12
Explanation:
Look at the number directly after the number you want to keep. I'm your case you want to keep the first two numbers and the number directly after is 4 so there is no need to round up. Keep your 12 without a decimal.
------------neutral particles in an atom
Answer:
neutrons :
Explanation:
Protons are positively charged, while electrons are negatively charged. Neutrons are electrically neutral, as the name suggests. The electric charge, noted Q , is a physical quantity.
calculate the mass of sodium sulphate required to prepare its 20%of solution in 100 g ofwater
Answer:
25 g
Explanation:
Mass percent implies the mass of solute dissolved in a solution
Mass percent = mass of solute/mass of solute + mass of solvent × 100/1
Since mass percent concentration= 20%
Mass of solvent = 100g
Let mass of solute = x
Hence;
20 = x/x +100 ×100/1
20/100= x/x + 100
0.2 = x/x + 100
0.2(x + 100) = x
0.2x + 20 = x
20 = x - 0.2x
20 = 0.8x
x= 20/0.8
x= 25 g
Which of the following elements does not lose an electron easily? NA F MG AL
Answer:
F
EXPLANATION
Among the given elements fluorine(F)can not lose electrons easily because of its high electron affinity, high nuclear charge and high electronegativity.
Answer:
F
Explanation:
it won't lose electron , rather it would gain electron to complete its octate......
Electronic Configuration of F = 2,7
So F will gain 1 electron ....
g When a 2.75g sample of liquid octane (C8H18) is burned in a bomb calorimeter, the temperature of the calorimeter rises from 22.0 °C to 41.5 °C. The heat capacity of the calorimeter, measured in a separate experiment, is 6.18 kJ/°C. Determine the ΔE for octane combustion in units of kJ/mol octane.
Answer:
The correct answer is 5021.25 kJ/mol octane
Explanation:
The heat absorbed by the calorimeter is given by:
heat absorbed = Ccal x ΔT
Given:
Ccal = 6.18 kJ/ºC (heat capacity of calorimeter)
ΔT= Final temperature - initial temperature = 41.5ºC-22.0ºC = 19.5ºC
We first calculate the heat absorbed:
heat absorbed = 6.18 kJ/ºC x 19.5ºC = 120.51 kJ
The change in internal energy (ΔE) is equal to the heat absorbed by the calorimeter. In order to determine ΔE in kJ/mol we have to divide the heat into the number of moles of octane (C₈H₁₈) burned in the calorimeter.
Molecular weight (C₈H₁₈) = (12 g/mol x 8) + (1 g/mol x 18) = 114 g/mol
Moles of C₈H₁₈= mass/molecular weight= (2.75 g)/(114 g/mol)= 0.024 moles
Finally, we calculate ΔE:
ΔE = heat absorbed/moles of octane = (120.51 kJ)/(0.024 mol octane) = 5021.25 kJ/mol octane
List four examples of diffusion seen in daily life.
Answer:
Spraying perfume in one corner of the room and the smell travels to the other side of the room
Explanation:
Seawater is highly saline, which means it contains large amounts of dissolved salt. When seawater freezes and icebergs form, the water in the iceberg doesn’t take the salt with it. What effect will this phenomenon have on the concentration of salt in the water around the iceberg?
Answer:
Because the amount of liquid water decreases and the amount of dissolved salt remains constant, the concentration of salt in the liquid water around the iceberg will increase.
Explanation:
Answer:
Because the amount of liquid water decreases and the amount of dissolved salt remains constant, the concentration of salt in the liquid water around the iceberg will increase.
Explanation:
PLATO exact answer
The volume of a sample of pure HCl gas was 221 mL at 20°C and 111 mmHg. It was completely dissolved in about 50 mL of water and titrated with an NaOH solution; 18.7 mL of the NaOH solution was required to neutralize the HCl. Calculate the molarity of the NaOH solution.
