
is the mass of the water
c
is the specific heat of water
Δ
T
is the change in temperature, defined as the difference between the final temperature and the initial temperature of the sample
As the problem suggests, you can approximate the mass and the specific heat of the solution to be equal to those of the pure water sample.
The temperature increases by
0.121
∘
C
, so you know that
Δ
T
=
0.121
∘
C
→
positive because the final temperature is higher than the initial temperature
Plug in your values to find
q
=
125
g
⋅
4.18 J
g
−
1
∘
C
−
1
⋅
0.121
∘
C
q
=
63.22 J
So, you know that the solution absorbed
63.22 J
, which implies that the dissolution of the salt gave off
63.22 J
. In other words, you have
Δ
H
diss
=
−
63.22 J
Convert the mass of sodium hydroxide to moles by using the compound's molar mass
2.4
⋅
10
−
4
g
⋅
1 mole NaOH
39.997
g
=
6.00
⋅
10
−
6
moles NaOH
You know that the enthalpy of dissolution when
6.00
⋅
10
−
6
moles of sodium hydroxide are dissolved in water, so use this info to find the enthalpy of dissolution when
1
mole of the salt dissolves
1
mole NaOH
⋅
−
63.22 J
6.00
⋅
10
−
6
moles NaOH
=
−
1.054
⋅
10
7
J
Finally, convert this to kilojoules
1.054
⋅
10
7
J
⋅
1 kJ
10
3
J
=
1.054
⋅
10
4
kJ
Therefore, you can say that the enthalpy of dissolution, or molar enthalpy of dissolution, for sodium hydroxide is
Δ
H
diss
=
−
1.1
⋅
10
4
.
kJ mol
−
1
−−−−−−−−−−−−−−−−−−−−−−−−−−−
The answer is rounded to two sig figs, the number fo sig figs you have for the mass of sodium hydroxide.
SIDE NOTE The accepted value for the enthalpy of dissolution of sodium hydroxide in water at
25
∘
C
is
Δ
H
diss
=
−
44.51 kJ
Explanation:
i hope its right
strong acid + weak base salt + water
the type of salt is ?
,..
there are 4 properties of salt
1. The salt of a strong acid and a strong base is neutral
2. The salt of a strong acid and a weak base is acidic
3. The salt of a weak acid and a strong base is basic
4. Salt of a weak acid and a weak base depends on the value of the ionization constant of the acid and base
So the salt from strong acid + weak base is acidic
and salts of strong acids and weak bases (pH<7) or of strong bases and weak acids (pH>7) will be partially hydrolyzed
7. Which agency of the government in the Philippines is monitoring the movement of the earth crust? a. DENR c. DOST b. PAGASA d. PHIVOLCS
Answer:
Is d PHIVOLCS
Explanation:
PHIVOLCS stands for Philippine Institute of Volcanology and Seimology.
This agency monitors the movements of the earth's crust and warns if there is any possibility of disaster such as volcanic, tsunami and earthquake.
what are the steps to measure the density of a solid?
Answer:
Look below
Explanation:
The formula for density is:
[tex]Density=\frac{mass}{volume}[/tex]
Therefore in order to find the density of a solid, you must find the mass and the volume first.
To find the mass, you can use a scale.
To find the volume, you can use the water displacement method. For example, if you fill the water of a graduated cylinder to 10 mL, and then you put a rock inside, and it rises to 15 mL, then the volume (of the rock) is 15mL-10mL=5mL.
Show and explain the stereoisomerism exist in the compound.
(Please answer this i need to submit my assignment before the dateline)
Answer:
There are chiral centers on the molecule thus making it a molecule with stereoisomers.
Explanation:
Stereoisomerism is defined: a form of isomerism in which molecules have the same molecular formula and sequence of bonded atoms (constitution), but differ in the three-dimensional orientations of their atoms in space.
The easiest way to see if this definition is true for any molecule is to see if there are any chiral centers / asymmetric centers. To do this, you would need to look for an sp3 hybridized (tetrahedral) carbon on the molecule with four different groups attached to it. For example, the C in -CH3 would not be a chiral center as there are 3 of the same H's attached to it.
