Al wonders if adding salt to water will affect how long it takes the water to
freeze. Al thinks that salt water will freeze more quickly than fresh water.
He decides to check his hypothesis by conducting an experiment. Al takes
two ice trays and fills one with distilled water and the other with distilled
water that has two tablespoons of salt added. He makes sure he puts
exactly the same amount of water in each ice tray. Al takes the trays and
puts them side by side in the freezer. Al checks the ice trays every 10
minutes to see if the water in each tray has begun to freeze. Al finds that
after 20 minutes the water in the ice tray without the salt has started to
form ice, while the ice tray with the salt water is still completely liquid.
Ku
Answers
The hypothesis is that salt water freezes faster than fresh water.
The dependent variable is time taken for ice to appear.
The independent variable is presence or absence of salt
The constants are the amount of water in each tray, freezing conditions and length of time of exposure to freezing condition.
The control group is the tray to which salt was not added
The experimental group is the tray to which salt was added
The presence of solutes in a solution causes the freezing point depression.
A solution is made up of a solute and a solvent. In the presence of a solute, the freezing point of a pure solvent is decreased. This is because freezing point is a colligative property.
Colligative properties depend on the amount of solute present.
Hence, the pure water freezes faster (ice begin to appear earlier) than the salt water.
The hypothesis put forward in this experiment was found to be invalid by the experiment.
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Related Questions
Determine the grams of sodium chloride produced when 10 g of sodium react with 10 grams chlorine gas according to the equation 2Na + Cl2 = 2 NaCl
Answers
Answer:
16 g
Explanation:
Step 1: Write the balanced equation
2 Na + Cl₂ ⇒ 2 NaCl
Step 2: Identify the limiting reactant
The theoretical mass ratio (TMR) of Na to Cl₂ is 46:71 = 0.65:1.
The experimental mass ratio (EMR) of Na to Cl₂ is 10:10 = 1:1.
Since EMR > TMR, Cl₂ is the limiting reactant
Step 3: Calculate the mass of NaCl produced
The theoretical mass ratio of Cl₂ to NaCl is 71:117.
10 g Cl₂ × 117 g NaCl/71 g Cl₂ = 16 g NaCl
the overall take away of an experiment’s results is the______. A. hypothesis B. introduction C. conclusion
Answers
Answer:
conclusion
Explanation:
it can't be a hypothesis since tests are carried out to verify so it is not a theory
an introduction to an experiment only gives the basis of what we are investigating therefore nothing has been proven and the question is still unanswered
The overall takeaway of an experiment’s results is the conclusion. Hence, option C is correct.
What is a hypothesis?A hypothesis is a testable statement about the relationship between two or more variables or a proposed explanation for some observed experiment.
The overall takeaway of an experiment’s results can't be a hypothesis since tests are carried out to verify so it is not a theory
An experiment only gives an idea about the investigation therefore nothing has been proven and the question is still unanswered.
Hence, the overall takeaway of an experiment’s results is the conclusion.
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balance this equation
Si Cl4 + H2O → Si (OH4) + HCl
Please give a detailed explanation
Answers
Answer:
4HCl + SiO2 → 4H2O + SiCl4
axit clohidric Silic dioxit nước Silic tetraclorua
Axit
Explanation:
Answer:
SiCl4 + 4H2O--->Si(OH4)+4HCl
Explanation:
if you put a 4 in front of H2O it means you will have 8 hydrogens(you multiply 4 by 2) then the oxygens will be 4..on the other side that hydrogen in the brackets holds it's on 4 so that 4 isn't for both the hydrogen and the oxygen...and if you put a 4 in front of the HCl that simply means it's for both the hydrogen and oxygen.
I hope this helps
The table describes how some substances were formed.
Substance
P.
Q
Description
Formed by boiling pure water
Formed by combining three hydrogen atoms to every nitrogen atom
Formed by adding 5 g of sugar to 1 L of water
Formed by compressing carbon under high pressure
R
S
Based on the given descriptions, which substance is most likely a mixture?
P
Q
R
S
Answers
Explanation:
Which is a pure substance?
