Calculate the mass of NaOH
required to prepare a 0.343M
solution dissolved in 2500mL
of water.
Answer:
will this work or help?
Explanation:
Calculate the mass of NaOH required to prepare a 0.343 M solution dissolved in 2500 mL of water. 0.343 M = x mol / 2.5 L = 0.86 mol 0.86.
I have a flask filled with water and on top a stopper .
I heat it over a flame .
after some time what will happen to the stopper
Answer:
A vacuum flask (also known as a Dewar flask, Dewar bottle or thermos) is an insulating storage vessel that greatly lengthens the time over which its contents remain hotter or cooler than the flask's surroundings. Invented by Sir James Dewar in 1892, the vacuum flask consists of two flasks, placed one within the other and joined at the neck. The gap between the two flasks is partially evacuated of air, creating a near-vacuum which significantly reduces heat transfer by conduction or convection.

The typical design of a Thermos brand vacuum flask, used for maintaining the temperature of fluids such as coffee.

Laboratory Dewar flask, Deutsches Museum, Munich

Diagram of a vacuum flask

A cryogenic storage dewar of liquid nitrogen, used to supply a cryogenic freezer
Vacuum flasks are used domestically, to keep beverages hot or cold for extended periods of time, and for many purposes in industry.
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What is the molarity of 15.0 milliliters of an unknown acid that is titrated
with a 1.25 M NaOH solution and required 24.65 milliliters of base to
complete the titration?
Answer:
~2.054M
Explanation:
In this question ,I am going to assume that the acid is monoprotic acid(contains only one hydrogen) which I'll represent by HA.
Chemical equation:
NaOH(aq) + HA(aq)----->NaA(aq) + H2O(l)
The mole ratio of NaOH:HA is 1:1
1.25M NaOH=1.25 Moles/L or 1.25 moles /1000ml of NaOH
(1.25 moles /1000ml) x (24.65ml)=0.0308125 moles NaOH
Mole ratio is 1:1
So, moles of HA are also 0.0308125 moles
volume of HA =15ml
To find molarity of HA:
=(0.0308125 moles x 1000ml)/(15ml)
~2.054M of HA
~Hope it helps:)
MgCl2 + NaOH → Mg(OH)2 +Naci
Balance
A sample of river wayer contains 125mg per dm^3 of dissolved soilds. Calculate the mass of dissolved soilds in grams in 250 cm^3 of this sample of river water. Giver your answer to 2 significant figures (4 marks)
I will give brainilist to anyone who answers
The mass of a substance is the product of its density and volume. Thus, the mass of the dissolved solids with a density of 125 mg/dm³ with a volume of 250 cm³ is 31.25 mg.
What is density?Density of a substance is the measure of its mass per unit volume. Thus it describes how much denser the substance is in a given volume. Mathematically it is the ratio of mass to the volume.
Density of a substance depends on the mass, volume, bond type, temperature and pressure. The ratio of density of a substance with the density of water is called its specific gravity.
It is given that the density of the dissolved solids is 125 mg/dm³ and the volume is 250 cm³ or 0.25 dm³. Thus the mass can be calculated as follows:
density = mass/volume
mass = density × volume
= 0.25 dm³ × 125 mg/dm³
= 31.25 mg
Hence, the mass of the dissolved solids in the river wayer is 31.25 M=mg.
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Which of the following elements has the lowest electron affinity?
a. Si
b. F
c. Cl
d. K
Answer:
k
Explanation:
electron affinity (EA) depends on various factors like effective nuclear charge (enc) , size of the atom, ellipticity of sub-shell (ep) , nature of configuration.
more is the enc more will be the EA
more is the size less will be the EA
more valance shell ellipticity (closer to the nuclei) more will the EA ( all given element posses P orbital in the valance shell)
20 mL of hydrogen measured at 15° C is heated to 35°C.
What is the new volume at the same pressure?
V2 = 21.4 ml
Explanation:
Note: When dealing with gases, make sure that you change the units from °C to K.
T1 = 15°C + 273 = 288K
T2 = 35°C + 273 = 308K
V1 = 20 ml
V2 = ?
We use Charles's law to solve V2:
V1/T1 = V2/T2
or
V2 = (T2/T1)V1
= (308K/288K)(20 ml)
= 21.4 ml
HELP ASAP PLEASE CHEMISTRY
The rate of reaction was measured during a chemical reaction. After the first 3 seconds, the rate of reaction was 1.8 x10−6 M/s. Which of the following would you expect after another 3 seconds?
The rate would be lower, and the concentration of products would be higher.
The rate would be lower, and the concentration of products would be lower.
The rate would be higher, and the concentration of products would be higher.
The rate would be higher, and the concentration of products would be lower.
Answer:
The rate would be higher, and the concentration of products would be lower.
Explanation:
The correct answer is The rate would be lower, and the concentration of products would be higher.
The rate of reaction refers to the speed with which reactants are converted into products.
