Answer:
answer is b
Explanation:
All elements in a row have the same number of electron shells. Each next element in a period has one more proton and is less metallic than its predecessor
Answer:
a) Graph
b) Weight balance or gas syringe or upside-down measuring cylinder
Explanation:
a) Identifying a trend in temperature change over time - The best tool for this scenario is to represents the temperature daily, weekly, monthly or annually on graph to interpret the fluctuation in temperature owing to local seasonal changes and weather conditions
b) Measuring the mass of a product of a chemical reaction - If the product is solid or liquid then the balance is used to measure the mass. If the product is a gas, then gas syringe or upside-down measuring cylinder is used.
Answer: 4.5 moles of 
can be made from complete reaction of 3.0 moles of Al.
Explanation:
The given reaction equation is as follows.
This shows that 2 moles of Al reacts with 6 moles of HCl. So, the amount of HCl required to react with 1 mole Al is three times the amount of HCl.
Therefore, 3 moles of Al will react with 9 moles of HCl to give 3 moles of 
and 
moles of .
The reaction equation now will be as follows.
The moles can also be written as 4.5 moles.
Thus, we can conclude that 4.5 moles of can be made from complete reaction of 3.0 moles of Al.
Answer:
1.602 moles CO
Explanation:
To convert from liters to moles, divide by 22.4:
35.88 L / 22.4 = 1.602 moles CO
The amount of sample that is left after a certain period of time, given the half-life, h, can be calculated through the equation.
A(t) = A(o) (1/2)^(t/d)
where t is the certain period of time. Substituting the known values,
A(t) = (20 mg)(1/2)^(85.80/14.30)
Solving,
A(t) = 0.3125 mg
Hence, the answer is 0.3125 mg.