1. soda
2. gasoline
3. salt water
4. carbon dioxide
carbon dioxide
Bromine, a liquid at room temperature, has a boiling point of 58°C and a melting point of -7.2°C. Bromine can be classified as a
1. compound.
2. impure substance.
3. mixture.
4. pure substance.
pure substance.
Answer:
the answer is
Explanation:
Sugar and water make a homogeneous mixture (the same proportions of its components throughout any given sample).
. Fire can be extinguished by: - a. Lowering temperature below ignition temperature b. Cutting the supply of oxygen c. Removing non-combustible substances from surroundings d. Both a & b
Answers
Answer:
B. Cutting the supplies of oxygen
which property is a physical property
Answers
Answer:
a
Explanation:
because it is matter . It has change in molèculaŕ level
In an electrochemical cell, equilibrium is the point at which:
A. None of these
B. both electrodes have an equal number of electrons.
C. ion concentrations are no longer changing and the voltage is 0.
D. Equilibrium cannot be reached in a voltaic cell because electrons only flow in one direction.
Answers
Answer:
C. ion concentrations are no longer changing and the voltage is 0.
Explanation:
Electrochemical cells are a device that generates current from redox reactions. In the cell, the equilibrium is reached when the voltage drops to 0. Thus, option C is correct.
What is an electrochemical cell?An electrochemical cell is a voltaic device that uses chemical energy to generate electrical energy and vice versa. It is of two types electrolytic and galvanic cells depending on the energy it produces.
The electrochemical cell comprises two electrodes namely an anode and cathode, a salt bridge or the porous barrier, and an external connection.
The connection shows the voltage that indicates the equilibrium. When the current flow stops and the voltage reaches zero, the electrochemical cell is said to be in equilibrium.
Therefore, no change in the ionic concentrations and zero voltage indicates equilibrium.
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What type of reaction is shown below:
Ethanoic acid + propanol -> propyl ethanoate + water
A. Polymerization
B. Addition (water)
C. Elimination
D. Esterification
Answers
Answer:
c
Explanation:
because mix with propanol
A which statements contain conclusions?
B. Which statements refer to research?
C. Which statement contains a shypothesis?
D. Which statements contain observations?
E. Which statements describe an experinera?
F. Which statement supports the hypothesis?
G. In which statement is the problemi delined?
H. Which statement contain date?
I. Which is the variable in the experiment?
J. What is the control in the experiment?
K. Bhich statement includes an inference?
Answers
G. In which statement is the problemi delined?
differences between properties of convalent and ionic bond.
Answers
Ionic bonds will be a metal + a nonmetal, and electrons
are transferred from the metal to the nonmetal.
A covalent bond will be a nonmetal only. Nonmetals will not give up their electrons so electrons are shared.
I have also written this on the whiteboard in the image provided.
oxidation number of Fe in Fe2(CO3)2
Answers
Answer:
+2
Explanation:
Oxidation number of an element, also called its oxidation state, is the number of electrons its atoms lost or gain in the process of forming a chemical compound.
To determine the oxidation state of an element or compound;
- The sum of all the oxidation numbers in a neutral compound must equal zero (0).
In the compound: Fe2(CO3)2
This compound is a neutral one, hence, its oxidation state is equal to zero (0).
It contains a polyatomic ion (carbonate ion) i.e. CO3 2-, whose net charge is -2.
Hence, to find the oxidation number of Iron (Fe), which is represented by X, in the compound, we say;
X(2) + -2(2) = 0
2X + -4 = 0
2X - 4 = 0
2X = 4
X = +2
Therefore, the oxidation number of Fe in Fe2(CO3)2 is (+2)
The compound Fe2(CO3)2 is called Iron (II) carbonate
Oxidation number of Fe in [tex]\rm Fe_2(CO_3)_2[/tex] is 2. An atom's oxidation number is a positive or negative number.
A notion used in chemistry to characterise the relative electron distribution and the level of oxidation or reduction of atoms in a compound or ion is known as the "oxidation number," sometimes known as the "oxidation state." Based on the presumption that electrons in chemical bonds are entirely transmitted to the more electronegative atom, it is a method of bookkeeping that assigns a notional charge to each individual atom in a molecule or ion.
