Answer:
c. the center of curvature of the two sides of the lens
A pan containing 20.0 grams of water was allowed to cool from a temperature of 95.0 °C. If the amount of heat released is 1,200 joules, what is the approximate final temperature of the water?
75 °C
78 °C
81 °C
87 °C
Answer:
81 °C
Explanation:
This is a calorimetry question so a few things you will need for this. The calorimetry equation q=mcΔT & the specific heat of water (4.2J/g•°C). Other definitions are:
q = heat added/released by a sample
m = mass of sample
c=specific heat of sample
ΔT = change in temperature
from here we can rearrange the equation to state:
q/(mc) = ΔT
1200J/((20.0g)(4.2J/g•°C)) = ΔT
14°C = ΔT
If the starting temperature was 95.0°C and we know that the temperature was cooled by 14°C then the final temperature of the water would be 81.
Answer:
C. 81 c
Explanation:
took the test :)
Chemical changes can change which properties of a substance?
Group of answer choices
Reactivity
Color
Malleability
All of the above
Answer:
» Reactivity and color
Explanation:
though color is very minor answer because it also relates to a physical property.
[tex].[/tex]
Freezing water cracking limestone
a
Chemical Change
b
Physical Change
Answer:
Freezing water and cracking limestone are physical changes.
If you burn a citronella candle near your picnic will it keep mosquitoes away
Answer:
Thanks!!!
Explanation:
Answer:
true
Explanation:
(Physical Science)
Which group of metals includes elements with one valence electron? (1 point)
A. alkaline earth metals
B. rare earth metals
C. alkali metals
D. transition metals
Answer:
C
Explanation:
alkali metals are the Group I elements, which have 1 electron in their valence shells
Answer:
Alkali metals are the elements which have only one valence electron in their outermost or ultimate shell.
Explanation:
Alkaline Earth metals have 2 valence electron in their outermost shell and readily give up their 2 electron to achieve stability.
Rare Earth Metals have 3 valence electron in their outermost shell and they have high magnetic moments and divert range of magnetic structure.
Alkali Earth metals have 1 valence electron.
Transition metals generally have 2 valence electron .
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Plzzzzzz help me Write electronic configuratof sodium and chlorine in the term of subshell ?
Answer:
ans:Ne=2,8,1
ans:2,8,7
What effect does fermented sugar have in beer brewing
Answer:
If the sugar concentration level of the must becomes too high at any given point--either at the beginning or during the fermentation--it starts to have an inhibiting effect on the yeast's ability to produce alcohol. In other words, the higher sugar concentration starts to act as a preservative effecting the fermentation in a negative way.
Explanation:
Fermentation is the process by which yeast converts the glucose in the wort to ethyl alcohol and carbon dioxide gas -- giving the beer both its alcohol content and its carbonation.
surely help:) I’ll brainlist!
Answer:
A. The product formed have more energy than the reactants.
This is because it is an endothermic reaction.
[tex].[/tex]
Which of these are PHYSICAL changes?
А.
cutting, tearing, freezing, thawing, folding.
mixing without chemical changes
B.
burning, rusting, forming a new substance from
two different substances, exploding, cooking
Answer:
the answer to this problem is a
what is the concentration of hydrogen ion, H+, present in a water sample if 100. ml of the sample requires 7.2 ml of 2.5 x 10 -3 M NaOH to be neutralized
Answer: 1.8x10^-4 M H+
Explanation: The number of moles of NaOH added to the 100 ml soultion will be equal to the number of moles of H+ present in that solution.
Moles NaOH in 7.2 ml of 2.5x10^-3 M NaOH
(2.5x10^-3 M NaOH) is the same as 2.5x10^-3 moles NaOH/liter
(2.5x10^-3 moles NaOH/liter)*(7.2 ml)*(1 liter/1000ml) = 1.8x10^-4 moles NaOH used to titrate 100 ml of the acid. That means there was 1.8x10^-4 moles of H^+ in 100 ml.
