Answer: There are [tex]4.13 \times 10^{-3}[/tex] moles of Pb are contained in [tex]2.49 \times 10^{25}[/tex] atoms Pb.
Explanation:
According to the mole concept, 1 mole of every substance contains [tex]6.023 \times 10^{23}[/tex] atoms.
Hence, number of moles present in [tex]2.49 \times 10^{25}[/tex] atoms of Pb are as follows.
[tex]No. of moles = \frac{2.49 \times 10^{25}}{6.023 \times 10^{23}}\\= 4.13 \times 10^{-3} mol[/tex]
Thus, we can conclude that there are [tex]4.13 \times 10^{-3}[/tex] moles of Pb are contained in [tex]2.49 \times 10^{25}[/tex] atoms Pb.
The titration of HCl with NaOH is an example of:
A. a weak acid-weak base titration,
B. a weak acid-strong base titration.
c. a strong acid-strong base titration.
D. a strong acid-weak base titration.
Answer:
I’m pretty sure it’s C
Explanation:
AP Ex
When sodium chloride is dissolved in water, the freezing point of water _________. A. increases B. first increases, then decreases C. does not change D. decreases
The presence of a non-volatile salt will decrease the freezing point of water and this process is called depression in freezing point. Thus option D is correct.
What is freezing point?Freezing point of a substance is the temperature at which it converts from its liquid state to solid state where, both the states are in equilibrium. Freezing point of water is zero degree celsius.
The freezing point of a solvent depends on some parameters such as the bond type, molecular weight, temperature, pressure etc.
When a non-volatile solute is added to the solvent its freezing point decreases from its initial value. Because presence of non-volatile salts will affect the intermolecular attraction and thereby the energy that must be applied to freeze the compound.
Therefore, the freezing point of water decreases, when sodium chloride is added into it. Thus option D is correct.
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A balloon is inflated with 1.25 L of helium at a temperature of 298K. What is
the volume of the balloon when the temperature is 310K?
Answer:
What is
the volume of the balloon when the temperature is 310K?
What is the initial and final mass of the zinc and copper?
Answer:the final mass of copper is 3.84 g. There was an increase in mass of 1.84 g from the initial mass of 2.0 g.
Explanation:
determine the maximum amount of NaN03 that was produced during the experiment. Explain how you determined the amount
Answer:
9 moles of NaNO3 is obtained
Explanation:
The balanced chemical reaction equation for the reaction is;
Al(NO3)3 + 3NaCl-------> 3NaNO3 + AlCl3
Now, we have to determine the limiting reactant. The limiting reactant yields the least amount of NaNO3.
1 mole of Al(NO3)3 yields 3 moles of NaNO3
4 moles of Al(NO3)3 yields 4 * 3/1 = 12 moles of NaNO3
Also,
3 moles of NaCl yields 3 moles of NaNO3
9 moles of NaCl yields 9 * 3/3 = 9 moles of NaNO3
Hence, NaCl is the limiting reactant and 9 moles of NaNO3 is obtained.
9 moles of NaNO₃ is obtained.
Balanced chemical reaction:
[tex]Al(NO_3)_3 + 3NaCl-----> 3NaNO_3 + AlCl_3[/tex]
From the reaction, it is seen that the limiting reactant yields the least amount of NaNO₃.
1 mole of Al(NO₃)₃ yields 3 moles of NaNO₃
4 moles of Al(NO₃)₃ yields 4 * 3/1 = 12 moles of NaNO₃
Also,
3 moles of NaCl yields 3 moles of NaNO₃
9 moles of NaCl yields 9 * 3/3 = 9 moles of NaNO₃
Hence, NaCl is the limiting reactant and 9 moles of NaNO₃ is obtained.
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1. Watch how the solubility of a gas changes as pressure is increased and then decreased during the run. Which of the following statements correctly explain the relationship between the solubility of a gas and its pressure?