The -4 stands for the overall charge that the carbonate ions provided, and the x is the Fe's oxidation number.
2x + (-4) = 0
2x - 4 = 0
2x = 4
x = 4/2
x = 2
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Which are aspects covered by Bohr's atomic model?
Electrons can have a measured radius.
Higher orbits have lower energies.
Electrons orbit the nucleus.
Electrons do not have energy, the energy is determined by the orbit.
Answers
Answer:
Electrons can have a measured radius.
Electrons do not have energy, the energy is determined by the orbit.
Explanation:
because I have got it right.
The correct answer is, "Electrons do not have energy, the energy is determined by the orbit."
In the Bohr model of the atom, electrons are arranged in energy levels. The energy of an electron is determined by the energy level in which it is found.
When electron an the electron moves from a lower to a higher energy level it absorbs energy. When the electron moves from a higher to a lower energy level, it radiates energy. This energy is observed in the form of visible light.
Thus, in the Bohr's model, electrons are arranged in energy levels. The energy level where an electron is found determines its energy.
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You are given two aqueous solutions with different ionic solutes (Solution A and Solution B). What if you are told that Solution A has a greater concentration than Solution B by mass percent, but Solution B has a greater concentration than Solution A in terms of molality? Is this possible? If not, explain why not. If it is possible, provide example solutes for A and B and justify your answer with calculations.
Answers
Answer:
Yes, it is possible. Let us consider an example of two solutions, that is, solution A having 20 percent mass RbCl (rubidium chloride) and solution B is having 15 percent by mass NaCl or sodium chloride.
It is found that solution A is having more concentration in comparison to solution B in terms of mass percent. The formula for mass percent is,
% by mass = mass of solute/mass of solution * 100
Now the formula for molality is,
Molality = weight of solute/molecular weight of solute * 1000/ weight of solvent in grams
Now molality of solution A is,
m = 20/121 * 1000/80 (molecular weight of RbCl is 121 grams per mole)
m = 2.07
Now the molality of solution B is,
m = 15/58.5 * 1000/85
m = 3.02
Therefore, in terms of molality, the solution B is having greater concentration (3.02) in comparison to solution A (2.07).
Which of the following is an aldehyde?
Answers
Answer:
D
Explanation:
I wish it will help you thank you
An aldehyde is a functional group that has the general formula CₓH₂ₓ₊₁CHO. The compound in option C is an aldehyde. Thus, option C is correct.
What is an aldehyde?An aldehyde is a type of functional group that has a carbon atom that shares a double bond with an oxygen atom and another single bond with the R group and H group (R−CH=O).
The aldehyde functional group gives a specific chemical property to the species. The first compound is CH₃CH₂CH₂COOH is a carboxylic acid functional group. The second compound is CH₃CH₂CH₂COOCH₃ is an ester.
The third compound is CH₃CH₂CH₂CHO an aldehyde group as (R−CH=O) functional group is present. The fourth compound is CH₃CH₂CH₂COCH₃, ketone.
Therefore, option C is an aldehyde.
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what is the light transmission of gallium?
Answers
Explanation:
the intensity of a He-Ne laser (633 nm ,5 mW) transmitted by different Gase samples is observed to change in correlation with the Nd-yttrium-aluminium-garnet laser pulse (532 nm, 7.8ns ,3mJ) which excites them
How can we identify that the absorption of heat has occurred?
Answers
Answer:
rise in temperature and the effect it has on our global weather patterns
PLS HELP ASAP 15 POINTS TYSM which of the following is a consequence of urban heat islands? a) increased precipitation downwind of the city b) increased winds within the city c) increased precipitation upwind of the city d) decreased winds within the city
Answers
Answer:
Hey!
Your answer is definitely A!
Explanation:
Hope this helps!
:>
In an ecosystem, the following is a consequence of urban heat islands which is increased precipitation downwind of the city.
What is an ecosystem?Ecosystem is defined as a system which consists of all living organisms and the physical components with which the living beings interact. The abiotic and biotic components are linked to each other through nutrient cycles and flow of energy.
