Answer:
Observation
-I smell onions
-My dog weighs 45 pounds
-It is 85 degrees outside today
Predictions
-My dog will bark at the vacuum cleaner
although he has never seen it before
-My mother is going to cook spaghetti for
supper next Tuesday
-It will be a long, hot summer
Explanation:

As depth increases, the density of the layers decreases.
Ammonia is formed by a reaction between hydrogen and nitrogen as shown by the equation below.
N2(g) + 3H2(g) = 2NH3(g)
1 mole of ammonia contains 17 g
Therefore 10.78 g of ammonia are equivalent to 10.78/17 = 0.6341 moles
The mole ratio of hydrogen to ammonia is 3 : 2
Therefore, moles of hydrogen used will be 0.6341 × 3/2 = 0.9512 moles
1 mole of hydrogen is equivalent to 2 g
Thus, the mas of hydrogen will be 0.9512 moles × 2 = 1.9023 g
Answer:
Fe₂O₃ and C are reactants
Fe and CO₂ are products
Explanation:
Reactants:
Chemical species that are present on left side of chemical reaction equation are called reactants.
Product:
Chemical species that are present on right side of chemical reaction equation are called product.
Chemical equation:
2Fe₂O₃ + 3C → 4Fe + 3CO₂
In this reaction 2 mole of iron oxide is react with three moles of carbon and produced four moles of iron and three moles of carbon dioxide. There are equal numbers of atoms of all elements present on both side of chemical reaction so this reaction follow the law of conservation of mass.
Law of conservation of mass:
According to the law of conservation mass, mass can neither be created nor destroyed in a chemical equation.
Explanation:
This law was given by french chemist Antoine Lavoisier in 1789. According to this law mass of reactant and mass of product must be equal, because masses are not created or destroyed in a chemical reaction.
Explanation:
Molar mass of HBr = 81 g/mol
Molar mass of nitrogen dioxide gas = 46 g/mol
Molar mass of ethane = 30 g/mol
Graham's Law states that the rate of effusion or diffusion of gas is inversely proportional to the square root of the molar mass of the gas. The equation given by this law follows the equation:

So, the gas with least molar mass will effuse out fastest from the container and that is ethane gas.
The formula for average kinetic energy is:

where,
k = Boltzmann’s constant = 
T = temperature = 273.15 K ( at STP)
As we can see from the formula that kinetic energy depends upon only temperature of the gas molecule.
So, from this we can say that all the gas molecules have the same average kinetic energy at this temperature.