400.0 ml of a gas is collected at 745.0 mm hg. what will the volume be at standard pressure
(std pressure = 760.0 mm hg)?

392.1 mL

Explanation:

Ideal gas law says:

PV = nRT

where P is absolute pressure, V is volume, n is amount of gas in moles, R is the universal gas constant, and T is absolute temperature.

If n, R, and T are held constant:

P₁ V₁ = P₂ V₂

Plugging in values:

(745.0 mmHg) (400.0 mL) = (760.0 mmHg) V

V = 392.1 mL

answer: the correct answer is 1.

explanation: there are various process in which a radioactive nuclei decays:

1) alpha decay: in this process, a heavier nuclei decays into lighter nuclei by releasing alpha particle. the mass number is reduced by 4 units.

2) electron capture: in this decay process, a parent nuclei absorbs an electron and gets converted into a neutron. simply, a proton and an electron combines together to form a neutron. mass number does not change in this process.

3) gamma ray emission: it is a decay process in which an unstable nuclei gives excess energy by a spontaneous electromagnetic process. this decay releases . this process does not change the mass number.

4) positron emission: it is a type of decay process, in which a proton gets converted to neutron and an electron neutrino. this is also known as -decay. in this the mass number remains same.

from the above information, we see that only alpha-decay is producing a change in the mass number of the nucleus.

the answer is a. hope this .