It is C. because the sunlight bounces off the moon causing it to be visible only at night.
Answer: pure substances.
Explanation:
The given substances are:
All what surrounds us, which has mass and occupies spaces, is matter. There are two kind of matter: pure substances and mixtures.
Pure substances have a uniform and constant composition. On the other hand, mixtures are combinations of two or more pure substances in any arbitratry ratio.
Pure substances may be elements or compounds. The elements are the substances conmposed by one only kind of atom. In the list of substances given, Li and O₂ are elements: all the atoms in Li are lithium, and all the atoms in O₂ are oxygen atoms.
Compounds are the chemical combination of two or more different kind of atoms. In the given list H₂O₂ and NaCl are compounds. As you see, H₂O₂ contains atoms of hydrogen and oxygen, chemically bonded, in a fixed ratio (2 atoms of hydrogen by 2 atoms of oxygen). And NaCl has atoms of Na (sodium) and Cl (chlorine), chemicaly bonded, in a fixed ratio (1:1).
There are only 118 known elements and you can find them in any modern periodic table. Therer are virtually infinitely many compounds since many different combinations of the elements can be attained.
Elements and compounds have in common that they are classified as pure substances.
Answer:
23.8g
Explanation :
Convert 2.0M into mol using mol= concentration x volume
2.0M x 0.1L (convert 100mL to L since the units for M is mol/L)
= 0.2 mol
We can now find grams by using the molar mass of KBr
=119.023 g/mol (Found online) webqc.org
but can be be calculated by using the molecular weight of K and Br found on the periodic table
We can now calculate the grams by using grams=mol x molar mass
119.023g/mol x 0.2mol
= 23.8046 g
=23.8g (rounded to 1decimal place)
Glucose has empirical formula C6H12O6. So its formula mass can be calculated from that: 12.01x6 + 1.008x12 + 16.00x6 = 72.06 + 12.096 + 96.00 = 180.156 which needs to be rounded to two decimals to get 180.16 g/mole<span>.</span>