Answer:
[tex]molarity =6.9\times 10^{-3}\ M\\[/tex]
Explanation:
We know that , the reaction of HCl and NaOH is given as follows
[tex]NaOH+HCl=NaCl +H_2O[/tex]
Given that
Pressure = 111 mm Hg
[tex]P=111\times 13.6\times 10^{-3}\times 9.81\times 1000=14.809\ kPa[/tex]
Temperature = 20°C
T=20+273=293 K
Volume= 221 m L
V=0.221 L
Number of moles of HCl is given as follows
[tex]n=\dfrac{P\times V}{R\times T}\\n=\dfrac{0.148\times 0.221}{0.821\times 293}=1.3\times 10^{-4}\ moles[/tex]
From the above reaction we can say that
Number of moles of HCl=Number of moles of NaOH
Volume of NaoH is given as follows
V=18.7 = 0.0187 L
Therefore molarity
[tex]molarity =\dfrac{n}{V_{NaOH}}\\molarity =\dfrac{1.3\times 10^{-4}}{0.0187}=6.9\times 10^{-3}\ M\\molarity =6.9\times 10^{-3}\ M\\[/tex]
A sample of O2 gas is collected over water at 25oC at a barometric pressure of 751 torr. The vapor pressure of water at 25oC is 23.8 torr. What is the partial pressure of the O2 gas in the sample
Answer:
727.7 torr
Explanation:
Since the gas was collected over water, it is likely to be saturated with water vapour and the total pressure is given as;
Ptotal = Pgas + Pwater
From the question;
Ptotal = 751 torr
Pgas = ?
Pwater = 23.8 torr
Making Pgas subject of equation, we have;
Pgas = Ptotal - Pwater
Pgas = 751 torr - 23.8 torr
Pgas = 727.7 torr
how many sigma and pi bonds in propionic bond
pls help...
You are a forensic scientist working on a murder case. You have taken the blood sample from the crime scene and put it through Electrophoresis and Southern blotting. What step do you need to take next? A. Add ethanol B. Add restriction enzymes C. Add minisatellites D. Add radioactive probes
Add minisatellites. Hence, option C is correct.
What is Electrophoresis?Electrophoresis is a laboratory technique used to separate DNA, RNA or protein molecules based on their size and electrical charge.
You are a forensic scientist working on a murder case. You have taken the blood sample from the crime scene and put it through Electrophoresis and Southern blotting. you need to add minisatellites.
Hence, option C is correct.
Learn more about Electrophoresis here:
https://brainly.com/question/13949940
#SPJ2
What is the precipitate in the following reaction?
2AgNO3(aq) + Na2S(aq) → Ag2S(s) + 2NaNO3(aq)
Answer:
2Ag(+1)(aq) + S(-2)(aq) --> Ag2(+1)S(-2)(aq)
Explanation:
The final equation is
2Ag(+1)(aq) + S(-2)(aq) --> Ag2(+1)S(-2)(aq)
2Ag(+1)NO3(-1)(aq) + Na2(+1)S(-2)(aq) --> Ag2(+1)S(-2)(s) + 2Na(+1)NO3(-1)(aq)
AgNO3, Na2S, and NaNO3 are all strong electrolytes, so we immediately separate those, making the new equation:
2Ag(+1)(aq) + 2NO3(-1)(aq) + 2Na(+1)(aq) + S(-2)(aq) --> Ag2(+1)S(-2)(s) + 2Na(+1)(aq) + 2NO3(-1)(aq)
After that, you cancel out all the ions that appear more than once, which in this case would leave us with a final equation of...
2Ag(+1)(aq) + S(-2)(aq) --> Ag2(+1)S(-2)(aq)
Answer:
Explanation:
C
how to make a salt by neutralization reaction
Answer:
Acid+Base=Salt+water
This is the formula of neutralization reaction.
According to this formula you can make salts by reacting an acid with a base.
Hope this helps ❤❤❤.
Which of the following may suggest a catalyst has been used in a reaction, given the energy diagram for the same reaction without a catalyst?
A 35 L tank of oxygen is at 42°C with an internal pressure of 5000.mmHg. If the temperature changes to 88°C, what would the new pressure be ? the volume is held constant
Answer:
5730 mmHg.
Explanation:
The following data were obtained from the question:
Initial temperature (T1) = 42 °C.
Initial pressure (P1) = 5000 mmHg.
Final temperature (T2) = 88 °C.
Final pressure (P2) =.?
Next we shall convert celsius temperature,T(°C) to Kelvin temperature, T(K).
This can be obtained as follow:
T(K) = T(°C) + 273
Initial temperature (T1) = 42 °C.
