Answer:
57.124.18 Pascals
Explanation:
The pressure that each person exerts on the ground is given by:
Pressure = force/area
The force that each person exert is given by:
Force = mass (kg) x acceleration due to gravity (10 m/s2)
1 lb = 0.4536 kg, hence;
250 lb person = 113.398 kg
120 lb person = 54.431 kg
Force exerted by the 250 lb person = 113.398 x 10 = 1133.98 kg/m2
Force exerted by 120 lb person = 54.431 x 10 = 544.31 kg/m2
16 inch2 = 0.0103226 m2
Pressure exterted by 250 lb person = 1133.98/0.0103226
= 109,854.11 pascals
Pressure exerted by 120 lb person = 544.31/0.0103226
= 52,729.93 Pascals
Difference in pressure = 109,854.11 - 52,729.93
= 57,124.18 Pascals
Hence, a 250 lb person will exert 57.124.18 Pascals pressure more than a person of 120 lb on a foot with a 16 inch2 area.
A teacher asks students to describe the physical properties of 10 mL of vinegar and 10 mL of milk. When the students finish listing the physical properties in their science notebooks, the teacher pours the vinegar and milk into the same beaker. The students are surprised to see a white solid substance form within the beaker as the two substances are combined.
What occurs within the beaker as the teacher mixes the vinegar and milk?
1. A chemical change that produces a precipitate
2. A physical change that creates a new substance
3. A physical change that produces a precipitate
4. A chemical change that produces no new substances
Answer:
1. A chemical change that produces a precipitate
Explanation:
A solid substance that is formed from a liquid phase is called a precipitate.
A reaction that produces a precipitate is called a precipitation reaction.
Precipitation reactions are an example of a chemical change.
Thus the correct answer is option 1: A precipitate was formed when vinegar and milk were mixed (as there were no solid substances when they were apart).
1. What kinds of metals are REALLY reactive? why?
2. What kinds of non-metals are REALLY reactive? why?
3. What group on the periodic table doesn’t react at all? why?
Answer:
1. Alkali metals (group 1)
2. halogens (Group 17)
3. noble gasses (group 18)
Explanation:
1. alkali metals only have one valence electron meaning that they really want to lose that one valence electron to get a full octet.
2. halogens have 7 valence electrons meaning that they just need to gain 1 to get a full octet.
3. Nobel gasses already have a full octet meaning that they don't want to react. (atoms only react to get a full octet)
I hope this helps. Let me know if anything is unclear.