Answer:
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Answer is 3
because on the periodic table, the small number above every element is the number of protons
Density is the measure of a material's mass per unit volume, used in many aspects of science, engineering and industry. Density can be calculated by dividing an object's mass by its volume. Since different materials have different densities, measuring an object's density can help determine which materials are in it. Finding the density of a metal sample can help to determine its purity.When measuring liquids and regularly shaped solids, mass and volume can be discovered by direct measurement and these two measurements can then be used to determine density. Using a pan balance, determine and record the mass of an object in grams. Using a vernier caliper or ruler, measure the length, depth and width of the object in centimeters. Multiply these three measurements to find the volume in cubic centimeters. Divide the object's mass by its volume to determine its density. Density is expressed in grams per cubic centimeter or grams per milliliter.
(this can be split into two paragraphs)
95.6 cal
are needed.
Explanation:
Use the following equation:
q
=
m
c
Δ
T
,
where:
q
is heat energy,
m
is mass,
c
is specific heat capacity, and
Δ
T
is the change in temperature.
Δ
T
=
T
final
−
T
initial
Known
m
=
125 g
c
Pb
=
0.130
J
g
⋅
∘
C
T
initial
=
17.5
∘
C
T
final
=
42.1
∘
C
Δ
T
=
42.1
∘
C
−
17.5
∘
C
=
24.6
∘
C
Unknown
q
Solution
Plug the known values into the equation and solve.
q
=
(
125
g
)
×
(
0.130
J
g
⋅
∘
C
)
×
(
24.6
∘
C
)
=
400. J
(rounded to three significant figures)
Convert Joules to calories
1 J
=
0.2389 cal
to four significant figures.
400
.
J
×
0.2389
cal
1
J
=
95.6 cal
(rounded to three significant figures)
95.6 cal
are needed.
Answer:
[MgSO₄] = 890 mM/L
Explanation:
In order to determine molarity we need to determine the moles of solute that are in 1L of solution.
Solute: MgSO₄ (10.7 g)
Solvent: water
Solution: 100 mL as volume. (100 mL . 1L / 1000mL) = 0.1L
We convert the solute's mass to moles → 10.7 g / 120.36 g/mol = 0.089 moles
Molarity (mol/L) → 0.089 mol/0.1L = 0.89 M
In order to calculate M to mM/L, we make this conversion:
0.89 mol . 1000 mmoles/ 1 mol = 890 mmoles