On the given molecule there are 4 chiral centers which makes it a chiral molecule and thus a stereoisomer. Any molecule with one or more chiral centers has stereoisomerism. In this molecule it is easy to see as the chiral centers are the carbons with the wedges and dashes bonded to them indicating the 3D orientation of the constituents. With dashes denoting into page toward the back, and wedges denoting out of the page toward you.
How does refrigeration keep food fresher?
It speeds up reaction rates within stored food.
It slows down reaction rates within stored food.
It causes food molecules to stop vibrating.
Cold air surrounds food and slows the spoiling process.
Answer:
Cold air surrounds food and slows the spoiling process
If 75% of the atoms are in the higher-energy parallel state, how many 21 cm photons are emitted per second by the cloud
Why was the measurement unit for metal content in Experiments 1 and 2 different? In Experiment 1:
To identify why a metal measurement was different in the experiments look for the variable that was different in the experiment and analyze how this change affected the results.
What is an experiment?An experiment is a procedure that aims at probing or discovering something. For example, you can test if a plant grows faster/slower by using an experiment.
What causes different results in similar experiments?The most common cause for this situation is that one of the factors or variables is slightly different. For example, if I add 50mL of water to a plant rather than 20mL of water every day this might cause different results.
Based on this, if the metal content was different you should analyze if any of the factors changed in this experiment and find out how this change affected the general results.
Note: This question is incomplete because there is limited information about the experiment; due to this, I answered it based on general knowledge.
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A. Which number is equal to the number of protons in the atom
What ion causes hardness of water?
Answer:
calcium ions
Explanation:
Water hardness is due to the presence of calcium ions, and to a lesser extent, magnesium, iron, and manganese.
given nitrogen 1 oxide and oxygen how can one differenciate the two
Answer:
Nitrogen has an atomic number of seven, while the atomic number of oxygen is eight. That means nitrogen has seven protons in the nucleus of each atom, as well as seven electrons surrounding the nucleus. Oxygen has eight protons and electrons. Atoms combine with one another to form molecules.
What type of galaxy is the Milky Way?
O elliptical galaxy
O barred-spiral galaxy
O irregular galaxy
O large-clustered galaxy
Answer:
B is the answer
We are in a spiral galaxy but as of late scientists believe we are in a barred-spiral galaxy.
Explanation:
Hope this helped.
A brainliest is always appreciated.
Milky way is a type of barred-spiral galaxy.
What is a galaxy?
A galaxy is defined as a system of stars, stellar remainings, interstellar gas, dust, dark matter, which are bound together by means of gravity.The word is derived from the Greek word which literally means 'milky',as a reference to the Milky Way galaxy which contains the Solar System.
Most of the mass which is present in a galaxy is present in the form of dark matter, out of which only a few percent of the mass
is visible. Supermassive black holes are a common characteristic which are present at the centres of galaxies.
Galaxies are categorized as per their morphology in the shape of elliptical, spiral, or irregular. Many are believed to have supermassive black holes which are present at their centers. The Milky Way's central black hole which is present , also known as Sagittarius A*, has a mass which is four million times greater than the Sun.
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How would you prepare 0.400L of 0.155M Sr(OH)2 from solid Sr(OH)2?
Initially, we will consider only solutions of a solid in ... (d) Calculate the volume (in mL) of 0.1065 M Sr(OH)2 required to titrate 25.00 mL of 0.2465 M.
:
Explanation:
Which statement best describes a physical change? Changes can occur to certain chemical properties of the substance, but the overall shape of the substance will remain the same. Changes can occur to certain physical properties of the substance, but the overall shape of the substance will remain the same. Changes can occur to physical properties of a substance, but the chemical composition of the substance remains the same. Changes can occur to chemical properties of a substance, but the chemical composition of the substance remains the same.2
Ill give you brainliest
Explanation:
A physical change can not change the chemical makeup of a substance. If it did, it would be considered a chemical change. It can, however, be physically changed.
