Answer:
A Variac or Powermite; gradually; 50-60%.
Explanation:
A chemical reaction can be defined as a chemical process which typically involves the transformation or rearrangement of the atomic, ionic or molecular structure of an element through the breakdown and formation of chemical bonds to produce a new compound or substance.
Some of the laboratory apparatus (equipment) used for conducting a chemical reaction are conical flask, Bunsen burner, beaker, tongs, crucible, round bottom flask etc.
In order to heat a round bottom flask in a heating mantle, plug the heating mantle into a Variac or Powermite which is typically used for controlling the level of temperature. Turn the heat up gradually, and do not exceed 50-60% of the maximum output of the device, so as to avoid any electrical issues such as overloading, short-circuit etc.
The safety precautions that must be taken when using a round bottom flask are;
I. A proper inspection of the round bottom flask for cracks, irregularities or any imperfection.
II. Ensure you avoid heating the flask while it is closed.
III. When suspending the round bottom flask on a stand, you should ensure that you use a clamp for stability.
Which of the following is an example of chemical weathering?
plant roots splitting rocks
acid dissolving limestone
water breaking rocks
wind breaking down rock
Answer:
Estoy deprimido y odio la vida. Así que sí
The substance krypton has the following properties normal melting point 115.9 K normal boiling point: 119.8 K triple point: 0.72 atm. 115.8 K critical point: 54.3 atm. 209.4 K A sample of krypton at a pressure of 1.00 atm and a temperature of 149.2 K is cooled at constant pressure to a temperature of 107.8 K Which of the following are true?
a) The final state of the substance is a solid
b) One or more phase changes will occur
c) The final state of the substance is a liquid
d) The sample is initially a gas
e) The solid initially present will vaporize.
Answer:
B. One or more phase change occur
C. the final state of substance is liquid
D. the sample initially gas
Explanation:
The pressure p = 1.00 atm
The temperature t = 149.2K
The temperature > 119.8K
119.8K being the normal boiling point.
This shows that the krypton is a gas
After it has cooled the pressure = 1.00 atm
The temperature T dropped to 107.8K
T < 115.9K
The melting point has been put as 115.9K
This is a liquid. The final state of the substance is a liquid. Since the temperature is less than the melting point and the pressure is 1.00 atm
which of the following is NOT a function of the skeletal system?
A. supports the body
B. gives shape to the body
C. enables the body to move
D. yransports nlood throughout the body
Answer:
A yan hehehehe
salamat puso ma ah
the reaction between potassium metal and water produces potassium hydroxide and hydrogen gas.
the correct equation for this reaction is:
A: K + H2O—> KOH + H2
B: K + H2O—>KOH + H
C: 4K + 3H2O—> 4KOH + 2H
D: 2K + 2 H2O—> 2KOH + H2
Answer:
2K + 2H₂O → 2KOH + H₂
Explanation:
The reactants are:
Potassium metal = K
Water = H₂O
The products are:
Potassium hydroxide = KOH
Hydrogen gas = H₂
The reaction equation is given as;
Reactants → Products
2K + 2H₂O → 2KOH + H₂
The reaction is a single displacement reaction
Zack and Frankie were planning a game of flashlight tag on both Friday and Saturday night.
Answer:
oKaY?!
Explanation:
Naturally occurring silicon consists of three isotopes with the following isotopic masses and abundances. Isotope Isotopic mass (u) Abundance (%) 2828 Si 27.976926532727.9769265327 92.229792.2297 2929 Si 28.9764947228.97649472 4.68324.6832 3030 Si 29.9737702229.97377022 3.08723.0872 Calculate the average atomic mass of naturally occurring silicon to at least four significant figures.
The question is incomplete, the complete question is;
Silicon has three naturally occurring isotopes with thefollowing masses and natural abundances:
Isotope Mass ({\rm amu}) Abundance (%)
{\rm Si}-28 27.9769 92.2
{\rm Si}-29 28.9765 4.67
{\rm Si}-30 29.9737 3.10
Calculate the atomic mass of silicon.
Answer:
28.09 amu (to four significant figures)
Explanation:
Given that;
Isotope Mass Abundance (%)
Si-28 27.9769 92.2
Si-29 28.9765 4.67
Si-30 29.9737 3.10
So we now have;
Relative atomic mass of silicon;
(27.9769 × 0.9218) + (28.9765 × 0.0471) + (29.9738 × 0.0312)
25.789 + 1.365 + 0.9351 = 28.09 amu (to four significant figures)
Which statement describes a change that occurs during a chemical reaction?
OA. The atoms in a substance start to move faster until they are no longer touching each other.
OB.
Atoms in the original substances are arranged in a different way to make new substances
OC!
The atoms in a substance change their properties so they can become a new substance.
OD.