A. As pressure decreases, the concentration of gas molecules in the solution increases.
B. The concentration of gas particles in the solution is higher at 4.25 atm than at 1.00 atm.
C. The solubility of a gas decreases with a decrease in pressure.
D. The solubility of nitrogen gas at 2.00 atm is twice the solubility of the gas at 1.00 atm.
E. Fewer gas molecules are soluble at higher pressures.
F. More gas molecules are soluble as pressure is increased.
G. As pressure is increased, the rate at which gas molecules enter the solution decreases.
2. At a certain temperature, the solubility of N2 gas in water at 3.08 atm is72.5mg of N2 gas/100 g water. Calculate the solubility of N2 gas in water, at the same temperature, if the partial pressure of N2 gas over the solution is increased from 3.08 atm to 8.00 atm .
Answer:
A. As pressure decreases, the concentration of gas molecules in the solution increases.
D. The solubility of nitrogen gas at 2.00 atm is twice the solubility of the gas at 1.00 atm.
F. More gas molecules are soluble as pressure is increased.
The solubility is 188.3 mg of N2 gas/100 g water.
Explanation:
As the pressure on the gas decreases, the volume of gas molecules in the solution increases due to having distance from each other. The solubility of nitrogen gas at 2.00 atm is twice the solubility of the gas at 1.00 atm because there is more pressure on the gas molecules so due to more compression, the gas becomes more soluble. More gas molecules are soluble as pressure is increased. The solubility is 188.3 mg of N2 gas/100 g water if the atmospheric pressure is increases from 3.08 atm to 8.00 atm. This value is calculated with the help of formula i.e. P2/P1 = S2/S1.
how much corn syrup should be added to water to make 200 mL of a 10% by volume solution
To make 200 mL of a 10% by volume solution, add 20 mL corn syrup to water.
What is volume solution?Volume percent of a solution is defined as the ratio of the volume of solute present in a solution to the volume of the solution as a whole. It means that the volume of a closed figure determines how much three-dimensional space it can occupy. In terms of numerical value, volume is the amount of three-dimensional space enclosed by a closed surface. For example, a substance's space can be solid, liquid, gas, or plasma, or any other space-occupying shape. The volume percentage of a solution can be calculated by dividing the volume of solute by the volume of solution and multiplying the result by 100. The basic formula for volume is length width height, whereas the basic formula for area of a rectangular shape is length width height. The calculation is unaffected by how you refer to the various dimensions: you can, for example, use 'depth' instead of 'height.'To learn more about volume solution, refer to:
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A 500.0 g sample of aluminium, I initially at 25.0 degrees, absorbs heat from its surroundings and reaches a final temperature of 90.7 degrees. How much heat (in KJ) has been absorbed by the sample? To one decimal place
Specific heat= 0.9930j g-1 K-1 for aluminium
A 500.0 g sample of aluminum, initially at 25.0 degrees, absorbs heat from its surroundings and reaches a final temperature of 90.7 degrees. 32.62245 kJ heat has been absorbed by the sample.
What is specific heat?The term specific heat is defined as the amount of heat required to increase the temperature of 1 gram of a substance 1 degree Celsius (°C).
To calculate the amount of heat absorbed by the sample, use the formula:
Q = mcΔT
where Q is the amount of heat absorbed by the sample, m is the mass of the sample, c is the specific heat of aluminum, and ΔT is the change in temperature of the sample.
Substituting the given values into the formula, we get:
Q = 500.0 g × 0.9930 J/g·K × (90.7°C - 25.0°C)
Q = 500.0 g × 0.9930 J/g·K × 65.7 K
Q = 32,622.45 J
To convert the result to kilojoules (kJ), we divide by 1000:
Q = 32.62245 kJ
Thus, the amount of heat absorbed by the sample is 32.6 kJ.
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To obtain pure lead, lead (II) sulfide is burned in an atmosphere of pure oxygen. The products of the reaction are lead and sulfur trioxide (SO3). Write a balanced chemical equation for this process. How many grams of lead will be produced if 2.54 grams of PbS is burned with 1.88 g of O2? Express your answer to the correct number of significant figures. Be sure to show all steps completed to arrive at the answer. (Hint: be sure to work the problem with both PbS and O2).
