Answer:
Acid Phosphatase (AP) Test
Explanation:
Acid phosphate is an enzyme that is found in the body. It is secreted majorly by the prostrate gland into the seminal fluid. The acid phosphatase test is used to test for the presence of semen in items.
Scott chose the acid phosphatase test because it is very useful in testing for semen on large items such as blankets. The reaction time for an acid phosphatase test for semen is less than 30 seconds. Seeing that the test was completed in three minutes, Scott concluded that the positive reaction was as a result of some other fluid.
The detectives reported that an overturned bowl of grapes and watermelon was found at the scene as well as a broken glass that had contained wine. Scott knew that some fruit juices like that of watermelon give a positive reaction to the acid phosphatase test but with more time that of the semen fluid because the reaction is a very slow one.
Scott concluded that there was no presence of semen on the blanket and therefore there was no sexual assault.
DAE
On the first day of school, a class of fifth-grade students are given four identical cubos of hard clay. The cubes are placed in four different conditions until the last day of school. At that time, the students make the following
observations
Sample 1: classroom cabinetno noticeable changes
Sample 2 near a window lighter in color
Sample 3: freezer - small cracks near comers
Sample 4 bottle of water small amount of algae on top Which sample shows evidence of physical weathering?
Sample 1
Sample 2
оооо
C
Samples
Sample 4
Answer:
sample 3
Explanation:
i did this
Answer:
Sample 3
Explanation:
physical weathering means the breaking down of an object physically and the small cracks represent physical change.
Which two climates have very low levels of precipitation
A dry and polar
B polar and highlands
C highlands and temperate marine
D temperature marine and temperature continental
Answer:
B highlands and polar, very little percipitation is found in polar regions, and high lands contributes to that
Explanation:
Answer:
B!
Explanation:
got it right on quiz. edu2021
Consider a reaction that connects the ends of a chain of carbons to form a ring. The closure of the ring results in the formation of a new chemical bond, with the bonding electrons going into a bonding sigma molecular orbital at a lower energy. Which of the following statements correctly describes the resulting enthalpy, entropy, and heat changes? Mark all that are correct.
A. The entropy of the surroundings decreases (AS surr < 0) because the closure of the ring results in fewer conformations for the system.
B. The system releases energy to the environment, because its internal energy decreases.
C. The entropy of the surroundings increases (AS surr > 0) because the surroundings absorb heat released by the reaction, and become more disordered.
D. The entropy of the system decreases (AS sys < 0) because the closure of the ring reduces the number of conformations the ring can adopt.
E. The enthalpy or internal energy of the system decreases (AH sys < 0) because the electrons that form the bond enter an orbital that is at a lower energy.
Answer:
The system releases energy to the environment, because its internal energy decreases.
The entropy of the surroundings increases (AS surr > 0) because the surroundings absorb heat released by the reaction, and become more disordered.
The entropy of the system decreases (AS sys < 0) because the closure of the ring reduces the number of conformations the ring can adopt.
The enthalpy or internal energy of the system decreases (AH sys < 0) because the electrons that form the bond enter an orbital that is at a lower energy.
Explanation:
Now we know that when a reaction is exothermic heat is given off. In this case, we have a reaction that connects the ends of a chain of carbons to form a ring. The bonding electrons now move into a lower energy bonding sigma molecular orbital.
This leads to a decrease in the entropy and enthalpy of the system because energy is given off, the closure of the ring reduces the number of conformations the ring can adopt and the electrons that form the bond enter an orbital that is at a lower energy.
The entropy of the surroundings is increased as energy is given out. The surroundings absorb heat released by the reaction, and become more disordered.
What contains more hydrogen atoms, 1.0 mole of H20 or 1.0 moles of НЗО?
H20
H30
both are equal
cannot be determined
(please show ur work)
Gaseous butane CH3CH22CH3 will react with gaseous oxygen O2 to produce gaseous carbon dioxide CO2 and gaseous water H2O. Suppose 0.58 g of butane is mixed with 0.874 g of oxygen. Calculate the maximum mass of water that could be produced by the chemical reaction. Round your answer to 3 significant digits.