Atoms in the original substances are changed into different atoms to make new substances,
Answer - B Atoms in the original substances are arranged in a different way to make new substances
6- A favorable condition for two elements to form an ionic bond is?
a- both should be electronegative
b- one should have low electron affinity and the other low ionization energy.
C- one should have high electron affinity and the other low ionization energy.
d- both should be highly electronegative
Answer: C- one should have high electron affinity and the other low ionization energy.
Explanation:
Ionization energy is the energy required to remove the electron from an isolated gaseous atom.
Electron affinity is the tendency of an isolated atom to attrcat the electrons towards itsellf.
An ionic bond is formed when an element completely transfers its valence electron to another element. The element which donates the electron is known as electropositive element or the metal and it can donate electron easily if it has low ionization energy.
The element which accepts the electrons is known as electronegative element or non metal and it can easily accept the electron if it has high electron affinity.
Which macromolecules break apart by hydrolysis?
Answer:
Dehydration synthesis reactions build molecules up and generally require energy, while hydrolysis reactions break molecules down and generally release energy. Carbohydrates, proteins, and nucleic acids are built up and broken down via these types of reactions, although the monomers involved are different in each case.
Explanation:
1)
If I have 45 liters of helium in a balloon at 25°C and increase the
temperature of the balloon to 55° C, what will the new volume of the
balloon be?
Answer:
52.8 Liters
Explanation:
Gay-Lussacs law states that P1/T1 = P2/T2
if:
P1 = 45T1 (in Kelvins) = 25 + 273.1 =298.1P2= ?T2 = 55 + 273.1 = 328.1then:
45/298.1 = P2/328.1
P2 = 52.8
The new volume of the balloon is 52.8 Liters this can be calculated by using gas laws.
Charles law:Charles law states the volume occupied by a fixed amount of gas is directly proportional to its absolute temperature. It is given by
V₁/T₁ = V₂/T₂
What information do we have?
V₁ = 45 L
T₁ = 25 + 273.1 =298.1 K
T₂ = 55 + 273.1 = 328.1 K
To find:
V₂= ?
On substituting the values:
45/298.1 = V₂/328.1
V₂ = 52.8 L
Thus, the volume of the balloon is 52.8 liters.
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How does the structure of gills in a fish enable it to live in a watery environment?
A. The gills allow the fish to take in carbon dioxide from the water.
B. The lungs of the fish are made up of tiny air sacs.
C. The gills allow the fish to take in oxygen from the water.
D. The villi absorb oxygen into the bloodstream.
Answer:
C. The gills allow the fish to take in oxygen from the water.
In the reaction shown below, cobalt ...
Co(s) + Ni (C2H302)2(aq) → Co(C2H302)2(aq) + Ni(s)
A) gains electrons and is reduced
B) loses electrons and is oxidised
C) loses electrons and is reduced
D) gains electrons and is oxidised
B) loses electrons and is oxidised
Its oxidation number is 0 in Co(s) and +2 in Co(C2H302)2(aq), hence it gets oxidised
In the reaction as mentioned below:-
[tex]Co(s) + Ni(C2H302)2aq -- > Co(C2H3O2)2aq + Ni(s)[/tex]
As shown in reaction cobalt losses elections so the reaction is oxidised. Thus, option b is correct.
What is oxidation?Oxidation is a type of reaction in which loss of electrons and gain of protons is takes place during a reaction by molecules, atom or ion. Oxidation takes place when the oxidation state of a molecule, atoms or ion is increased.
The opposite reaction is called as reduction in which gains of electron and loss of protons is takes place . In reduction reaction the oxidation state of molecules, atoms or ion is decreased.
Oxygen has been added to a compound as an older method of oxidation. Although oxygen is typically added to a compound in compliance with the loss of electrons requirements and the oxidation state increase.
Therefore, we can say that in the reaction
[tex]Co(s) + Ni(C2H302)2aq -- > Co(C2H3O2)2aq + Ni(s)[/tex]
As shown in reaction cobalt losses elections so the reaction is oxidised. Thus, option b is correct.
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What is the mass, in grams, of a pure iron cube that has a volume of 3.80 cm?
Answer:
2.66 g of Fe, can be obtained from the reaction
Explanation:
Let's think the reaction:
2Fe₂O₃ + 6CO → 4Fe + 6CO₂
Ratio is 2:4, so If i have x moles of iron (III) oxide, I will produce the double of moles of Fe.
Mass / Molar mass = Mol
3.80 g / 159.7 g/m = 0.0237 moles
0.0237 moles . 2 = 0.0475 moles
Molar mass Fe = 55.85 g/m
Mol . Molar mass = Mass → 0.0475 m . 55.85 g/m = 2.66 grams
Explanation:
Directions: Select the words that make the sentence a true statement Below is a food web showing the flow of energy through a marine ecosystem marine mammals tuna fish aquida craba zooplankton amall fishes doad animal material 3 phytoplankton In this ecosystem are considered predators and are their prey
Answer: in this ecosystem tuna fish are considered predators and small fishes are their prey.