1) What is the atis of 0.367 moles of CaCI?
A) 40.7 g
B) 111 g
C) 0.033 g
D) 246 B
entropy increases when
A. dew forms from water vapor in the air
B. boiling water cools to room temperature
C. sodium chloride crystals dissolve in water
D. hydrogen gas and oxygen gas combine to form liquid water
Answer:
A. dew forms from water vapor in the air
Explanation: As dew formation is spontaneous process, therefore, entropy of the universe will increase.
The solution in a titration experiment whose concentration is
known is called the
a standard solution
b acid
c indicator
d base
Answer: It is indeed A.Standard Solution.
Hope this helps you!
In chemistry, densities of substances are often compared to the density of this substance
Answer:
Density of Water
Explanation:
Al +
O2 -
->
AlO3
Balancing chemical equations
Answer:
Aluminium + Dioxygen = Ruby
Reaction Type
Synthesis
Redox (Oxidation-Reduction) Reaction Beta
Al + O2 = Al2O3 might be a redox reaction.
Reactants
Aluminium - Al
13Al Aluminum Element 13
Dioxygen - O2
Lox O₂ Oxygen Oxygen Gas Liquid Oxygen Triplet Oxygen Diatomic Oxygen Molecular Oxygen O2 Bond Polarity
Products
Ruby - Al2O3
Al2O3 Molar Mass Al2O3 Oxidation Number
Exothermic or Endothermic?
Al(s) 4 mol 0 kJ/mol 0 kJ
O2(g) 3 mol 0 kJ/mol 0 kJ
Al2O3(s) 2 mol -1669.8 kJ/mol -3339.6 kJ
ΔH°rxn -3339.6 kJ
ΣΔH°f(reactants) > ΣΔH°f(products), so the reaction is exothermic.
Explanation:
If 70 mL of a 0.4 M Ba(NO3)2 solution is mixed with excess amount of a Na2CO3 solution, what is the theoretical yield of the precipitate
The theoretical yield of BaCO3 is 5.5
What is theoretical yield?The theoretical yield is the yield calculated from the stoichiometry of the reaction. The equation of the reaction is;
Ba(NO3)2(aq) + Na2CO3 (aq) ------> BaCO3(s) + 2NaNO3(aq)
Number of moles of limiting reactant: 0.4 M × 70/1000 = 0.028 moles
Since the reaction is 1:1,om;y 1 mole of BaCO3 is formed. Hence, mass of BaCO3 = 0.028 moles × 197 g/mol = 5.5g
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what is a forensic paleontologist?
dum it down for me
Answer:
the use of paleontology as a scientific tool
Explanation:
Answer: A forensic paleontologist is a scientist who uses their knowledge of fossils and ancient remains to help solve crimes and investigate mysteries. They apply principles from paleontology, the study of ancient life, to analyze evidence found at crime scenes or archaeological sites.
write the molecular formula for each listed compound:
dinitrogen trioxide & nitrogen monoxide hydrochloric acid & chloric
acid sulfuric acid & sulfurous acid
Answer:
dinitrogen trioxide = N2O3
nitrogen monoxide = NO
hydrochloric acid = HCl
chloric acid = HClO3
sulfuric acid = H2SO4
sulfurous acid = H2SO3
What is the number of protons neutrons and electrons in a family Osito that is used in medical diagnosis atomic number 43 mass number 99 charge of 7+
Answer:
43 protons
36 electrons
56 neutron
Explanation:
neutron is mass number minus proton number.
in a non neutral atom the electron is determined after minusing the charges or electron lost.
the number of proton obviously is 43
How many moles of water are produced from the combustion of 42,0
grams of methane, CH?
