Answer:
characteristics i believe
I think it is the gas and the heat in it
Answer
A. It changes the rate, R
Explanation
When we change the concentration of the reactants in a chemical reaction, it affects the rate of reaction that happens in the process. Typically, the rate of reaction will decrease with time if the concentration of the reactants decreases because the reactants will be converted to products. Similarly, the rate of reaction will increase when the concentration of reactants are increased.
Answer:
number of moles=volume/molar volume or mass/molar mass
Answer : The pressure of the helium gas is, 1269.2 mmHg
Explanation :
To calculate the pressure of the gas we are using ideal gas equation:

where,
P = Pressure of
gas = ?
V = Volume of
gas = 210. mL = 0.210 L (1 L = 1000 mL)
n = number of moles
= 0.0130 mole
R = Gas constant = 
T = Temperature of
gas = 
Putting values in above equation, we get:


Conversion used : (1 atm = 760 mmHg)
Thus, the pressure of the helium gas is, 1269.2 mmHg