Answer:
D. The melting of ice
Explanation:
An endothermic reaction ABSORBS heat from its surroundings, it does NOT give heat off into its surroundings.
so...
When a match burns, it gives of heat. So A is incorrect.
When water goes from a vapor into a liquid, the water molecules loose kinetic energy, they do not gain it. And since temperature is the measure of the average kinetic energy in a substance, the water vapor looses heat. If the process was endothermic, it would be gaining heat. So B is incorrect.
When propane gas combusts, the explosion lets off heat into its surroundings, it does not absorb heat. So C is incorrect.
Here's what happens when something melts: the molecules inside the substance receive more and more kinetic energy, until the substance's molecules have enough kinetic energy to vibrate and wiggle past each other, breaking their structure. When ice melts it is receiving kinetic energy from its surroundings, and again, since temperature is the measure of the average kinetic energy in a substance, the process is absorbing heat. Q.E.D.,
D is the correct answer.
(2) 16N (4) 239Pu
The radioactive isotope of the element with unstable energy in the nucleus is called a radioisotope. Neon with atomic mass 19 particlehas charge +1 and mass 0.
When a radioactive element undergoes decay they emit some types of particles like alpha, beta, or positron particles. The alpha particle has a +2 charge and a mass number of 4.
The beta particle has a -1 charge and a mass number of 0, while the positron has a particle charge of +1 and a mass number of 0.
In the decay of the Neon element, the positron is emitted can be shown as:
Therefore, option 3. atom emits positron particle.
Learn more about radioisotopes here:
Answer: The correct answer is option 3.
Explanation: There are three types of particles that are emitted when a radioisotope undergo decay process:
1. Alpha particle: This particle is emitted when a radioisotope undergoes alpha decay process. The charge on the particle is +2 and mass number is 4.
2. Beta-particle: This particle is emitted when a radioisotope undergoes beta-minus decay process. The charge on the particle is -1 and mass number is 0.
3. Positron particle: This particle is emitted when a radioisotope undergoes beta-plus decay process. The charge on the particle is +1 and mass number is 0.
For the given options undergoing decay processes:
Option 1:
It emits beta-particle.
Option 2:
It emits beta-particle.
Option 3:
It emits positron-particle.
Option 4:
It emits alpha particle.
Hence, the correct option is Option 3.
B Bromine gas reacts with a solution of potassium chloride to form potassium bromide and chlorine gas.
C Potassium bromine gas reacts with liquid chlorine to form potassium chloride in solution and bromine gas.
D Chlorine gas reacts with potassium bromide to form potassium chloride in solution and liquid bromine.
The volume of the gas sample would be 477.78 mL.
The student is asking about the change in volume of a gas sample when the pressure is increased. This can be solved using Boyle's law, which states that the pressure and volume of a gas are inversely proportional at constant temperature. The equation for Boyle's law is: P1 * V1 = P2 * V2
We are given the initial conditions: T1 = 25.2°C, V1 = 536 mL, and P1 = 0.838 atm. We need to find V2 when P2 = 0.937 atm. Using the Boyle's law equation, the volume can be calculated as: V2 = (P1 * V1) / P2
Plugging in the values, we get: V2 = (0.838 atm * 536 mL) / 0.937 atm = 477.78 mL
Therefore, the volume of the gas sample would be 477.78 mL (Option A) when the pressure is increased to 0.937 atm.
#SPJ11
M1m1 = M2m2
where M1 is the concentration of the stock solution, m1 is the mass of the stock solution, M2 is the concentration of the new solution and m2 is its new mass.
M1m1 = M2m2
.925(m1) = .35(250)
m1 = 94.59 g
Answer: 94.59 grams of 92.5 % by mass solution will be needed.
Explanation:
Mass of sulfuric acid is 250 grams of 35 % by mass solution:
Mass of in 250 g of 35 % solution = 87.5 g
Mass of 92.5 % needed to make 35 % by mass solution.
Mass of the solution required = 94.59 g
94.59 grams of 92.5 % by mass solution will be needed.
B. Thermometer
C. Barometer
D. Hygrometer
The answer is C. Barometer