CH4+O2 =
CO2 + H2O
[tex]\underline{\underline{\large\bf{Given:-}}}[/tex]
[tex]\red{\leadsto}\:[/tex][tex]\textsf{Amount of Methane,} [/tex][tex]\sf CH_4 = 42\:grams [/tex]
[tex]\underline{\underline{\large\bf{To Find:-}}}[/tex]
[tex]\orange{\leadsto}\:[/tex][tex]\textsf{Moles of water produced from reaction } [/tex][tex]\sf [/tex]
[tex]\\[/tex]
[tex]\underline{\underline{\large\bf{Solution:-}}}\\[/tex]
[tex]\sf Molar \:mass \:of \: CH_4 :- [/tex][tex]\sf \implies 1\times (atomic \: mass \:of \:Carbon )+ 4\times [/tex]
[tex]\sf (atomic\:mass \: of \: hydrogen)[/tex]
[tex]\sf \implies 1 \times 12+ 4\times 1 [/tex]
[tex]\sf \implies 16 grams [/tex]
[tex]\green{ \underline { \boxed{ \sf{Moles \: of \: CH_4= \frac{Amount \:of \: CH_4}{Molar \: mass \: of \:CH_4} }}}}[/tex]
[tex]\begin{gathered}\\\implies\quad \sf \frac{42}{16} \\\end{gathered} [/tex]
[tex]\begin{gathered}\\\implies\quad \sf 2.625 moles \\\end{gathered} [/tex]
The balanced reaction for combustion of methane is-
[tex]\green{ \underline { \boxed{ \sf{CH_4+2O_2 \longrightarrow CO_2+2H_2O}}}}[/tex]
By observation-
[tex]\longrightarrow[/tex]Water produced by 1 mole of methane = 2 moles
[tex]\longrightarrow[/tex]Water produced by 2.625 mole of methane = 2 × 2.625
[tex]\quad\implies[/tex] 5.250 moles
1) (d) Metal M has two isotopes. The table below shows the mass numbers and percentage abundances of the isotopes. Percentage abundance (%) Mass number 30 203 70 205 Calculate the relative atomic mass (A) of metal M. Give your answer to 1 decimal place. Relative atomic mass (1 decimal place) (2) T14
The relative atomic mass of the metal, M is calculated as 204.4amu.
How to calculate relative atomic mass?The relative atomic mass of a isotopic element can be calculated by summing the abundance of each isotope in the element. That is;
(mass no of isotope 1 × % abundance) + (mass no of isotope 2 × % abundance)
According to this question, metal M has two isotopes with the following mass numbers and % abundance:
Isotope 1 = 30%, 203Isotope 2 = 70%, 205(30/100 × 203) + (70/100 × 205)
60.9 + 143.5 = 204.4
Therefore, the relative atomic mass of the metal, M is calculated as 204.4amu.
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Which of the following non-mineral nutrients is only needed in small doses?
potassium
zinc
calcium
nitrogen
Answer:
Explanation:
Nitrogen is a non-mineral
The other 3 are minerals.
So the answer is Nitrogen
Answer:
nitrogen is a non mineral
Calculate the enthalpy of each reaction per
mole of reactant using the formula below, which
also converts joules to kilojoules. Record to 2
significant figures.
ΔH = -q/moles * kj/1000J
Reaction 1: __ kJ/mol
Reaction 2: __ kJ/mol
Answer:
Reaction 1: -450 kJ/mol
Reaction 2: -81 kJ/mol
Explanation:
These were the correct answers on Edge, 2022. Hope it helps!
Answer:
-450 and -81 are correct
Explanation:
edge 2022
2. Give an example of a chemical or physical process that illustrates the law of
conservation of mass.
Answer:
when wood burns
(PLS MARK BRAINLIEST) (hope it helps!)
Explanation: when wood burns, the mass of the soot, ashes, and gases equals the original mass of the charcoal and the oxygen when it first reacted. So the mass of the product equals the mass of the reactant
Identify this molecule:
a) alcohol
b) hydrocarbon
c) carbohydrate
d) lipid
e) amino acid
Answer:
C)
Explanation:
can ubguys help me to answer it
which among the following can be attracted by a magnet, why?
an iron-
a piece of paper