Explanation: This is just an easy smart guess why? because the Tuna fish(predator) eat the small fishes(prey) as if what it looks like in the chart.
Im not sure about this question but i hope this helps
Answer:
in this ecosystem tuna fish are considered predators and small fishes are their prey.
Explanation:
The currently accepted model of the atom includes an electron cloud.
A. True
B. False
Answer:
True
Explanation:
Answer: True
Explanation:
PLSS HELP ME
Think critically, explain why some fronts produce stronger storms than others. GIVE 2 EVIDENCES PLSSS.
I WILL GIVE YOU BRAINLIEST
How can a chemical reaction speed up? Pack in more of the reactant to increase the
A. catalyst B. concentration
C. surface area
D. temperature
Answer:
A. catalyst.
Explanation:
Catalyst is something that causes things to decay. I think catalyst is the right answer from what i know from Miraculous Ladybug... Did you know the show was originally going to be an anime?
[2071]State and explain Kohlrusch's law.
(2071]Why does the specific conductance decreases and equivalent conductance increase
with dilution of a solution of electrolyte?
ito unit How does it Vary with dilution?
1101
PLEASE HELP PLEASE HELP PLEASE HELP PLEASE HELP PLEASE HELP PLEASE HELP PLEASE HELP PLEASE HELP PLEASE HELP PLEASE HELP PLEASE HELP PLEASE HELP!!!
DUE IN 5 MINUTES
TRUE OR FALSE? CHEMISTRY PLEASE ONLY ANSWER IF YOU’RE 100% SURE!!
Answer:
true mark me brainlist
Explanation:
For each trial, enter the amount of heat lost by the metal, qmetal.
Hint: The specific heat of water is 4.184 J/goC. Be careful of your algebraic sign here and remember that the change in temperature is equal to the final temperature minus the initial temperature. Your answer should be reported to 4 digits.
Note: You should always carry 1 or 2 extra digits beyond the number of significant figures until your final calculation.
Trial # MASS Metal Ti metal Mass cool water Ti water Tr q metal
#1: 183.428 101.2 70.001 24.2 38.2
#2: 183.430 101.0 70.008 24.0 37.8
#3 183.430 100.7 70.271 23.2 36.6
Answer:
Trial 1: Heat lost by the metal = -4100 J
Trial 2: Heat lost by the metal = -4042 J
Trial 3: Heat lost by the metal = -3940 J
Explanation:
Assuming that all of the heat lost by the metal is transferred to the water and no heat is lost to the surroundings; Heat lost by metal = heat gained by water. Qmetal = -Qwater
Note: If the experiment was carried out in a calorimeter of known heat capacity, some heat is lost to the calorimeter.
Hence, Qmetal = -(Qwater + Qcalorimeter)
Quantity of heat, q = mass * specific heat capacity * temperature change
Trial 1
mass of water = 70.001 g
specific heat capacity of water = 4.184 J/g/°C
Initial temperature of water = 24.2 °C
final temperature of mixture = 38.2 °C
Temperature change of water = 38.2 - 24.2 = 14.0 °C
Heat gained by water = -(70.001 * 4.184 * 14.0) = -4100 J
Therefore, heat lost by the metal = -4100 J
Trial 2
mass of water = 70.008 g
specific heat capacity of water = 4.184 J/g/°C
Initial temperature of water = 24.0 °C
final temperature of mixture = 37.8 °C
Temperature change of water = 37.8 - 24.0 = 13.8 °C
Heat gained by water = -(70.008 * 4.184 * 13.8) = -4042 J
Therefore, heat lost by the metal = -4042 J
Trial 3
mass of water = 70.271 g
specific heat capacity of water = 4.184 J/g/°C
Initial temperature of water = 23.2 °C
final temperature of mixture = 36.6 °C
Temperature change of water = 36.6 - 23.2 = 13.4 °C
Heat gained by water = -(70.271 * 4.184 * 13.4) = -3940 J
Therefore, heat lost by the metal = -3940 J
4. What are the freezing and boiling points of water on the Fahrenheit scale? On the
Celsius scale?
If a wave is traveling at 36 m/s and has a frequency of 6 Hz, what is its wavelength?