Energy enters the system through the process of photosynthesis .Animals play an important role in transfer of energy as they feed on each other.As a result of this transfer of matter and energy takes place through the system .Living organisms also influence the quantity of biomass present.By decomposition of dead plants and animals by microbes nutrients are released back in to the soil.
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can you answer with working out
Answers
How is polyethene formed?
A. None of these
B. The double bond on reactive ethene molecules breaks allowing them to bond with each other and form a chain.
C. Double bonds are very strong. This means when ethene is heated, hydrogens will be removed before the double bonds break. When ethene molecules lose hydrogens, their carbons bond with each other forming branching chains.
D. Polyethene is formed by the formation of double bonds between carbons in ethane molecules.
Answers
Answer:
c
Explanation:
because 2× is strong. hydrogen will be remove
Explanation:
Poly(ethene) is formed when several monomers of ethene (an alkene) are joined together. Ethene can take part in this type of reaction as it is has a double bond (it's unsaturated) which opens up to allow multiple monomers to form a chain. This reaction occurs when ethene is heated and put under pressure in the presence of a catalyst.
calculate the volume of hydrogen produced at s.t.p when 25g and zinc are added to excess dilute hydrochloric acid at 31 degrees and 778 mm Hg pressure ( H= 1 , Zn = 65 , cl = 35.5 , volume of gas at stop = 22.4 dm cube
Answers
Answer:
The volume of hydrogen gas produced at s.t.p. is 9.419 dm³
Explanation:
The balanced chemical equation for the reaction is given as follows;
Zn + 2HCl → ZnCl₂ + H₂
Therefore, we have;
One mole of Zn reacts with 2 moles of HCl to produce one mole of ZnCl₂ and one mole of H₂
Number of moles of Zn present = 25/65 = 5/13 = 0.385 moles
Therefore, number of moles of H₂ produced = 0.385 moles
The volume of hydrogen gas produced is given by the relation
PV = nRT, we have;
R = 8.3145 J/(mol·K)
V = nRT/P = 0.385 ×8.3145 ×298.15/(101325)= 0.009419 m³ = 9.419 dm³
The volume of hydrogen gas produced at s.t.p. = 9.419 dm³.
Chemistry is often called the __________ science because it involves the study of the materials in the universe and the changes these materials undergo
Answers
Answer:
Central
Explanation:
Chemistry is often called the central science because of connects the physical sciences, life sciences and applied sciences.
Chemistry is the study of matter and changes undergone by matter. This makes chemistry to occupy a central place in many scientific disciplines including medicine, engineering, pharmacy, geology etc. Basic knowledge of chemistry is usually required by experts in these disciplines.
Ribbon diagrams shows secondary structures and appear less detailed than other model types. In one to two sentences, give a reason the chemists would use ribbon diagrams. What type of information do they provide?
Answers
Answer:
They show helixes and proteins
Explanation:
Ribbon diagrams are the Richardson diagrams that represent the protein structures. Chemist prefers using Ribbon diagrams to show the various structure of the proteins.
What are ribbon diagrams?The Ribbon diagram is used to represent the structural organization of the protein in the polypeptide chains or individually. It shows the three-dimensional structure and organization of the protein framework.
The ribbon diagram for the secondary structure of the protein shows the intramolecular and intermolecular structure along with helixes and bonding. It shows the detailed structure of the protein organization including the helix and sheets.
Therefore, the ribbon diagram is used by chemists to determine the structure of the protein as they give the details about the helix and sheet.
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How to learn question answer
Answers
Answer:
sjdjdn. ekdkdnd. ksossksn. sodkd
Answer:
The best way to learn any answer is to read it and then write it down in a paper. Finish your chapters and if you find problem in memorizing them, just jot them down! Jotting down answers will not only help you in memorizing answers for the exam, but will also boost long term memories
PLEASE HELP!! Which object listed best represents the following energy transformation: electrical -> thermal?
a. flashlight
b. electric saw
c. toaster
d. gas powered scooter
e. the sun
f. wind turbine
g. iPod
h. Stereo Speaker Vibrating
Answers
Answer:
The right option is (c) toaster
why there are two chloride ions for every calcium ion
Answers
Answer:
The valency of calcium is +2
Explanation:
Calcium is in group two. The members of group two are divalent metals that loose two electrons to form M^2+.