Answer:
0.378 g of H₂₂O can be produced.
Explanation:
The combustion reaction is:
2CH₃(CH₂)₂CH₃ + 13O₂ → 8CO₂ + 10H₂O
We convert the mass of reactants to moles:
0.58 g . 1mol / 58.1g = 0.00998 moles of butane
0.874 g . 1mol / 32g = 0.0273 moles of O₂
Oxygen is the limiting reactant. Look at stoichiometry.
2 moles of butane need 13 moles of oxygen to react
Then, 0.00998 moles of gas may react to (0.00998 . 13) / 2 = 0.06487 moles of oyxgen. I only have 0.0273 moles, so i do not have enough oxygen to complete the reaction.
Let's find out the product.
13 moles of oyxgen can produce 10 moles of water.
Then 0.0273 moles of O₂ may produce (0.0273 . 10)/13 = 0.021 moles
We convert to mass → 0.021 mol . 18g /1mol = 0.378 g
Energy can generally be considered to be either kinetic energy or potential energy. Some specific forms of energy, such as
electrical, magnetic, and gravitational energy, can operate in the space around objects and affect other objects that come near. In
these examples
A. energy is continuously created.
B. energy is continuously destroyed.
C. energy exists in a field.
D. all of these
Answer:
d hope it's right hope this helps
Answer:
Energy exists in a field.
Explanation:
Electrical field, magnetic field, and gravitational field.
A and B are wrong otherwise the law of conservation of energy would be violated
Which energy resource causes the greatest waste disposal concerns?
solar power
nuclear
coal
geothermal power
The diagram illustrates photosynthesis.
Which best describes what is happening in the area marked X?
Carbon dioxide enters the stem through xylem.
Oxygen enters the stem through stomata.
Water is carried to the leaves by stomata.
Water is carried to the leaves by xylem.
Answer:
I think Water is carried to the leaves by xylem.
Answer:
d
Explanation:
Examine the diagram of the cell cycle. Which label identifies the stage in which the DNA is copied and the cell grows? W X Y Z
Explanation:
w is the stage in which dna is copied and cell grows.
Answer:
w
Explanation:
ecology is the study of what
Answer:
Relative organisms
Explanation:
Ecology is a branch of biology that deals with the relations of organisms to one another and to their physical surroundings and conditions.
hope this helps:)
A student reacts 13 moles of iron with 21 moles of oxygen according to the following equation:
4Fe(s) + 3O2(g) +2Fe2O3(s)
How many moles of iron(III) oxide will the reaction produce?
a
34 moles
b
13 moles
c
6.5 moles
d
44 moles
Answer:
Explanation:
C
The limiting reactant in this reaction is Fe. 4 moles of Fe gives 2 moles of ferric oxide. Hence, 13 moles of Fe will give 6.5 moles of iron (iii)oxide.
What is limiting reactant ?The reactant which is not sufficient in amount determines the yield of the reaction and it is called the limiting reactant of the reaction.
In the given reaction, 4 moles of iron reacts with 3 moles of oxygen to give 2 moles of iron oxide.
given , no.of moles of oxygen gas present in the sample = 21 moles
no.of moles of Fe = 13 moles.
Here, 28 moles of Fe is needed to react with 21 moles of oxygen. Hence, Fe is the limiting reactant.
4 moles of Fe gives 2 moles of iron (III)oxide. Hence, number of moles of the product , formed from 13 moles of Fe is calculated as follows:
(13 moles ×2 moles)/4moles = 6.5m moles
Therefore, 6.5 moles of iron (III)oxide is formed from 13 moles of Fe.
Find more on limiting reactant :
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3. A gram food sample is burned completely in a calorimeter that contains 1000. of water The temperature of the water increases 23.65 degrees * C . How many Calories does the food have per gram ?
The food has 23629.64 cal
Further explanationGiven
mass = 1000 g of water
temperature increases 23.65 * C
Required
The energy of the food
Solution
Heat absorbed by water :
Q = m . c . Δt
Q = 1000 g x 4.184 J/g°C x 23.65 °C
Q = 98951.6 J
1 Joules = 0.2388 Calories
98951.6 J = 23629.64 cal
If a substance has a large mass and a small volume how dense is it
Answer:
Very dense.