Answer:
wave length=speed*frequency
=36*6
=216 m
What is CaF2(aq) + Rb
Answer:
RbF2 + Ca
Explanation:
Since Rb is located in IIA as well as Ca, Rb has ion form Rb2+
Hence CaF2 + Rb → RbF2 +Ca
Please be reminded, this answer may not be 100% correct
Sodium chloride (NaCl) is an ionic compound. We can effectively model it as sodium atoms with one electron removed next to chlorine atoms with one electron added. The attractive force between the positive and negative charges holds the crystal together. If we model the sodium and chlorine ions as point charges separated by 0.28 nm, the spacing in the crystal, what is the magnitude of the attractive force between two adjacent ions
Answer:
The attractive force between the sodium and chloride ions has a magnitude of -2.94 x 10⁻⁹ N
Explanation:
An electron is a negatively-charged particle. The charge on an electron is -1.6 x 10⁻¹⁹ C. This is also known as the fundamental unit of charge, e. A proton has the same charge as as electron but its charge is positive.
The charge on the chloride ion is negative and is due to an electron whereas the charge on the sodium ion is positive and is due to a proton.
The magnitude of the force of attraction between two charges is given by the Coulomb's law: F = Kq₁q₂/r²
where K is a constant = 9 x 10⁹ N.m₂.C⁻², q₁ = -1.6 x 10⁻¹⁹ C, q₂ = +1.6 x 10⁻¹⁹ C, r = 0.28 nm = 0.28 x 10⁻⁹ m
F = {(9 x 10⁹ N.m₂.C⁻²) (-1.6 x 10⁻¹⁹ C) (+1.6 x 10⁻¹⁹ C)} / (0.28 x 10⁻⁹ m)²
F = -2.94 x 10⁻⁹ N
Therefore, the attractive force between the sodium and chloride ions has a magnitude of -2.94 x 10⁻⁹ N
Which chemical used to make explosives is a fertilizer-based explosive, but requires nitric acid as a component to be an explosive compound, and has a wide range of uses, including as a noncorrosive de-icing material for sidewalks?
a. Aluminum nitrate
b. Triacetone triperoxide (TATP)
c. Hexamethylene triperoxide diamine (HMTD)
d. Urea nitrate
Answer:
d. Urea nitrate
Explanation:
Urea nitrate is a fertilizer-based explosive that is produced in one step by reaction of urea with nitric acid. The is an exothermic reaction, therefore, necessary steps and precautions must be taken to ensure safety during the process. The equation of the reaction is given below:
(NH₂)₂CO (aq) + HNO₃ (aq) → (NH₂)₂COHNO₃ (s)
It is as easily-made explosive and can also be used as a catalyst in Diels-Alder reactions of aromatic amines.
In the presence of water, urea nitrate readily decomposes to its original components, urea and nitric acid.
On its own, urea is commonly used as a deicer for sidewalks as it is a noncorrosive de-icing material. However, it is a more costly method of deicing, compared to other methods and it is best used where water runs off into vegetation than into a water-body or a storm drain because of its high-oxygen demand which could result in its reducing the oxygen level of the water body. It It is readily found in nature (in our urine) and is also synthesized artificially. It has a very high nitrogen content, and is most often used as a nitrogen‐based fertilizer.
How many grams of iron are needed to produce 3 g of iron(III) chloride?
Answer:
5 its just what i do
Explanation:
A 50.0mL flask filled with a solution of hydrogen peroxide has a total mass of 88.5 g. The mass of the flask is 16.5 g. The density of the hydrogen peroxide solution is
Answer:
1.44 g/mL
Explanation:
total mass is mass of the flask plus mass of the solution
TM = Flask + H2O2
88.5 = 16.5 + x
x = 72.0 gram
density = mass/volume
H2O2 density = 72/50
= 1.44 g/mL
Explain the difference between atom and element
Answer:
an atom is the smallest part of an element that has the properties of that element
it can't be broken further into smaller substances
an element is the simplest chemical
it consists of one type of atoms
so you can consider atoms as the building block of an element
What do scientists think is the
reason the mollusks have been so
successful through time?
B
Answer: Body plans change as new challenges arise.
Explanation:
The mollusks are the invertebrate animals. They live marine environment. They live in shallow waters. They have been found in variety of marine habitats so this indicates their adaptiveness to different conditions. They have body plan that comprises of shell, mantle, radula and muscular foot that helps in survival and adaptation in different conditions. The shell and mantle are hard structures which protect these animals from predators and also help them to camouflage. Also the muscular foot helps in locomotion. Radula helps in feeding. Oysters, snails are some examples of mollusks.
What is the relationship between the mass of the boat and the mass of the displaced
liquid?
The mass of the boat is equal to the mass of the liquid which is displaced by placing the boat in the liquid.
What is Archimedes' Principle?
Archimedes' Principle states that the buoyant force of the object is equal to the weight of the water which is displaced by the boat. If the weight of the water that is displaced by the boat is less than that of the weight of the boat, then in this case the boat sinks. Archimedes' principle or the buoyant force is very useful for the calculation of the volume of an object that does not have a regular shape.
The mass of the displaced liquid is always equal to the volume of the liquid multiplied by the density of the fluid. When a boat is placed in the water, the volume of displaced water is equal to the mass of the boat which is placed in it.
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