Question

Three isotopes exist for potassium. Approximately 93 % of all potassium atoms have a mass of 39 u. 7 % of potassium atoms have a mass of 41 u. A very small proportion of potassium atoms have a mass of 40 u. What is the atomic mass of potassium?

(a) 33.40 u (b) 39.14 u (c) 40.07 u (d) 40.86 u

Answer #1

6. There are 5.00x1026 atoms/m3 in a container of argon gas
(atomic mass number 40). The pressure in the container when the
atoms have a rms speed of 350 m/s is:
A. 4.53x104 N/m2
B. 1.01x104 N/m2
C. 1.01x105 N/m2
D. 1.36x105 N/m2
E. None of the above.
7. Calculate the heat energy required to increase the
temperature of 120 g of copper from 20.0 °C to
180 °C.

PLEASE ANSWER ALL QUESTIONS AND EXPLAIN
1.) The nucleus of an atom has 95 protons and there
are several isotopes that exist in equal amounts; which is true
a. there must be 95 neutrons
b. the atomic mass is 95
c. the molar mass must be 190g/mol
d. each isotope has a different number of
neutrons
2) What does "X" represent in the following atomic symbol?
A) mercury (Hg)
B) chlorine (Cl)
C) scandium (Sc)
D)...

The molar mass of carbon is 12.0107 g/mol. This molar mass
includes all isotopes of Carbon in the fractions that are naturally
found in the atmosphere and living organisms. A 12.0 g sample of
carbon from living matter decays at the rate of 184 decays/minute
due to the radioactive 14C in it.
a) What fraction of these carbon atoms were 14C?
b) A second identical sample is put in a spaceship that is
traveling with a speed of 0.8c relative...

1. The maximum weight percentage of carbon atoms (which are
very small atoms) that can be contained in spaces between the iron
atoms in a crystal of face-centered cubic iron at 1333 deg F (723
degC) is 0.8%C.
(a) To what approximate atomic percentage does this
correspond?
(b) On the average, how many unit cells of face-centered cubic
iron would have to be examined before encountering a carbon
atom?
2. (a) Briefly explain the concept of driving force.
(b) What...

1.
Slices of pizza for a certain brand of pizza have a mass
that is approximately normally distributed with a mean of 67.8
grams and a standard deviation of 2.29 grams.
a) For samples of size 14 pizza slices, what is the standard
deviation for the sampling distribution of the sample mean?
b) What is the probability of finding a random slice of pizza
with a mass of less than 67.1 grams?
c) What is the probability of choosing a...

Q1: What is the definition of isotopes?
A: Two elements that have same number of electrons, protons
and neutrons B: Two elements that have different number of
electrons C: Two elements that have identical number of protons,
but different number of neutrons D: Three elements that have
identical number of protons
Q2: Which compound has the highest boiling point in this
series?
A: Water B: Ethylene C: Caron Tetrachloride D: Ethyl
Alcohol
Q3: What is the definition of mole of...

1. True or False? It is
possible for a common hydrogen
nucleus to emit an alpha particle.
Hint: An alpha particle is a
helium nucleus with two protons and two neutrons. A common hydrogen
nucleus has only one proton and no neutrons.
(a) True
(b) False.
16. X-rays are most similar to which of the
following:
(a) alpha particles
(b) beta particles
(c) gamma rays
2. True or False? All isotopes of the same element have
a different number of...

A study of reading comprehension in children compared three
methods of instruction. The three methods of instruction are called
Basal, DRTA, and Strategies. As is common in such studies, two
pretest variables were measured before any instruction was given.
One purpose of the pretest was to see if the three groups of
children were similar in their comprehension skills prior to the
start of the study. The READING data set described in the Data
Appendix gives two pretest measures that...

answer all these questions please with the right question number
next to its letter
1-When the population standard deviation is unknown
AND the sample size is less than 30, the test
statistic to use is:
A
t
B
The Binomial Dristribution
C
The Z Distribution
D
Chi-Square
4-What do we call the statement (rule you create) that
determines if the null hypothesis is rejected?
A
Decision rule
B
Test statistic
C
Alternate hypothesis
D
Critical mass
8-
The mean length...

Radioactive Half-life
Years
Element A Remaining Radioactive Atoms
Element B Remaining Radioactive Atoms
Element C Remaining Radioactive Atoms
Element D remaining Radioactive Atoms
0
100
100
100
100
1000
50
85
90
95
2000
25
72
81
90
3000
13
61
73
86
4000
6
52
66
81
5000
3
44
59
77
6000
2
38
53
74
7000
1
32
48
70
8000
0
27
43
66
9000
0
23
39
63
10000
0
20
35
60
11000...

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