Explanation:
Conceptually, you are taking a large amount of atoms and putting them into a small container. This means the spaces between atoms has to be smaller and the substance is more dense. (see image)
Mathematically, the equation for density is mass divided by volume ([tex]Density=\frac{m}{v}[/tex] ). If you divide a big number by a small number, you still have a pretty big number (ex 4/2=2 versus 6/1=6)
Sound waves travel better through solid than through a gas. Example why this is true
Answer:
This is because molecules in a solid are packed against each other. When a vibration begins, the molecules of a solid immediately collide and the compression wave travels rapidly.
Explanation:
HURRY PLEASE
If 12 grams of sodium reacts with 16 grams of chlorine, how much sodium chloride is Formed?
A. 4 g
B. 12 g
C. 28 g
D. 30 g
Answer:
6.576 g NaCl
Explanation:
2Na + Cl2 --> 2 NaCl
Step 1: Find out moles of Na and Cl to determine the limiting reactant:
moles Na = 12/23 = 0.52 moles Na
moles Cl2 = 16/71=0.225 moles Cl2
ratio Na:Cl is 2.3:1 so Cl is the limiting reactant.
Step 2: How many moles of NaCl are formed:
moles NaCl = moles Cl2 x (1 mol NaCl/2 moles Cl2) = 0.225/2 = 0.1125 moles NaCl
Step 3:
mass NaCl = moles NaCl x MM NaCl = 0.1125 x 58.45 = 6.576 g NaCl
Which of the following are made possible by energy transfer from the Sun? Choose all that apply.
A. biofuels
B. nuclear power using uranium
C. wind power
D. hydroelectric power using a dam
This is Really Science but I couldn’t find it but please help ASAP!
A sample of compound A (a clear, colorless gas) is analyzed and found to contain 4.27g carbon and 5.69g oxygen. A sample of compound B (also a clear, colorless gas) is analyzed and found to contain 5.19g carbon and 13.84g oxygen. Are these data an example of the law of definite proportions, the law of multiple proportions, or neither? What do these data tell you about substances A and B?
Answer:
law of multiple proportions
Explanation:
The law of multiple proportions states that, if two elements A and B, combine to form more than one chemical compound. Then the various masses of one element A, which combine separately with a fixed mass of element B are in simple multiple ratio.
We can see that the ratio of oxygen that combines with carbon in the two compounds( A and B) is 1:2. This demonstrates the law of multiple proportions.
The substances A and B must be CO and CO2 respectively.
Here’s the answers I wasn’t asking a question hehe!Subtract the mass of the filter paper (0.27g) from the mass of the paper and copper (0.98 g). Record the difference in the data table as the amount of copper.
You already converted mass to moles for the reactants. Now convert mass to moles for the product, copper
all for edge
ANSWERS!!!
what causes a massive star wars a turn into a super red giant
Answer:
The core turns its hydrogen to helium and stops nuclear fusion which causes the outer shells of hydrogen to collapse.
Explanation:
This results in higher temperature and pressure which in turn causes the outer shells to expand and cool as a red giant.
show the formation of Mgion and Oion.
Predict: During positron emission, a protonis transformed into a neutronand a positron, which is emitted.The positron will fly through space until it encounters an electron.How will positron emissionaffect the atomic number and mass number of the atom
Answer:
See explanation
Explanation:
A positron is also called a positive electron. It results from the transformation of a proton into a neutron.
When a nucleus decays by positron emission, the atomic mass of both the parent and daughter nuclei remain the same but the atomic number of the daughter nucleus decreases by 1 compared to that of the parent nucleus. The daughter nucleus is now found one place to the left of the parent nucleus in the periodic table.
This leads to an increase in the Neutron/Proton ratio.
What kind of reaction is this? *
Na + C1, → NaCl
Pls help me I’m having a hard day pls answer these?
Answer:the first one is D second one is A and the third one is A :D
Explanation:
1. A gas has a volume of 5.30 mL and a mass of 24.10 grams. What is the
density?
