Answer:
Explanation:
Atoms of an element with the same mass number make up an isotope of the element. Different isotopes of the same element cannot have the same mass number, but isotopes of different elements often do have the same mass number, e.g., carbon-14 (6 protons and 8 neutrons) and nitrogen-14 (7 protons and 7 neutrons).
Answer: NO I know sorry
Which of the following sources could not be used to obtain the DNA of a person lost in a mass disaster? used and unwashed clothing or bed sheets food found in the victim's refrigerator sunglasses regularly used by the person a toothbrush used by the person
Which of the following sources could not be used to obtain the DNA of a person lost in a mass disaster?
used and unwashed clothing or bed sheetsfood found in the victim's refrigeratorsunglasses regularly used by the persona toothbrush used by the personAnswer :food found in the victim's refrigerator could not be used to obtain the DNA of a person lost in a mass disaster.
So, correct answer is 2nd one.
Zn(s) + 2 HCl(aq) —> ZnCl2(aq)
+ H2(g)
If a scientist wanted to create 10L of hydrogen gas at RTP, what mass of HCl would they need to start with?
Answer:
First write the balanced equation for the reaction of HCl with Zn (NOTE: the previous answer did NOT do this and thus obtained an incorrect answer)
Zn + 2HCl ==> ZnCl2 + H2(g)
moles of H2 desired: PV = nRT
n = PV/RT = (1 atm)(10L)/(0.0821 Latm/Kmol)(298K)
n = 0.409 mole H2 desired
moles Zn needed:
0.409 moles H2 x 1 mole Zn/2 moles HCl = 0.204 moles Zn needed
mass Zn needed = 0.204 moles Zn x 65.4 g/mol = 13.4 g Zn needed (to 3 sig. figs.)
Explanation:people always get this wrong but i got you
Please help it really important, I will mark brainliest please
Answer:
S0rRy i d0nT kn0w fRenCh
According to this video, how do scientists use data to study/monitor earthquakes and tsunamis?
Answer:
ewan ko po
Explanation:
sana makatulong
Determine the molecular formula for a compound that has a molecular mass of 52.0 g/mole
and and is composed of 92.31% carbon and 7.69% hydrogen.
Answer:
C4H4
Explanation:
92.31% of 52.0 g/mol is 48.0012 g/mol
7.69% of 52.0 g/mol is is 3.9988 g/mol
Carbon has a gram-formula mass of about 12, which goes into 48.0012 about 4 times, so there should be 4 atoms of Carbon
Hydrogen has a gram-formula mass of about 1, which goes into 3.9988 about 4 times, so there should also be 4 atoms of hydrogen
K2HPO4 is a highly water-soluble salt. It can be used as a buffering agent, food additive, or
fertilizer. The neutralization of phosphoric acid with potassium hydroxide can be used to form
potassium hydrogen phosphate.
H3PO4 + 2KOH K2HPO4 + 2H2O
100 g of phosphoric acid (H3PO4) is reacted with excess potassium hydroxide. The final mass
of K2HPO4 produced is found to be 163 g.
What is the percent yield?
Answer:
91.7%
Explanation:
The percent yield when it could be used as a buffering agent should be considered as the 91.74%.
Calculation of the percent yield:Since we know that
Number of moles = Mass in gram / Molar mass
And,
Molar mass of H3PO4 = 97.994 g/mol
So,
Number of moles of H3PO4
= 100 g / 97.994 g/mol
= 1.02 mol
Now
Molar mass of K2HPO4 = 174.2 g/mol
So,
Theoretical yield of K2HPO4 = 174.2 g/mol * 1.02 mol
= 177.684 g
So finally
Percent yield = Actual yield * 100 / Theoretical yield
= 163 g * 100 / 177.684 g
= 91.74%
hence, The percent yield when it could be used as a buffering agent should be considered as the 91.74%.