Since they form M^2+, they form ionic bonds with two uninegative ions. Chlorine is in group 17. This implies that its valency is -1 and it accepts one electron when it participates in an ionic bond.
Hence it will take two chlorine atoms to receive two electrons from one calcium atom in an ionic bond making the ratio of calcium to chlorine in the compound 2:1.
3. How did ethanol use affect the shortage of corn available to consumers during and
after the drought of 2012? Do you think that commodities in one sector should be used
in another economic sector? How might the concept of needs and wants affect your
analysis of this issue?
Answers
Due to drought, the production of corn decreases and shortage of it occurs.
Effects of droughtYes, commodities in one sector should be used in another sector because scientist invented methods in which one commodity is used in several sectors for the production of new products.
Corn was used for the production of ethanol which causes the shortage of corn that was available to consumers during and after the drought condition of 2012 so we can conclude that due to drought, the production of corn decreases and shortage of it occurs.
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Calcula el %m/v de alcohol en una mezcla utilizada para la desinfección de manos formada por: 15 ml de agua (densidad=1g/ml), 105 g de etanol (densidad: 0,798 g/ml) y 4,5 gramos de jabón líquido (densidad= 1,5 g/ml)
Answers
Answer:
%m/v =70%
Explanation:
El %m/v es una unidad de concentración que se define como cien veces la división entre la masa de una sustancia (En gramos) y el volumen total en el que esta sustancia se encuentra (en mL).
En el problema, debemos hallar la masa de etanol (Alcohol) y el volumen total de la solución.
Masa alcohol:
Ya te la dan en el problema: 105g
Volumen solución:
Volumen agua: 15mL
Volumen etanol: 105g × (1mL / 0.798g) = 131mL
Volumen Jabón líquido: 4.5g × (1mL / 1.5g) = 3mL
Volumen: 15mL + 131mL + 3mL
149mL
Así, el %m/v de alcohol en la solución es:
%m/v = (105g / 149mL) × 100
%m/v =70%
Es la representación escrita de un cambio químico, se construye con simbología, la cual fue establecida para una mejor interpretación universal de las reacciones.
Answers
En un cambio químico, las propiedades de las nuevas sustancias son diferentes de las originales, las partículas son diferentes y el número de partículas puede cambiar.
Si bien la distinción entre cambio físico y químico es útil, debería verse más como un continuo.
Las reacciones químicas pueden revertirse, pero esto puede resultar difícil en la práctica.
which chloride is a coloured solid rtp
Answers
Answer:
sodium chloride
hope that helped :)
Answer:
Chlorine is a greenish yellow gas at room temperature and atmospheric pressure. ... yielding chlorine water, and from this solution a solid hydrate of ideal ...
4. (01.05 MC)
Rubbing alcohol evaporates from your arm quickly, leaving a cooling effect on your skin. How do the molecules of gas compare to the molecules as a liquid? (4 points)
The gas particles move faster, have the same molecular composition, and have weaker attractions between them than the liquid particles
The gas particles move faster than the liquid particles, and the bonds of the molecules are broken during evaporation to allow gas atoms to spread apart.
The gas particles move slower but have the same molecular structure and the same attraction between them as the liquid particles.
The gas and liquid particles move at the same speed, but the bonds of the molecules are broken during evaporation to allow the gas atoms to spread apart
Answers
Answer:
The correct option is;
The gas particles move faster, have the same molecular composition, and have weaker attractions between them than the liquid particles
Explanation:
The properties of the gas molecules in comparison to liquids are
1) The gas molecules are widely spread out
2) After evaporation and while in conditions favorable to the gaseous state, the kinetic energy of a gas is larger than the inter molecular attractive forces
3) A gas fills the container in which it is placed
For liquids
1) There are strong intermolecular forces holding the molecules together in a liquid
2) Liquid attractive forces in a liquid are strong enough to hold neighboring molecules
3) The volume of a liquid is definite.