No, elements are pure substances. However, if you mix two elements together, it depends on how well you mix them. Mixtures of two elements can be completely homogeneous, or extremely heterogeneous.
Brass is an alloy (a homogeneous mixture).
No, Concrete is a homogeneous mixture.
An element is a pure substance composed of only one type of atom and is homogeneous. A compound is a pure substance composed of two or more elements chemically bonded together and is homogeneous. Both elements and compounds are homogeneous in nature.
Brass is a homogeneous mixture because it is a solid solution of copper and zinc. Both elements are uniformly distributed at a microscopic level within the brass, resulting in a consistent composition throughout the material.
A leaf is a homogeneous mixture. This means that it is uniformed and has the same elements that are found throughout.
Nickel and silicon are elements. Gasoline is a homogeneous mixture.
This mixture is not homogeneous.
Visible particles would be heterogeneous elements of a mixture. A truly homogeneous mixture would have no visible particles. However, you could still have an approximately homogeneous mixture with visible particles, evenly distributed throughout the mixture.
Calcium bromide, CaBr2, is a compound. It is not an element, because elements are individual species and they are found in the periodic table. It is not a homogeneous or heterogeneous mixture, because it is a single entity.
The sun is a star made primarily of hydrogen and helium gases undergoing nuclear fusion, making it a homogeneous mixture of elements.
A heterogeneous mixture is a sum of pure substances which are not soluble in each other while a homogeneous mixture is a mixture wherein its constituents do not appear separately. Methanol is an example of a homogeneous mixture.
Bronze is an alloy. I've never heard of classifying metals as homogeneous or heterogeneous. If I had to put it in one, well it's definitely not heterogeneous, because that would consist of a mixture of dissimilar components. An alloy has a uniform 'mixture' of elements, so I guess that would make it homogeneous!