Answer:

Explanation:
We are asked to find the mass of a sample of metal. We are given temperatures, specific heat, and joules of heat, so we will use the following formula.

The heat added is 4500.0 Joules. The mass of the sample is unknown. The specific heat is 0.4494 Joules per gram degree Celsius. The difference in temperature is found by subtracting the initial temperature from the final temperature.
- ΔT= final temperature - initial temperature
The sample was heated <em>from </em> 58.8 degrees Celsius to 88.9 degrees Celsius.
- ΔT= 88.9 °C - 58.8 °C = 30.1 °C
Now we know three variables:
- Q= 4500.0 J
- c= 0.4494 J/g°C
- ΔT = 30.1 °C
Substitute these values into the formula.

Multiply on the right side of the equation. The units of degrees Celsius cancel.

We are solving for the mass, so we must isolate the variable m. It is being multiplied by 13.52694 Joules per gram. The inverse operation of multiplication is division, so we divide both sides by 13.52694 J/g

The units of Joules cancel.


The original measurements have 5,4, and 3 significant figures. Our answer must have the least number or 3. For the number we found, that is the ones place. The 6 in the tenth place tells us to round the 2 up to a 3.

The mass of the sample of metal is approximately <u>333 grams.</u>
First, calculate the number of moles of sodium present with the given mass,
31.5 g of sodium x (1 mol sodium/ 23 g sodium) = 1.37 mol sodium
It is given in the equation that for every 2mols of sodium, one mol of H2 is produced.
mols of H2 = (1.37 mols sodium)(1 mol H2/ 2 mols sodium)
mols of H2 = 0.685 mols H2
Then, at STP, 1 mol of gas = 22.4 L.
volume of H2 = (0.685 mols H2)(22.4 L / 1 mol)
volume of H2 = 15.34 L
Answer: 15.34 L
That would be 'ionises' .
Bacteria can’t live without humans
Answer:
her results has good precision
Explanation:
accuracy and precision