Initial temperature (T1) = 42 °C + 273 = 315 K
Final temperature (T2) = 88 °C.
Final temperature (T2) = 88 °C + 273 = 361 K
Finally, we shall determine the new pressure.
Since the volume of the container is constant, the new pressure can be obtained as follow:
Initial temperature (T1) = 315 K.
Initial pressure (P1) = 5000 mmHg.
Final temperature (T2) = 361 K.
Final pressure (P2) =.?
P1/T1 = P2/T2
5000/315 = P2/361
Cross multiply
315 x P2 = 5000 x 361
Divide both side by 315
P2 = (5000 x 361) / 315
P2 = 5730.1 ≈ 5730 mmHg
Therefore, the new pressure is 5730 mmHg.
The intake stroke of a positive displacement compressor is most similar to that of a
A. thermostatic expansion valve.
B. auxillary electric water pump.
C. one-stroke variable displacement compressor.
D. two-stroke cylinder engine.
Answer:
D. two-stroke cylinder engine.
Explanation:
Two-stroke cylinder engine: In chemistry, the term "two-stroke cylinder engine" is described as one of the types of "internal combustion engine" that tends to complete a single "power cycle" possessing two different strokes of the "piston" during a particular "crankshaft revolution".
It generally consists of two different strokes that are being often known as power or exhaust and suction stroke.
In the question above, the given statement signifies the "two-stroke cylinder engine".
Explain this
When a small piece of glowing sodium is placed inside a gas jar filled with chlorine gas, the sodium continues to burn brightly but when the gas is replaced by argon gas, the glowing sodium becomes extinguished.
Answer:
Because Argon is a inert gas
Explanation:
Inert gases don't take place in any experiments
Answer:
Below.
Explanation:
The sodium reacts strongly with the chlorine to form NaCl and the heat of reaction continues the brightness, whereas it does not react with the inert gas argon and soon cools down.
Label the following as either an Element, Compound, or Mixture.
Answer:
27. Element (Because it contains all same atoms)
28. Compound (It contains atoms held together through chemical bonds)
29. Element (it contains all same atoms)
33. Mixture (It contains different atoms but they are not held together through chemical means)
34. Compound (Different atoms held together through chemical means)
35. Mixture (Mixture of elements and compounds)
30. Element (it contains all same atoms)
31. Mixture (Mixture of elements and compounds)
32. Element (Contain all same atoms although held together through chemical means they are not compounds)
what happens when ca no3 2 is heating it gives CaO ,NO2 and 02
Answer:
balanced equation:
2Ca(NO3)2 (aq)-----> 2CaO (s) + 4NO2 (g) + O2 (g)
So heating 2 moles of Ca(NO3)2 gives 2 moles of CaO, 4 moles of NO2 and 1 mole of O2. This is a heat decomposition reaction. It gives a white precipitate (CaO), and brown pungent gas (NO2).
Answer:
The balanced equation of the reaction is below.
Explanation:
2Ca(NO3)2 -----> 2CaO + 4NO2 + O2.
For which of the following reactions will a decrease in pressure shift the equilibrium to the left?
A). 2A2 (g) + B2 (g) --> 2A2B (g)
B). 2AB (g) --> A2 (g)+ B2 (g)
C). 2A2F3 (g) --> 4A (g) + 3F2 (g)
D). 2B (s) + 2HA (aq) --> 2BA (aq) + H2 (g)
Answer: I just took the test, the answer is A.
Explanation:
Si el elemento "X" tiene 8 protones y el elemento "Y" tiene 11 protones, al reaccionar ¿Qué tipo de enlace pueden formar? Seleccione una: a. Metálico. b. Covalente puro. c. Covalente polar. d. Iónico.
Answer:
D; Iónico
Explanation:
El elemento con 8 protones es oxígeno, mientras que el elemento con 11 protones es sodio.
El sodio es un metal alcalinotérreo, mientras que el oxígeno no es un metal.
En general, cuando tenemos un elemento metálico como el sodio, que se une con uno no metálico como el oxígeno, el tipo de enlace formado como resultado de la transferencia completa de electrones desde la capa de valencia del sodio a la capa de valencia del oxígeno para completar su propia configuración de octeto se denomina enlace electrovalente o, más generalmente, enlace iónico