<u>Answer:</u> The density of substance is 
<u>Explanation:</u>
To calculate density of a substance, we use the equation:

We are given:
Mass of substance = 61.6 g
Volume of substance = 
Putting values in above equation, we get:

Hence, the density of substance is 
Using charles law
v1/t1=v2/t2
v1=49ml
v2=74
t1=7+273=280k
t2=?
49/280=74/t2
0.175=74/t2 cross multiply
0.175t2=74
t2=74/0.175
t2=422k or 149celcius
Answer:
D.) They often form hydroxide ions.
Explanation:
They generate hydroxide ions in water. they are soapy to touch and bitter in taste. they conduct electricity.
(all bases have hydroxide ions)