66 A student wants to design a controlled experiment to solve the following problem: When placed in a freezer, will hot water or cold water reach 0°C faster?
The student plans to place two containers with equal masses of water (one hot and one cold) in the same freezer in the classroom.
a List three conditions the student should keep constant for the hot-water and cold-water setups when planning this experiment. [3]
b For each condition you name, give a scientific reason why the condition needs to be the same for both the hot-water and cold-water setups
Answer:
Explanation:
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write short note on earth sheltering
Answer:
hfxyktxykt
Explanation:
An earth shelter is a structure (usually a house) with earth (soil) against the walls, on the roof, or that is entirely buried underground.
An earth sheltered house in Switzerland (Peter Vetsch)
Earth acts as thermal mass, making it easier to maintain a steady indoor air temperature and therefore reduces energy costs for heating or cooling.
Earth sheltering became relatively popular after the mid 1970s, especially among environmentalists. However, the practice has been around for nearly as long as humans have been constructing their own shelters.
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The CO2 that builds up in the air of a submerged submarine can be removed by reacting it with sodium peroxide. 2 Na2O2 (s) + 2 CO2 (g) → 2 Na2CO3 (s) + O2 (g)
If a sailor exhales 150.0 mL of CO2 per minute at 20oC and 1.02 atm, how much sodium peroxide is needed per sailor in a 24 hr period?
Answer: The sodium peroxide needed per sailor in a 24 hr period is 674 grams.
Explanation:
According to ideal gas equation:
[tex]PV=nRT[/tex]
P = pressure of gas = 1.02 atm
V = Volume of gas = 150.0 ml = 0.15 L
n = number of moles of carbon dioxide = ?
R = gas constant =[tex]0.0821Latm/Kmol[/tex]
T =temperature =[tex]20^0C=(20+273)K=293K[/tex]
[tex]n=\frac{PV}{RT}[/tex]
[tex]n=\frac{1.02atm\times 0.15L}{0.0821 L atm/K mol\times 293K}=0.006moles[/tex]
[tex]2Na_2O_2(s)+2CO_2(g)\rightarrow 2Na_2CO_3(s)+O_2(g)[/tex]
According to stoichiometry:
2 moles of carbon dioxide require = 2 moles of sodium peroxide
Thus 0.006 moles carbon dioxide require= [tex]\frac{2}{2}\times 0.006=0.006[/tex] moles of sodium peroxide
Mass of sodium peroxide needed for 24 hour=[tex]moles\times {\text {Molar mass}}=0.006mol\times 78g/mol\times 24\times 60=674g[/tex]
Thus sodium peroxide needed per sailor in a 24 hr period is 674 grams.
The amount (in grams) of sodium peroxide needed per sailor in a 24 hr period is 673.92 g
Determination of the mole of CO₂Volume (V) = 150 mL = 150 / 1000 = 0.15 L Temperature (T) = 20 °C = 20 + 273 = 293 KPressure (P) = 1.02 atmGas constant (R) = 0.0821 atm.L/Kmol Mole of CO₂ (n) =?Using the ideal gas equation, we can obtain the mole of CO₂ as follow:
n = PV / RT
n = (1.02 × 0.15) / (0.0821 × 293)
n = 0.006 mole
How to determine the mole of Na₂O₂ required2Na₂O₂ + 2CO₂ → 2Na₂CO₃ + O₂
From the balanced equation above,
2 moles of CO₂ required 2 moles of Na₂O₂.
Therefore,
0.006 mole of CO₂ will also require 0.006 mole of Na₂O₂.
How to determine the mass of Na₂O₂ required Mole of Na₂O₂ = 0.006 mole Molar mass of Na₂O₂ = (23×2) + (16×2) = 78 g/mol Mass of Na₂O₂ =?Mass = mole × molar mass
Mass of Na₂O₂ = 0.006 × 78
Mass of Na₂O₂ = 0.468 g per minute
Mass of Na₂O₂ required for 24 h = 0.468 × 24 × 60 = 673.92 g
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Which of these does not cause seasonal change?
A.the tilt of the Earth’s axis
B.the Earth’s orbit around the sun
C.the Earth’s distance from the sun
D.which side of the Earth is tilted toward the sun
Answer:
C.the Earth’s distance from the sun
Explanation:
Distance Does Not Cause Seasons
It is a common misconception that seasons occur because of Earth's elliptical orbit around the Sun, with winter occurring when Earth is farthest away from the Sun, and summer when it is closest to it. However, our planet's distance from the Sun has little effect on the onset of seasons.
The distance of the earth from the sun does not cause seasonal change. Therefore, option (C) is correct.
What is the reason for the seasonal changes?The seasons are changing depending on the sunlight reaching the Earth as it orbits around the sun during the year. The season changes are caused by the Earth as it is tilted on its axis. The earth travels each year in a loop around the sun.
The hemisphere of the Earth has tilted towards or away from the Sun. Because of that, there are different types of seasons are formed which are experienced in a whole year.
Summer season occurs on the earth when the hemisphere is tilted towards the sun and winter occurs in the hemisphere tilted away from the sun.
Because sunrays travel directly to the surface of Earth, the hemisphere which is tilted toward the sun is warmer. So they are less scattered in the atmosphere.
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Identify processes that change matter to a liquid state.
Processes in which matter changes between liquid and gaseous states are vaporization, evaporation, and condensation.
When the temperature or pressure of a system change, there occurs a change in the state of matter. The process that change the solid state into the liquid state is called the melting.
What is melting?The process in which the solid is changed into a liquid is defined as the melting. The temperature at which a solid change to a liquid is known as the melting point.
The other process in which a gas changes to a liquid is known as the condensation. This process is found to be the reverse of evaporation, where liquid water becomes a vapor.
Thus the two processes that change matter to a liquid state are melting and condensation.
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1. Which of these is NOT found in the nucleus of an atom?
neutrons
protons
electrons
the mass of the atom
Answer:
Electrons
Explanation:
Answer:
Electrons are not found in the nucleus for they are orbiting the atom.
pls do this and don't just do it for the points pls help me I need it
Answer:
what do you want me to do my friend my best friend who is a dreamer
Complete the sentensent.Use the present simple or the present continuous.
_____ (your son/ ever talk) to strangers?
Answer:
does your son ever talk to strangers?
Explanation:
A balloon is filled with 26L of helium in the morning when the temperature is
17°C. By noon the temperature has risen to 32°C. What is the new volume of
the balloon?
Answer:
V1T1=V2T2
Explanation:
V2=V1T1/T2
The final volume of the gas can be determines using the Charles's law of volume and temperature. The volume of helium when temperature increased to 32 °C increases to 48.9 L.
What is Charles's law ?Charles's law states that, at constant pressure, the volume and temperature of a gas are in direct proportionality. Thus, as the temperature increases, volume of the gas increases.
Hence, V/T = constant
Let V1 and T1 be the initial volume and temperature and V2 and T2 be the final quantities. Then, the relation can be stated as ;
V1/ T1 = V2/ T2
Given that initial quantities:
V1 = 26 L
T1 = 17 °C
Final temperature T2 =32 °C
Then, final volume V2 = V1 T2/T1
V2 = (26 L × 32°C)/ 17 °C = 48.9 L
Therefore, the volume of helium gas increases to 48.9 liters.
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help Mepleaseeeee !!!
Answer:
The 500kg boulder
Explanation:
please see the picture above! thanks
Answer:
cohesion
Explanation: the sticking together of particles of the same substance
How can a chemical reaction be sped up?
Select from the drop-down menu to correctly complete the statement.
Pack in more of the reactant to increase the
A) Catalyst
B) Concentration
C) Surface Area
D) Temperature
Answer: monki says d
Explanation: monki big brain oof
Answer:
d
Explanation:
Energy changes WITHIN an energy type is called what?
Answer:
What is energy transformation? One type of energy can change into another type of energy. Energy transformation means the changing of energy from one type to another, e.g. from kinetic energy to electrical energy, or from potential energy to kinetic energy.
Explanation:
Answer:
It may seem a bit weird, but, I'm only doing this so that you can make that other person brainliest.
Explanation:
Which equation is NOT balanced?
A. 2H2 + O2® 2H2O
B. H2 + H2 + O2® H2O + H2O
C. 2H2 + O2® H2O
D. 4H2 + 2O2® 4H2O
Answer:
C
Explanation
On the reactants side there is 4 Hydrogen atoms in total and two oxygen atoms on the left however on the right there is two hydrogen atoms and one oxygen atom. Leaving this equation unbalanced
The equation that is NOT balanced is [tex]\rm 2H_2 + O_2\rightarrow H_2O[/tex]. The correct answer is option C.
In a balanced chemical equation, the number of atoms of each element on the reactant side must be equal to the number of atoms of each element on the product side.
In equation A, there are 4 hydrogen atoms and 2 oxygen atoms on both the reactant and product sides, so it is balanced.In equation B, there are 4 hydrogen atoms and 2 oxygen atoms on both the reactant and product sides, so it is balanced.In equation C, there are 4 hydrogen atoms and 2 oxygen atoms on the reactant side, but only 2 hydrogen atoms and 1 oxygen atoms on the product side. Therefore, it is not balanced.In equation D, there are 8 hydrogen atoms and 4 oxygen atoms on both the reactant and product sides, so it is balanced.In conclusion, equation C. [tex]\rm 2H_2 + O_2\rightarrow H_2O[/tex] is the one that is NOT balanced. It has an unequal number of oxygen atoms on the reactant and product sides.
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As you move down a group of the periodic table how does the atomic radius of the atoms change
Answer:
An atom gets larger as the number of electronic shells increase; therefore the radius of atoms increases as you go down a certain group in the periodic table of elements. In general, the size of an atom will decrease as you move from left to the right of a certain period.
Explanation:
Me and my best friend. Gotta love her.
Answer:
cool
Explanation:
the electrolyte in automobile lead storage batteries is a 3.75 sulfuric acid solution that has density of 1.230g/mL. calculate the mole fraction.
The mole fraction of sulfuric acid : 0.073
Further explanationGiven
3.75 M sulfuric acid solution that has density of 1.230 g/mL
Required
The mole fraction
Solution
3.75 M = 3.75 mol/L
For 1 L solution :
mass of solution = 1230 g
mass Sulfuric acid : 3.75 mol x 98 g/mol=367.5 g
mass water = 1230-367.5 = 862.5 g
mol water = 862.5 : 18 g/mol= 47.92
mol total = 3.75 + 47.92 = 51.67
mole fraction of sulfuric acid :
= 3.75 : 51.67
= 0.073
It protects the sensitive tips of your fingers and toes
Answer:
What Do Nails Do? Nails protect the sensitive tips of fingers and toes. We don't need our nails to survive, but they do support the tips of our fingers and toes, protect them from injury, and help us pick up small objects.
What is the chemical formula for sodium sulfate
Answer:
Na2So4
Explanation:
Na is group 1, so has a charge of 1+
Sulphate’s formula is SO4 2-,
because sulphate has double the charge of Na, you need two Na’s to make it equal.
Therefore it’s Na2SO4
How many grams are in 8.5 moles of lithium oxide?
Which of these is an example of water in liquid form
Answer:
???????????????????????
Answer:
river or lake
Explanation:
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Answer:
I'd say "a" because not everything with plants and animals is perfectly organized together nothing ever is.
The boiling point of ethanol is 78.3 degrees Celsius. The boiling point of
ethanol on the Kelvin scale is approximately... *
Answer:
K = 351.3
Explanation:
The relationship between the Celsius scale and kelvin scale is;
K = 273 + C
Since the Celsius temperature = 78.3
The kelvin temperature is given as;
K = 273 + 78.3
K = 351.3
lime kilns are very large. why is this necessary?
why are cells small?
Answer:
you know what i really dont know but imagine if they were huge
Explanation:
Which describes an atom that has fewer neutrons than protons and more lecterns than protons?
Answer:
An atom that has fewer neutrons than protons and more electrons than protons is a negative ion. The negatively charged particles in an atom are the electrons. The charge an atom carries depends on the balance between the number of protons and electrons in an atom.
Explanation:
how is this equation read?
4Na (1) +Mn(SO 4 ) 2 (aq) Mn (3) +2Na 2 SO
How many grams are in 8 moles of AI?
Answer:
c. 216 g
Explanation:
There is actually 215.852304 but when you round it, you will get 216
This is a sign of a chemical reaction that involves the production of bubbles or fizzing
Answer:
gas production
Explanation:
Answer:
gas formation
Explanation:
frothy bubbles produced by carbon dioxide gas are a sign that a chemical reaction has occurred when a based is mix with acid.
I RLLY NEED HELP. Use Image B (picture above) and calculate the density of a ring that has a mass of 32 grams. Read Page 11 "Measure Volume Using Displacement" on your textbook before answering this question. Formula: D=m/V m=_____ V= _____ , then the density (D) is equal to D= ______ This question requires three answers. Don't forget the units! *
Answer:
Mass of ring = 32 g
Volume of ring = 4 mL
Density of ring = 8 g/mL
Explanation:
From the question given above, the following data were obtained:
Mass of ring = 32 g
Volume of water = 64 mL
Volume of water + ring = 68 mL
Density of ring =?
Next, we shall determine the volume of the ring. This can be obtained as follow:
Volume of water = 64 mL
Volume of water + ring = 68 mL
Volume of ring =?
Volume of ring= (Volume of water + ring) – (Volume of water)
Volume of ring = 68 – 64
Volume of ring = 4 mL
Finally, we shall determine the density of the ring. This can be obtained as follow:
Mass of ring = 32 g
Volume of ring = 4 mL
Density of ring =?
Density = mass / volume
Density of ring = 32 / 4
Density of ring = 8 g/mL