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Choose the combination of factors that creates fog. Record the description of the factors in the Student Guide,
Relative Humidity
Air Temperature
Air Pressure
Check
Pause
Answer:
Relative Humidity
Air Temperature
Explanation:
Relative humidity and air temperature are the factors that creates fog. When the moist and warm air makes contact with the cooler air, water vapor condenses due to low temperature of that region that causes for the formation of fog. So we can say that relative humidity and air temperature are the main factors for the formation of fog in that region.
Answer:
High Cold High
Explanation:
Antonio and Addie want to know if perfume fumes affect plant height. They place five identical bean plants in five identical light boxes. In four of the boxes, they place 200 milliliters (mL) of perfume at different distances from the plants, and they make observations twice a week for one month. Which choice best identifies the observation data that should be included in their data table?
Answer:
I think its C I'm sorry if I'm wrong good luck guys!
Explanation:
Which represents the overall (net) reaction of this mechanism: step 1: H2O2 + I- → H2O + OI- step 2: H2O2 + OI- → H2O + O2 + I- Note that I- acts as a catalyst in this reaction.
A. 2H2O2 → 2H2O + O2
B. H2O2 → H2 + O2
C. H2O2 + I- → OI- + H2O
D. H2O2 + OI- → H2O + O2 + I-
Answer:
A. 2H₂O₂ → 2H₂O + O₂
Explanation:
1. H₂O₂ + I⁻ → H₂O + OI⁻2. H₂O₂ + OI⁻ → H₂O + O₂ + I⁻If we make a net sum of both reactions, we're left with:
H₂O₂ + I⁻ + H₂O₂ + OI⁻ → H₂O + OI⁻ + H₂O + O₂ + I⁻Grouping species:
2H₂O₂ + OI⁻ + I⁻ → 2H₂O + OI⁻ + O₂ + I⁻There is OI⁻ at both sides, so it is eliminated -same goes for the catalyst, I⁻-.
2H₂O₂ → 2H₂O + O₂Thus the answer is option A.
What are the three types of diagrams in science? This if eight grade science
Answer: bar graph, circle graphs, line graphs
Explanation:
An airplane has a mass of 12,000kg. If it is accelerating at 16m/sec2, what is its force?(round to the nearest whole number) NEED THIS ASAP
Answer:
[tex]F=1.92x10^5N[/tex]
Explanation:
Hello!
In this case, since the force exerted by an object with a certain mass an acceleration is:
[tex]F=m*a[/tex]
We can plug in the given mass of 12,000 kg and acceleration of 16 m/s^2 to obtain:
[tex]F=12,000kg*16m/s^2\\\\F=192,000kg*m/s^2\\\\F=1.92x10^5N[/tex]
Best regards!
1. Mixing Water at Two Temperatures
a. One flask contains 150.0 g water at 20.0 °C. A second flask contains 350.0 g water at 95.0 °C. If the two water samples are mixed, what will the final temperature of the water be?
-Assume that the density of water it 1.000 g/cm^3
-The specific heat capacity for water is 4.184 J/g °C
Answer:
[tex]T_f=72.5\°C[/tex]
Explanation:
Hello!
In this case, since this a problem in which the cold water is heated by the hot water, we can write:
[tex]Q_{hot}+Q_{cold}=0[/tex]
Thus, by plugging in the mass, specific heat and temperatures, we obtain:
[tex]m_{hot}C_{hot}(T_f-T_{hot})+m_{cold}C_{cold}(T_f-T_{cold})=0[/tex]
Now, we can also write:
[tex]m_{hot}(T_f-T_{hot})+m_{cold}(T_f-T_{cold})=0[/tex]
Then, after applying some algebra, it is possible to obtain:
[tex]T_f=\frac{m_{hot}T_{hot}+m_{cold}T_{cold}}{m_{hot}+m_{cold}}[/tex]
If we plug in, we obtain:
[tex]T_f=\frac{350.0g*95.0\°C+150.0g*20.0\°C}{350.0g+150.0g}[/tex]
[tex]T_f=72.5\°C[/tex]
Best regards!
(b) Why must acidic gases be treated before they are released into the atmosphere?
