Answer:
There are three rules on determining how many significant figures are in a number:
Non-zero digits are always significant.
Any zeros between two significant digits are significant.
A final zero or trailing zeros in the decimal portion ONLY are significant.
<h3>Answer:</h3>
Option-D, "their elements have very similar properties and exhibit a clear trend" is the correct answer.
<h3>Explanation:</h3>
In periodic table the elements are arranged in tabular form with respect to their atomic masses, atomic numbers, electronic configurations and chemical properties. It is called periodic because the properties of elements repeats periodically.
Furthermore, the rows from left to right also called Periods basically shows the metallic and non metallic characters of elements. \those on the left are metals and those at the rights are non metals.
The columns from top to bottom are called as Groups. Groups contain elements of same chemical properties.
<h3>Example:</h3>
Group I elements are called as <em>Alkali Metals</em>. They all have one valence electron and hence, loose one electron to form the corresponding cation. i.e.
M → M⁺¹ + 1 e⁻
Group VII elements are called <em>Halogens</em>, they all are non metals and tend to gain one electron to form the corresponding halide ion. i.e.
X + 1 e⁻ → X⁻¹
The lanthanides and actinides are separated from the rest of the periodic table, usually appearing as separate rows at the bottom. The reason for this placement has to do with the electron configurations of these elements.
The answer is b hope it helps u good luck
Answer:
41.3 °C
Explanation:
From the question given above, the following data were obtained:
Mass (M) of water = 27.56 g
Heat (Q) loss = 2443 J
Final temperature (T2) = 62.5 °C
Initial temperature (T1) =?
NOTE: The specific heat capacity (C) of water is 4.18 J/g°C
Thus, we can obtain the initial temperature of the water by using the following formula:
Q = MC(T2 – T1)
2443 = 27.56 × 4.18 (62.5 – T1)
2443 = 115.2008 (62.5 – T1)
Divide both side by 115.2008
2443 / 115.2008 = (62.5 – T1)
21.20645 = 62.5 – T1
Collect like terms
21.20645 – 62.5 = – T1
– 41.3 = – T1
Divide both side by – 1
– 41.3 /– 1= – T1 / –1
41.3 = T1
T1 = 41.3 °C
Thus, the initial temperature of the water was 41.3 °C
