Answer:
C
Explanation:
As the size of a star increases, luminosity increases. If you think about it, a larger star has more surface area. That increased surface area allows more light and energy to be given off.
John Snow studied cholera in London in the 1800s. He determine that the source of this epidemic was a contaminated well. In this example, the contaminated well was the
carrier.
host.
reservoir.
pathogen.
Answer:
C -- Reservior
Reservior -- a supply or source of something.
Which type of bond shows two or more atoms sharing electrons?.
Answer:
Covalent blood
Explanation:
A covalent bond is the force of attraction that holds together two atoms that share a pair of valence electrons. The shared electrons are attracted to the nuclei of both atoms. This forms a molecule consisting of two or more atoms. Covalent bonds form only between atoms of nonmetals.
70 POINTS NEED HELP ASAP. ONLY CORRECT ANSWERS PLEASE.
A calorimeter was filled with 200 g of water. The temperature of the water in the calorimeter dropped from 55.0 °Celsius to 22.6 °Celsius. The specific heat of water is 4.184 J/g°C. Calculate, q, the heat released by the reaction.
A. -27,112 J
B. -2710 J
C. 1891 J
D. 18,911 J
Answer:
A
Explanation:
We can use the heat transfer equation:
[tex]\displaystyle q = mC\Delta T[/tex]
Therefore:
[tex]\displaystyle \begin{aligned} q_\text{sol} & = m_\text{sol}C_\text{sol}\Delta T \\ \\ & = (200.\text{ g})\left(\frac{4.184\text{ J}}{\text{g - $^\circ$C}}\right)(22.6\text{ $^\circ$C}-55.0\text{ $^\circ$ C}) \\ \\ &= (200.\text{ g})\left(\frac{4.184\text{ J}}{\text{g - $^\circ$C}}\right)(-32.4\text{ $^\circ$C}) \\ \\ & \approx -27112 \text{ J} \end{aligned}[/tex]
In conclusion, the answer is A.
Note: Assuming that the reaction took place in the water, the heat released by the reaction should be positive instead of negative. Because the temperature of the water decreased, the reaction is endothermic. Hence, the water lost heat (what we calculated above) while the reaction absorbed heat. The heat released (or, rather, absorbed) by the reaction is thus +27,112 J. However, for the purposes of this question, A is the best choice.
b) Do all waves require a medium? Explain. (2 points)
Explanation:
Not all waves actually require a physical medium through which to travel. This fact allows us to put all waves into two broad categories:
Mechanical Wave - A wave that requires a physical medium through which to travel. Example - sound waves. Sound waves can not travel through a vacuum (empty space).
Electromagnetic Waves - Do not require a physical medium through which to travel. Electromagnetic waves can travel through a vacuum. Examples: Radio waves, visible light, x-rays, etc.
Select the correct statement.
Acidic solutions contain no OH - ions.
Basic solutions contain no H + ions.
Basic solution contain no OH - ions.
Basic solutions contain some H + ions.
Answer:
d) basic ions contain some H+ ions got it right
Explanation:
i got it right
What is the freezing point of a solution in which 2.50 grams of sodium chloride are added to 230.0 ml of water
The freezing point of a solution in which 2.5 grams of NaCl is added t0 230 ml of water is : - 0.69°C
Determine the freezing point of the solution
First step : Calculate the molality of NaCl
molality = ( 2.5 grams / 58.44 g/mol ) / ( 230 * 10⁻³ kg/ml )
= 0.186 mol/kg
Next step : Calculate freezing point depression temperature
T = 2 * 0.186 * kf
where : kf = 1.86°c.kg/mole
Hence; T = 2 * 0.186 * 1.86 = 0.69°C
Freezing point of the solution
Freezing temperature of solvent - freezing point depression temperature
0°C - 0.69°C = - 0.69°C
Hence the Freezing temperature of the solution is - 0.69°C
Learn more about The freezing point of a solution in which 2.5 grams of NaCl is added t0 230 ml of water is : - 0.69°C
You are asked to perform an experiment. When you perform the experiment you notice the vessel is warming. What type of reaction is taking place
Exothermic type of reaction is taking place because this type of reaction generates heat energy.
What is exothermic reaction?Exothermic reactions refer to those chemical reactions that produce heat energy and release that heat energy to the surrounding environment.
So we can conclude that exothermic type of reaction is taking place because this type of reaction generates heat energy.
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How many ml of a 14. 0 m nh3 stock solution are needed to prepare 200 ml of a 4. 20 m dilute nh3 solution?.
Answer:
60 mL
Explanation:
200 mL = 0.2 L
We know that:
Molarity = Moles / Liters
So:
4.20 M = moles / 0.2 L
moles = 4.20 x 0.2 = 0.84
Then:
14.0 M = 0.84 moles / Liters
Liters = 0.84 moles / 14.0 M = 0.06 L
Since they want the answer in mL, convert 0.06 to get 60 mL
A section of a topographic map is shown below
Answer:
1800
Explanation:
2000 - 40(5) = 1800
Hydrochloric acid (HCI) and acetic acid (HC, H2O2) are both acids.
HCl completely dissociates in water, while HC2H2O2 does not.
