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.
Lead is a toxic metal that affects the central nervous system. A Pb-contaminated water sample contains 0.0011% Pb by mass. 13.6 × 10³ ml water contains 150 mg of Pb.
<h3>How to calculate the mass of solution ? </h3>
Given percentage of Pb present in the sample solution is 0.0011%
That means 0.0011 grams of Pb present in the 100g of solution.
So,
= 
= 13.6 × 10³ g water
<h3>What is Density ? </h3>
The mass per unit volume is called density. Density is represented as D or ρ.
It is expressed as:

where,
ρ = Density
m = mass of the object
V = Volume of object
Now put the value in above expression we get


V = 13.6 × 10³ ml
Thus from the above conclusion we can say that Lead is a toxic metal that affects the central nervous system. A Pb-contaminated water sample contains 0.0011% Pb by mass. 13.6 × 10³ ml water contains 150 mg of Pb.
Learn more about the Density here: brainly.com/question/1354972
#SPJ4
<span>O2 travels slower than H2, Ne, N2, and CO. This is due to the fact that O2 has a heavier molecular weight than the others. O2 has a weight of 32 grams per mole. N2 and CO are the next highest with 28 grams per mole. Ne is 20 grams per mole, and H2 is 2 grams per mole.</span>
Answer:
I found this on the internet People need to breathe, and so do lots of other animals—and plants! Breathing is part of a process called respiration. During respiration, a living thing takes in oxygen from the air and gives out carbon dioxide.
Explanation:
10 Interesting Things About Air | NASA Climate Kidsclimatekids.nasa.gov › 10-things-air
Your welcome!