Answer:
infrared waves are longer than gamma rays
Explanation:
according to the order :
radio, microwaves, infrared, light, ultraviolet, X-ray, gamma rays
radio waves have the highest wavelenght and lowest frequency, gamma rays have the highest frequency and lowest wavelength.
Answer:
The answer is: (a) positive; (b) negative.
Explanation:
The change in enthalpy (ΔH) of a reaction is the amount of energy absorbed or released during a chemical reaction carried out at constant pressure.
a) In an endothermic chemical reaction, heat energy is absorbed by the system from the surrounding. Therefore, the sign of enthalpy change for an endothermic process is positive, ΔH= positive.
b) In an exothermic chemical reaction, heat energy is released by the system into the surrounding. Therefore, the sign of enthalpy change for an exothermic process is negative, ΔH= negative.
Steel is an alloy and consists of more than one element (mainly iron and carbon), therefore steel is a mixture.
The independent variable in the experiment is the soap and the dependent variable in the experiment is the number of water drops on the surface of the penny. The control is the penny without soap.
Answer:
D: Carbon
Explanation:
The periodic table lists all the known elements. When looking at it, the only choice you will find is carbon. Therefore, carbon is the element.
Carbon is also by itself, just C.
Water is H2O, which is a molecule due to the 2 different elements.
Carbon Dioxide is CO2, which is a molecule due to the 2 different elements.
Air is just a mixture of different gas molecules, so therefore it is not an element.
