Question

name: review scientific key pol
date: block:
review homework - due wednesday 10/16
thats on periodill - looking across the periodic table
when you look across the periodic table or look at the rows you find that the elements have increasing atomic numbers.
portion of the periodic table of the elements
key
atomic symbol
element name
atomic mass
groups
13 14 15 16 17 18
he
ne
ar
h
hydrogen
1.01
al si p s cl
as se br kr
sb te i xe
at rn
remember the atomic number is the number of protons in an atom. the atomic number increases as you move across.
chemical symbol
c
atomic number
6
atomic mass
12.01
try this!! example: look at the row starting with boron (b). how does boron (b) compare to carbon (c). (read the answer choices and then look at the period table to see if it makes sense)
*remember you need to note that the atomic number at the top is the number of protons
a. carbon has more protons than boron.
b. boron has a higher atomic number than carbon.
c. boron and carbon have the same number of electrons and protons.
d. carbon has fewer protons and neutrons than boron.
physical properties of matter review
try this!!
the volume of both cubes is 50 cm³. if the mass of cube y is 25 g and the mass of cube z is 50 g, what can you conclude about the masses. (hint: do the math find the density of both and compare)
a. cube z is twice as dense as cube y.
b. cube y is twice as dense as cube z.
c. the density of both cubes are the same.
d. cube y is half as dense as cube z.
key concepts: density
d = m/v
m=mass look for # and g, mg, or kg. ex. 30 g
v=volume look for # and cm, m, km or l, ml or kl. ex. 60 cm³
water has a density of 1 g/ml³
density greater than 1 will sink in water
density less than 1 will float
look at layers and then look for which layer is at the top and which is at the bottom. look at the solid object and identify if it floats in one liquid and sinks in another.
if the object is in the liquid layer it more dense than the liquid.
if the object is on top of the liquid layer it is less dense than the liquid.
remember: same material=same density

Explanation:

Step1: Calculate density of Cube Y

The density formula is $D = \frac{m}{v}$. Given $m_Y=25\ g$ and $v = 50\ cm^3$, then $D_Y=\frac{m_Y}{v}=\frac{25}{50}= 0.5\ g/cm^3$.

Step2: Calculate density of Cube Z

Given $m_Z = 50\ g$ and $v = 50\ cm^3$, then $D_Z=\frac{m_Z}{v}=\frac{50}{50}=1\ g/cm^3$.

Step3: Compare the densities

We have $D_Z = 2D_Y$, which means Cube Z is twice as dense as Cube Y.

Answer:

A. Cube Z is twice as dense as Cube Y.