Answer:
because they react with other gases of atmosphere and pollute the environment
why is seawater a better conductor of electricity than freshwater?
Answer:
please refer to the attachment above;)
Answer:
Because it contains Na+ and Cl- ions, Which are conductors of electricity
Explanation:
Please help :) hope you have a good day
Have a wonderful day :) thanks for the points
b. If you have 50 grams of Molybdenum-99, how many grams will remain
after 11 days?
Answer:
6.25gm
half life is 66hrs 11 days is 24*11 then take that and divide by 66 to find out how many time it will have halved and half 50 by that many times
Explanation:
If you have 50 grams of Molybdenum-99, after 11 days, 2.7 g will remain.
Molybdenum-99 follows first-order decay.
What is first-order decay?First-order decay means that for a population of atoms (e.g. radioactive), molecules, or anything else, a constant fraction/unit time is converted to something else.
The half-life (th) of Mo-99 is 66 h.
We will find its rate constant (k) using the following expression.
k = ln2 / th = ln2 / 66 h = 0.011 h⁻¹
Next, we will convert 11 days to hours, knowing that 1 day = 24 h.
11 d × 24 h/1 d = 264 h
If we start with 50 g of Mo-99, we can calculate the remaining mass after 264 h using the following expression.
[tex][Mo] = [Mo]_0 \times e ^{-k \times t} }\\\\[Mo] = 50g \times e ^{-0.011 h^{-1} \times 264 h} } = 2.7 g[/tex]
where,
[Mo] is the final amount of Mo-99.[Mo]₀ is the initial amount of Mo-99.t is the elapsed time.If you have 50 grams of Molybdenum-99, after 11 days, 2.7 g will remain.
Learn more about first-order decay here: https://brainly.com/question/14478152
name the two criteria that is used to determine if a substance is pure or not
Answer:
Melting and Boiling Point Determination
The physical properties of a substance can be used to establish its purity. These properties include the melting point and boiling point. Different substances tend to have different melting and boiling points, and any pure substance will have a specific melting and boiling point.
what is the chemical equation for methamphetamine
Answer:
C10H15N is the chemical equation for methamphetamine
Is water made of plant cells or animal cells
•plant
•animals
•niether
Answer:
i think niether
Explanation:
Name this branched alkane shown in Figure 18-1.
Answer:
3–ethyl–2,2–dimethylhexane
Explanation:
To name the compound given in the question above, do the following:
1. Determine the parent name by determining the longest continuous carbon chain. In this case, the longest continuous carbon chain is 6. Hence, the parent name is Hexane.
2. Identify the substituent group attached to the compound. In this case, we have one ethly group (–CH₂CH₃) and two methyl groups (–CH₃)
3. Locate the position of the substituents by giving them the lowest possible count. In this case,
The two methyl groups (–CH₃) are located at carbon 2
The ethly group (–CH₂CH₃) is located at carbon 3.
4. Combine the above to obtain the name of the compound.
The name of the compound is:
3–ethyl–2,2–dimethylhexane
Which of the following is an ether?
A)
B)
C)
D)
What is an electrolytic cell?
Answer:
An electrolytic cell is a cell that converts electrical energy into chemical energy.
Any device in which electrical energy is converted to chemical energy or vice versa is referred to as an electrolytic cell. A typical cell consists of two metallic or electronic conductors held apart and in contact with an electrolyte, which is usually a dissolved or fused ionic compound.
What is an electrolytic cell ?An electrolytic cell is a type of electrochemical cell that uses an external source of electrical energy to force a chemical reaction that would not occur otherwise. A voltage applied between the cell's two electrodes, an anode and a cathode immersed in an electrolyte solution, serves as the external energy source.
Electrons in the form of an electric current are deliberately pumped through the chemicals in the section to induce an oxidation-reduction reaction. An electrolytic cell is a setup used to electrolytically decompose water into hydrogen and oxygen.