Concentration of H^+ = (1.8x10^-4 moles H)/0.100 l) = 1.8x10^-4 M H+
(pH of 3.74)
SURELY SOMEONE HELP it’s urgent plllss I’ll brainlist u/5 star!!! answer the ones u know. :)
Answer:
3 exothermic reaction. only that much
Hi,
These are the answers.
• Question 2. C , Substance dissolves
• Question 3. D , Exothermic reaction
• Question 4. C , Endothermic reaction takes place
• Question 5. A , the products formed has more energy than reactants
Hope it helps you... pls mark brainliest if it helped you
Compare and contrast the three types of mixtures (solutions, colloids, and suspensions).
Answer:
solutions is a homogenous mixture while colloids and suspensions are heterogeneous mixtures made up of 3 or more substances
Explanation:
homogeneous- made up of one thing
heterogeneous- made up of 2 or more things
What is the control in the experiment?
Answer:
C. the amount of drug x given to mice
Revision has a atoMic number of 37 and a mass number of 85. HIW many protons, neutrons and electrons does an ion of rubidium with a 1+ charge have
Answer: 37 protons, 48 neutrons, and 36 electrons.
Explanation: I assume "Revision" is Rubidium. It is atomic number 37, so it has 37 protons. It's atomic mass is 85, so it has an average of (85-37) = 48 neutrons. It has a charge of +1, so one electron of the original 37 has left.
What is the mass of six of these marbles? What is the volume? What is the
density?
Answer:
All right. So let's calculate the density of a glass marble. Remember that the formula for density is mass over volume. So if I know that the masses 18.5 g. And I know that the um volume is 6.45 cubic centimeters. I can go ahead and answer this to three significant figures. So it's going to be 2.87 grams per cubic centimeter. Okay, that's our density. Now, density is an intensive process. Okay. We're an intensive property. I really should say. It doesn't depend on how much you have. Mhm. If I have one marble, its density is going to be 2.87 g per cubic centimeter. If I have two marbles, the density will be the same because I'll double the mass and I'll also double the volume. So when I divide them I'll get the same number. Okay, that's what makes it an intensive property. No matter how many marbles I have, they'll have the same density. Mass though is not an intensive property. So if I have six marbles and I want to know what the massive six marbles is. Well, I know the mass of each marble is 18.5 g. So the mass of six marbles Is going to be 100 11 g. Because mass is an extensive property. It depends on how much you have. If I change the number of marbles, I'm going to change the mass. That's an extensive property. All right. So we've calculated the density. We've calculated the mass and then what happens to the density of one marble compared to six marbles as we mentioned before. Since densities and intensive property, the densities will be the same, no matter how may.
Explanation:
what is force ?write its effects.
Answer:A force is a push or pull upon an object resulting from the object's interaction with another object.
A force acting on an object causes the object to change its shape or size, to start moving, to stop moving, to accelerate or decelerate
All the following process produces hematite except
A roasting of siderite
B oxidation of iron
C oxidation of magnetite
D drying of limonite
E no correct answer
Answer:
D)driying of limonite these is the answer
Express 0.021 in scientific
notation.
[ ? ]10
Answer:
0.021 in scientific notation is 2.1 x 10^-2
Explanation:
Since there are two zeros before the non-zero digits, 10 should be raised to -2.
hope this helps
Using scientific notation, one can express extremely big or extremely small values. When a number between 1 and 10 is multiplied by a power of 10, the result is represented in scientific notation. 0.021 in scientific notation is 2.1 x 10⁻².
A way to express numbers that are either too large or too little to be conveniently stated in decimal form is through scientific notation. It is also known as "scientific form" in Britain, because scientists, mathematicians, and engineers frequently use it for intricate calculations involving large numbers.
A condensed manner of writing numbers is known as scientific notation (also known as standard form). A number is represented by a number from 1 to less than 10, multiplied by a power of 10, when it is written in scientific notation.
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sound travels at 331m/s. How long would it take for sound to travel across lake tahoe, which is 21.6 miles long
Answer:
It would take sound 104.998 seconds to travel across lake tahoe.