The rate of reaction decreases as the reaction progresses because more reactants are being converted into products.
As such, the reactant concentration decreases and the concentration of products increases.
Hence, after three seconds, the rate would be lower, and the concentration of products would be higher.
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What is the pH of 0.0000043M HNO3 ? (3 sig figs, round the last digit only if needed)
Answer:
pH = 5.37
Explanation:
We'll begin by obtaining the concentration of the hydrogen ion in the solution. This can be obtained as follow:
HNO₃ (aq) —> H⁺ (aq) + NO₃¯ (aq)
From the balanced equation above,
1 mole of HNO₃ produced 1 mole of H⁺.
Therefore, 4.3×10¯⁶ M HNO₃ will also produce 4.3×10¯⁶ M H⁺.
Finally, we shall determine the pH of the solution. This can be obtained as follow:
Concentration of Hydrogen ion [H⁺] = 4.3×10¯⁶ M
pH =?
pH = –Log [H⁺]
pH = –Log 4.3×10¯⁶
pH = 5.37
Therefore, the pH of the solution is 5.37
Whilst Et₃CCl is unreactive towards water even at elevated temperatures, Et₃SiCl is hydrolyzed rapidly. Explain the origin of these differences and provide a reaction scheme with mechanistic details for the hydrolysis of Et₃SiCl.
Answer:
See Explanation
Explanation:
In discussing the reason why Et₃SiCl is more easily hydrolysed than Et₃CCl, we must remember that the electronegativity difference between silicon and chlorine is much higher than the electronegativity difference between carbon and chlorine.
As a result of this, the Si-Cl bond in Et₃SiCl is more polar and hence susceptible to attack by water than the C-Cl bond in Et₃CCl.
Also, it is postulated that the presence of vacant d orbitals on silicon assists hydrolysis in Et₃SiCl. Such vacant orbitals are absent in carbon hence Et₃CCl does not undergo hydrolysis.
The reaction scheme is shown in the image attached to this answer.
You have a block of wood with a mass of 700 grams and a volume of 1100 cm.
What is the density of wood?
In a neutral solution, the concentration of H+ is
Group of answer choices
Answer:
equal to [OH-]
Hydrogen ion concentration is more conveniently expressed as pH, which is the logarithm of the reciprocal of the hydrogen ion concentration in gram moles per liter. Thus, in a neutral solution the hydrogen ion (H+) and the hydroxyl ion (OH−)
Juan Carlos placed 35 grams of ice into a dry, 200-gram container. The top
of the container was attached tightly. When the ice was completely melted, the
student measured the mass of the container with the liquid water. What should the
mass of the liquid water in the container be?
A. 35 grams
B. 165 grams
C. 200 grams
D. 235 grams
Mass of the liquid water in the container is 35 grams-
Mass doesn't depends upon the state of compounds.The mass of the liquid water in the container should be 35 grams.
Mass would not change during a change of state because the number of particles does not change during a state change. It does not matter if a substances freezes, boils, melts, sublimates.
So, the mass of liquid water in the container is the same as ice. Hence, the correct option is (A).
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which of the following does not contain a covalent bond ( please answer asap!! )
Answer:
Option 4
Explanation:
Fusion reactions power the _____ in space. Humans currently use fusion in _____ , but researchers are seeking more applications.
Answer:
Sun and the stars, nothing humans don't use fusion at all
Explanation:
Nuclear fusion reactions power the sun in space. Humans currently use fusion in nuclear weapons by means of nuclear reactions, but researchers are seeking more applications.
What are nuclear reactions?There are two types of nuclear reactions which are nuclear fusion and nuclear fission .They involve the combination and disintegration of the element's nucleus respectively.
In nuclear fission, the nucleus of the atom is bombarded with electrons of low energy which splits the nucleus in to two parts .Large amount of energy is released in the process.It is used in nuclear power reactors as it produces large amount of energy.
In nuclear fusion,on the other hand, is a reaction which occurs when two or more atoms combine to form a heavy nucleus.Large amount of energy is released in the process which is greater than that of the energy which is released in nuclear fission process.
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Water flows more easily than syrup, which means water has
A. higher viscosity than syrup
B. lower viscosity than syrup
C. equal viscosity to syrup
Answer:
lower viscosity than syrup
Answer:
higher viscosity than syrup flows more easily than syrup.
Please give me Brainliest answer
What volume of 15.9 M Nitric acid would be required to make 7.2 L of 6.00 M nitric acid? (hint: dilution problem) will mark brainliest if correct
a. 2.72 L
b. 686.88 L
c. .075 L
d. 272
Answer:
d
Explanation:
Perform the following
mathematical operation, and
report the answer to the
appropriate number of
significant figures.
4.7257 - 3.12 = [?]
Answer:
1.61
Explanation:
I got this answer from a calculator and it's correct.
Tides are the rise and fall of surface levels of Earth's ocean water caused by the gravitational effects of which two celestial objects?