Electrochemical cells that generate an electric current are known as voltaic or galvanic cells, whereas those that generate chemical reactions, such as electrolysis, are known as electrolytic cells.
Thus, Any device in which electrical energy is converted to chemical energy or vice versa is referred to as an electrolytic cell.
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#3. How does a fever aid an immune response?
Answer:
it can tell and show what pathogen is in you as well what type and mutation so then your body can fight back and remember the genetic dna so then you will be immune in some way.
Explanation:
Question;
How does a fever aid an immune response?
Answer:
One type of immune cell jumps into the fray after body temperature rises, according to experiments in mice. A fever fights infection by helping immune cells to crawl along blood-vessel walls to attack invading microbes
Which of the following particles has the smallest
mass?
A) electron
C) neutron
B) hydrogen atom
D) proton
Answer:
AN ELECTRON HAS THE SMALLEST MASS!
Answer:
A) electron
good luck, i hope this helps :)
3.Which of these is NOT part of the cell theory? * "
all living things are made of cells
Ocells come only from other cells
cells are the smallest living unit of an organism
O all living things have blood cells
Answer:
Cells are the smallest living unit of an organism
Answer:
all living things living things have blood cells
Explanation:
this is because robert hooke did not make this apart of the theory
How many particles are in 4g of NaCl? (1mol of NaCl = 58g) – 2 step conversion
Answer:
4.16 * 10²⁴ particles
Explanation:
1. We convert from grams to moles
4 g NaCl / 58 g of NaCl = 0.0689655172 moles
-> 0.0690 moles
2. Now we will convert from moles to particles by multiplying by avogadro's number..
0.0690 * 6.022 *10²³ = 4.15518 * 10²⁴ particles or 4.16 * 10²⁴ particles
The compound cobalt (II) sulfate forms a hydrate with seven water molecules per formula unit. What are the name and formula of the hydrate
Answer: The formula of the hydrate will be [tex]CuSO_4.7H_2O[/tex] and the name of the compound is copper sulphate heptahydrate.
Explanation:
Water of crystallisation is the number of water molecules that combine chemically in definite molecular proportion with the concerned salt in the crystalline state.
The formula of the hydrate will be [tex]CuSO_4.7H_2O[/tex] and the name of the compound is copper (II) sulphate heptahydrate as there are 7 molecules of water.
Given the atomic mass of select elements, calculate the molar mass of each salt.
Element Molar mass
(g/mol)
Beryllium (Be) 9.012
Magnesium (Mg) 24.31
Cobalt (Co) 58.93
Cadmium (Cd) 112.41
Bromine (Br) 79.90
Match the numbers to the appropriate blanks in the sentences below. Make certain each sentence is complete before submitting your answer.
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1. The molar mass of MgBr2 is The molar mass of M g B r 2 is blank..
2. The molar mass of BeBr2 is The molar mass of B e B r 2 is blank..
3. The molar mass of CoBr2 is The molar mass of C o B r 2 is blank..
4. The molar mass of CdBr2 is The molar mass of C d B r 2 is blank..
neptune has an average distance to the sun of 30.06 au in two or more complete sentences explain how to calculate the orbital period of neptune
Answer:
As per Kepler's law we know that \frac{T_1^2}{T_2^2} = \frac{R_1^3}{R_2^3}T22T12=R23R13as we know that for earth the time period is 1 year and its distance is 1 AUnow from above formula we can saylet the time period of Neptune is T and its distance is given as R = 30.06 AUnow we will have\frac{1^2}{T^2} = \frac{1^3}{30.06^3}T212=30.06313by rearranging the above equation we haveT^2 = (30.06)^3T2=(30.06)3T = 164.8 yearsT=164.8yearsso it will have time period of 164.8 yearspls help me on this it's about acceleration
Answer:
1: A b/c the table is showing that each different surface resulted in different time for acceleration.
2: D b/c the if the same force is applied to two different masses, the smaller masses would be impacted more and move faster. The larger an object is, then the greater the force you will need for it to move the same distance as the smaller masses.