Which statement best describes these two acids?
O HCl is a strong acid, HC2H2O2 is a weak acid.
O HCl is a weak acid, HC2H3O2 is a weak acid.
O HCl is a strong acid, HC2H2O2 is a strong acid.
O HCl is a weak acid, HC2H2O2 is a strong acid.
Answer:
I think that A or C is the correct answer
Answer:
HCl is a strong acid, HC2H2O2 is a weak acid.
Explanation:
strong acid: completely dissociates in water
weak acid: partially dissociates in water
If it is 9 am in San Francisco, is it also 9 am in New York? Why or why not?
PLEASE HURRY PLEASE
Answer:
It wouldn't be 9am in New York because San Francisco is 3 hours behind of New York
Explanation:
Which following is an opinion about friction
Answer:
please give a photo of it
Gold is an element. Which is
true about gold?
A. It cannot be broken down into another
substance.
B. It cannot be bonded together.
C. It can be broken down into another
Answer:
Gold is dense, soft, shiny, and most malleable of all the metals known. Gold is a transition metal that is attacked by chlorine, fluorine, and cyanide. Gold is the 79th element in the periodic table. it has 79 protons in its nucleus and 79 outter electrons.
Explanation:
please consider as brainlest if i helped you
Answer:
The answer should be A. It cannot be broken down into another substance. :)
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A balloon contains 6.5 L of helium and has a pressure of 1.5 atm. If the balloon expands to a volume of 10.0 L, what would the pressure be in the balloon?
Answer:
The pressure of the balloon is 0.98 atm
Explanation:
Using the equation P1V1 = P2V2, you can solve for the value of V2, which is 0.98 atm.
(P1V1)/P2 = V2
Plug in the numbers:
(6.5*1.5)/10.00
=0.975 atm
=.98 atm
How much volume of butanol should be combined with 30.0 mL ethanol to make a 5.88% volume percent solution of ethanol in butanol
Percentage volume is the ratio of the mass of solute to the volume of the solution. The 510 ml volume of butanol should be combined with 30.0 mL ethanol.
What is volume percent?Volume percent is the percentage ratio of the volume of the solute to the volume of solution multiplied by 100. It is given as,
[tex]\rm Percent \; volume = \rm \dfrac{ \text{volume of solute}}{\text{volume of solution}}\times 100 \%[/tex]
Given,
Percent volume = 5.88%
Volume of solute = 30.0 mL
Substituting values in the equation above:
[tex]\begin{aligned} \rm Percent \; volume &= \rm \dfrac{ \text{volume of solute}}{\text{volume of solution}}\times 100 \%\\\\5.88 &=\rm \dfrac{30}{V} \times 100\%\\\\&= 510.20\end{aligned}[/tex]
Therefore, 510 ml is the volume of butanol that should be added to the solution.
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A. Write the name of the alkane next to the drawing of the molecule. (2 points)
The names of the alkanes are all shown below;
3-methyl heptane2-methyl pentane2-methyl heptane2-methyl hexane 3-methyl hexaneWhat is an alkane?An alkane is a hydrocarbon that contains only hydrogen and carbon in which all the carbon to carbon bonds are saturated.
The names of the alkanes are all shown below;
3-methyl heptane2-methyl pentane2-methyl heptane2-methyl hexane 3-methyl hexaneLearn more about alkanes:https://brainly.com/question/24036551
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Which properties are true of petroleum? Select all that apply.
A)Petroleum was once living organisms.
B)Petroleum is found in sedimentary rock.
C)Petroleum is made from silicon based compounds.
D)Petroleum is used to make plastics.
E)Petroleum is used to make petrochemicals.
Petroleum is used to make plastics,Petroleum is used to make petrochemicals,Petroleum is found in sedimentary rock these properties are true of petroleum.
What is mean by Petroleum?Petroleum, also known as crude oil, or simply oil, is a naturally occurring yellowish-black liquid mixture of mainly hydrocarbons, and is found in geological formations. The name petroleum covers both naturally occurring unprocessed crude oil and petroleum products that consist of refined crude oil.Petroleum is used to make plastics,Petroleum is used to make petrochemicals,Petroleum is found in sedimentary rock these properties are true of petroleum.
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Which of the following can be said in the crystallization of liquid salt.
A.
Answer:
Correct option is D)
Explanation:
Crystallization is the process that is used to separate a pure solid in the form of its crystals from a solution.
Copper sulphate, salt, and potash alum can be purified by this method. In this process, the solution of the substance is heated and then cooled to form crystals.
8.
A chain bracelet is found. It looks as though it might be made of either gold or of
copper. When the bracelet is submerged in a graduated cylinder containing water, the
volume of the water rises from 9.2 cm to 11.7 cm3. The bracelet has a mass of 45 g. Is
the bracelet made of gold or copper? (Note: The density of gold is 19.3 g/cm and the
density of copper is 8.92 g/cmº.)
Answer:
The bracelet is made of gold.
