Can someone explain question 3 i know the answer but i need an explanation

What is the type of the reaction below? bacl2 + h2so4 → 2 hci + baso4 double replacement synthesis single replacement decomposition

In positive numbers less than 1, the zeros between the decimal point and non zero are significant

Agroup of students were investigating the force of gravity. they began by dropping a foam ball from a height of 3 meters into a bucket of sand. the ball hit the sand in 0.306 seconds. they dropped additional balls of approximately the same diameter, but of different masses. here is the data they collected. based on this experiment and the collected data, what would their conclusion be?