Please answer the following questions clearly:

1a)
(ii) Why would a 15 year old male need more calcium than a 30 year old male?

(iii) Why does a 25 year old pregnant female need more protein than a non-pregnant 25 year old female?

1b) A hammer hits a nail, what is the size of the force acting on it?

1c) A lift is moving upwards, and slowing down. Compare the forces (tension and weight) about what would happen now.

1d) Describe why a 15 year old female needs more iron than a 15 year male.

1e) When Iron is mixed with hydrocholic acid, what do you get?

1f) A candle burns, the formula for the reaction is --> Candle Wax + Oxygen = Carbon Dioxide + Water, where did the Oxygen come from?

2a) Two 16 year old males weigh the same weight. Explain why they need different amounts of energy.

2b) When Iron is combined with Sulphur to produce the compound Iron Sulphide, what can they both not do, once a compund?

Thanks for helping! x

1a) (ii) A 15-year-old male needs more calcium than a 30-year-old male due to the fact that during adolescence, the body undergoes significant growth and bone development. Calcium is essential for building strong bones and teeth. As the 15-year-old is still in the growth phase, he requires more calcium to support the rapid growth and ensure the proper development of his skeletal system.

(iii) A 25-year-old pregnant female needs more protein than a non-pregnant 25-year-old female because protein is crucial for the growth and development of the fetus. Protein is used to build and repair tissues, produce enzymes and hormones, and support various physiological functions. During pregnancy, the demand for protein increases to support the growth of the placenta, amniotic fluid, and fetal tissues.

1b) When a hammer hits a nail, the force acting on the nail is typically the force of the hammer striking it. The size of this force depends on factors such as the strength of the person swinging the hammer and the speed or velocity with which the hammer strikes the nail.

1c) When a lift is moving upwards and slowing down, the forces acting on it include the tension force (exerted by the supporting cable or rope) and the weight force (due to gravity acting on the lift and its occupants). If the lift is slowing down, it means that the tension force is becoming weaker or decreasing relative to the weight force. Eventually, if the tension force becomes smaller than the weight force, the lift may come to a stop or start moving downward.

1d) A 15-year-old female needs more iron than a 15-year-old male primarily because females experience menstrual blood loss, which results in a higher requirement for iron. Menstruation causes a monthly loss of blood, and with it, iron from the body. To compensate for this loss, females require more iron in their diet to maintain adequate levels of iron and avoid iron deficiency anemia.

1e) When Iron is mixed with hydrochloric acid, the resulting chemical reaction produces iron chloride and hydrogen gas. The balanced chemical equation for this reaction is:

Fe + 2HCl → FeCl₂ + H₂

1f) In the given reaction representing the burning of a candle, the oxygen comes from the surrounding air. Oxygen is a component of air, and it is required for combustion (burning). As the candle burns, it combines with oxygen from the atmosphere to produce carbon dioxide and water vapor.

2a) Two 16-year-old males who weigh the same may need different amounts of energy due to differences in their metabolic rates, activity levels, and overall body composition. Metabolic rate can be influenced by various factors, including genetics, muscle mass, and hormonal differences. Additionally, individuals with higher levels of physical activity may require more energy to support their active lifestyle.

2b) Once iron and sulfur combine to form iron sulfide, they cannot individually exhibit the chemical properties they possessed before bonding to form the compound. In a chemical compound, elements bond together to form a new substance with unique properties that differ from those of the individual elements. Therefore, once iron and sulfur bond to form iron sulfide, they cannot separate and exhibit their original properties until the compound is chemically broken down.

1a) To understand why a 15-year-old male needs more calcium than a 30-year-old male, we first need to understand the role of calcium in the body. Calcium is crucial for strong and healthy bones, teeth, and muscles. During the teenage years, individuals experience significant growth spurts, and their bodies require more calcium to support bone development. This is especially true for males, as they tend to have higher muscle mass and bone density compared to females. Therefore, it is important for a 15-year-old male to consume more calcium to meet their body's increased demand for growth and development.

1b) When a hammer hits a nail, the force acting on the nail is dependent on the strength and speed of the hammer's strike. To determine the exact size of the force, you would need to measure the acceleration and mass of the hammer, as described by Newton's second law of motion (F = m * a). By measuring the mass of the hammer and its acceleration at the moment of impact, you can calculate the force exerted on the nail.

1c) When a lift (or elevator) is moving upwards and slowing down, the forces involved include tension and weight. Tension refers to the force exerted by the lift's cable to keep it suspended and moving, while weight is the force of gravity acting on the lift and its occupants. When the lift slows down, the tension and weight forces will vary. Specifically, the tension force in the cable will decrease, while the weight force remains constant. Consequently, the occupants in the lift may experience a feeling of being momentarily lighter as the tension force decreases.

1d) It is inaccurate to state that a 15-year-old female needs more iron than a 15-year-old male. In fact, both genders have different iron requirements and during adolescence, their needs are influenced more by factors such as growth, puberty, and menstruation rather than gender specifically. Females generally have higher iron requirements due to blood losses during menstruation, and this need continues throughout their reproductive years. Males, on the other hand, generally have lower iron requirements but still need sufficient intake to support muscle growth and overall health.

1e) When iron is mixed with hydrochloric acid (not hydrocholic acid), a reaction occurs. The iron reacts with the hydrochloric acid to form iron chloride and hydrogen gas. The chemical equation for this reaction is:

Fe(s) + 2HCl(aq) → FeCl2(aq) + H2(g)

The iron reacts with the hydrochloric acid to produce iron chloride in aqueous form (FeCl2) and bubbles of hydrogen gas (H2) are released.

1f) The oxygen required for the candle to burn comes from the air. Air is composed of various gases, including oxygen, nitrogen, carbon dioxide, and trace amounts of other gases. Oxygen from the air combines with the carbon atoms in the candle wax (which is mainly composed of hydrocarbons) during combustion, resulting in the formation of carbon dioxide and water vapor. This process is known as combustion or burning.

2a) Two 16-year-old males who weigh the same may still need different amounts of energy due to variations in their metabolic rates and activity levels. Factors such as body composition, height, weight, muscle mass, and activity level can influence an individual's energy requirements. Each person has a unique metabolism that determines how efficiently their body burns calories to support basic bodily functions and physical activity. Therefore, even if they have the same weight, their energy needs may differ based on these individual factors.

2b) Once iron and sulfur combine to form iron sulfide, the resulting compound can no longer exhibit the properties of the separate elements. Iron and sulfur are both chemical elements, and when they chemically react and form iron sulfide, they lose their individual characteristics. Iron sulfide is a compound with its own distinct properties and behaviors. This means that iron and sulfur, once combined as iron sulfide, cannot perform their original functions or exhibit independent chemical behaviors.