Explanation:
The bracelet displaces the water by [tex]11.7cm^3-9.2cm^3 = 2.5cm^3[/tex] and thus has a volume of [tex]2.5cm^3[/tex]. If the bracelet has a mass of 45g, we know that the density of the bracelet is then [tex]\frac{45g}{2.5cm^3}[/tex], which can be simplified to [tex]18\frac{g}{cm^3}[/tex]. This is closer to the density of gold, so it can be assumed that the bracelet is made of gold.
Empirical formula of a compound is XY2 if its empirical formula weight is equal to its vapour density calculate the molecular formula of the compound.
Explanation:
Hope it helps you!!A gas a temperature of 269.5K. What is the temperature in C°
Answer:
269.5k is equivalent to -3.65 c
Explanation:
1 Kelvin = 1 - 273.15 = -272.15 Celsius
269.5 Kelvin = 269.5 - 273.15 = -3.65 Celsius
hope it helped :)
269.5 K
to find:269.5 K in C°
solution:formula= 0K − 273.15 = -273.1°C
= -3.65 °C.
How many outer atoms and lone pairs are present in a molecule with a trigonal pyramidal shape?.
Answer:
There are three nuclei and one lone pair, so the molecular geometry is trigonal pyramidal.
Explanation:
Apple seeds contain a compound that forms cyanide when it comes into contact with enzymes in the
digestive system. According to the CDC, a fatal dose of cyanide for humans is 1. 8mg/kg BW. You measure
2. 0mg of cyanide in a single, crushed-up apple seed. How many apple seeds would you need to ingest to
reach this level the threshold dose? Hint: Don't forget to include your body weight in kg in your calculations). (50 kg weight)
[tex]\tt \dfrac{2}{50}\times x=1.8\\\\x=\dfrac{1.8\times 50}{2}=45~apple~seeds[/tex]
if you mix baking soad with vinegar what will happen DONT CHEAT will it be a cheimcal reaction or a Physical reation
Answer:
Chemical Reaction
Explanation:
because one is a base and the other is an acid. Baking soda is a basic compound called sodium bicarbonate.
A 25.00 mL sample of a hydrochloric acid solution was titrated to completion with 34.55 mL of 0.1020 M sodium hydroxide. What was the concentration of the hydrochloric acid
The concentration of hydrochloric acid with a volume of 25mL titrated with 34.55 mL of 0.1020 M sodium hydroxide is 0.141M.
How to calculate concentration?The concentration of an acid in a titration procedure can be calculated using the following expression:
CaVa = CbVb
Where;
Ca = concentration of acidCb = concentration of baseVa = volume of acidVb = volume of baseCa = ?Cb = 0.102MVa = 25mLVb = 34.55mLCa × 25 = 0.102 × 34.55
25Ca = 3.52
Ca = 0.141M
Therefore, the concentration of hydrochloric acid with a volume of 25mL titrated with 34.55 mL of 0.1020 M sodium hydroxide is 0.141M.
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A piece of iron is heated to 120'C then placed in a calorimeter containing 50g of water. The water temperature is raised from 30°C to 40°C. Assuming the specific heat of water is 4. 18 J/8'C and the specific heat of
Iron is 0. 44 J/g C, what is the mass of the piece of iron?
118. 8
59. 45
39. 6
752
Answer:
Mass of iron = 59.375 gm
Explanation:
Calories ( or joules) are added to the water by the hot steel so at the endpoint they are BOTH at 40 C
The water gains:
4.18 j/g-C * 50 * (40-30 C) = 2090 j
The steel gave up 2090 j going from 120 to 40 C
2090 = .44 j/g-C * m * (120-40) solve fro m = 59.375 gm
HELP ASAP SCIENCE GIVING BRAINLIST FOR CORRECT
Answer:
Jellyfish :)
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An object that has potential energy may have this energy because of its
a acceleration
b location
c momentum
d speed
Answer:
i have no idea. let's say location because it has to be somewhere.
Explanation:
I
An ice cube is placed on a kitchen counter. which best describes heat flow in this situation? heat flows from the ice to the counter, causing the molecules in the counter to move more quickly. heat flows from the ice to the counter, causing the molecules in the counter to move more slowly. heat flows from the counter to the ice, causing the molecules in the counter to move more quickly. heat flows from the counter to the ice, causing the molecules in the counter to move more slowly.
An ice cube is placed on a kitchen counter then heat flows from the counter to the ice, causing the molecules in the counter to move more slowly.
What is heat flow?Heat flow is a process in which heat is transfered from hot body to the cold body.
So, when we place an ice cube to the counter of the kitchen and here ice is a colder body and counter is a warmer body so transfer of heat takes place from counter to the ice cube. As a result of which movement of particles of counter gets slow and of ice increases.
Hence in the given situation heat flows from the counter to the ice, causing the molecules in the counter to move more slowly.
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Answer:
D
Explanation:
Edge 2022
What is the effective nuclear charge for magnesium?.
Answer: Heyo Kenji Here! Here's your answer- Mg =1s2 2s2 2p6 3s2 = [Ne]3s2, therefore magnesium has 10 core electrons from its 1s2, 2s2, 2p6 orbitals. Magnesium is element 12, so it has 12 protons and a nuclear charge of 12.
Explanation: Hope this helps!
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- Kenji ^^