Answer:
4.5472g/ml rounded of to 4 s.f
Explanation:
Density= Mass/ Volume
How many grams of moles are in 94.2 g of C02?
Answer:
Moles to grams carbon dioxide
1 mole is equal to 1 moles Carbon Dioxide, or 44.0095 grams.
Explanation:
Moles to grams carbon dioxide
1 mole is equal to 1 moles Carbon Dioxide, or 44.0095 grams.
In the presence of an acid catalyst, cyclohexanol (100.16 g/mol) is dehydrated to give cyclohexene (82.14 g/mol) and water. Reaction scheme illustrating the dehydration of cyclohexanol in the prescence of acid catalyst to cylcohexene and water. A dehydration reaction starting with 4.1 g cyclohexanol produces 3.0 g cyclohexene. Calculate the percent yield for this reaction. Report your answer with two significant figures.
Answer:
88%
Explanation:
Step 1: Write the balanced equation
C₆H₁₁OH ⇒ C₆H₁₀ + H₂O
Step 2: Calculate the moles corresponding to 4.1 g of C₆H₁₁OH
The molar mass of C₆H₁₁OH is 100.16 g/mol.
4.1 g × 1 mol/100.16 g = 0.041 mol
Step 3: Calculate the theoretical yield, in moles, of C₆H₁₀
The molar ratio of C₆H₁₁OH to C₆H₁₀ is 1:1. The theoretical yield of C₆H₁₀, in moles, is 1/1 × 0.041 mol = 0.041 mol.
Step 4: Calculate the mass corresponding to 0.041 moles of C₆H₁₀
The molar mass of C₆H₁₀ is 82.14 g/mol.
0.041 mol × 82.14 g/mol = 3.4 g
Step 5: Calculate the percent yield of C₆H₁₀
We will use the following expression.
percent yield = experimental yield/theoretical yield × 100%
percent yield = 3.0 g/3.4 g × 100% = 88%
help me please i do not understand
Answer:
1 g/cm3
Explanation:
The formula for density is mass/volume
The mass is 100 g and the volume is 100 cm3
100 g/100 cm3=1 g/cm3
Draw all four products obtained when 2-ethyl-3-methyl-1,3-cyclohexadiene is treated with HBr at room temperature and show the mechanism of their formation. For the mechanism, include lone pairs and charges in your answer. Do not draw out any hydrogen explicitly. Do not use abbreviations such as Me or Ph.
Answer:
See explanation below
Explanation:
In this case we have reaction of addition. In this case a diene reacting with an acid as HBr. This reaction is known as Hydrohalogenation, and, as we have a diene, this kind of reaction can be done as 1,4 addition. Which means that the reaction will be undergoing with an adition in the carbon 1, and carbon 4.
At room temperature we can expect that this reaction can be done in thermodynamic conditions, Now, as the problem states that is forming 4 products, we can expect products of a 1,2 addition too. This product can be formed if the reaction is taking place in the most stable carbocation, and then, by resonance, we can expect the 1,4 product too.
Now, the HBr can be attacked by the double bond of the first position, giving two possible products or by the double bond of the third position giving the other two products. These products are all possible, obviously the most stable will be the major of all of them, but the other three are perfectly possible. One product is formed without doing much, and the other by resonance. Same happens with the other double bond.
In the picture below, you have the mechanism for all the 4 products.
Hope this helps
The increase in electro negativity when moving left to right on the periodic table can be explained by what?
Answer: Decrease in size
Explanation:
Electronegativity is defined as the property of an element to attract a shared pair of electron towards itself.
On moving across a period from left to right, the size of an atom decreases because the electrons get added to the same shell and the nuclear charge keeps on increasing. Thus the electrons get more tightly held by the nucleus.
As, the size of an element decreases, the valence electrons come near to the nucleus. So, the attraction between the nucleus and the shared pair of electrons increases. Thus electronegativity increases.
How many moles of O2 are needed to produce 2.5 moles of water?
Answer:
Mass of oxygen = 16 * 1.25 = 20 g
Explanation: