<u>Answer:</u> 1.0 kilograms.
<u>Explanation:</u>
One kilogram is equal to a thousand grams.
Supposing x to be the number of kilograms equal to one thousand and eight grams, we can write it as:
1 kg = 1000 grams
x kg = 1008 grams
To solve for x, we can simply divide 1008 grams by 1000 thousand grams to get the answer.
x = 1008 / 1000
x = 1.008
Rounding this value to the nearest tenth, it will become 1.0 kilograms.
Answer:

Explanation:
Subscripts are numbers written after elements, subscripts indicate how many of each atom there are in a compound.
If 40.0 grams of magnesium is reacted with an excess of nitric acid. 3.3 g of hydrogen gas will be produced.
<h3>What is Stoichiometry ?</h3>
Stoichiometry helps us use the balanced chemical equation to measure quantitative relationships and it is to calculate the amounts of products and reactants that are given in a reaction.
<h3>What is Balanced Chemical Equation ?</h3>
The balanced chemical equation is the equation in which the number of atoms on the reactant side is equal to the number of atoms on the product side in an equation.
Now we have to write the balanced equation
Mg + 2HNO₃ → Mg(NO₃)₂ + H₂
According to Stoichiometry

= 3.3 g H₂
Thus from the above conclusion we can say that If 40.0 grams of magnesium is reacted with an excess of nitric acid. 3.3 g of hydrogen gas will be produced.
Learn more about the Stoichiometry here: brainly.com/question/16060223
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<span>H2O2
First, let's determine how many moles of hydrogen and oxygen atoms we have. Start by looking up the atomic weights of those elements:
Atomic weight hydrogen = 1.00794
Atomic weight oxygen = 15.999
Moles hydrogen = 1.33 g / 1.00794 g/mol = 1.319522987 mol
Moles oxygen = 21.3 g / 15.999 g/mol = 1.331333208 mol
We now have a ratio of 1.319522987 : 1.331333208 and we want a ratio of small integers that is close. Start by dividing all the numbers in the ratio by the smallest value, giving:
1 : 1.008950371
This ratio is acceptably close to 1:1 so I assume the formula is of the form HnOn where n is a small integer. Let's initially assume that n is 1, so the mass would be
1.00794 + 15.999 = 17.00694
Obviously 17 is far smaller than 34.1. So let's divide 34.1 by 17.00694 and see what n should be:
34.1 / 17.00694 = 2.005063815
So the formula we want is H2O2, which is hydrogen peroxide.</span>