Answer:- B:
is the right answer.
Solution:- The balanced equation is:

We have been given with 8.75 grams of oxygen and asked to calculate the grams of hydrogen needed to react with given grams of oxygen according to the balanced equation.
From balanced equation, 1 mole of oxygen reacts with 2 moles of hydrogen.
So, let's convert grams of oxygen to moles and multiply it by the mole ratio to calculate the moles of hydrogen that are easily converted to grams on multiplying by it's molar mass.
The complete set up looks as:

= 
Hence, the right option is B:
.
Answer:


Explanation:
<u>First mixture</u>:
40 wt% methanol - 60 wt% water 200 kg


<u>Second mixture</u>:
70 wt% methanol - 30 wt% water 150 kg


Final mixture:




If, the compositions are constant, the only variables are the mass of each mixture used in the final one, so there can be only one independent balance.
Answer:
C
Explanation:
Neon is a noble gas, which is monoatomic.
Answer: There are 4.8 x 1024 hydrogen atoms in 2.0 moles of CH4
The initial temperature of the copper piece if a 240.0 gram piece of copper is dropped into 400.0 grams of water at 24.0 °C is 345.5°C
<h3>How to calculate temperature?</h3>
The initial temperature of the copper metal can be calculated using the following formula on calorimetry:
Q = mc∆T
mc∆T (water) = - mc∆T (metal)
Where;
- m = mass
- c = specific heat capacity
- ∆T = change in temperature
According to this question, a 240.0 gram piece of copper is dropped into 400.0 grams of water at 24.0 °C. If the final temperature of water is 42.0 °C, the initial temperature of the copper is as follows:
400 × 4.18 × (42°C - 24°C) = 240 × 0.39 × (T - 24°C)
30,096 = 93.6T - 2246.4
93.6T = 32342.4
T = 345.5°C
Therefore, the initial temperature of the copper piece if a 240.0 gram piece of copper is dropped into 400.0 grams of water at 24.0 °C is 345.5°C.
Learn more about temperature at: brainly.com/question/15267055