Calculate the amount (in moles) of gas which occupies 250cm³ at STP

Which statement describes evidence of a chemical reaction? a) ice melting eliminate b) water boiling c) lighting a match d) grape juice freezing

The formation of a solid, also known as a is an indication of a chemical change. precipitate particulate particle powder

Select the correct answer from each drop-down menu.describe what happens to a carbon-11 atom when it undergoes positron emission.the decay of a carbon-11 atom _1_, and this causes it to emit _2_.options for 1: > changes a neutron into a proton> changes a proton into a neutron> is hit with a neutron> reconfigures its protons and neutronsoptions for 2: > a negatively charged electron-sized particle> a positively charged election-sized particle> two atoms and several neutrons> two neutrons and two protons