Evaporation of water off of the surface of leaves
a
Chemical Change
b
Physical Change
MAY SOMEONE HELP ME PLZZ
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?
Answer: Rubber source, temperature, thinkness, thread design, driving pattenrs, weather, etc.
Explanation: There are many variables. Here are a few I would include in a tire lifetime study:
1. Type of rubber, including source
2. Thickness of tire
3. Design of tire thread
4. Life as a function of average speed and road surface
5. Expected outside temperature and wet conditions
6. Driving conditions of speed and both acceleration and deceleration parameters (e.g., tire life when slamming on the brakes or accelerating quickly)
A catalyst that has a different phase than the reactants is a(n) _______. A. exergonic catalyst B. endergonic catalyst C. homogeneous catalyst D. heterogeneous catalyst E. autocatalyst
Answer: Heterogeneous Catalyst
Explanation: The word heterogeneous means "different phases" or insoluble in science.
Read the information in the table below:
Reaction
Description Energy to IS break bonds is more tha renergy release to form bonds Energy to break bonds is less than energy release to form bonds
Which type of reaction is represented by B?
Answer: Exothermic
Explanation: The energy of the reactants is leass than that of the products. Conservation of energy means that the excess is given off, or exothermic.
How long does S waves travel through earths crust
Answer:
For the distance range 50 to 500 km, the S-waves travel about 3.45 km/s and the P-waves around 8 km/s.
IF HELPED MARK AS BRAINLIEST
Answer:
For the distance range 50 to 500 km, the S-waves travel about 3.45 km/s and the P-waves around 8 km/s.
Comparison between availability of food & population in current scenario.
In UAE.
(10-marks)
100-200 words please
Answer:
Answer is in the attachment
hope it's helpful
How would you calculate the density of an object?
mass/volume
mass * volume
mass/area
weight/mass
Answer:
Mass/Volume
Explanation:
Answer:
[tex]{ \sf{density = \frac{mass}{volume} }}[/tex]
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.
How old is a piece of cotton cloth if the half-life of carbon-14 is 5,730 years, and the carbon-14 composition of the cloth is 22 percent that of living plants?
Answer:5600 years
Explanation:
the amount of time it takes for the quantity to lose 50% (Half life) of its value. The half-life of carbon-14 is about 5600 years. Thus, after 5600 years, a piece of cotton cloth will contain half the carbon-14 that was in the original cotton plant.
How are elements arranged on the periodic table?
a. they are arranged to highlight similarities between elements
b. they are arranged to highlight different elements with similar isotopes
c. they are arranged in order from most abundant to very rare and unstable
d. they are arranged in order of the date of discovery
Answer:
the elements are listed in order of increasing atomic number. The atomic number is the number of protons in the nucleus of an atom.In a periodic table arranged in order of increasing atomic number, elements having similar chemical properties naturally line up in the same column.
The elements on the periodic table are arranged on the basis of highlighting similarities between elements. Thus, the correct option for this question is A.
How elements are arranged on the periodic table?The elements on the periodic table are basically arranged on the basis of increasing their atomic number. These atomic number is represented by the number of protons in the nucleus of an element.
According to the question, the elements possessing identical chemical properties are arranged in the same group. For example, group 17 is known as the halogen group. Among this group, the elements bear one electron short to fulfill their octet.
The whole periodic table comprises of 18 groups and 7 periods.
Therefore, the elements on the periodic table are arranged on the basis of highlighting similarities between elements. Thus, the correct option for this question is A.
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Help me,I’m so confused ..and explain pls
Answer:
1. is 50...
75/1.5 = 50
2. is 600...
300/5 is 600
3.
Part A: 45 minutes= 0.75 hours
Part B: 5.3
Explanation:
Don't agree? The calculator says other wise....
i checked it its correct.
Is it correct or wrong
Answer:
i think correct
Explanation:
i am not sure but i hope it will help you
Adding the number of protons to the number of neutrons determines what about the atom?
A
the atomic number
B
the atomic mass
(Hint: protons + neutrons = ?)
Calculate the moles in 3x10^22molecules of water
Answer:
It is 0.05 moles of water
Explanation:
From avogadro's number:
[tex]{ \sf{6.02 \times {10}^{23} \: mole cules= 1 \: mole }} \\ { \sf{3 \times {10}^{22} \: molecules = ( \frac{3 \times {10}^{22} }{6.02 \times {10}^{23} }) \: moles }} \\ \\ { \sf{ = 0.05 \: moles}}[/tex]
Answer:
[tex]\boxed {\boxed {\sf 0.05 \ mol \ H_2O}}[/tex]
Explanation:
We are asked to calculate the number of moles of water, given the molecules of water.
We will convert moles to molecules using Avogadro's Number or 6.022 × 10²³. This is the number of particles (atoms, molecules, formula units, etc.) in 1 mole of a substance. In this case, the particles are molecules of water or H₂O.
We will convert using dimensional analysis, so we must set up a ratio using Avogadro's Number.
[tex]\frac {6.022 \times 10^{23} \ molecules \ H_2O} { 1 \ mol \ H_2O}[/tex]
We are converting 3 × 10²² molecules of water to moles, so we must multiply the ratio by this value.
[tex]3 \times 10^{22} \ molecules \ H_2O*\frac {6.022 \times 10^{23} \ molecules \ H_2O} { 1 \ mol \ H_2O}[/tex]
Flip the ratio so the units of molecules of water cancel.