Explanation:
First let's convert the miles to meters, so, 21.6 miles = 34754.4 meters
Now, we will divide this number in meters by 331. So, 34754.4 / 331 = 104.998
And what will the unit be? Seconds will be the unit for time here so 104.998 seconds.
PLZ HELP MEEE
A tire company wants to determine what kind of rubber will last the longest for their tires. What are some variables that the researchers will want to make controlled variables?
In an experiment, we can define 3 types of variables.
Independent variables: Are these ones that the scientist can control and modify, in this case, would be the kind of rubber for the tires.
Dependent variables: Are the variables that react to the changes in the independent variables. In this case, would be "how much lasts each type of rubber".
Controlled variables: Are all of these variables that also have an impact on the dependent variable, so we need to control them (fix them) so they do not affect the study of the independent variable.
So, for this particular experiment, to find controlled variables we need to think on what things do affect the durability of tires.
Some examples can be:
The material of the ground where the tires are being tested.The temperature of the ground where the tires are being tested.The type of car where the tires are being tested.The speed at which the tires are being tested.The internal pressure at which the tires are being tested.If you want to learn more, you can read:
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The periodic table below shows major regions in different colors. Which answer choice describes the noble gases?
A. All of the elements of Period 1 in orange boxes
B. The two separate rows of elements in dark and light blue boxes at the bottom
C. All of the elements in green boxes
D. All of the elements of Group 18 in orange boxes
Answer:
D. all of the elements of Group 18 in orange boxes
What causes the pressure inside oxygen tanks to change as they are filled?
A. The volume of the container changes.
B. The temperature of the gas changes.
C. The number of gas molecules changes.
D. The pressure outside the tanks changes.
Answer:
the answer is the number of gas molecules changes.
Nate and Vic are trying to determine the atomic mass of the atom shown below. Nate thinks it has an atomic mass of 11 u, while Vic thinks it has an atomic mass of 6 u. Who is correct and why?
A. Nate is correct. An isotope’s atomic mass is based on the number of protons and neutrons in the nucleus.
B. Vic is correct. An isotope’s atomic mass is based on the number of electrons in the electron cloud.
C. Vic is correct. An isotope’s atomic mass is based on the number of protons in the nucleus.
D. Neither is correct. The atomic mass is based on the number of neutrons in the nucleus. This isotope’s atomic mass is 5 u.
Answer: A is correct. I don't see the "element shown below," but it isn't needed to answer this question.
Explanation: By definition, the atomic mass is based on the sum of protons (1 AMU each) and neutrons (1 AMU each). Electrons are assigned a value of 0 AMU.
What is the signifcence of H, 2H, 3 H, H2, 2 He, Na,
Snaco, ouco, CO, 460?
H=hydrogen,H2=hydrogen atoms,
In what condition do iodine and phosphorus react?
Answer:
reaction of phosphorus with the helegones
32,235 kg/1991 m3 solve in scientific notation
Answer:
jrikgni
Explanation:j
55
Plant and Animal Cells
С
B
F
1 20 points
Which letter represents the brain of the cell?
о B
H
H
Why
E
D
G
Answer:
Nucleus is known as the brain of the cell.
correct option is B letter
If gasoline costs $3.13 per gallon, how many gallons of gasoline could you purchase for $21.00 ?
Round your answer to the nearest hundredth place.
____________ gallons
Answer:
7 gallons
Explanation:
Just do the math
$21 x 1 gallon/$3 =7 gallon
Dissolving salt in water is what kind of reaction
O Endothermic reaction
O Exothermic reaction
O No answer text provided
O No answer text provided
Answer:
endothermic reaction
Explanation:
because salt dissolve water
Answer:
EXOTHERMIC REACTION AS WHEN YOU TOUCH IT YOU WILL FEEL SOME HEAT.
Define density, and list two reasons it is important in science
Answer:
The density is the mass per unit volume of a substance.
Density is important when working out if something will float in water, and it can also be useful for calculating the mass of a specific volume of a substance.
Explanation:
