Q = mcθ
Where m = mass of water in kg.
c = specific heat capacity in kJ/kg⁰C, c for water = 4200 kJ/kg⁰C
θ = temperature rise in ⁰C
Q = 100*4200* 20 Note here the temperature rise is 20 ⁰C
Q = 8 400 000 J
In calories, 4.2 J = 1 Calorie
= 8 400 000 / 4.2 = 200 000
Q = 200 000 Calories
Complete question:
A volume V= 2.48 L of an ideal nitrogen gas (N2) are at temperature T= 0.964°C and pressure p = 1.49 atm. Find the number of moles of the gas.
Answer:
The number of mole of the gas is 0.164 mol.
Explanation:
Given;
volume of the ideal gas, V = 2.48 L
temperature of the gas, T = 0.964 °C = 273K + 0.964 = 273.964 K
pressure of the gas, P = 1.49 atm
The number of moles of the gas is calculated by using ideal gas equation;
PV = nRT
where;
n is the number of moles of the gas
R is ideal gas constant = 0.082057 L.atm/mol.K

Therefore, the number of mole of the gas is 0.164 mol.
<h2>Answer: Mercury</h2><h2 />
The Mariner 10 probe was launched by NASA on November 3rd, 1973, with the purpose of exploring the characteristics of two planets in the solar system that were closest to the Sun, Mercury and Venus.
In addition, it was launched to explore the atmosphere and surface of both planets and <u>prove that it was possible to use gravitational assistance</u> (also called <u>slingshot effect</u>, a special orbital maneuver in order to use the gravitational field energy of a planet or massive body to accelerate or slow the probe and change the direction of its trajectory) in long interplanetary trips to save fuel.
In this case, <u>Mariner 10 first arrived at Venus</u> and succeded in using its gravitational field to accelerate its trajectory towards Mercury.
V=f*wavelength
30m/s=f*(0.35m)
f=85.7 Hz