Reaction of sodium with water
Sodium metal reacts rapidly with water to form a colourless solution of sodium hydroxide (NaOH) and hydrogen gas (H2). The resulting solution is basic because of the dissolved hydroxide. The reaction is exothermic. During the reaction, the sodium metal may well become so hot that it catches fire and burns with a characteristic orange colour. The reaction is slower than that of potassium (immediately below sodium in the periodic table), but faster than that of lithium (immediately above sodium in the periodic table).
2Na(s) + 2H2O → 2NaOH(aq) + H2(g)
The grams that would be produced from 7.70 g of butanoic acid and excess ethanol is 7.923grams
calculation
Step 1: write the chemical equation for the reaction
CH3CH2CH2COOH + CH3CH2OH → CH3CH2CH2COOCH2CH3 +H2O
step 2: find the moles of butanoic acid
moles= mass/ molar mass
= 7.70 g/ 88 g/mol=0.0875 moles
Step 3: use the mole ratio to determine the moles of ethyl butyrate
moles ratio of CH3CH2CH2COOH :CH3CH2CH2COOCH2CH3 is 1:1 therefore the moles of CH3CH2CH2COOCH2CH3 = 0.0875 x78/100=0.0683moles
step 4: find mass = moles x molar mass
= 0.0683 moles x116 g/mol=7.923grams
Equation: 2K + S --> K2S
Chemical formula: K2S
Answer:
c) 387g
Explanation:
Water;
Mass = 250g
Specific heat = 4.184
Initial Temp, T1 = 25 + 273 = 298K
Final Temp, T2 = 35 + 273 = 308K
Heat = ?
H = mc(T2 - T1)
H = 250 * 4.184 (308 - 298)
H = 10460 J
Iron;
Initial Temp, T2 = 95 + 273 = 368K (Upon converting to kelvin temperature)
Mass = ?
Final Temp, T1 = 35 + 273 = 308
Heat = 10460 (Heat lost by iron is qual to heat gained by water)
Specific heat = 0.45
H = mc(T2-T1)
M = 10460 / [0.45 (308 - 368)]
M = 10460 / 27
M = 387g
Answer:
D, Li2S
Explanation:
This is because Lithium, which is in group IA of the periodic table, has a charge of +1. Sulfur will have a charge of -2 because it is in group 6A in the periodic table, which means to balance these out, there needs to be 2 lithium ions which would result in a charge of +2. With Lithium now having a charge of +2 due to having two atoms in the compound, and sulfur already having a charge of -2 as one atom, these two cancel out meaning the compound is neutral.