[tex]3 \times 10^{22} \ molecules \ H_2O*\frac{ 1 \ mol \ H_2O} {6.022 \times 10^{23} \ molecules \ H_2O}[/tex]
[tex]3 \times 10^{22} *\frac{ 1 \ mol \ H_2O} {6.022 \times 10^{23}}[/tex]
[tex]\frac {3 \times 10^{22}} {6.022 \times 10^{23}} \ mol \ H_2O[/tex]
[tex]0.04981733643 \ mol \ H_2O[/tex]
The original value of molecules of water ( 3 × 10²² ) has 1 significant figure, so our answer must have the same number of sig figs. For our answer that is the hundredth place. The 9 in the thousandth place tells us to round the 4 in the hundredth place up to a 5.
[tex]0.05 \ mol \ H_2O[/tex]
3×10²² molecules of water are equal to 0.05 moles of water.
Write the symbol of atoms as per John Dalton.
please tell fast
Answer:
In his 1805 work, "A New System of Chemical Philosophy," Dalton propounded the tenets of his atomic theory: The chemical elements are made of atoms. The atoms of an element are identical in mass. Atoms of different elements have different masses.
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The density of a substance is 1.63 grams per milliliter. What is the mass of 0.25 liters of the substance in grams?
Answer:
407.5 g
Explanation:
Hope it helps.
What is the process in which matter changes from the liquid to the solid state?
A. melting
B. freezing
C. boiling
D. vaporizing
Answer:
freezing
Explanation:
hope it is helpful
Answer:
freezing. b.
Explanation:
2. All organisms obtain and use
In order to live.
Answer:
Energy . ......
Hope this helps you!
11. What is the mass of the object in the picture below? The density is 0.789g/mL.
Hint: You will need to find the volume first!
Answer: 3.156 grams
Explanation: The additional volume is 4 ml. (0.789 g/ml)*(4 ml) = 3.156 grams
Calculate the no. of moles in 25gm of calcium phosphate
Plz Fast Urgent
Answer:
0.162 mol
Explanation:
n=m/M
M= 20*3 + 15*2 + 8*4*2
M=154 g/mol
n=25g/154g/mol
n=0.162 mol
The number of moles in 25 grams of calcium phosphate is 0.162 mol.
What are moles?Mole is a SI unit that is used to measure the quantity of any substance in a specific amount. To calculate the moles, we will divide the mass of the substance by the molar mass of that substance.
n = m/M
Calcium phosphate is a chemical compound that contains calcium and phosphorus or phosphoric acid, and it is used to treat the low calcium in the body and thyroid and parathyroid.
The molar mass of calcium sulfate is 154 g/mol
The mass of calcium sulfate is 25 grams
Putting the value in the equation
n = m/M
n = 25g / 154 g/mol = 0.162 mol
Thus, the moles of calcium sulfate are 0.162 mol.
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Nhiệt phân hoàn toàn 1,88g Cu(NO3)2.Khí bay ra cho hấp thụ vào H2O tạo thành 2 l dd A. Dd A có pH= ?
Answer: theo mình thì mình làm như sau
cu(no3)2 nhiệt phân hết
\Rightarrow nNO2= 0,02mol
nO2=0,005mol
khi hấp thụ O2 và NO2 vào nước ta có
2NO2 + 1/2 O2\Rightarrow 2HNO3
phản ứng là vừa đủ nên
nHNo3= 0,02 mol
pH HNO3=2
khi cho 0,001mol NaOH vào thì phản ứng trung hòa
H+ + OH- \Rightarrow H20
nHNO3=0,02/20=0,001
nhận thấy nH+ =nOH- nên phản ứng vừa đủ
pH của dd Y=7
theo mình giải là như vậy
Explanation:
Which of the following would electrolysis NOT be used for?
A. Producing electricity
B. Extracting reactive metals
C. Plating metals onto other metals
D. Producing hydrogen gas
Answer:
D
Explanation:
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Producing hydrogen gas. Hence, option D is correct.
What is electrolysis?Electrolysis is described by two half-reactions. These half reaction are the oxidation half-reaction and reduction half-reaction.
Electrolysis involves the transfer of electrons. Each half reaction is characterized by the loss or gain of electrons.
The only reason why producing hydrogen gas is not used most of the time is because electrolysis has very low efficiency, most of the energy finishes up being converted to heat and 95% of the hydrogen is produced by steam reforming.
Hence, option D is correct.
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Write an ionic equation for oxygen reacting with water to form hydroxide ions at the cathode
Explanation:
oxygen (O)will react with water(H2O) to form hydroxide which is (OH
a plant dies if it's phloem tissue is removed .why?
1 Write the correct symbol, with both superscript and subscript,
for each of the following. Use the list of elements in the front
inside cover as needed: (a) the isotope of platinum that contains
118 neutrons, (b) the isotope of krypton with mass number 84,
(c) the isotope of arsenic with mass number 75, (d) the isotope of
magnesium that has an equal number of protons and neutrons.
Answer:
+27 66 514 3800
Explanation:
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20 point for right answer
Answer:The below file contains the answer
Explanation:
Drag the appropriate answer to the correct location on the concept map below.
2. What evidence is there that green ink is a mixture?
Answer:
The fact that the green ink separated from the rubbing alcohol proves that it is indeed a mixture.
WHATS H2O??????????????
Answer:
Explanation:
water
H. 2. O is the chemical formula for water, meaning that each of its molecules contains one oxygen and two hydrogen atoms
i need help with this
Answer:
1. The graph is showing the monthly rainfall between April to July.
2. The month is on the X axis.
3. The inches of the monthly rainfall is on the Y axis.