A)stars and planets
B)comets and meteors
C)earthquakes and volcanoes
D)moon and sun
Answer:
D)Moon and sunExplanation:
Because the gravitational pull of the moon is weaker on the far side of the Earth, inertia wins, the ocean bulges out and high tide occurs.
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Which statement about hydrocarbons is FALSE?
a
The number one use of hydrocarbons is as a fuel
source.
b
Most hydrocarbons we use today come from
sustainable, renewable sources.
с
Hydrocarbons are useful in industries from
transportation to road work to cosmetics.
d
The bulk of hydrocarbons we use today were
formed hundreds of millions of years ago.
Answer:
b
Explanation:
Hydrocarbons provide 84% of the world's energy, but they are non-renewable. Hydrocarbons are the most economic form of energy.
The diagram shows genetic structures.
Which label best represents the area marked Y?
chromosome
protein
gene
DNA
Answer:
The correct answer is - DNA (check image).
Explanation:
In this diagram, The W mark is the nucleus of the cell X is the chromosome Y represents the DNA and Z is the gene. Gene is the segment of the DNA and DNA is the pat of the chromosome with histone. Chromosomes are present in the nucleus of the cell. These all are the structures of the genetic structures.
Thus, the correct answer is - DNA.
Answer:
dna
Explanation:
edge
Al aumentar la temperatura ¿Cómo varía la presión?
Answer:
california y nueva york
Explanation:
Answer:
las partículas se mueven más rápido, y por lo tanto tienen mayor velocidad, por lo tanto mayor impulso y por lo tanto mayor fuerza cuando chocan con las paredes, por lo que la presión aumenta.
Explanation:
Which is true for a substance that releases energy?
OA. The energy release decreases the molecular motion and the kinetic energy of the substance.
B. The energy release decreases the molecular motion but increases the kinetic energy of the substance.
C. The energy release increases the molecular motion and the kinetic energy of the substance.
D. The energy release increases the molecular motion but decreases the kinetic energy of the substance.
E. The energy release is used only to change the state of the substance.
Please help this will determine my grade so I beg help me out and my grade
Answer:
C: checking your email
Explanation:
I believe that C would be impossible, as you cannot use wireless networks without radio waves
18. How many grams are in 563 mL of chlorine gas at STP?
Answer:
[tex]at \: stp : \\ 22400 \: ml \: are \: occupied \: by \: 71 \: g \: of \: chlorine \\ 563 \: ml \: will \: be \: occupied \: by \: ( \frac{563}{22400} \times 71) \:g \\ = 1.78 \: g[/tex]
6.
An element with high conductivity would be found in which
category?
Alkaline earth metals
transition metals
Group 1 metal
Alkali metals
***Why would you not pick the others?
what is non polar covalent bond
Answer:
It is formed between two atoms of the same elements having same electronegativity in which the bonding electrons are equally shared between them. In this case, the centre of the positive charge coincides with the centre of the negative charge in theecular molecule. H, N: 0. etc. are the molecules in which non polar covalent bonds invalved. These substances are called non polar substances.
Answer:
A nonpolar covalent bond is a covalent bond in which the bonding electrons are shared equally between the two atoms. In a nonpolar covalent bond, the distribution of electrical charge is balanced between the two atoms.
Explanation:
Circle the solution with the highest concentration
a. 5.0M
c. 0.6M
b. 1.0M
d. 0.75M
Answer:
answer is option a..............
I’m brain dead, anyone know this shi
Answer:
Option 1
Explanation:
p can hold upto 6 e-.
It would be easy if it gains 2e-, instead of losing 4e-, to be stable.
It gains 2e, and gets a charge of - 2e.
It forms O (2-)
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How many moles are there in 993.6 grams of potassium sulfate (K2SO4)?
Answer:
5.702 mol K₂SO₄
General Formulas and Concepts:
Atomic Structure
Reading a Periodic TableCompoundsMolesStoichiometry
Using Dimensional AnalysisExplanation:
Step 1: Define
[Given] 993.6 g K₂SO₄
[Solve] moles K₂SO₄
Step 2: Identify Conversions
[PT] Molar Mass of K: 39.10 g/mol
[PT] Molar Mass of S: 32.07 g/mol
[PT] Molar mass of O: 16.00 g/mol
Molar Mass of K₂SO₄: 2(39.10) + 32.07 + 4(16.00) = 174.27 g/mol
Step 3: Convert
[DA] Set up: [tex]\displaystyle 993.6 \ g \ K_2SO_4(\frac{1 \ mol \ K_2SO_4}{174.27 \ g \ K_2SO_4})[/tex][DA] Divide [Cancel out units]: [tex]\displaystyle 5.7015 \ mol \ K_2SO_4[/tex]Step 4: Check
Follow sig fig rules and round. We are given 4 sig figs.
5.7015 mol K₂SO₄ ≈ 5.702 mol K₂SO₄