Can lead replace iron?

We can block light by placing obstacles in its path, but it's much more difficult to block sound. Why? Sound waves are transverse waves. Sound waves can move through various mediums. Sound waves have high frequencies.

Negatively-charged electrons randomly dispersed in a sea of positive charge. A) Bohr Model B) Nuclear Model C) Plum Pudding Model D) Quantum Mechanical Model

Mary's cat looks tame when sleeping, but wild when awake.

What is the difference between the molar mass and the empirical formula mass of a compound? when are these masses the same, and when are they different? when different, how is the molar mass related to the empirical formula mass?

Is saltwater a mixture or solution. Why?

A 40.0 g drinking glass is filled with hot liquid. The liquid transfers 1,000. J of energy to the glass. If the temperature of the glass increases by 50.0 degrees Celsius, what is the specific heat of the glass?

What is the percent by mass of oxygen in propanal, CH3CH2CHO? (1) 10.0% (3) 38.1% (2) 27.6% (4) 62.1%

In which orbitals would the valence electrons for selenium (Se) be placed? s orbital and f orbital s orbital only s orbital and p orbital d orbital only

Hydrogen reacts with chlorine to form hydrogen chloride (HCl (g), Delta. Hf = - 92.3 kJ/mol) according to the reaction below. Upper H subscript 2 (g) plus upper C l subscript 2 (g) right arrow 2 upper H upper C l (g). Which statement is correct?

Below is the lewis structure of the fluoramine nh2f molecule. nfhh count the number of bonding pairs and the number of lone pairs around the left hydrogen atom.