Answer : The new pressure if the volume changes to 560.0 mL is, 280 mmHg
Explanation :
According to the Boyle's, law, the pressure of the gas is inversely proportional to the volume of gas at constant temperature and moles of gas.

or,

where,
= initial pressure = 560.00 mmHg
= final pressure = ?
= initial volume = 280 mL
= final volume = 560.0 mL
Now put all the given values in the above formula, we get:


Therefore, the new pressure if the volume changes to 560.0 mL is, 280 mmHg
Decreasing the turns of wire
A. 1/2
Explanation- There is a 5/10 chance of choosing on of the numbers which simplifies to 1/2
Answer: 14.1g
Explanation:
Given that,
number of moles of SiO2 = 0.235 moles
Mass in grams = Z (let unknown value be Z)
Molar mass of SiO2 = ?
To get the molar mass of SiO2, use the atomic mass
Silicon = 28g;
Oxygen = 16g
i.e Molar mass of SiO2 = 28g + (16g x 2)
= 28g + 32g
= 60g/mol
Now, apply the formula
Number of moles = Mass / molar mass
0.235 moles = Z / 60g/mol
Z = 0.235 moles x 60g/mol
Z = 14.1 g
Thus, the mass of SiO2 is 14.1 grams.