Answer:
19. Option B. ⁰₋₁B
20. Option D. ²¹⁰₈₄Po
Explanation:
19. ²²⁸₈₈Ra —> ²²⁸₈₉Ac + ʸₓZ
Thus, we can determine ʸₓZ as follow:
228 = 228 + y
Collect like terms
228 – 228 = y
y = 0
88 = 89 + x
Collect like terms
88 – 89 = x
x = –1
Thus,
ʸ ₓZ => ⁰₋₁Z => ⁰₋₁B
²²⁸₈₈Ra —> ²²⁸₈₉Ac + ʸₓZ
²²⁸₈₈Ra —> ²²⁸₈₉Ac + ⁰₋₁B
20. ᵘᵥX —> ²⁰⁶₈₂Pb + ⁴₂He
Thus, we can determine ᵘᵥX as follow:
u = 206 + 4
u = 210
v = 82 + 2
v = 84
Thus,
ᵘᵥX => ²¹⁰₈₄X => ²¹⁰₈₄Po
ᵘᵥX —> ²⁰⁶₈₂Pb + ⁴₂He
²¹⁰₈₄Po —> ²⁰⁶₈₂Pb + ⁴₂He
Answer:
138 mg
Explanation:
A company is testing drinking water and wants to ensure that Ca content is below 155 ppm (= 155 mg/kg), that is, <em>155 milligrams of calcium per kilogram of drinking water</em>. We need to find the maximum amount of calcium in 890 g of drinking water.
Step 1: Convert the mass of drinking water to kilograms.
We will use the relation 1 kg = 1000 g.
Step 2: Calculate the maximum amount of calcium in 0.890 kg of drinking water
Scientists tell people which issues are the most important describes an important role scientists have in society.
In addition to advising policymakers and other stakeholders about the best and wisest steps to take toward a human-centered society, scientists have a crucial role to play in preventing unwise and dangerous decisions. This promotes scientific knowledge and strengthens cross-cultural relationships and collaborative research. Additionally, they shouldn't overlook the objective, perpetually unfinished nature of science. With the help of a transdisciplinary cross-talks method, we emphasize the significance of information transfer across all scientific disciplines.
Due to the specific ways in which they aid in understanding how the world functions, scientists are crucial to society. It is a mode of thinking that helps us organize our knowledge in order to comprehend how things operate on a deeper level.
Learn more about Scientists here
brainly.com/question/22249890
#SPJ9
Steel Wool + Oxygen (Fire) The steel wool is a grayish color and has a rough surface. Oxygen is transparent It looks like a powder, and like if it was rusted steel wool but then broken apart and turned into a powder Well Iron oxide is 7 grams and steel wool combined is 7 grams so you can say that the mass was conserved Yes, this is a chemical change because the steel wool rusted and rust is a chemical change, so iron oxide is cause because if a physical change.
Egg + Heat The egg has a yellow yolk in the middle while there is some type of liquid at the border of the yolk, but it is clear, the heat is hot but transparent The egg turned into a delicious food called an omelet what was yolk staid as a liquid but got a tad harder, but the transparent border around it turned white It was conserved because the eggshell was 4 grams and the fried egg is 41 grams It is a chemical change because it results in the formation of new particles, and the chemical bonds break up and new ones are formed.
Water + Heat The water is a clear liquid, while the heat is very hot but transparent The water turned into a type of oxygen -Water Vapor- If 5 g of water becomes a gas it becomes 5 g of water vapor. The mass of the liquid water is simply transferred into the mass of the newly formed water vapor. There was no chemical reaction because the water vapor can be turned back to water also it just changed from a liquid to a gas and did not change its composition
Zinc + Hydrogen Chloride Zinc: a white/silver metallic solid. Hydrogen chloride (dilute hydroelectric acid) a transparent, colorless liquid with a very low pH (acidic). Zinc "dissolved" in hydrogen chloride, while emitting a colorless gas. The liquid remains a colorless liquid, possibly still having a low pH from the unused acid. The colorless gas collected in a test tube gives a popping sound when ignited with a burning wooden splint, so it is not air embedded in the zinc, nor dissolved in hydroelectric acid. Well although the zinc chloride is 12 grams and not 15 the gas that was released was 3 grams and as we all know 3 + 12 is 15 so you could say that the mass was conserved The production of a new substance (most probably hydrogen) from the reaction of the two reactants. When a few drops of the liquid product are evaporated on a watch glass, a white residue is left. When a few drops of the liquid hydroelectric acid are evaporated on a watch glass, there is no residue. This proves that a new product (hydrogen gas), (white powder, zinc chloride) is produced instead of zinc being physically dissolved in hydroelectric acid.
Sodium Hydroxide + Copper Sulfate Sodium hydroxide is a turbid solution and copper sulfate is in form of bright blue crystals. When their solutions are mixed with each other, a pale blue precipitate of basic copper hydroxide & a solution of neutral salt sodium sulfate will be formed. The sodium hydroxide and the copper sulfate combined make a total of 67 grams and the product is split because the sodium sulfate is 47 grams and the copper hydroxide is 20 grams but all together it is still 67 grams so you could say that the mass was conserved The proof of the reaction is the appearance of pale blue precipitates of basic copper hydroxide & a solution of neutral salt sodium sulfate.
The property that determines an atom;s ability to attract electrons shared in a chemical bond is electronegativity. The correct answer is C.
