Answer:
STP in chemistry is the abbreviation for Standard Temperature and Pressure. STP most commonly is used when performing calculations on gases, such as gas density. The standard temperature is 273 K (0° Celsius or 32° Fahrenheit) and the standard pressure is 1 atm pressure.
Answer:
-177.9 kJ.
Explanation:
Use Hess's law. Ca(s) + CO2(g) + 1/2O2(g) → CaCO3(s) ΔH = -812.8 kJ 2Ca(s) + O2(g) → 2CaO(s) ΔH = -1269.8 kJ We need to get rid of the Ca and O2 in the equations, so we need to change the equations so that they're on both sides so they "cancel" out, similar to a system of equations. I changed the second equation. Ca(s) + CO2(g) + 1/2O2(g) → CaCO3(s) ΔH = -812.8 kJ 2CaO(s) → 2Ca(s) + O2(g) ΔH = +1269.8 kJ The sign changes in the second equation above since the reaction changed direction. Next, we need to multiply the first equation by two in order to get the coefficients of the Ca and O2 to match those in the second equation. We also multiply the enthalpy of the first equation by 2. 2Ca(s) + 2CO2(g) + O2(g) → 2CaCO3(s) ΔH = -1625.6 kJ 2CaO(s) → 2Ca(s) + O2(g) ΔH = +1269.8 kJ Now we add the two equations. The O2 and 2Ca "cancel" since they're on opposite sides of the arrow. Think of it more mathematically. We add the two enthalpies and get 2CaO(s) + 2CO2(g) → 2CaCO3(s) and ΔH = -355.8 kJ. Finally divide by two to get the given equation: CaO(s) + CO2(g) → CaCO3(s) and ΔH = -177.9 kJ.
Acids are ionic compounds (a compound with a positive or negative charge) that break apart in water to form hydrogen ion (H+). Characteristics of acid: Acid taste sour. Acids also react strongly to metals, generally with the evolution of hydrogen gas (Eg: Zn + HCI). Also strong acids are dangerous and can burn your skin off. Acids change litmus red. Acids become less acidic when mixed with bases. An acid has Ph scale of under 7.
Well, gold is way different form other say for instance what if you get a really good ring not to expensive or cheap, but its in between those characteristics what if u get a gold ring to compare now one might tarnish or fade, but if you really look at it that gold one will not it really all dependents on what metals your talking about cause all metals aren't the same some fade and some don't . Also the oxygen level is weak for other metals, but gold it different it can still keeps its shine .
- That's the best explanation i can give IF ITS NOT ENUH OR NOT RIGHT JUH COMMENT BELOWW↓↓ I WILL THINK OF SOMEThING ELSE THANKS! YOU HAVE A GREAT DAYY .