Answer: 2.20 g Pb
They gave us the masses of two reactants and asked us to determine the mass of the product. We will need a chemical equation with masses and molar masses, so, let's gather all the information in one place.
Mᵣ: 239.27 32.00 207.2
2PbS + 3O₂ ⟶ 2Pb + 2SO₃
m/g: 2.54 1.88
Se prepara una concentración molar 0.5M de hidróxido de sodio (NaCH) con la finalidad de determinar el grado de acidez de una bebida embotellada. Calcula la cantidad de gramos de hidróxido de sodio (NaCH) que se requiere para preparar 5 litros de dicha solución.
Answer:
100 g
Explanation:
Primero hay que calcular el número requerido de moles de NaOH, usando la definición de molaridad:
Molaridad = moles / litros0.5 M = moles / 5 Lmoles = 2.5 molesAhora hay que convertir 2.5 moles de NaOH en gramos, usando su masa molecular:
2.5 mol * 40 g/mol = 100 gSe requieren 100 gramos de NaOH.
2x²=8.pls help me i really need it
Explanation:
2x²=8
x²=8/2
x=√4
x=2
hope it helps.
Answer:
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[tex] {2x}^{2} = 8 \\ {x}^{2} = \frac{8}{2} \\ {x}^{2} = 4 \\ x = \sqrt{4} \\ x = 2[/tex]
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Which best describes the total mass of substances before and after a
combustion reaction?
A. The mass is the same because atoms are not created or
destroyed.
B. The mass is greater after the reaction because the number of
atoms increases.
C. The mass is the same because the molecules do not change.
D. The mass is less after the reaction because gases are produced.
Answer:
B. The mass is greater after the reaction because the number of
atoms increases.
2+4 help please i will fail 6th grade
Answer:
6
Explanation:
lol
The substance ammonia has the following properties: normal melting point: 195.4 K normal boiling point: 239.8 K triple point: 5.9×10-2 atm, 195.3 K critical point: 111.5 atm, 405.5 K At temperatures above 405.5 K and pressures above 111.5 atm, NH3 is a _________ . NH3 does not exist as a liquid at pressures below atm. NH3 is a _________ at 5.90×10-2 atm and 249.5 K. NH3 is a _________ at 1.00 atm and 236.0 K. NH3 is a _________ at 24.6 atm and 185.6 K.
Answer:
a) Superficial fluid
b) 5.9*10^-2 atm
c) Gas
d) Liquid
e) Solid
Explanation:
a) At temperatures above 405.5 K and pressures above 111.5 atm, NH3 is a superficial fluid because liquid and gases does not exit at temperature and pressure greater than 405.5 K and 111.5 atm
b) NH3 does not exist as a liquid at pressures below 5.9*10^-2 atm , That is below the triple point there is existence of liquid
c) NH3 is a Gas at 5.90×10^-2 atm and 249.5 K.
d) NH3 is a Liquid at 1.00 atm and 236.0 K. because pressure and temperature ( standard ) is between the given normal melting and boiling point
e) NH3 is a solid at 24.6 atm and 185.6 K . because the pressure here is more than that of triple point while the temperature is lesser
Given the reaction: N2(g) +2O2(g) ⇌ 2NO2(g) The forward reaction is endothermic. Determine which of the following changes would result in more product being produced.
I. Increase NO2
II. Decrease O2
III. Add a catalyst
IV. Increase the temperature
V. Increase the pressure
A. I and II
B. II, III, and V
C. IV and V
D. II and IV
Answer:
C
Explanation:
increasing the temperature will favour the forward reaction therefore the reaction system will try to counteract that by producing more heat and NO2 therefore increases the amount of products produced
increasing the pressure will favour the forward reaction as it has more moles of substance therefore if the forward reaction is favored, more product will be produced
Answer:
C.) lV and V
Explanation:
I got it correct on founders edtell