Answer:
a: iron is a substance
Explanation:
because its hard and brittle and classified as a metal
Explanation:
Given
The enthalpy of formation of RbF (s) is –557.7kJ/mol
The standard enthalpy of formation of RbF (aq, 1 m) is –583.8 kJ/mol
The enthalpy of solution of RbF = Enthalpy of RbF (aq) - Enthalpy of formation of RbF (s)
= -583.8 - (-557.7) kJ/mol
= -26.1 kJ/mol
The enthalpy is negative which means that the temperature will rise when RbF is dissolved.
Hello!
I'm going to have to infer that you meant "grams" and not "gallons" :-)
Anyways, to find the density, you need to the divide mass over volume (d = m/V).
Since we are given the volume being 15.0 mL, and the weight being 40.5 grams, we can find the density of the aluminum block.
40.5 grams / 15.0 mL = 2.7 g/mL
Therefore, the density of the aluminum block is 2.7 grams per milliliter.
The law of conservation of mass states that in a chemical reaction, the total mass of reactants is equal to the total mass of products. ... Because atoms are only rearranged in a chemical reaction, there must be the same number of sodium atoms and chlorine atoms in both the reactants and products.
Electrons = protons
protons = atomic number
protons + neutrons = atomic mass
Therefore: a) protons + 7 = 15
protons= 15 -7
protons= 8
B) Remember proton = atomic number
so atomic number = 8
C)Now we know the atomic number so we can easily check on the periodic table what element has an atomic number of 8, which is Oxygen
