1) Compounds:
a) Chemically combined.
b) Components change properties.
c) Fixed proportions.
2) Mixtures:
a) Physically combined.
b) Components retain properties.
c) Variable proportions.
3) Both:
a) Made of elements.
b) 2 or more components.
A compound is a pure substance because its molecule cannot be broken down into simpler particles by physical means. For example water (H₂O) is a chemical compound made of two elements (hydrogen and oxygen).
In chemical change new substances are formed, the atoms are rearranged and the reaction is followed by an energy change.
There are no chemical bonds between substances in the mixture.,For example, mixture is solution of water and alcohol.
Gold is known to be an element. The term that best describes 10-karat gold is that it is an homogeneous mixture.
- Gold as an element of often has an ideal state of purity where there contains nothing but gold atoms.
A heterogeneous mixture is known to be a mixture that cannot be chemically sound everytime. Gold jewelry is known to be a homogeneous mixture as it is always will look good and remain unchanged for a long time.
As good example of homogeneous products, e.g a 1-kilogram 24-karat gold bar has unique properties.
Learn more about Gold from
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Answer:
B or A
Explanation:
choose wether A or B... give it a higher level of thinking. and good luck!
Answer:
The empirical formula of a compound is Na2Cr2O7
Explanation:
Empirical formula is defined as the lowest ratio of elements present in any substance. In order to determine the empirical formula for a substance containing these elements we have to follow some steps.
1.In the first step, we have to divide the given mass of an element with its molecular mass to convert the mass to moles.

Similarly, the moles of Cr and O in that compound were calculated and found as 0.396 and 1.3875, respectively.
2. Then the next step is to determine the lowest moles and divide all the moles with that lowest mole. As here the lowest mole is 0.396. So on dividing the moles of Na, Cr and O with 0.396, we will obtain the ratio as 1:1:3.5.
3. As the ratio consists of a fractional number, we have to multiply it with the smallest possible integer to convert it to whole number. In this case, if we multiply it with 2 , we will get the ratio as 2:2:7.
Thus, the empirical formula for the compound can be written as Na2Cr2O7.